Papers by Amandianeze Obasi
Environmental Science and Pollution Research, 2006
Goal, Scope and Background This paper is a part of the research work on ‘Integrated treatment of ... more Goal, Scope and Background This paper is a part of the research work on ‘Integrated treatment of industrial wastes towards prevention of regional water resources contamination — INTREAT’ the project. It addresses the environmental pollution problems associated with solid and liquid waste/effluents produced by sulfide ore mining and metallurgical activities in the Copper Mining and Smelting Complex Bor (RTB-BOR), Serbia. However, since the minimum solubility for the different metals usually found in the polluted water occurs at different pH values and the hydroxide precipitates are amphoteric in nature, selective removal of mixed metals could be achieved as the multiple stage precipitation. For this reason, acid mine water had to be treated in multiple stages in a continuous precipitation system-cascade line reactor. Materials and Methods All experiments were performed using synthetic metal-bearing effluent with chemical a composition similar to the effluent from open pit, Copper Mining and Smelting Complex Bor (RTB-BOR). That effluent is characterized by low pH (1.78) due to the content of sulfuric acid and heavy metals, such as Cu, Fe, Ni, Mn, Zn with concentrations of 76.680, 26.130, 0.113, 11.490, 1.020 mg/dm3, respectively. The cascade line reactor is equipped with the following components: for feeding of effluents, for injection of the precipitation agent, for pH measurements and control, and for removal of the process gases. The precipitation agent was 1M NaOH. In each of the three reactors, a changing of pH and temperature was observed. In order to verify efficiency of heavy metals removal, chemical analyses of samples taken at different pH was done using AES-ICP. Results Consumption of NaOH in reactors was 370 cm3, 40 cm3 and 80 cm3, respectively. Total time of the experiment was 4 h including feeding of the first reactor. The time necessary to achieve the defined pH value was 25 min for the first reactor and 13 min for both second and third reactors. Taking into account the complete process in the cascade line reactor, the difference between maximum and minimum temperature was as low as 6°C. The quantity of solid residue in reactors respectively was 0.62 g, 2.05 g and 3.91 g. In the case of copper, minimum achieved concentration was 0.62 mg/dm3 at pH = 10.4. At pH = 4.50 content of iron has rapidly decreased to < 0.1 mg/dm3 and maintained constant at all higher pH values. That means that precipitation has already ended at pH=4.5 and maximum efficiency of iron removal was 99.53%. The concentration of manganese was minimum at pH value of 11.0. Minimum obtained concentration of Zn was 2.18 mg/dm3 at a pH value of 11. If pH value is higher than 11, Zn can be re-dissolved. The maximum efficiency of Ni removal reached 76.30% at a pH value of 10.4. Discussion Obtained results show that efficiency of copper, iron and manganese removal is very satisfactory (higher than 90%). The obtained efficiency of Zn and Ni removal is lower (72.30% and 76.31%, respectively). The treated effluent met discharge water standard according to The Council Directive 76/464/EEC on pollution caused by certain dangerous substances into the aquatic environment of the Community. Maximum changing of temperature during the whole process was 6°C. Conclusion This technology, which was based on inducing chemical precipitation of heavy metals is viable for selective removal of heavy metals from metal-bearing effluents in three reactor systems in a cascade line. Recommendations and Perspectives The worldwide increasing concern for the environment and guidelines regarding effluent discharge make their treatment necessary for safe discharge in water receivers. In the case where the effluents contain valuable metals, there is also an additional economic interest to recover these metals and to recycle them as secondary raw materials in different production routes.
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Research Journal of Environmental Sciences, 2008
ABSTRACT
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Toxicological & Environmental Chemistry, 2008
The aim of this study was to assess the toxicity reduction of wastewaster after treatment with fl... more The aim of this study was to assess the toxicity reduction of wastewaster after treatment with fly ash. Fly ash is a waste material which is formed as a result of coal burning in power plants, but has the potential to adsorb heavy metal ions. The present study examined the adsorption ...
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Industrial wastewater containing heavy metals is of great concern because of their toxic impact t... more Industrial wastewater containing heavy metals is of great concern because of their toxic impact to living species and environments. Removal of metal ions from industrial effluent using nano-particles is an area of extensive research. This study collected wastewaters and effluents from 11 industrial companies in tanning, electronic plating, printed circuit board manufacturing, semi-conductor, and metal surface treatment industry and studied in detailed the major and trace element compositions to develop potential fingerprinting technique for pollutant source identification. The results showed that electronic plating and metal surface treatment industry produce high Fe, Mn, Cr, Zn, Ni and Mo wastewater. The tanning industry and the printed circuit board manufacturing industry released wastewater with high Fe and Cr, Cu and Ni, respectively. For semi-conductor industry, significant dissolved In was detected in wastewater. The absorption experiments to remove heavy metals in waters were conducted using Fe3O4 nano-particles. Under optimal conditions, more than 99 % dissolved metals were removed in a few minutes.
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Colloids and Surfaces B-biointerfaces, 2011
A novel organic–inorganic nanocomposite cation-exchanger has been synthesized via sol–gel method.... more A novel organic–inorganic nanocomposite cation-exchanger has been synthesized via sol–gel method. It was characterized on the basis of FTIR, XRD, SEM, TEM, AFM and Raman studies. The structural studies reveal semi-crystalline nature of the material with the particle size ranging from 1–5 nm. Physiochemical properties such as ion-exchange capacity, chemical and thermal stability of composite material have also been determined. Bifunctional behavior of the material has been indicated by its pH titrations curves. The nanocomposite material exhibits improved thermal stability, higher ion-exchange capacity and better selectivity for toxic heavy metals. The ion-exchange material shows an ion-exchange capacity of 1.8 meq g−1 for Na+ ions. Sorption behavior of metal ions on the material was studied in different solvents. The cation exchanger was found to be selective for Pb(II), Hg(II) and Zr(IV) ions. The limit of detection (LOD) and the limit of quantification (LOQ) for Pb(II) ion was found to be 0.85 and 2.85 μg L−1. Analytically important separations of heavy metal ions in synthetic mixtures as well as industrial effluents and natural water were achieved with the exchanger. The practical utility of polyanilineZr(IV)sulphosalicylate cation exchanger has been established for the analysis and recovery of heavy metal ions in environmental samples.► The present work reports the synthesis, characterisation and applications of a novel nano-composite polyanilineZr(IV)sulphosalicylate cation exchanger, while the other manuscript (CEJ-D-10-02410) reported poly-o-toluidine zirconium(IV)tungstate. ► This work claims superior physiochemical properties in terms of higher ion-exchange capacity (1.8 meq g−1 for Na+), better chemical and thermal stability. ► Its characterization has been done on the basis of AFM and RAMAN spectroscopy, besides FTIR, XRD, SEM and TEM studies.
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Environmental Science & …, 1972
... (Nalco). &amp;amp;amp;#x27; Chemical Treatment of Wastewater from Mining and Mineral Proc... more ... (Nalco). &amp;amp;amp;#x27; Chemical Treatment of Wastewater from Mining and Mineral Processing,&amp;amp;amp;quot; Eog. Mining J., April 1971. ... He has extemitie experience in water and waste water rreatment plant engineering and sales and has presented papers on waste treatment and biofiltration. ...
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Journal of Hazardous Materials, 1998
Fly ash is one of the most abundant waste materials; its major components make it a potential age... more Fly ash is one of the most abundant waste materials; its major components make it a potential agent for the adsorption of heavy metal contaminants in water and wastewaters. The objective of this study was to measure the changes in toxicity of and heavy metals in a municipal (Salisbury, MD) wastewater treatment plant (SWTP) effluent on treatment with fly ash. The effluent from SWTP after treatment with fly ash for 4 h showed a significant reduction in toxicity, Cu and Pb, and PO43− and NO3− contents. Toxicity of the effluent was measured using the marine luminescent microorganisms—Vibrio fischeri (‘Microtox’ test). Heavy metals (Cu, Pb and Zn) were measured using Atomic Absorption Spectrophotometry. Fly ash removed Cu and Pb from the effluent (through adsorption), and the removal of these toxic heavy metals resulted in the reduction of toxicity.
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Journal of Geochemical Exploration, 1998
... Metal removal from solutions depends on the pH, the initial concentration, the bark species .... more ... Metal removal from solutions depends on the pH, the initial concentration, the bark species ... Bark loaded with heavy metals was analyzed by scanning electron microscopy 'SEM' and infrared ... Such materials can be recycled for the production of secondary metal using the current ...
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Water Research, 2003
Clays (especially montmorillonite and bentonite) are widely used as barriers in landfills to prev... more Clays (especially montmorillonite and bentonite) are widely used as barriers in landfills to prevent contamination of subsoil and groundwater by leachates containing heavy metals. For this reason it is important to study the adsorption of metals by these clays. The sorption of seven metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) on Na-montmorillonite was studied as a function of pH and in the presence of ligands, forming complexes of different stabilities with the metals of interest. The continuous column method was used as it better simulates natural conditions. The total capacity of Na-montmorillonite towards these metals was determined. The pH variations influence to a higher extent the concentrations of Cu, Pb and Cd in the effluent. Moreover the results suggest that complex formation hinders the sorption of the metals on the clay, with an increasing influence in the order: Mn ⩽ Pb ⩽ Cd ⩽ Zn < Ni < Cu < Cr. The evaluation of the total capacity of Na-montmorillonite shows that this clay is a good sorbent towards all examined metals.
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Journal of Chemical …, 1994
... 3 APPLICATION OF NATURAL ZEOLITES FOR POLLUTION CONTROL ... They suggested that clinoptilolit... more ... 3 APPLICATION OF NATURAL ZEOLITES FOR POLLUTION CONTROL ... They suggested that clinoptilolite exchange capacity depends significantly on the zeolite treatment method and they ... Their results showed a dual action of ion-exchange and oxidation for iron removal, and ...
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Toxicological & Environmental Chemistry, 2009
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Bioresource Technology, 2007
Discharge of heavy metals from metal processing industries is known to have adverse effects on th... more Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment. Conventional treatment technologies for removal of heavy metals from aqueous solution are not economical and generate huge quantity of toxic chemical sludge. Biosorption of heavy metals by metabolically inactive non-living biomass of microbial or plant origin is an innovative and alternative technology for removal of these pollutants from aqueous solution. Due to unique chemical composition biomass sequesters metal ions by forming metal complexes from solution and obviates the necessity to maintain special growth-supporting conditions. Biomass of Aspergillus niger, Penicillium chrysogenum, Rhizopus nigricans, Ascophyllum nodosum, Sargassum natans, Chlorella fusca, Oscillatoria anguistissima, Bacillus firmus and Streptomyces sp. have highest metal adsorption capacities ranging from 5 to 641 mg g(-1) mainly for Pb, Zn, Cd, Cr, Cu and Ni. Biomass generated as a by-product of fermentative processes offers great potential for adopting an economical metal-recovery system. The purpose of this paper is to review the available information on various attributes of utilization of microbial and plant derived biomass and explores the possibility of exploiting them for heavy metal remediation.
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Environmental Management and Health, 2001
... T. Sundararajan, Department of Civil Engineering, Pondicherry Engineering College, Pillaichav... more ... T. Sundararajan, Department of Civil Engineering, Pondicherry Engineering College, Pillaichavady,Pondicherry, India. S. Sivamurthy Reddy, Department of Civil Engineering, PondicherryEngineering College, Pillaichavady, Pondicherry, India. Acknowledgements. ...
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Water research, 2001
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Chemosphere, 2004
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Separation and Purification Reviews, 2011
The removal of some heavy metals Cu (II), Cd(II), Mn(II), Pb(II) As(III), and As(V) from water so... more The removal of some heavy metals Cu (II), Cd(II), Mn(II), Pb(II) As(III), and As(V) from water solution using absorption and nanofiltration membrane techniques is presented. The influence of temperature, sorbent mass, solution pH, flow rate and sorbent chemical modification in the adsorption process are discussed. Among the listed sorbents the best performers for higher initial heavy metal concentration are: montmorillonite, kaolin, tobermorite, magnetite, silica gel and alumina that removed more than 80% from a solution of initial concentration range 1–100 ppm for cadmium, chitosan coated magnetic nanoparticles modified with α-ketoglutaric acid removed >95% from a solution of initial concentration 200 ppm for copper, polymeric cation exchanger containing nano-Zr(HPO3-S)2 absorbs 98% of lead with initial concentration 80 ppm, acid modified carbon black has absorption efficiency of 80% with initial concentration 200 ppm of As(V); and polonite sorbent absorb 98.7% of manganese with initial concentration 0.01 ± 0.031 ppm. For the nanofiltration (NF) membrane, research showed removal efficiencies around 97% for cadmium (initial concentration C0 = 500 ppm), 99.9% for copper (C0 = 12000 ppm), 84% lead (C0 = 0.64 ppm, 93% As (V) and 89% As (III) (total arsenic concentration = 600 ppm) and 98% for Mn (C0 =310 ppm).
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Bioresource Technology, 2001
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International Journal of Environmental Studies, 1990
A highly sensitive method has been developed for the removal of trace metal such Cr, Mn, Fe, Co, ... more A highly sensitive method has been developed for the removal of trace metal such Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, As, Sb, present in synthetic as well as in wastewater (complex) samples by adsorption of their diethyldithiocarbamates chelates on microcrystalline naphthalene in different pH ranges. The percentage removal of individual metals was found to be more than 99%, whereas that of trace metals from the mixed synthetic as well as complex samples was found to be between 95 to 99% due to interference by other metals. A fluidized bed reactor has been used for removal of trace metals present in synthetic as well as in complex samples (wastewater) in a laboratory experiment. The method is very efficient for the pre‐concentration of these metals from a large volume of the aqueous phase and can be used for the recovery of heavy metals from the effluent of electroplating industries.
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