Search Results (217)

Diethyl phthalate (DEP) is a commonly utilized plasticizer that has gained significant attention due to its widespread occurrence in the environment and its harmful impact on human health. The primary objective of this study was to evaluate and compare several (ultraviolet) UV-(peracetic acid) PAA advanced oxidation processes based on hydroxyl radicals to degrade DEP. The effect of UV-LEDs incorporating PAA at different UV ranges (UV-A, λ = 365 nm; UV-C, λ = 254 nm and VUV, λ = 254 nm) was evaluated. The results demonstrated that DEP was successfully degraded in both the UVC/PAA (removal rate 98.28%) and VUV/PAA (removal rate 97.72%) processes compared to the UVA/PAA process (removal rate of 2.71%). The competitive method evaluated the contribution of R-O•, which were 24.08% and 33.92% in UVC/PAA and VUV/PAA processes, respectively. We also evaluated the effects of peroxymonosulfate (PMS) dosages, UV irradiation, pH and anion coexistence on the removal of DEP. In the UVC/PAA system, DEP degradation was particularly effective (removal rate about 95.52%) over a wider pH range (3–9). As the concentration of HCO₃⁻ ions increased, there may have been some inhibition of DEP removal. The inhibitory effect of HA and Cl⁻ ions on DEP removal were negligible. Analysis of the intermediates revealed that DEP degradation primarily occurred via two pathways: hydrolysis and hydroxylation reactions. This study presents a potential mnethod for the removal of phthalates and offers some guidance for the selection of appropriate disinfection technologies in drinking water treatment. Full article

A carbon-based material was synthesized using potato peels (BPP) and banana pseudo-stems (BPS), both of which were modified with manganese to produce BPP-Mn and BPS-Mn, respectively. These materials were assessed for their ability to activate peroxymonosulfate (PMS) in the presence of MnCO₃ to degrade acetaminophen (ACE), an emerging water contaminant. The materials underwent characterization using spectroscopic, textural, and electrochemical techniques. Manganese served a dual function: enhancing adsorption properties and facilitating the breaking of peroxide bonds. Additionally, carbonate ions played a structural role in the materials, transforming into CO₂ at high temperatures and thereby increasing material porosity, which improved adsorption capabilities. This presents a notable advantage for materials that have not undergone de-lignification. Among the materials tested, BPS exhibited the highest efficiency in the carbocatalytic degradation of ACE, achieving a synergy index of 1.31 within just 5 min, with 42% ACE degradation in BPS compared to BPS-Mn, which achieved 100% ACE removal through adsorption. Reactive oxygen species such as sulfate, hydroxyl, and superoxide anion radicals were identified as the primary contributors to pollutant degradation. In contrast, no degradation was observed for BPP and BPP-Mn, which is likely linked to the lower lignin content in their precursor material. This work addressed the challenge of revalorizing lignocellulosic waste by highlighting its potential as an oxidant for emerging pollutants. Furthermore, the study demonstrated the coexistence of various reactive oxygen species, confirming the capacity of carbon-based matrices to activate PMS. Full article

Peroxymonosulfate (PMS)-based advanced oxidation processes have shown potential for the removal of organic contaminants; however, the preparation of catalysts with high degradation efficiencies and rapid reaction rates remains a challenge. In this study, we have successfully synthesized CoFe bimetallic modified corn cob-derived biochar (CoFe/BC) for the activation of PMS, achieving the rapid and efficient degradation of bisphenol F (BPF). The synthesized CoFe/BC catalyst demonstrated excellent catalytic performance, achieving over 99% removal within 3 min and exhibiting a removal rate of 90.0% after five cycles. This could be attributed to the cyclic transformation of Co and Fe, which sustained rapid PMS activation for BPF degradation, and Co⁰/Fe⁰ played a significant role in the cyclic transformation. Furthermore, the electron paramagnetic resonance tests confirmed that •SO₄⁻ and •OH were the primary reactive oxygen species, while •O₂⁻ played a minor role in BPF degradation. This study highlights the high degradation efficiency, rapid reaction rate, excellent magnetic separation properties, and exceptional reusability of CoFe/BC catalysts for BPF removal, providing valuable insights for practical wastewater treatment. Full article

The application of advance oxidation processes (AOPs) based on the activation of peroxymonosulfate (PMS) is a great concern for wastewater treatment. Herein, ZrO₂-3DG was constructed using a hydrothermal method for the degradation of tetracycline (TC) with PMS. The defective ZrO₂-3DG materials were also prepared with plasma treatment. SEM and XPS results show that the ZrO₂-3DG composite and the corresponding defective materials were successfully fabricated. The ZrO₂ particles are distributed uniformly on the substrate material. Plasma can induce defects on the composite materials and create highly active sites. TC degradation results show that the ZrO₂-3DG/PMS system can achieve a degradation efficiency of 92.9% for TC. The influences of defects on materials, light irradiation and sulfate accumulation were investigated. It has been found that defects can induce an inhibiting effect on the degradation process, which can be tuned by plasma time. The defective ZrO₂-3DG/PMS system exhibits excellent resistance to the accumulation of sulfate, even showing enhanced degradation performances in specific conditions. The light irradiation has led to a higher degradation efficiency with the accumulation of sulfate compared with a dark environment. These findings give great guidance to the application of the ZrO₂-3DG/PMS system for environmental protection. Full article

In this work, NiCo₂O₄ was synthesized from bimetallic oxalate and utilized as a heterogeneous catalyst to active peroxymonosulfate (PMS) for the degradation of tetracycline (TC). The degradation efficiency of TC (30 mg/L) in the NiCo₂O₄ + PMS system reached 92.4%, with NiCo₂O₄ exhibiting satisfactory reusability, stability, and applicability. Radical trapping test and electron paramagnetic resonance (EPR) results indicated that SO₄^•−, •OH, O₂^•−, and ¹O₂ were the dominating reactive oxygen species (ROS) for TC degradation in the NiCo₂O₄ + PMS system. Seven intermediates were identified, and their degradation pathways were proposed. Toxicity assessment using T.E.S.T software (its version is 5.1.1.0) revealed that the identified intermediates had lower toxicity compared to intact TC. A rice seed germination test further confirmed that the NiCo₂O₄ + PMS system effectively degraded TC into low-toxicity or non-toxic products. In conclusion, NiCo₂O₄ shows promise as a safe and efficient catalyst in advanced oxidation processes (AOPs) for the degradation of organic pollutants. Full article

In this study, the sodium perborate (SP)-activated peroxymonosulfate (PMS) process was used to enhance the coagulation efficiency of cyanobacteria with polymeric aluminum chloride (PAC), aiming to efficiently mitigate the impact of algal blooms on the safety of drinking water production. The optimal concentrations of SP, PMS, and PAC were determined by evaluating the removal rate of OD₆₈₀ and zeta potential of the algae. Experimental results demonstrated that the proposed ternary PMS/SP/PAC process achieved a remarkable OD₆₈₀ removal efficiency of 95.2%, significantly surpassing those obtained from individual treatments with PMS (19.5%), SP (5.2%), and PAC (42.1%), as well as combined treatments with PMS/PAC (55.7%) and PMS/SP (28%). The synergistic effect of PMS/SP/PAC led to the enhanced aggregation of cyanobacteria cells due to a substantial reduction in their zeta potential. Flow cytometry was performed to investigate cell integrity before and after treatment with PMS/SP/PAC. Disinfection by-products (DBPs) (sodium hypochlorite disinfection) of the algae-laden water subsequent to PMS/SP/PAC treatment declined by 57.1%. Moreover, microcystin-LR was completely degraded by PMS/SP/PAC. Electron paramagnetic resonance (EPR) analysis evidenced the continuous production of ${\mathrm{S}\mathrm{O}}_4^{•-}$, •OH, ¹O₂, and ${\mathrm{O}}_2^{•-}$, contributing to both cell destruction and organic matter degradation. This study highlighted the significant potential offered by the PMS/SP/PAC process for treating algae-laden water. Full article

This study investigated the degradation of sulfolane using pressurized ozonation under varying initial concentrations and the influence of different catalysts and peroxymonosulfate activation methods on the degradation efficiency. Initial sulfolane concentrations of 1 mg L⁻¹, 20 mg L⁻¹, and 100 mg L⁻¹ were tested over 120 min, revealing a degradation efficiency of 73%, 41%, and 18%, respectively. The addition of various metal ions (Zn²⁺, Mg²⁺, Cu²⁺, Ni²⁺, and Co²⁺) demonstrated that only zinc and magnesium enhanced degradation, with zinc achieving a 92% removal efficiency and magnesium achieving 86%. Different doses of magnesium and zinc were further tested, showing optimal degradation at specific concentrations. The combination of PMS with ozonation was explored, revealing that zinc activation did not significantly enhance degradation, while NaOH activation achieved near-total degradation, with a 100 mg L⁻¹ NaOH concentration. Varying PMS concentrations indicated that altering pH was more effective than changing PMS dosage. Finally, the impact of pH changes in both reverse osmosis water and tap water matrices confirmed that higher pH levels significantly improved degradation efficacy, achieving up to 98% removal with NaOH concentrations of 50 mg L⁻¹ in reverse osmosis water. These results suggest that optimizing pH and catalyst type are critical for enhancing sulfolane degradation in pressurized ozonation systems. Full article

In recent years, the excessive use and improper disposal of antibiotics have led to their pervasive presence in the environment, resulting in significant antibiotic pollution. To address this pressing issue, the present study synthesized nickel–iron-layered double hydroxides (NiFe-LDHs) with varying molar ratios using a hydrothermal method, employing these LDHs as catalysts for the oxidative degradation of doxycycline, with peroxymonosulfate (PMS) serving as the oxidant. X-ray diffraction analysis confirmed that the synthesized NiFe-LDHs exhibited a hexagonal crystal structure characteristic of layered double hydroxides. Experimental results demonstrated that the catalytic efficiency of NiFe-LDHs increased with both the dosage of the catalyst and the concentration of PMS, achieving a high degradation efficiency for doxycycline at a catalyst concentration of 0.5 g/L. Furthermore, the catalytic performance was notably effective across a range of pH conditions, with the highest degradation efficiency being observed at a Ni–Fe molar ratio of 3:1. The activation of PMS by NiFe-LDHs for the catalytic degradation of pollutants primarily occurs through singlet oxygen (¹O₂), superoxide radicals (O₂⁻·), and sulfate radicals (SO₄⁻·). The study also proposed three potential degradation pathways for doxycycline, indicating that the final degradation products have lower environmental toxicity. This research offers novel approaches and methodologies for the treatment of antibiotic-contaminated wastewater. Full article

Heterogeneous Mg-Fe oxide/biochar (MgFeO@BC) nanocomposites were synthesized by a co-precipitation method and used as biochar-based catalysts to activate peroxymonosulfate (PMS) for sulfamethoxazole (SMX) removal. The optimal conditions for SMX degradation were examined as follows: pH 7.0, MgFeO@BC of 0.4 g/L, PMS concentration of 0.6 mM and SMX concentration of 10.0 mg/L at 25 ℃. In the MgFeO@BC/PMS system, the removal efficiency of SMX was 99.0% in water within 40 min under optimal conditions. In the MgFeO@BC/PMS system, the removal efficiencies of tetracycline (TC), cephalexin (CEX), ciprofloxacin (CIP), 4-chloro-3-methyl phenol (CMP) and SMX within 40 min are 95.3%, 98.4%, 98.2%, 97.5% and 99.0%, respectively. The radical quenching experiments and electron spin resonance (ESR) analysis suggested that both non-radical pathway and radical pathway advanced SMX degradation. SMX was oxidized by sulfate radicals (SO₄^•−), hydroxyl radicals (•OH) and singlet oxygen (¹O₂), and SO₄^•− acted as the main active species. MgFeO@BC exhibits a higher current density, and therefore, a higher electron migration rate and redox capacity. Due to the large number of available binding sites on the surface of MgFeO@BC and the low amount of ion leaching during the catalytic reaction, the system has good anti-interference ability and stability. Finally, the intermediates of SMX were detected. Full article

Persulfate-based advanced oxidation processes have emerged as a promising approach for the degradation of organic pollutants in aqueous environments due to their ability to generate sulfate radicals (SO₄^−·) within catalytic systems. In this study, peroxydisulfate (PDS) and peroxymonosulfate (PMS) were investigated with the natural vanadium–titanium magnetite (VTM) as the activator for the degradation of acid orange II. The degradation efficiency increased with higher dosages of VTM or persulfate (both PDS and PMS) at lower concentrations (below 10 mM). However, excessive PMS (higher than 10 mM) in the PMS/VTM system led to the self-consumption of free radicals, significantly inhibiting the degradation of acid orange II. The VTM-activated PDS or PMS maintained an effective degradation of acid orange II in a wide pH range (3~11), suggesting remarkable pH stability. The SO₄^−· was the main active species in the PDS/VTM system, while hydroxyl radical (·OH) also contributed significantly to the PMS/VTM system. In addition, PMS exhibited better thermal stability during VTM activation. Coexisting ions in an aqueous environment such as bicarbonate (HCO₃^–), carbonate (CO₃^2–), and hydrogen phosphate (HPO₄^2–) had obvious effects on persulfate activation. Our study systematically investigated the different activation processes and influencing factors associated with PDS and PMS when the natural VTM was used as a catalyst, thereby providing new insights into the persulfate-mediated degradation of organic pollutants in aqueous environments. Full article

Advanced oxidation process based on heterogeneous activation of peroxymonosulfate (PMS) has received significant attention in wastewater remediation. Herein, a facile and effective electrochemical method was introduced in a tungsten sulfide (WS₂)-activated PMS process for the removal of a typical azo dye Acid Orange 7 (AO7) in aqueous solution. It was found that the electrochemical activation could remarkably promote the removal of organic pollutants by coupling with WS₂/PMS system. The elimination of AO7 in the electro-assisted WS₂-activated PMS (E/WS₂/PMS) system achieved 95.8% of AO7 removal in 30 min, with the optimal conditions of 1.0 g/L WS₂, 1.0 mM PMS, current density of 1.0 mA/cm² and initial pH of 6.5. Based on quenching experiments and EPR techniques, mechanistic studies confirmed that hydroxyl radical (^•OH) and singlet oxygen (¹O₂) are the primary reactive oxygen species for the oxidation of pollutants. In addition, the influences of pH, WS₂ dosage, PMS concentration, current density, common anions and humic acid on the AO7 removal are also investigated in detail. Furthermore, the system exhibited resistance to aqueous matrices, verifying the accepted applicability in real water (i.e., Yangtze River water and Shahu Lake water). In summary, this study demonstrates a green system for the effective removal of contaminants in water, holding significant implications for practical application. Full article

In this work, rice-husk-derived biochar (RBC) was synthesized by using simple one-step pyrolysis strategies and served as catalysts to activate peroxymonosulfate (PMS) for degrading sulfamethoxazole (SMX). When the annealing temperature (T) = 800 °C, RBC₈₀₀ exhibits the typical hardwood structure with several micropores and mesoporous. Furthermore, RBC₈₀₀ obtains more defect sites than RBC₆₀₀, RBC₇₀₀, and RBC₉₀₀. In the RBC₈₀₀/PMS system, the removal rate of the SMX reached 92.0% under optimal conditions. The kinetic reaction rate constant (k_obs) of the RBC₈₀₀/PMS system was 0.009 min⁻¹, which was about 1.50, 1.28, and 4.50 times that of the RBC₆₀₀/PMS (k_obs = 0.006 min⁻¹), RBC₇₀₀/PMS (k_obs = 0.007 min⁻¹), and RBC₉₀₀/PMS (k_obs = 0.002 min⁻¹) systems, respectively. In the RBC₈₀₀/PMS system, sulfate radical (SO₄^•−) is the main active species. Compared with other active sites, the hydroxyl group (C-OH) on the surface of RBC₈₀₀ interacts more strongly with PMS, which is more likely to promote the stretching of the O-O bond of the PMS, thus breaking into the activated state and significantly reducing the activation energy required for reaction. The degradation intermediates of SMX were speculated, and the toxicity analysis was conducted. Generally, this work reveals in depth the interaction between reactive sites of biochar-based catalysts and PMS at the molecular level. Full article

Heterogeneous persulfate activation is an advanced technology for treating harmful algae in drinking water sources, while it remains a significant hurdle in the efficient management of cyanobacterial blooms. In this study, super-dispersed cobalt-doped carbon nitride (2CoCN) was prepared to activate peroxymonosulfate (PMS) for simultaneous Microcystis aeruginosa inhibition and microcystin (MC-LR) degradation. When the initial PMS and 2CoCN concentrations were 0.3 g/L and 0.4 g/L, respectively, the efficiency of algal cell removal reached 97% in 15 min, and the degradation of MC-LR reached 96%. Analyses by SEM, TEM, and EEM spectra revealed that the reaction led to changes in algal cell morphology, damage to the cell membrane and cell wall, and the diffusion of thylakoid membranes and liposomes. The activities of antioxidant enzymes (superoxide dismutase and catalase) and antioxidants (glutathione) in algal cells generally increased, and the content of malondialdehyde increased, indicating severe damage to the cell membrane. Radical capture experiments confirmed that singlet oxygen (¹O₂) was the key species destroying algal cells in the 2CoCN/PMS system. The 2CoCN/PMS system was effective in removing M. aeruginosa within a wide pH range (3–9), and 2CoCN had good reusability. Additionally, three degradation products of MC-LR were identified by LC–MS/MS analysis, and a possible mechanism for the inactivation of M. aeruginosa and the degradation of MC-LR was proposed. In conclusion, this study pioneered the 2CoCN/PMS system for inhibiting M. aeruginosa and degrading microcystin, aiming to advance water purification and algae removal technology. Full article

The application of antibiotics has advanced modern medicine significantly. However, the abuse and discharge of antibiotics have led to substantial antibiotic residues in water, posing great harm to natural organisms and humans. To address the problem of antibiotic degradation, this study developed a novel catalytic membrane by depositing Co catalysts onto MXene nanosheets and fabricating the polyethersulfone composite (Co@MXene/PES) using vacuum-assisted self-assembly. The dual role of MXene as both a carrier for Co atoms and an enhancer of interlayer spacing led to improved flux and catalytic degradation capabilities of the membrane. Experimental results confirmed that the Co@MXene/PES membrane effectively degraded antibiotics through peroxymonosulfate activation, achieving up to 95.51% degradation at a cobalt concentration of 0.01 mg/mL. The membrane demonstrated excellent antibacterial properties, minimal flux loss after repeated use, and robust anti-fouling performance, making it a promising solution for efficient antibiotic removal and stable water treatment. Full article

Organic pollutants entering water bodies lead to severe water pollution, posing a threat to human health. The activation of persulfate advanced oxidation processes using carbon materials derived from MOFs as substrates can efficiently treat wastewater contaminated with organic pollutants. This research uses NH₂-MIL-101(Fe) as a substrate, doped with Fe²⁺ and Co²⁺, to prepare Fe/Co-CNs through a one-step carbonization method. The surface morphology, pore structure, and chemical composition of Fe/Co-CNs were investigated using characterization techniques such as XRD, SEM, TEM, XPS, FT-IR, BET, and Raman. A comparative study was conducted on the performance of catalysts with different Fe/Co ratios in activating PMS for the degradation of organic pollutants, as well as the effects of various influencing factors (the dosage of Fe/Co-CNs, the amount of peroxymonosulfate (PMS), the initial pH of the solution, the TC concentration, and inorganic anions) on the catalyst’s activation of persulfate for TC degradation. Through radical quenching experiments and post-degradation XPS analysis, the active radicals in the FeCo-CNs/PMS system were investigated to explain the possible mechanism of TC degradation in the Fe/Co-CNs/PMS system. The results indicate that Fe/Co-CNs-2 (with a Co²⁺ doping amount of 20%) achieves a degradation rate of 93.34% for TC (tetracycline hydrochloride) within 30 min when activating PMS, outperforming other Co²⁺ doping amounts. In addition, singlet oxygen (¹O₂) is the main reactive species in the reaction system. Full article