Journal of Cleaner Production 225 (2019) 1220e1229

Contents lists available at ScienceDirect

Journal of Cleaner Production

journal homepage: www.elsevier.com/locate/jclepro

Adsorption of reactive dyes on lignocellulosic waste; characterization,

equilibrium, kinetic and thermodynamic studies
€ kçe Didar Deg
Go ermenci a, *, Nejdet Deg
ermenci a, Vefa Ayvaog
lu a, Ekrem Durmaz b,
Dogan Çakır a, Emre Akan a
a
Department of Environmental Engineering, Faculty of Engineering and Architecture, Kastamonu University, 37100, Kastamonu, Turkey
b
Department of Forest Industrial Engineering, Faculty of Forestry, Kastamonu University, 37100, Kastamonu, Turkey

a r t i c l e i n f o a b s t r a c t

Article history: This study researched the use of the easily obtainable and economic agricultural waste of corn silk (CS)
Received 21 May 2018 for removal of Reactive Blue 19 (RB19) and Reactive Red 218 (RR218) dyes with the adsorption process.
Received in revised form Lignin, holocellulose, a-cellulose, thermogravimetric analysis (TGA), fourier transform infrared (FTIR) and
31 January 2019
scanning electron microscopy (SEM) analyses were completed with the aim of determining the physical
Accepted 24 March 2019
Available online 26 March 2019
and chemical characteristics of the lignocellulosic adsorbent and ash content was determined. Addi-
tionally, the contact duration of adsorption, concentration of dye, temperature and pH parameters were
investigated with equilibrium, kinetic and thermodynamic parameters determined to research the
Keywords:
Lignocellulosic waste
mechanism of adsorption. For both reactive dyes the removal efficiency is linked to the effective pH. With
Adsorption initial dye concentration of 200 mg/L, temperature of 25
C, and adsorbent concentration of 0.25 g/50 mL
Reactive red 218 fixed, maximum removal efficiency was 99% obtained at pH 2.0. The study calculated 6 different two-
Reactive blue 19 parameter isotherms and according to the best R2 value, the Temkin and Freundlich isotherm models
Corn silk were selected. The maximum capacity of CS for adsorption of RB19 and RR218 was 71.6 mg/g and
63.3 mg/g at adsorbent dose of 0.25 g/50 mL for initial dye concentration of 500 mg/L, pH 2.0 and 25
C.
According to the kinetic model results calculated with the aid of experimental data, a good adsorption
process occurred. Thermodynamic parameters like enthalpy variation (DH0), entropy variation (DS0) and
free Gibbs energy variation (DG0) were calculated with the aid of data obtained at different temperatures.
As temperature increased dye adsorption was observed to increase confirming this event is endothermic.
© 2019 Elsevier Ltd. All rights reserved.

1. Introduction bonds with cellulosic fibers (Isah et al., 2015). The largest classes of
dyes comprise the azo (nearly 70%) and anthraquinone (nearly 15%)
Synthetic dyes have widespread use in textiles, cosmetics, food, chromophore groups (Moussavi and Mahmoudi, 2009). Due to the
paper, carpet and plastics (Oguz et al., 2016). Annually about presence of electrophilic vinyl sulfone groups in highly water-
700,000 tons of dyes are produced and there are more than soluble reactive dyes, they have low fixation and lead to the for-
100,000 types of dye on the market (Banaei et al., 2017; Sezer et al., mation of highly colored wastewater. These dyes do not disinte-
2017). The textile industry is one of the most important sources of grate under aerobic conditions; however, under anaerobic
water pollution; it uses a considerable amount of water and pro- conditions the azo bond may transform into colorless, toxic and
duces large quantities of colored wastewater (Melo et al., 2014). cancerogenic aromatic amines (Guimaraes et al., 2012; Mustafa
Textile dyes are classified as anionic, cationic and nonionic types, et al., 2017; Siddiqua et al., 2017). Additionally, colored waste-
which are mostly direct, acid and reactive dyes (Joshi et al., 2004). water discharged into the receiving environment without pro-
The molecular structure of strongly-colored reactive dyes contains cessing, or with insufficient processing, prevents the passage of
a chromophore group (azo, anthraquinone, phthalocyanine and sunlight slowing the rate of photosynthesis. This reduces the dis-
triarylmethane) and a functional group that can create covalent solved oxygen value which negatively affects the ecosystem
(Chaudhari et al., 2017; Siddique et al., 2009). In recent years, a
range of physical, chemical and biological processes were applied to
* Corresponding author. remove a variety of textile reactive dyes. Many processes like
ermenci).
E-mail address: gdegermenci@kastamonu.edu.tr (G.D. Deg

https://doi.org/10.1016/j.jclepro.2019.03.260
0959-6526/© 2019 Elsevier Ltd. All rights reserved.
 G.D. Degermenci et al. / Journal of Cleaner Production 225 (2019) 1220e1229 1221

Fenton process (Siddique et al., 2014), electrocoagulation/coagula- at 103 ± 2
C to constant weight. The extractive-free samples were
tion (Taheri et al., 2013), ultrasound (Siddique et al., 2011), elec- used to determine lignin, holocellulose and a-cellulose content of
trooxidation (Petrucci and Montanaro, 2011), adsorption (Isah et al., CS. Calculation of the extractive content was as follows (Eq. (1)):
2015; Jiang et al., 2014; Moussavi and Mahmoudi, 2009), advanced

oxidation processes (Guimaraes et al., 2012), ozonation (Fanchiang m1  m2
Extractivesð%Þ ¼  100 (1)
and Tseng, 2009), membrane filtration (Koyuncu, 2002) and bio- m1
logical processing (Lourenço et al., 2001) have been used for the
This method is based on standard TAPPI T 222 om-11 (TAPPI,
removal of these pollutants. Adsorption, one of the effective
2011). Extracted samples of 1.0 ± 0.1 g (m1) were added to bea-
methods for dye removal, is more advantageous compared to other
kers containing samples of cold sulfuric acid (72%, v/v), 15 mL and
methods due to being economic, an easy process and ensuring full
were left in a bath at 20 ± 1
C for 2 h. After this, a total volume of
dye removal (Anbia et al., 2010). In recent years different adsorbent
575 mL of distilled water was added and the solution was boiled for
material has been used in attempts to remove organic material and
4 h, maintaining constant volume by frequent addition of hot water.
color. Though effective color removal may be obtained with active
Then specimens were filtered (MN 640 m filter paper, Machery-
carbon, it is very expensive (Malik et al., 2007). Naturally abundant,
Nagel, Germany) and washed with distilled water. The set filter-
cheap and effective materials requiring less processing such as
lignin was dried in an oven at 103 ± 2
C to constant weight,
agricultural and food industry by-products have been used
cooled in a desiccator and weighed (m2). For each determination,
frequently as adsorbents for the removal of dyes in recent times
the lignin content in samples was calculated as follows (Eq. (2)):
(Kallel et al., 2016). In the literature, some cheap absorbents used
for removal of dyes include mango stone biocomposite (Shoukat

m1
et al., 2017), almond shell residues (Deniz, 2013), garlic straw Ligninð%Þ ¼  100 (2)
m2
(Kallel et al., 2016), calcined mussel shells (El Haddad et al., 2014),
cucumis sativus peel (Lee et al., 2016), abelmoschus esculentus seed Extracted samples of 4.0 ± 0.1 g (m1) with ethanol (96%, v/v)
(Nayak and Pal, 2017), sunflower seed hull (Oguntimein, 2015), were put in 250 mL Erlenmeyer flasks with 160 mL water, 1.5 g
haloxylon recurvum plant stems (Hassan et al., 2017), powdered NaClO2 and 0.5 mL glacial acetic acid. They were kept in a hot water
orange waste (Irem et al., 2013), green adsorbents (Singh et al., bath at 78e80
C for 1 h. The top of the Erlenmeyers containing the
2017), cross-linked chitosan/oil palm ash composite beads (Hasan samples were closed with a 50 mL Erlenmeyer. The Erlenmeyers
et al., 2008), modified spent tea leaves (Wong et al., 2019), and were mixed by shaking during the reaction. After 1 h, 1.5 g NaClO2
wheat bran (Çiçek et al., 2007). Among these materials, waste and 0.5 mL acetic acid were added to the mixture. The reaction was
lignocellulosic material is widely used as adsorbent due to being continued for 1 h. Three repetitions are enough for annual plants.
found abundantly in nature and being cheap (Noreen et al., 2013). After all treatment, the holocellulose solutions were filtered in a
In this study the aim was to remove reactive dye pollutants from glass crucible and washed with distilled water. They were dried at
industrial wastewater using a lignocellulosic adsorbent with the 103 ± 2
C and then weighed (m2) (Libby, 1962). The holocellulose
adsorption method. For this purpose, the adsorption capacity of the content in samples was calculated as follows (Eq. (3)):
agricultural waste product of lignocellulosic CS for anionic RB19

and RR218 dyes was determined with the adsorption process. With m1
Holocelluloseð%Þ ¼  100 (3)
the aim of determining physical and chemical characterization of m2
the lignocellulosic adsorbent, lignin, holocellulose, a-cellulose,
The a-Cellulose proportion of the samples was determined with
TGA, FTIR, and SEM analyses were completed and ash content was
holocellulose (TAPPI T 203 os-71) (TAPPI, 1975). 2.0 ± 0.1 g (m1)
determined. Additionally, the contact duration of adsorption, dye
holocellulose was placed in a beaker and 10 mL 17.5% NaOH solu-
concentration, temperature and pH parameters were investigated
tion was added to the beaker. They were mixed and after 2 min, the
to find equilibrium, kinetic and thermodynamic parameters and to
samples in the beaker were pressed with a glass rod. Three min
research the adsorption mechanism.
after this step, 5 mL 17.5% NaOH solution was added to the beaker.
Five min after this step, 5 mL 17.5% NaOH solution was added to the
2. Material and methods
beaker, again. Five min after this step, 5 mL 17.5% NaOH solution
was added to the beaker, again. Then, the solution was left in a
2.1. Preparation and characterization of the adsorbent
water bath at 20
C for 30 min. After this process, 33 mL distilled
water was added and mixed and they were left at 20
C for 1 h.
The CS used in this study was obtained from domestic producers
Then, the solution was filtered (MN 640 m filter paper, Machery-
in Turkey as a by-product. The samples were boiled 3 times for
Nagel, Germany). Firstly, the samples were washed with 100 mL
30 min in 50 g of 0.5 L water, washed 3 times with distilled water,
8.3% NaOH and then they were washed with distilled water. Sec-
filtered through a cotton cloth and dried in an oven at 60
C for 3
ondly, the samples were washed with 15 mL 10% acetic acid and
days. The dried materials were crushed in a mixer and sieved to
then they were washed with distilled water until the samples were
obtain a particle size between 250 and 500 mm.
bleached completely. They were dried at 103 ± 2
C and then
weighed (m2). The a-cellulose content in samples was calculated as
2.2. Chemical composition
follows (Eq. (4)):
Determination of the chemical components of CS was based on

m2
the Technical Association of the Pulp and Paper Industry (TAPPI) a  celluloseð%Þ ¼  100 (4)
m1
standard methods with the exception of holocellulose determined
according to Wises’s sodium chlorite method (Wise et al., 1946). To The raw sample 3.0 ± 0.1 g (m1) was put in a 250 mL Erlenmeyer.
optimize the extraction (ethanol solubility) with the classical Then 100 mL hot distilled water was added and placed in a boiling
method according to TAPPI (T 204 om-88), a sample of CS of water bath. This was boiled for 3 h. It was filtered (MN 640 m filter
4.5 ± 0.2 g (m1) was first extracted (80:1) with ethanol (96% v/v) in paper, Machery-Nagel, Germany) and weighed (m2) (TAPPI T 207
a Soxhlet apparatus for 5 h, with 4 solvent recirculations per hour om-88) (TAPPI, 1992a). The hot water solubility content in samples
for annual plants. After the extraction, the samples (m2) were dried was calculated as follows (Eq. (5)):
1222 G.D. Degermenci et al. / Journal of Cleaner Production 225 (2019) 1220e1229

 gave the pHpzc (Akkaya and Güzel, 2014).

m1  m2
Hot Water Solubilityð%Þ ¼  100 (5)
m1 2.6. Preparation of the dye solution
The ceramic crucibles were dried at nearly 600
C for 15 min.
Then they were kept in a desiccator for 45 min and then Reactive dyes were brought from a textile factory in Bursa. RB19
weighed. Raw samples of 4.0 ± 0.1 g (m1) were placed in ceramic and RR218 were chosen because they are often used in the textile
crucibles and then the crucibles were closed (TAPPI T 211 om- industry especially for dyeing cotton, silk, nylon, and wool. The
85) (TAPPI, 1992b). They were put in an ash oven at 575
C un- stock solutions of RB19 and RR218 dyes were prepared by dis-
til all carbon was removed. The samples in the crucible were solving 1000 mg/L of dyes in distilled water and then the working
occasionally mixed. This process continued for 8e10 h. All black concentrations were prepared by successive dilutions of the stock
particles should be lost and the samples should be completely solution. The initial pH of each run was adjusted using 0.1 M so-
white by the end of this time. After that, the sample was lutions of NaOH and H2SO4 before mixing with the CS. All chemicals
weighed (m2). The ash content in samples was calculated as and reagents used in the study were of analytical grade and sup-
follows (Eq. (6)): plied by Merck. The properties and molecular structure (Reife and
Freeman, 1996; Taheri et al., 2013) of RB19 and RR218 are shown


m2 in Table 1.
Ashð%Þ ¼  100 (6)
m1
2.7. Study of dyes removal by CS

The adsorption experiments were conducted on the CS in 50 mL

2.3. Scanning electron microscopy (SEM) Erlenmeyer flasks containing RB19 and RR218 dye solutions. All
batch adsorption experiments were agitated on a shaker (IKA KS
The surface morphology of the CS before and after adsorption 3000i) at 300 rpm constant shaking rate for 24 h to ensure equi-
was observed by scanning electron microscopy (SEM, model librium was reached with temperature controlled. After adsorption,
Quanta FEG 250), operated at 15 kV. The samples were coated with the contents were filtered (MN 640 m filter paper, Machery-Nagel,
gold in a vacuum environment before screening. Germany) and measured at maximum wavelengths of the dyes (l:
593 nm for RB19 and l: 548 nm for RR218) using a double beam
2.4. Thermogravimetric analysis (TGA) and fourier transform UVevis spectrophotometer (Hach Lange DR6000).
infrared (FTIR) Experiments may be categorized into four sections: (a) Effect of
initial concentration, pH and temperature on time, (b) fitting of
The surface functional groups of CS were analyzed using an data to adsorption equilibria, (c) thermodynamic parameters and
Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) (d) kinetic models. Stock solutions of 1000 mg/L were prepared by
spectrometer in the spectral range of 600e4000 cm1 (resolution dissolving appropriate amounts of RB19 and RR218 dye powders in
4 cm1, scans 24). Thermogravimetric analyses of CS were per- distilled water. Various experimental parameters i.e., initial con-
formed using Thermo Gravimetry/Differential Thermal Analyzer centrations (10e500 mg/L), adsorbent dosage (0.025e1 g), pH
(TG/DTA, HITACHI STA7300 Model). CS weighing 7.7 mg was put (2.0e12.0), contact time (5e60 min), and temperature (25e55
C)
into an alumina sample pan and heated from 50 to 850
C at a ranges were investigated and optimized. For studies of the
heating rate of 10
C/min under a nitrogen atmosphere with flow adsorption isotherm, adsorbent dosage (0.25 g) and 50 mL of dye
rate of 20 mL/min. solutions (RB19 and RR218) were agitated for equilibrium times at
different initial concentrations (10e500 mg/L) with pH 2.0 particle
size 250e500 mm at 25
C. Thermodynamic parameters and ki-
2.5. Point of zero charge (pHpzc)
netics were evaluated at different temperatures and time intervals,
respectively.
For determination of the point of zero charge (pHpzc) of the CS,
The removal efficiency dyes of the applied adsorbent and the
0.01 M NaCl concentration series (50 mL) were used. The pH was
adsorption capacity were calculated by Eqs. (7)e(9):
adjusted between 2.0 and 12.0 by adding 0.1 M HCl or 0.1 M NaOH.
Then 0.15 g of CS was added to the solution and shaken (IKA KS

C0  Ce
3000i) for 48 h. The final pH values of the samples were measured. Dye Removalð%Þ ¼  100 (7)
C0
The DpH (initial pH-final pH) have been plotted against the initial
pH. The point of intersection of the resulting curve with abscissa

Table 1
General properties and chemical structure of RB19 (Taheri et al., 2013) and RR218 dye (Reife and Freeman, 1996).

Generic name Reactive Blue 19 Reactive Red 218

Commercial name Remazol Brilliant Blue R Reactive Red P6B

Abbreviation RB19 RR218
Functional group/Chemical base Anthraquinone Monochlorotriazine/Azo
lmax (nm) 593 548

Molecular formula
 G.D. Degermenci et al. / Journal of Cleaner Production 225 (2019) 1220e1229 1223

 Table 3
C0  Ce The values for lignocellulosic agricultural by-products.
qe ¼ V (8)
m Agricultural Lignocellulose (%) References
by-products (LigninþHolocellulose)


C0  Ct Corn stover 77 ± 0.1 Wartelle and Marshall (2006)
qt ¼ V (9) 80 ± 0.1
m Rice husk Krishnani et al. (2008)
Fall leaf litters 86 ± 0.8 Tezcan and Atıcı (2017)
Sugarcane bagasse 70 ± 0.1 Kan et al. (2017)
where C0 (mg/L) is the initial concentration of RB19 and RR218
Sugarcane leaf 83 ± 0.5 Moodley and Gueguim
dyes, Ce (mg/L) is the equilibrium concentration of RB19 and RR218 Kana (2017)
dyes, Ct (mg/L) is the concentration of RB19 and RR218 dyes at time Corn cob 88 ± 0.2 Wartelle and Marshall (2006)
t, V (L) is the volume of dye solution, m (g) is the weight of Corn silk 88 ± 0.8 Present Study
adsorbent, qt (mg/g) is adsorption capacity at given time t, and qe
(mg/g) is the amount of equilibrium adsorption capacity.

3. Results and discussion

3.1. Characterization of CS

The chemical content of CS is shown in Table 2. The extractives,

a-cellulose, holocellulose, hemicellulose, lignin, hot water solubil-
ity and ash content of CS were 13%, 42%, 66%, 24%, 22%, 13% and
1.7%, respectively. When the results are examined, CS is a good
source of cellulose.
This agricultural by-product appears to be lignocellulosic as it
mainly comprises a-cellulose, hemicellulose, and lignin. Linked to
the composition and physical features of lignocellulosic by-
products, it is a basic source of fibers, chemicals and other indus-
trial products (Reddy and Yang, 2005). Values for some primary
lignocellulosic agricultural by-products obtained at significant
amounts and low cost in studies are given in Table 3. Lignocellulosic
waste has many advantages compared to other natural material Fig. 1. SEM images of CS before (a (vertical view),b) and after (c,d) adsorption (RB19
such as high adsorption capacity, large amounts, low costs and use and RR218).
in fuel production, paper production, and as adsorbent and ion
exchange resins (Miretzky and Cirelli, 2010; Wartelle and Marshall,
2006).
With the aim of observing the effects of the adsorption pro-
cesses on microstructures, the SEM micrographs of CS before and
after RB19 and RR218 dye adsorption processes are given in Fig. 1.
The lignocellulosic material has a fibrous structure due to lignin
content, with crystalline regions due to cellulose and amorphous
structure. When the SEM vertical view micrograph of CS (Fig. 1 (a))
before dye adsorption is examined, it appears to be a layered
structure that contains pores between these layers.
The adsorbent micropores are smaller than 2 nm, mesopores are
2e50 nm and those above 50 nm are macropore structures (Oztürk€
and Malkoc, 2014). When SEM images are examined, it appears the
pores in this agricultural waste are macropores. When Fig. 1 (c, d) is
examined, the adsorbent surface appeared to be covered with RB19
and RR218 after adsorption on CS.
The thermal disintegration of CS was researched with TGA
(Fig. 2). The disintegration of the biomass occurred in four different Fig. 2. Thermogravimetric curves.
stages of water, hemicellulose, a-cellulose and lignin loss. On Fig. 2,
the small mass loss around 149
C is due to desorption of water. The
mass losses at 250e350
C and 350e550
C are due to disintegra-
tion of a-cellulose and hemicellulose in the adsorbent structure,
Table 2
respectively. The mass loss at 375e800
C is due to lignin, ash and
Chemical content of CS.
silica (Vasile et al., 2011). The peaks observed above 250
C are
Components Content (%) probably exothermic peaks formed linked to disintegration of
Extractives 13 ± 0.5 hemicellulose, cellulose and lignin structures (Yang and Qiu, 2011).
a-Cellulose 42 ± 1.0 This analysis shows a clear variation in the structure of the material.
Holocellulose 66 ± 0.5
FTIR is a method to determine surface functional groups and the
Hemicellulose 24 ± 1.0
Lignin 22 ± 0.3 FTIR spectra are shown on Fig. 3. The peaks in the band interval
Hot water solubility 13 ± 0.4 2800-3600 cm1 are phenols like lignin, pectin and cellulose con-
Ash 1.7 ± 0.1 taining hydrogen bonds. There is OeH strain vibration in the band
1224 G.D. Degermenci et al. / Journal of Cleaner Production 225 (2019) 1220e1229

Fig. 3. ATR-FTIR spectra before and after adsorption RR218 and RB19 by CS.

interval 3280 cm1 belonging to hydroxyl functional groups due to

the presence of carboxylic acid. At 2920 cm1 band interval there is
CeH strain from aliphatic groups, at 1631 cm1 band interval the
peaks are carbonyl C]O strain, while peaks from 1417 to 1519 cm1
interval are aromatic C]C ring strain. There is CeO strain from
phenol groups at 1239 cm1, with CeOeC strain from hemicellu-
lose at 1099-1123 cm1 band interval in the composition. The peaks
observed at 1023 cm1 band are characteristic CeO strain from
lignin in the composition, while in 950-700 cm1 band interval
there are vibrations indicating the presence of a-cellulose
(Miraboutalebi et al., 2017; Sayg ılı and Güzel, 2016; Xiao et al.,
Fig. 4. Effect of pH on removal of RB19 and RR218 (a and b); Point of zero charge of CS
2001). A few surface functional groups could be recognized on used for adsorption experiment (c).
the proposed adsorbent utilizing the FTIR spectrum. Although there
was no change in specific frequencies, the intensity of all peaks
decreased on FTIR. Therefore, the adsorption of the dyes onto the CS capacity of the adsorbent together with increased dye removal
was thought to occur as physical adsorption. (Aksu and Do € nmez, 2003). As the initial pH value increases, the
adsorbent surface begins to gain negative load and electrostatic
repulsion is created between the negative adsorbent surface and
3.2. Effect of initial pH on adsorption
the dye anions due to excess OH ions, which reduces dye removal.
The initial pH value is the most important factor in removal of According to the results obtained, optimum pH was chosen as 2.0
dyes from wastewater. The pH effect on CS adsorption of RB19 and considering the removal efficiency of RB19 and RR218 dyes (nearly
RR218 dyes was researched by varying the initial pH value from 2.0 99%). The pH values of real textile wastewater vary between 6 and
10 (Ghaly et al., 2014). As a result, the use of excessive amounts of
to 12.0 while fixing the dye concentration at 200 mg/L, temperature
at 25
C and adsorbent concentration at 0.25 g/50 mL. For each pH acidic solutions to fix the pH values of wastewater forms a disad-
vantage. However, in experiments at high pH values removal effi-
value studied, the variation in adsorbed dye amounts per unit
adsorbent mass and dye removal efficiency for RB9 and RR218 with ciencies were much lower compared to pH 2 (Fig. 4).
initial pH value and variation according to pHpzc for zero surface
load of CS are given in Fig. 4. 3.3. Effect of adsorbent dosage on adsorption
At pH below the zero load point, the surface has positive electric
load, while at higher pH it has negative load. At low pH values, With the aim of determining the effect of adsorbent dosage, one
there is an increase in electrostatic interaction between positive of the most important parameters affecting adsorption, experi-
adsorbent and dye anions due to the tendency of Hþ ions to attract ments were completed with solutions with initial dye concentra-
to the solid surface. This results in an increase in adsorption tion of 200 mg/L and adsorbent dosage in the interval 0.025e1.0 g/
 G.D. Degermenci et al. / Journal of Cleaner Production 225 (2019) 1220e1229 1225

concentration reduces dye removal efficiency, with adsorption ca-

pacity for RB19 increasing from 2.0 to 71.6 mg/g and adsorption
capacity for RR218 increasing from 2.0 to 63.3 mg/g. In Table 4, the
comparison of maximum adsorption capacity of some dyes on
various adsorbents was listed. Agricultural by-products are
frequently used in dye removal because of their low costs. These by-
products can be modified with some processes to increase their
adsorption capacity and with the help of this: the amount of waste
to be sent to landfill could be reduced by the commercial use of the
agricultural by-products as adsorbent (Wong et al., 2019).

3.5. Effect of temperature on adsorption

One of the most important parameters affecting adsorption

capacity is the temperature of the fluid solution. With the aim of
determining the effect of temperature on adsorption of both
anionic dyes with CS, initial pH was fixed at 2.0, initial dye con-
Fig. 5. Effect of adsorbent dosage on CS; initial RB19 and RR218 conc.: 200 mg/L; pH:
2.0; 25
C.
centration at 400 mg/L, with adsorbent dosage 0.25 g/50 mL with
temperatures investigated at 25, 35, 45 and 55
C. As seen on Fig. 7,
the adsorption removal efficiency for both anionic dyes increase
50 mL. The experimental results are given in Fig. 5. As the adsorbent from 80.1 to 84.3% for RB19 and from 68.6% to 85.2% for RR218 as
dosage increased, the adsorption capacity reduced from 141 to the temperature increases from 25 to 55
C. The temperature values
9.8 mg/g. However, the RB19 and RR218 dye removal efficiencies of real wastewater vary from 35 to 45
C (Ghaly et al., 2014). For
increased from 34% to 99% with increased adsorbent amount. This treatment of real wastewater using corn silk, the variation in
increase in adsorption may be explained by the increase in surface discharge temperature of real wastewater will not significantly
area and volume of pores where adsorption occurs. As a result, the affect removal performance (Fig. 7). With the temperature increase,
most appropriate adsorbent amount for reactive dye removal was the adsorption capacities increased from 64.1 to 67.5 mg/g for RB19
determined as 0.25 g/50 mL. and from 54.9 to 68.2 mg/g for RR218. As temperature increases,
adsorption appears to increase which confirms that this event is
endothermic. Positive adsorption entropy shows an increase in ir-
3.4. Effect of initial concentration of RB19 and RR218 dyes regularity during the process. The reason for this is that water
molecules are freed as a result of molecular exchange between dye
With the aim of investigating the effects of initial concentrations molecules and functional groups on the CS surface and, thus ir-
of the two anionic dyes (RB19 and RR218), adsorption experiments regularity increases at the solid/fluid interface (Banaei et al., 2017).
were completed with pH 2.0, 0.25 g adsorbent dosage and tem-
perature 25
C with dye concentrations from 10 to 500 mg/L with
3.6. Adsorption isotherm
results given in Fig. 6. For the first 90 min of contact the dye
adsorption was rapid, while after 360 min it appeared to reach
Adsorption isotherms are used to explain the relationship be-
equilibrium. The contact duration to determine equilibrium con-
tween adsorbent and adsorbate under fixed temperature and
centration was 24 h. For calculation of kinetic constants, the contact
equilibrium conditions, in addition to being used to calculate the
duration was chosen as 240 min. At low dye concentrations, the dye
maximum adsorption capacity. There are many isotherms to
removal efficiency (nearly 100%) was high due to empty binding
determine adsorption at the solid-fluid interface. This study
areas on the adsorbent. At high dye concentrations nearly all of the
calculated the two-parameter isotherms of Langmuir, Freundlich,
binding areas on the adsorbent surface are filled, so dye removal
Temkin, Dubinin-Radushkevich, Halsey and Harkins-Jura and chose
reduces (Sun et al., 2010). On Fig. 6, the increase in initial
according to the best R2 value. Table 5 shows the linear adsorption
equations and calculated isotherm constants.
The Langmuir model explains single-layer homogeneous
adsorption on a surface, while the Freundlich equation describes
heterogeneous surface energies changing linked to adsorption
temperature (Sun et al., 2010). The Langmuir isotherm may be
insufficient to fully explain the equilibrium form of heterogeneous
adsorption mechanisms forming in single-layer adsorption. The
basic characteristic of the Langmuir equation may be stated as the
dimensionless differentiation factor RL (Eq. (10));

1
RL ¼ (10)
1 þ KL C0

Here C0 (mg/L) is initial dye concentration. If RL is larger than 1, the

adsorption process is unfavorable, if it is equal to 1 it is linear and if
it has a value between 0 and 1 it is favorable (occurs spontaneously)
and if it is 0 it is irreversible (Ooi et al., 2017). The RL value calcu-
lated for reactive dyes for concentrations from 10 to 500 mg/L was
Fig. 6. Effect of initial concentration on CS; pH: 2.0; adsorbent dosage: 0.25 g/50 mL; found to be 0<RL < 1. This situation shows the adsorption process
25
C. occurs spontaneously.
1226 G.D. Degermenci et al. / Journal of Cleaner Production 225 (2019) 1220e1229

Table 4
Utilization of some agricultural and food industry by-product adsorbents for the removal of some dyes from wastewater.

Dyes Adsorbent qe (mg/g) References

Crystal Violet Biocomposite (Mango stone) 352.79 Shoukat et al. (2017)

Methyl Orange Almond Shell 39.357 Deniz (2013)
Direct Red 80 Garlic Straw 107.53 Kallel et al. (2016)
Cationic Dye (Safranin) Calcined mussel shells 196.67 El Haddad et al. (2014)
Acid Blue 113 Cucumis sativus peel 59.81 Lee et al. (2016)
Methylene Blue Abelmoschus esculentus seed 205.656 Nayak and Pal (2017)
Textile Wastewater Sunflower Seed Hull 169.5 Oguntimein (2015)
Methylene Blue Haloxylon Recurvum Plant Stems 22.93 Hassan et al. (2017)
Reactive Navy Blue Powdered Orange Waste 30.28 Irem et al. (2013)
Malachite Green Citrus Limetta Peel 8.733 Singh et al. (2017)
Malachite Green Zea Mays Cob 16.72 Singh et al. (2017)
Reactive Blue 19 Cross-Linked Chitosan/Oil Palm Ash Composite Beads 400 Hasan et al. (2008)
Reactive Blue 19 Wheat Bran 117.6 Çiçek et al. (2007)
Reactive Red 195 Wheat Bran 119.1 Çiçek et al. (2007)
Reactive Yellow 145 Wheat Bran 196.1 Çiçek et al. (2007)
Reactive Black 5 Modified spent tea leaves 71.9 Wong et al. (2019)
Methyl Orange Modified spent tea leaves 62.1 Wong et al. (2019)
Reactive Red 218 Corn Silk 63.3 Present study
Reactive Blue 19 Corn Silk 71.6 Present study

Table 5
Isotherm parameters related to dye adsorption at different initial concentrations on
CS.

Type RB19 RR218

Langmuir isotherm 1 1 1 1
¼ þ
qe qm qm KL Ce
qm (mg/g) 60.6 51.6
KL (L/mg) 2.87 3.17
RL 0.0014 0.0012
R2 0.90 0.83
Freundlich isotherm 1
lnqe ¼ lnKf þ lnCe
n
Kf [(mg/g)(L/mg)1/n] 36.6 33.2
1/n 0.14 0.11
R2 0.99 0.96
Temkin isotherm qe ¼ B lnKT þ B lnCe
KT (L/g) 304.6 1068.7
B (J/mol) 6.574 4.780
R2 0.99 0.93
Fig. 7. Effect of temperature on dye adsorption onto CS; pH: 2.0; adsorbent dosage: Dubinin-Radushkevich isotherm lnqe ¼ lnqm  bε2
0.25 g/50 mL, initial RB19 and RR218 conc.: 400 mg/L. b (mol2/J2) 6.25  108 6.28  108
qm (mg/g) 59.58 51.15
E (kJ/mol) 2.83 2.82
The Temkin adsorption isotherm model was proposed by noting R2 0.77 0.68

 

Halsey isotherm 1 1
the indirect effects of adsorption temperature and adsorbent- lnqe ¼ lnKH  lnCe
nH nH
adsorbate interactions on adsorption. This isotherm constant in- KH 3.6  1012 1.3  1014
creases as adsorption temperature increases and indicates endo- nH 7.318 9.125
thermic adsorption (Başar, 2006). R2 0.99 0.96
Harkins-Jura isotherm 1 BHJ 1
The Dubinin-Radushkevich (D-R) isotherm is generally applied ¼  logCe
q2e AHJ AHJ
to represent the adsorption mechanism with Gauss energy distri-
BHJ 2.56 3.12
bution on a heterogeneous surface. The E value representing the AHJ 3142.6 3366.4
mean adsorption energy per molecule of adsorbate in the D-R R2 0.91 0.95
isotherm provides information about whether the adsorption is
physical or chemical adsorption. Free energy values of adsorption
below 8.0 kJ/mol indicate physical adsorption occurs, while values In the equations b (mol2/J2) is the D-R isotherm constant and Ce
larger than 16 kJ/mol indicate chemical adsorption occurs. The (mg/L) is the adsorbate equilibrium concentration. In Table 5, the
mean adsorption energy per molecule of adsorbed material “E” and adsorption free energy values for adsorption of both anionic reac-
the Polanyi potential constant “Ɛ” are given by the following tive dyes on CS are smaller than 8 kJ/mol and so they are considered
equation (Eqs. (11), (12)) (Ooi et al., 2017): physical adsorption.
The regression coefficients for Temkin, Freundlich and Halsey
1 isotherms with RB19 reactive dye were calculated as 0.99. For
E ¼ pffiffiffiffiffiffi (11) RR218 reactive dye, the regression coefficients for the Freundlich,
2b
Halsey and Harkins-Jura isotherms were calculated as 0.96, 0.96
and 0.95, respectively. These models best explain the adsorption


1 process among the two-parameter isotherms. The Freundlich,
ε ¼ RT ln 1 þ (12) Harkins-Jura and Halsey isotherms best describe adsorption
Ce
mechanisms occurring on heterogeneous surfaces. This situation is
 G.D. Degermenci et al. / Journal of Cleaner Production 225 (2019) 1220e1229 1227

Table 6 adsorption on CS are given in Table 6.

Thermodynamic parameters for dye adsorption on CS; initial conc: 400 mg/L, pH: As seen in the obtained results, the negative values of Gibbs free
2.0; adsorbent dosage: 0.25 g/50 mL.
energy for dye adsorption on CS at different temperatures shows
Dyes Temperature (K) DG0 (kJ/mol) DH0 (kJ/mol) DS0 (J/mol K) R2 the adsorption process occurs spontaneously. The positive
RB19 298 0.4765 7.70 24.22 0.95 adsorption enthalpy (DH0) (7.70 and 26.44 kJ/mol) shows the pro-
308 0.2343 cess is endothermic. Comparing the adsorption equilibrium data for
318 0.0079 four different temperatures, as the temperature increases the dye
328 0.2502
adsorption appears to increase which supports the event being
RR218 298 1.8232 26.44 82.57 0.94
308 0.9975 endothermic. The positive (24.22 and 82.57 J/(mol K)) adsorption
318 0.1717 entropy (DS0) shows irregularity increases during the process. The
328 0.6540 reason for this may be explained by water molecules being freed as
a result of molecular exchange between the dye molecules and
functional groups on the CS surface and thus increased irregularity
explained as being due to the heterogeneous surface of the CS. at the solid/fluid interface (Bu et al., 2016).
Additionally, as the “1/n” value calculated for the Freundlich
isotherm approaches zero, it shows increased surface heterogene-
3.8. Adsorption kinetics
ity. For both reactive dyes (RB19 and RR218), the “1/n” value stated
in the Freundlich isotherm was calculated as 0.14 and 0.11,
The adsorption kinetics were researched for two different dyes
respectively.
with a single adsorbent. At different initial concentrations, the
pseudo-first degree, pseudo-second degree, Weber-Morris (intra-
3.7. Thermodynamic parameters particle diffusion model), Bangham, Elovich and Boyd kinetic
models were used to calculate rate constants and other parameters
Parameters like Gibbs free energy (DG0), enthalpy (DH0) and for the kinetic data and are listed in Table 7.
entropy (DS0) measure how the adsorption occurs from a ther- When the kinetic data for different concentrations of
modynamic viewpoint. Thermodynamic studies of adsorption of both dyes are investigated, the order is Pseudo-second-order>-
reactive dyes (RB19 and RR218) on CS were completed at four Bangham>Elovich>Boyd ¼ Pseudo-first-order with mean R2>0.97.
different temperatures (298, 308, 318 and 328 K). The thermody- The correlation coefficients (R2) for the pseudo-second-order ki-
namic parameters were calculated from the following equations netic model are higher than the other kinetic models. The qe values
(Eqs. (13), (14), (15)) (Ucun et al., 2008): calculated from pseudo second order kinetic model are also close to
the experimental data. Thus, pseudo-second-order kinetic is more
qe
Ka ¼ (13) appropriate to define the adsorption process (Zhang et al., 2015).
Ce
The Elovich model is used to explain heterogeneous solid surfaces
and when the adsorption isotherms are investigated it appears this
DS0 DH0 type of surface is present. At the same time, this model defines ion
lnKa ¼  (14)
R RT exchange in fluid phases. If a sufficient mixture is provided, the film
diffusion rate increases toward the limiting rate factor of the pore
DG0 ¼ DH0  T DS0 (15) diffusion point (Ge et al., 2016). In general, pore diffusion is a rate-
limiting factor in batch systems with high degrees of mixing. When
where Ka is the distribution coefficient. Using the Van’t Hoff the kinetic models are examined, the control mechanism for the
equation, the graph of 1/T against lnKa was drawn and the values of adsorption process is pore diffusion by considering the Bangham
the slope (DH0) and intersection (DS0) of the line were calculated. model. The Boyd equation is used to understand whether adsorp-
The thermodynamic parameters obtained for reactive dye tion occurs with external or intraparticle diffusion mechanisms. If

Table 7
Kinetic parameters related to adsorption with different initial concentrations of RB19 and RR218 dyes.

Kinetic model Parameter RB19 RR218

C0 (mg/L) C0 (mg/L)

100 200 400 100 200 400

Pseudo-first-order k1 (1/min) 0.0171 0.0114 0.0106 0.0247 0.0085 0.0076

lnðqe  qt Þ ¼ lnqe  k1 t qe (mg/g) 2.819 18.09 44.65 6.579 24.87 38.22
R2 0.79 0.96 1.00 0.95 0.98 0.99
Pseudo-second-order k2 (g/(mg min)) 0.0209 0.0023 0.0006 0.0091 0.0013 0.0007
t 1 1 qe (mg/g) 20.13 39.66 64.99 20.48 37.85 51.68
¼ þ t
qt k2 q2e qe R2 1.00 1.00 0.99 1.00 0.99 0.99
Intra-particle diffusion kid (mg/(g min0.5)) 0.3838 1.5322 3.3088 0.5984 1.8245 2.5985
qt ¼ kid ðtÞ1=2 þ C C (mg/g) 15.23 17.70 13.29 12.43 9.944 10.43
R2 0.67 0.91 0.98 0.82 0.97 0.98
Bangham K0 (L/(g mL)) 6.2999 2.6914 1.1507 3.2705 1.4970 1.0175



C0 k M aB (<1) 0.412 0.446 0.456 0.535 0.484 0.399
ln ln ¼ ln 0 þ aB ln t
C0  qt M V R2 0.96 1.00 0.99 0.98 0.99 0.98
Elovich aE (mg/(g min)) 5643.7 25.895 7.8619 102.09 6.3397 6.3632
1 1 b (g/mg) 0.657 0.178 0.086 0.442 0.154 0.111
qt ¼ lnðaE bÞ þ lnðtÞ
b b R2 0.87 0.99 0.98 0.96 0.99 0.96
Boyd Intercept ¼ 0 (pore diffusion controls) else 1.4615 0.2900 0.1367 0.6133 0.0390 0.1363


qe film diffusion controls intercept
Bt ¼  0:4977  ln 1 
qt R2 0.79 0.96 1.00 0.95 0.98 0.99
1228 G.D. Degermenci et al. / Journal of Cleaner Production 225 (2019) 1220e1229

the line on the Boyd graph passes through the origin, adsorption is 2-hydroxyethylammonium acetate-intercalated layered double hydroxide.
Colloid. Surf. Physicochem. Eng. Asp. 511, 312e319. https://doi.org/10.1016/j.
particle diffusion; if it does not it is accepted as occurring with film
colsurfa.2016.10.015.
diffusion (Guo et al., 2017). For the adsorption process to be able to Chaudhari, A.U., Paul, D., Dhotre, D., Kodam, K.M., 2017. Effective biotransformation
occur, first film diffusion and then pore diffusion must occur, to pass and detoxification of anthraquinone dye reactive blue 4 by using aerobic bac-
into the internal sections of the pores and then situations with both terial granules. Water Res. 122, 603e613. https://doi.org/10.1016/j.watres.2017.
06.005.
stages must occur, with bonding of the pollutant on the adsorbent €
Çiçek, F., Ozer, €
D., Ozer, €
A., Ozer, A., 2007. Low cost removal of reactive dyes using
occurring in the last stage. wheat bran. J. Hazard Mater. 146 (1), 408e416. https://doi.org/10.1016/j.
jhazmat.2006.12.037.
Deniz, F., 2013. Dye removal by almond shell residues: studies on biosorption
4. Conclusion performance and process design. Mater. Sci. Eng. C 33 (5), 2821e2826. https://
doi.org/10.1016/j.msec.2013.03.009.
El Haddad, M., Regti, A., Slimani, R., Lazar, S., 2014. Assessment of the biosorption
Characterization of the CS used as adsorbent was completed and kinetic and thermodynamic for the removal of safranin dye from aqueous so-
RB19 and RR218 dyes were successfully removed from aqueous lutions using calcined mussel shells. J. Ind. Eng. Chem. 20 (2), 717e724. https://
solutions. The presence of a variety of functional groups on the doi.org/10.1016/j.jiec.2013.05.038.
Fanchiang, J.M., Tseng, D.H., 2009. Degradation of anthraquinone dye C.I. Reactive
surface of the adsorbent and the macro-porous structure of the
Blue 19 in aqueous solution by ozonation. Chemosphere 77 (2), 214e221.
adsorbent were identified. The maximum removal efficiency for https://doi.org/10.1016/j.chemosphere.2009.07.038.
both reactive dyes were obtained at pH 2.0. With initial concen- Ge, H., Wang, C., Liu, S., Huang, Z., 2016. Synthesis of citric acid functionalized
trations of 500 mg/L, the maximum adsorption capacities for RB19 magnetic graphene oxide coated corn straw for methylene blue adsorption.
Bioresour. Technol. 221, 419e429. https://doi.org/10.1016/j.biortech.2016.09.
and RR218 dyes were determined as 71.6 mg/g and 63.3 mg/g, 060.
respectively. The increase in temperature was not observed to have Ghaly, A.E., Ananthashankar, R., Alhattab, M., Ramakrishnan, V.V., 2014. Production,
a significant effect on dye removal efficiency. The adsorption characterization and treatment of textile effluents: a critical review. J. Chem.
Eng. Process Technol. 5 (182), 1e18. https://doi.org/10.4172/2157-7048.1000182.
equilibrium data were determined to fit the Freundlich, Harkins- Guimaraes, J.R., Maniero, M.G., Nogueira de Araujo, R., 2012. A comparative study on
Jura and Halsey isotherms describing adsorption mechanisms on the degradation of RB-19 dye in an aqueous medium by advanced oxidation
heterogeneous surfaces. When the adsorption equilibrium data at processes. J. Environ. Manag. 110, 33e39. https://doi.org/10.1016/j.jenvman.
2012.05.020.
different temperatures are compared, dye adsorption appeared to Guo, Z., Liu, X., Huang, H., Jiang, L., 2017. Adsorption thermodynamics and kinetics
increase as temperature increased and this supports the event of yohimbine onto strong acid cation exchange fiber. Journal of the Taiwan
being endothermic. The kinetic model results calculated with the Institute of Chemical Engineers 71, 1e12. https://doi.org/10.1016/j.jtice.2016.05.
012.
aid of experimental data indicate a good adsorption process Hasan, M., Ahmad, A.L., Hameed, B.H., 2008. Adsorption of reactive dye onto cross-
occurred. It was concluded that removal of reactive dye with CS linked chitosan/oil palm ash composite beads. Chem. Eng. J. 136 (2), 164e172.
may be effective at pH values of 2.0. FTIR study showed the pres- https://doi.org/10.1016/j.cej.2007.03.038.
Hassan, W., Farooq, U., Ahmad, M., Athar, M., Khan, M.A., 2017. Potential biosorbent,
ence of various functional groups on the CS surface that are
Haloxylon recurvum plant stems, for the removal of methylene blue dye.
involved in the adsorption process. After the adsorption process, Arabian Journal of Chemistry 10, S1512eS1522. https://doi.org/10.1016/j.arabjc.
the intensity of peaks was reduced which revealed the interaction 2013.05.002.
of these functional groups with dye anions. The information ob- Irem, S., Mahmood Khan, Q., Islam, E., Jamal Hashmat, A., Anwar ul Haq, M.,
Afzal, M., Mustafa, T., 2013. Enhanced removal of reactive navy blue dye using
tained suggested that the CS could be used as an effective and powdered orange waste. Ecol. Eng. 58, 399e405. https://doi.org/10.1016/j.
economical adsorbent for the adsorption of RB19 and RR218. When ecoleng.2013.07.005.
the characteristics of the lignocellulosic waste used in the study are Isah, U., Abdulraheem, G., Bala, S., Muhammad, S., Abdullahi, M., 2015. Kinetics,
equilibrium and thermodynamics studies of CI Reactive Blue 19 dye adsorption
examined, it is expected that there are many different uses possible on coconut shell based activated carbon. Int. Biodeterior. Biodegrad. 102,
(wastewater treatment, cellulose source etc.) and new opportu- 265e273. https://doi.org/10.1016/j.ibiod.2015.04.006.
nities are present for the development of effective materials from Jiang, X., Sun, Y., Liu, L., Wang, S., Tian, X., 2014. Adsorption of C.I. Reactive Blue 19
from aqueous solutions by porous particles of the grafted chitosan. Chem. Eng.
these wastes. J. 235, 151e157. https://doi.org/10.1016/j.cej.2013.09.001.
Joshi, M., Bansal, R., Purwar, R., 2004. Colour removal from textile effluents. Indian J.
Fiber Text. Res. 29, 239e259.
Acknowledgements
Kallel, F., Bouaziz, F., Chaari, F., Belghith, L., Ghorbel, R., Chaabouni, S.E., 2016.
Interactive effect of garlic straw on the sorption and desorption of Direct Red 80
The authors would like to thank the Kastamonu University from aqueous solution. Process Saf. Environ. Protect. 102, 30e43. https://doi.
Scientific Research Projects Coordination Department under Grant org/10.1016/j.psep.2016.02.012.
Kan, X., Yao, Z., Zhang, J., Tong, Y.W., Yang, W., Dai, Y., Wang, C.-H., 2017. Energy
No. KU-HIZDES/2016-07 and the Kastamonu University Research performance of an integrated bio-and-thermal hybrid system for lignocellulosic
and Application Center for support. biomass waste treatment. Bioresour. Technol. 228, 77e88. https://doi.org/10.
1016/j.biortech.2016.12.064.
Koyuncu, I., 2002. Reactive dye removal in dye/salt mixtures by nanofiltration
References membranes containing vinylsulphone dyes: effects of feed concentration and
cross flow velocity. Desalination 143 (3), 243e253. https://doi.org/10.1016/
Akkaya, G., Güzel, F., 2014. Application of some domestic wastes as new low-cost S0011-9164(02)00263-1.
biosorbents for removal of methylene blue: kinetic and equilibrium studies. Krishnani, K.K., Meng, X., Christodoulatos, C., Boddu, V.M., 2008. Biosorption
Chem. Eng. Commun. 201 (4), 557e578. https://doi.org/10.1080/00986445. mechanism of nine different heavy metals onto biomatrix from rice husk.
2013.780166. J. Hazard Mater. 153 (3), 1222e1234. https://doi.org/10.1016/j.jhazmat.2007.09.
Aksu, Z., Do€nmez, G., 2003. A comparative study on the biosorption characteristics 113.
of some yeasts for Remazol Blue reactive dye. Chemosphere 50 (8), 1075e1083. Lee, L.Y., Gan, S., Yin Tan, M.S., Lim, S.S., Lee, X.J., Lam, Y.F., 2016. Effective removal of
https://doi.org/10.1016/S0045-6535(02)00623-9. Acid Blue 113 dye using overripe Cucumis sativus peel as an eco-friendly bio-
Anbia, M., Hariri, S.A., Ashrafizadeh, S.N., 2010. Adsorptive removal of anionic dyes sorbent from agricultural residue. J. Clean. Prod. 113, 194e203. https://doi.org/
by modified nanoporous silica SBA-3. Appl. Surf. Sci. 256 (10), 3228e3233. 10.1016/j.jclepro.2015.11.016.
https://doi.org/10.1016/j.apsusc.2009.12.010. Libby, C.E., Joint Textbook Committee of the Paper Indsutry, 1962. Pulp and Paper
Banaei, A., Samadi, S., Karimi, S., Vojoudi, H., Pourbasheer, E., Badiei, A., 2017. Science and Technology. McGraw-Hill, New York.
Synthesis of silica gel modified with 2,20 -(hexane-1,6-diylbis(oxy)) dibenzal- Lourenço, N.D., Novais, J.M., Pinheiro, H.M., 2001. Effect of some operational pa-
dehyde as a new adsorbent for the removal of Reactive Yellow 84 and Reactive rameters on textile dye biodegradation in a sequential batch reactor.
Blue 19 dyes from aqueous solutions: equilibrium and thermodynamic studies. J. Biotechnol. 89 (2), 163e174. https://doi.org/10.1016/S0168-1656(01)00313-3.
Powder Technol. 319, 60e70. https://doi.org/10.1016/j.powtec.2017.06.044. Malik, R., Ramteke, D., Wate, S., 2007. Adsorption of malachite green on groundnut
Başar, C.A., 2006. Applicability of the various adsorption models of three dyes shell waste based powdered activated carbon. Waste Manag. 27 (9), 1129e1138.
adsorption onto activated carbon prepared waste apricot. J. Hazard Mater. 135 https://doi.org/10.1016/j.wasman.2006.06.009.
(1), 232e241. https://doi.org/10.1016/j.jhazmat.2005.11.055. Melo, R.P.F., Barros Neto, E.L., Moura, M.C.P.A., Castro Dantas, T.N., Dantas Neto, A.A.,
Bu, R., Chen, F., Li, J., Li, W., Yang, F., 2016. Adsorption capability for anionic dyes on Oliveira, H.N.M., 2014. Removal of Reactive Blue 19 using nonionic surfactant in
 G.D. Degermenci et al. / Journal of Cleaner Production 225 (2019) 1220e1229 1229

cloud point extraction. Separ. Purif. Technol. 138, 71e76. https://doi.org/10. preparation and application for crystal violet adsorption: a mechanistic study.
1016/j.seppur.2014.10.009. Microporous Mesoporous Mater. 239, 180e189. https://doi.org/10.1016/j.
Miraboutalebi, S.M., Nikouzad, S.K., Peydayesh, M., Allahgholi, N., Vafajoo, L., micromeso.2016.10.004.
McKay, G., 2017. Methylene blue adsorption via maize silk powder: kinetic, Siddiqua, U.H., Ali, S., Iqbal, M., Hussain, T., 2017. Relationship between structure
equilibrium, thermodynamic studies and residual error analysis. Process Saf. and dyeing properties of reactive dyes for cotton dyeing. J. Mol. Liq. 241,
Environ. Protect. 106, 191e202. https://doi.org/10.1016/j.psep.2017.01.010. 839e844. https://doi.org/10.1016/j.molliq.2017.04.057.
Miretzky, P., Cirelli, A.F., 2010. Cr(VI) and Cr(III) removal from aqueous solution by Siddique, M., Farooq, R., Khalid, A., Farooq, A., Mahmood, Q., Farooq, U., Raja, I.A.,
raw and modified lignocellulosic materials: a review. J. Hazard Mater. 180 (1), Shaukat, S.F., 2009. Thermal-pressure-mediated hydrolysis of reactive blue 19
1e19. https://doi.org/10.1016/j.jhazmat.2010.04.060. dye. J. Hazard Mater. 172 (2), 1007e1012. https://doi.org/10.1016/j.jhazmat.
Moodley, P., Gueguim Kana, E.B., 2017. Development of a steam or microwave- 2009.07.095.
assisted sequential salt-alkali pretreatment for lignocellulosic waste: effect on Siddique, M., Farooq, R., Khan, Z.M., Khan, Z., Shaukat, S.F., 2011. Enhanced
delignification and enzymatic hydrolysis. Energy Convers. Manag. 148, decomposition of reactive blue 19 dye in ultrasound assisted electrochemical
801e808. https://doi.org/10.1016/j.enconman.2017.06.056. reactor. Ultrason. Sonochem. 18 (1), 190e196. https://doi.org/10.1016/j.ultsonch.
Moussavi, G., Mahmoudi, M., 2009. Removal of azo and anthraquinone reactive dyes 2010.05.004.
from industrial wastewaters using MgO nanoparticles. J. Hazard Mater. 168 (2), Siddique, M., Farooq, R., Price, G.J., 2014. Synergistic effects of combining ultrasound
806e812. https://doi.org/10.1016/j.jhazmat.2009.02.097. with the Fenton process in the degradation of Reactive Blue 19. Ultrason.
Mustafa, M.M., Jamal, P., Alkhatib, M.a.F., Mahmod, S.S., Jimat, D.N., Ilyas, N.N., 2017. Sonochem. 21 (3), 1206e1212. https://doi.org/10.1016/j.ultsonch.2013.12.016.
Panus tigrinus as a potential biomass source for Reactive Blue decolorization: Singh, H., Chauhan, G., Jain, A.K., Sharma, S.K., 2017. Adsorptive potential of agri-
isotherm and kinetic study. Electron. J. Biotechnol. 26, 7e11. https://doi.org/10. cultural wastes for removal of dyes from aqueous solutions. Journal of Envi-
1016/j.ejbt.2016.12.001. ronmental Chemical Engineering 5 (1), 122e135. https://doi.org/10.1016/j.jece.
Nayak, A.K., Pal, A., 2017. Green and efficient biosorptive removal of methylene blue 2016.11.030.
by Abelmoschus esculentus seed: process optimization and multi-variate Sun, D., Zhang, X., Wu, Y., Liu, X., 2010. Adsorption of anionic dyes from aqueous
modeling. J. Environ. Manag. 200, 145e159. https://doi.org/10.1016/j.jenvman. solution on fly ash. J. Hazard Mater. 181 (1), 335e342. https://doi.org/10.1016/j.
2017.05.045. jhazmat.2010.05.015.
Noreen, S., Bhatti, H.N., Nausheen, S., Sadaf, S., Ashfaq, M., 2013. Batch and fixed bed Taheri, M., Alavi Moghaddam, M.R., Arami, M., 2013. Techno-economical optimi-
adsorption study for the removal of Drimarine Black CL-B dye from aqueous zation of Reactive Blue 19 removal by combined electrocoagulation/coagulation
solution using a lignocellulosic waste: a cost affective adsorbent. Ind. Crops process through MOPSO using RSM and ANFIS models. J. Environ. Manag. 128,
Prod. 50, 568e579. https://doi.org/10.1016/j.indcrop.2013.07.065. 798e806.
Oguntimein, G.B., 2015. Biosorption of dye from textile wastewater effluent onto TAPPI, 1975. Alpha-, Beta- and Gamma-Cellulose in Pulp. Test Method T 203 os-71.
alkali treated dried sunflower seed hull and design of a batch adsorber. Journal TAPPI, 1992a. Water Solubility of Wood and Pulp. Test Method T 207 om-88.
of Environmental Chemical Engineering 3 (4), 2647e2661. https://doi.org/10. TAPPI, 1992b. Ash in Wood and Pulp. Test Method T 211 om-85.
1016/j.jece.2015.09.028. TAPPI, 2011. Acid-insoluble Lignin in Wood and Pulp. Test Method T 222 om-11.
Oguz, E., Bire, M., Nuhoglu, Y., 2016. Comparison between sorption and sono- Tezcan, E., Atıcı, O.G., 2017. A new method for recovery of cellulose from lignocel-
sorption efficiencies, equilibriums and kinetics in the uptake of direct red 23 lulosic bio-waste: pile processing. Waste Manag. 70, 181e188. https://doi.org/
from the aqueous solutions. Water, Air, Soil Pollut. 227 (8), 267. https://doi.org/ 10.1016/j.wasman.2017.09.017.
10.1007/s11270-016-2970-4. Ucun, H., Bayhan, Y.K., Kaya, Y., 2008. Kinetic and thermodynamic studies of the
Ooi, J., Lee, L.Y., Hiew, B.Y.Z., Thangalazhy-Gopakumar, S., Lim, S.S., Gan, S., 2017. biosorption of Cr (VI) by Pinus sylvestris Linn. J. Hazard Mater. 153 (1e2),
Assessment of fish scales waste as a low cost and eco-friendly adsorbent for 52e59. https://doi.org/10.1016/j.jhazmat.2007.08.018.
removal of an azo dye: equilibrium, kinetic and thermodynamic studies. Bio- Vasile, C., Popescu, C.-M., Popescu, M.-C., Brebu, M., Willfor, S., 2011. Thermal
resour. Technol. 245, 656e664. https://doi.org/10.1016/j.biortech.2017.08.153. behaviour/treatment of some vegetable residues. IV. Thermal decomposition of
€
Oztürk, A., Malkoc, E., 2014. Adsorptive potential of cationic Basic Yellow 2 (BY2) eucalyptus wood. Cellul. Chem. Technol. 45 (1e5), 29e42.
dye onto natural untreated clay (NUC) from aqueous phase: mass transfer Wartelle, L.H., Marshall, W.E., 2006. Quaternized agricultural by-products as anion
analysis, kinetic and equilibrium profile. Appl. Surf. Sci. 299, 105e115. https:// exchange resins. J. Environ. Manag. 78 (2), 157e162. https://doi.org/10.1016/j.
doi.org/10.1016/j.apsusc.2014.01.193. jenvman.2004.12.008.
Petrucci, E., Montanaro, D., 2011. Anodic oxidation of a simulated effluent con- Wise, L.E., Murphy, M., D’Adieco, A.A., 1946. Chlorite holocellulose, its fractionation
taining Reactive Blue 19 on a boron-doped diamond electrode. Chem. Eng. J. 174 and bearing on summative wood analysis and studies on the hemicelluloses.
(2e3), 612e618. https://doi.org/10.1016/j.cej.2011.09.074. Pap. Trade J. 122 (2), 35e43.
Reddy, N., Yang, Y., 2005. Biofibers from agricultural byproducts for industrial ap- Wong, S., Tumari, H.H., Ngadi, N., Mohamed, N.B., Hassan, O., Mat, R., Saidina
plications. Trends Biotechnol. 23 (1), 22e27. https://doi.org/10.1016/j.tibtech. Amin, N.A., 2019. Adsorption of anionic dyes on spent tea leaves modified with
2004.11.002. polyethyleneimine (PEI-STL). J. Clean. Prod. 206, 394e406. https://doi.org/10.
Reife, A., Freeman, H.S., 1996. Environmental Chemistry of Dyes and Pigments. 1016/j.jclepro.2018.09.201.
Wiley, New York. Xiao, B., Sun, X.F., Sun, R., 2001. Chemical, structural, and thermal characterizations
Saygılı, H., Güzel, F., 2016. Effective removal of tetracycline from aqueous solution of alkali-soluble lignins and hemicelluloses, and cellulose from maize stems, rye
using activated carbon prepared from tomato (Lycopersicon esculentum Mill.) straw, and rice straw. Polym. Degrad. Stabil. 74 (2), 307e319. https://doi.org/10.
industrial processing waste. Ecotoxicol. Environ. Saf. 131, 22e29. https://doi. 1016/S0141-3910(01)00163-X.
org/10.1016/j.ecoenv.2016.05.001. Yang, J., Qiu, K., 2011. Development of high surface area mesoporous activated
Sezer, G.G., Arıcı, M., Eruçar, I., €
_ Yeşilel, O.Z., Ozel, H.U., Gemici, B.T., Erer, H., 2017. carbons from herb residues. Chem. Eng. J. 167 (1), 148e154. https://doi.org/10.
Zinc (II) and cadmium (II) coordination polymers containing phenyl- 1016/j.cej.2010.12.013.
0
enediacetate and 4, 4 -azobis (pyridine) ligands: syntheses, structures, dye Zhang, Y., Wang, W., Zhang, J., Liu, P., Wang, A., 2015. A comparative study about
adsorption properties and molecular dynamics simulations. J. Solid State Chem. adsorption of natural palygorskite for methylene blue. Chem. Eng. J. 262,
255, 89e96. https://doi.org/10.1016/j.jssc.2017.08.002. 390e398. https://doi.org/10.1016/j.cej.2014.10.009.
Shoukat, S., Bhatti, H.N., Iqbal, M., Noreen, S., 2017. Mango stone biocomposite