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This study presents a novel pre-magnetized Fe0/ethylenediaminetetraacetic acid/air (pre-Fe0/EDTA/air) Fenton-like system to remove sulfamethazine (SMT). SMT removal only reached 10.6% in pre-Fe0/air system (0.2 g L−1, SMT 3 mg L−1, pH 5) while reached 88.5% in pre-Fe0/EDTA/air system within 1 h (0.2 g L−1, SMT 3 mg L−1, EDTA 2 mM, pH 5). EDTA could combine with FeII or FeIII to keep iron soluble in the solution and the fast activation of molecular oxygen by Fe-EDTA complex could induce the fast and more production of H2O2. It was found that much more H2O2 (5.1 mg L−1) and OH radical (26.4 μM) were produced in the pre-Fe0/EDTA/air system than in the pre-Fe0/air system (0.06 mg L−1, 0.6 μM) within 1 h. The degradation rate of SMT (1 0 3) in pre-Fe0/EDTA/air system (38.4 min−1) was also 2.3 times as large as that in the Fe0/EDTA/air system (17.0 min−1), owing to the fast corrosion rate of pre-Fe0. 81.5 mgL−1 total Fe ions could be generated in pre-Fe0/EDTA/air while 53.6 mg L−1 in Fe0/EDTA/air. Fe0 dosage (0.05–0.8 g L−1) and EDTA dosage (0–8 mM) were optimized and the optimal dosage for Fe0 and EDTA was 0.2 g L−1 and 2 mM, respectively. The degradation rate of SMT in pre-Fe0/EDTA/air system were 1.6–2.9 times at different initial pH (3–6) and 2.3–3.1 times in the presence of inorganic ions (SO42−, Cl− and HCO3−) and natural organic matter (NOM) compared with Fe0/EDTA/air system. Decrease of Fe0 contact angle in the presence of magnetization and EDTA enhanced the corrosion rate of Fe0. Accordingly, pre-Fe0/EDTA/air system would be a cost-effective and promising eco-friendly alternative for removal of SMT.

Decomposition of the peroxydisulfate ion (S2O82−, PS) to sulfate radicals (SO4 −) is a key step in sulfate radical-based advanced oxidation processes (SR-AOPs). In this study, quantum chemical investigations and calculation of activation energy were performed to reveal the decomposition process of S2O82− at the atomic level. Furthermore, the impacts of several main co-existing components (CCs), including inorganic cations, inorganic anions and organic molecules in wastewater, on the activation energy were evaluated. The results revealed that 3 steps were involved in the S2O82− decomposition: 1) the distance between two subgroups of the ground state of S2O82− (PSS0) increases from ∼0.15 to ∼0.215 nm driven by exogenous energy; 2) a transition occurs for S2O82− from PSS0 to the lowest triplet state (PST1); and 3) two subgroups of PST1 separate from each other spontaneously. The energy needed in the first step was demonstrated to be the activation energy. Moreover, two possible routes by which CCs affect the transition from PSS0 to PST1 were proposed. After ascertaining which route would be taken by different types of CCs, various methods of calculation were used to determine their impacts on S2O82− decomposition, i.e. promotion effect for H+, NH4+, Ca2+, Cl− and Br−, and inhibition effect for Na+, K+, Mg2+, NO3−, CO32−, SO42−, and all studied organic molecules, including acetic acid, benzene, bromoethane, 1-propanol and 4-chlorotoluene. The present study provided novel insights into the decomposition of S2O82− to SO4 −, and emphasized the effects of main co-existing inorganic ions and organic molecules in wastewater on SR-AOPs.

It is a great challenge to realize the effective removal and transform of emerging pharmaceuticals from aquatic environment. In this study, MnO2 was used as a catalyst to achieve the degradation of tetracycline (TC) in situ on the surface of three-dimensional graphene (3DG). The removal of TC were also evaluated at different temperature, pH and inorganic ions. Due to the synergistic effect of 3DG and MnO2, TC could be efficiently removed by 3DG/MnO2 composites. The removal data were fitted well with rate-retarded model, indicating that the adsorption of reaction products on the surface of 3DG/MnO2 composites could lead to saturation of surface and less reactive sites. Moreover, the reaction of TC with 3DG/MnO2 was endothermic, and reaction rate decreased with the increase of pH, due to the changes of properties of 3DG/MnO2 and TC. Inorganic ions could compete with TC for vacancy or the reactive sites on 3DG/MnO2 surface to inhibit the removal of TC. This work develops a potentially effective carbon material for simultaneous enrichment and degradation of organic pollutants and provides a new sustainable approach for wastewater treatment.

Synthetic phenolic antioxidants (SPAs) are usually used during the processes of worldwide production, manufacturing and biological sciences and ubiquitously occur in many environmental media. However, studies on the removal efficiencies and mechanisms of SPAs are extremely limited. In this work, tert-butylhydroquinone (TBHQ) was selected as a representative of commonly used SPAs, and its transformation behaviors were first investigated in Fe(VI) treatment, with emphasis on the roles of inorganic ions on the removal efficiencies, transformation pathways and mineralization during reactions. The results showed that TBHQ removal improved with increasing Fe(VI) dosage and decreased pH at low initial TBHQ concentrations. Its reaction rate constants (kapp) were 182.7–6346.5 M−1 s−1 in the studied pH range. The addition of 5 mM NO2− and HSO3− strongly suppressed the reaction, which is in line with of the low mineralization degree data; although no obvious effect of NH4+ was obtained, a 0% mineralization degree of this group indicated NH4+ limited the mineralization of oxidative intermediates of TBHQ by changing the nature of the high-valent iron species reactions. Nine intermediates were identified, and four routes, including direct oxidation, oxygen transfer, oxidation rearrangement and coupling, were deduced and was supported by the theoretical calculation. An extra route, namely, radical addition initiated by the generated ·NO2 and ·SO3− radicals, was also observed with the addition of NO2− and HSO3− in the Fe(VI) system. These findings can provide the basis for the removal and transformation trends of SPAs from drinking and wastewater.

Powder catalysts are difficult to recycle, which may induce secondary pollution and may limit their practical application. Herein, we successfully synthesized floating porous g-C3N4 (FPCN) using a melamine sponge and urea via a facile one-pot method, which can solve the recycling problem of powder catalysts. The highest elimination efficiency of 5 mg/L tetracycline (TC) reached 70% by 2 g/L FPCN without any stirring under visible light after 4 h. However, the elimination efficiency of 5 mg/L TC by 2 g/L powder g-C3N4 was only 36.9% under the same conditions. The good photocatalytic performance of FPCN is attributed to its 3D interconnected network and enhanced light absorption. The effects of inorganic ions and organic matters on the photocatalytic performance of FPCN were studied. Finally, we proposed a possible mechanism and pathway for degradation of TC.

Carbonaceous materials have attracted considerable attention as promising catalysts of persulfate (PS) activation for antibiotic degradation. In this work, an environment-friendly and low-cost carbonaceous material (Cr2O3/BC) was prepared by pyrolyzing chrome shavings, and the catalytic ability of Cr2O3/BC for PS activation was evaluated using tetracycline (TC) as the model antibiotic. The Cr2O3/BC/PS system exhibited ultrafast TC removal efficiency (99.9% removal rate within 5 min), which was owing to persistent free radicals, defective sites, and dispersed Cr2O3 particles, which were beneficial for the generation of free radicals, such as OH·, SO4·-, ·O2– and 1O2. Coexisting substances, such as inorganic ions and humic acid, exerted little effect on TC removal. In addition, 99.9% of TC removal rates were achieved in TC contaminated tap water. Cr2O3/BC/PS system also exhibited the high removal rates towards ciprofloxacin (98% removal rate within 5 min) and sulfadiazine (99.8% removal rate within 5 min). Surprisingly, no chromium was detected after TC degradation, indicating that no secondary pollution was generated. This work provides a feasible strategy for the high-value use of chrome shavings and a practical method for antibiotic removal.

A novel combined chlorine dioxide (ClO2)-photocatalysis technique was developed by dosing chlorite (ClO2−) in a visible light photocatalytic system. Active ClO2 radicals were produced through the activation of ClO2− by photoinduced ·OH radicals. It is for this reason that the degradation rate of norfloxacin (NOR) in the combined ClO2-photocatalysis system was promoted to 0.2672 min−1, approximately 6.6 times faster than the single photocatalytic system. The durable active ClO2 guaranteed the stability of the combined ClO2-photocatalysis system when facing external interferences, such as pH change, inorganic ions, and natural organic matter (NOM). Quantitative structure–activity relationship (QSAR) prediction and toxicity verification identified effective elimination of biological toxicity of NOR with the assistance of ClO2. Moreover, the residual ClO2− can be retransformed into ClO2 based on the ClO2−/ClO2 dynamic interchange mechanism, facilitating ClO2− residue elimination. ClO2− also served as the sacrificial agent of ·OH for promoting electron-hole separation and protecting photocatalysts from photo-erosion, which was responsible for the outstanding stability in multiple cycle tests. Results showed the novel combined technique can respond well to natural sunlight. This work provides a strategy for designing advanced oxidation processes (AOPs) by integrating ClO2 oxidation and photocatalytic oxidation to achieve degradation and detoxification of antibiotic wastewater under natural sunlight.

Wastewater recycling is an effective way to reduce the fresh water supply and pollutant discharge for industry. Nevertheless, wastewater recycling will inevitably lead to the accumulation of inorganic ions and organic pollutants, which can deteriorate the activated sludge system. A printing and dyeing wastewater (PDWW) recycling system was established in this study to investigate the mechanism of biological treatment system deterioration due to organic and inorganic pollutant accumulation. It was found that organic matter accumulation especially intermediate products of added dyes and auxiliaries is crucial for the biological treatment unit deterioration during the beginning of closed-loop PDWW recycling (first 40 days). In addition, inorganic salt accumulation, such as Ca2+, Na+, K+, SO42− and Cl−, can make it even worse afterwards. The results indicated that phenylalanine metabolism, synthesis and degradation of ketone bodies, butanoate metabolism and pyruvate metabolism were the four most significantly influenced metabolic pathways in the PDWW recycling system attributed to the organic matter accumulation. In addition, accumulated inorganic salts could inhibit glycan biosynthesis and metabolism, xenobiotic biodegradation and metabolism and lipid metabolic pathways in the PDWW recycling system, which ultimately deteriorated the biological treatment system.

Bromate, a potential carcinogen, is a well known highly persistent and environmentally recalcitrant contaminant. UV-254/sulfite-based advanced reductive pathways (ARPs) were proposed to eliminate bromate successfully from water. Experiments with N2, N2O, 2-chlorophenol, inorganic ions, and different pH (highly acidic to highly basic) proved that UV-254/sulfite successfully provides aqueous electron that effectively participate in bromate removal from water. Significant removal, 86%, of initially 39.0 µM bromate was achieved by UV-254/sulfite under conditions that dominate aqueous electron based pathways. The high second-order rate constant of 5.3 × 109 M−1 s−1 determined proved high reactivity of aqueous electron with bromate. The kinetic and removal efficiency of bromate showed linear relationship with the rate of aqueous electron formation. An increase in kinetic and removal efficiency of bromate was observed with increasing initial sulfite concentration and decreasing bromate concentration. The impacts of different initial concentrations of the typical ions commonly found in water were studied in detail to extend the UV-254/sulfite-based process for potential practical applications. The lower molar absorptivity of bromate at 254 nm determined proved insignificant removal of bromate under direct photolysis. The impacts of initial sulfite concentration on removal of bromate in UV-254/sulfite-based process also minimized role of direct photolysis. The cost evaluation and rapid decomposition of bromate into bromide proved UV-254/sulfite-based ARPs to be economical and highly rewarding in efficient decomposition of bromate and other inorganic oxyhalides.

The investigations on the influence of humic acids (HAs) being representatives of Natural Organic Matter (NOM) and inorganic salts (NaHCO3, Na2HPO4 and Na2SO4) representing inorganic ions in natural waters, on fouling and stability of a polyethersulfone ultrafiltration membrane in a photocatalytic membrane reactor (PMR) are reported. The influence of inorganic ions on the permeate flux was dependent on their concentration and was more significant at higher salts content. The HCO3− ions contributed to the permeate flux decline to the highest extent, which was attributed to both a higher feed pH and a formation of a dense fouling layer. In the presence of SO42− the permeate flux was higher than in case of other ions which was explained in terms of lower thickness of the fouling cake caused by repulsion of TiO2 particles by the membrane under such conditions. The most severe decrease of the permeate flux observed in the presence of a mixture of HAs and inorganic salts was attributed to the formation of a thick fouling cake caused by bridging effect between HAs molecules and TiO2 particles under high ionic strength conditions. The inorganic salts contributed also to a decrease of HAs decomposition rate due to the hole and hydroxyl radicals scavenging effect of the ions. It was found that the conditions prevailing in the PMR contributed to the loss of the membrane separation properties towards dextrans due to the abrasive action of TiO2 particles. However, the extent of the observed decrease in the dextrans rejection was dependent on the feed composition.

Removal of chlorendic acid, an emerging water pollutant and potential carcinogenic, was investigated by gamma radiation in the absence and presence of peroxymonosulfate (PMS, HSO 5 − ). The removal of chlorendic acid (1.40 μM initial concentration) by gamma radiation was promoted with PMS, i.e., 95% compared to 82% in the absence of PMS, at an absorbed dose of 1000 Gy. The removal of chlorendic acid by gamma-ray/PMS process was due to OH and SO 4 − . Second-order rate constants of 5.90 × 10 9 , 1.75 × 10 9 , and 2.05 × 10 9 M −1 s −1 for chlorendic acid with e aq − , OH, and SO 4 − , respectively, were determined. The removal efficiency of chlorendic acid was promoted with increasing initial PMS concentration and decreasing initial target contaminant concentration. The removal of chlorendic acid by gamma-ray/PMS was inhibited in the presence of CO 3 2− , NO 2 − , p -CBA, m -TA, and alcohols. The presence of Fe 2+ , Cu + , and Fe 3+ with gamma-ray/PMS promoted removal efficiency of chlorendic acid from 78% to 99, 94, and 89%, respectively, at 592 Gy. The degradation of chlorendic acid by OH and SO 4 − was found to be initiated at the carboxylate group as could be revealed from nature of the transformation by-products. Nevertheless, this study concluded that gamma-ray/PMS is of practical importance in treatment of natural water containing chlorendic acid, as potential detoxification of chlorendic acid solution can be revealed from 83% loss of chloride ion at 3000 Gy. In addition, gamma-ray/PMS process achieved efficient removal of chlorendic acid even in the presence of commonly found inorganic ions in natural water.

Cost and performance efficient integrations of biological treatments with membrane processes are very worthy for water and resource recovery among of which osmotic anaerobic digestion suffers from exactly elucidating desirable techno-economic features of key operating factors. Cost-performance effective draw solutions (DSs) were ascertained for forward osmosis (FO) and its anaerobic bioreactor (AnBR) configurations, anaerobic osmotic membrane bioreactor (AnOMBR) and [FO/AnBR]. In case study comprising literature data pre-screening, selected DS experiments, and preferability analysis, dual modeling was executed for prioritizing DSs eligible to osmotic AnBRs by analytic hierarchy process (AHP). Through AHP screening of 29 DSs' FO data, NaNO3, NaCl, MgCl2, CaCl2, NH4H2PO4, HCOONa and CH3COONa were established between the best 10% worth researching for osmotic AnBRs. Experiments showed that isothermally varied temperatures hardly affected DS performances in submerged, but DS concentration raises led to those distinguished by reverse solute fluxes. Reverse solute flux selectivity was differed significantly by DS kinds and FO configurations because of varying interactions among predominant inorganic ion and soluble organics. Submerged FO fed by distilled water provided better performance than sidestream but not by wastewater. Anaerobic bioactivities showed longer acclimation times increased by alkalinity unlike seawater (SW) and better CH4 productivity of organics enhanced by DS concentration. Upon AHP analyses, CaCl2, MgCl2, both organics, and SW were more techno-economically favorable DS kinds. Irrespective of technological alternatives, CaCl2 and MgCl2 were found as top two except just SW was the best for AnOMBR by low-cost supply. It was finally proved that eligible DSs should be designated technology-dependently due to their distinctive performances and replenishment costs, and topmost priority to SW should be attributed in sustainable wastewater reclamations by AnOMBR in coastal countries.

Developing transition metal/nitrogen/carbon catalysts with maximizing the dispersion degree of the active sites presented an enticing prospect for environmental remediation. In this study, we have designed the novel three-dimensional porous carbon aerogel (CA) supported iron and nitrogen co-doped carbon (FeNC-CA) catalysts via facile pyrolysis of iron phthalocyanine (FePc) confined within CA precursor by the double fixed-protection strategy. The synergistic enhancement effect between CA and well-dispersed FeNC in FeNC-CA-500 (pyrolysis at 500 °C) was conducive to the rapid removal of 4-chlorophenol (4-CP) via peroxymonosulfate activation, which achieved almost 100% removal efficiency and 66.8% mineralization rate in 18 min with ultralow catalyst dosage and iron ions leaching of 0.019 ppm, and the reaction rate constant was about 11.3, 9.3 and 6.6 times higher than that of the homologous FeNC-500, CA-500 and Fe-CA-500 catalysts, respectively. Based on the electrons spin resonance (ESR) and radical quenching experiments, the FeNC-CA-500/PMS system with selective removal ability of several aromatic compounds containing different substituents and strong flexibility in actual wastewater involving competing inorganic ions and natural organic matter confirmed that the nonradical pathway was dominant in 4-CP removal while the generated reactive oxygen species (ROS) played a relatively small roles. Further investigations by X-ray photoelectrons spectroscopy (XPS) and control experiments verified that the evenly dispersed iron active sites were essential in accelerating the catalytic reaction, and the carbon matrix and surface nitrogen sites were mainly responsible for the removal rate of 4-CP via nonradical pathway. These findings provided new insights for synthesis of a more promising iron-based catalyst for practical wastewater treatment.

WOS: 000384777200060, The development of antibiotic resistance in bacteria, which arises from the presence of antibiotics in wastewater systems, is one of the most important problems of human beings nowadays. In this study, the removal of norfloxacin (NFXN), a widely used antibiotic, from water was investigated by electro-Fenton method. This method combines the benefits of electrochemistry and Fenton's reaction for the electrocatalytic production of hydroxyl radical to oxidize bioresistant organic pollutants. Oxidation kinetics of NFXN has been evaluated and second order oxidation rate constant was determined as (1.34 +/- 0.03) x 10(9) M-1 s(-1). Mineralization behavior of NFXN has been examined by following total organic carbon changes during the electrolysis. A very high mineralization ratio (97.7%) for NFXN has been reached after 5 h electrolysis. This result suggests that electro-Fenton method is a very effective way to completely remove NFXN from water sources. A detailed investigation was conducted to determine the oxidation intermediates of NFXN using HPLC, LC-MS, GC-MS and IC analysis. These analyses revealed the formation of ten different aromatic oxidation intermediates, eleven short-chain substances and three inorganic ions during the mineralization of NFXN, Anadolu University Research Projects Commission [1401F009], Financial support of Anadolu University Research Projects Commission (Project No: 1401F009) is gratefully acknowledged. Authors also thank to Assoc. Prof. Dr. Erol SENER and Anadolu University Plant, Drug and Scientific Researches Center (BIBAM) for the LC-MS analysis.

The high-efficient extraction of vanadium using primary amine and its application in the utilization of the chromium-bearing vanadium slag (V–Cr slag) were studied in this work. The extraction mechanism and the possible difficulties in the application were both considered. From the results, the extraction percentage of vanadium using free primary amine with the hydrogen bond association mechanism is higher than that in the acidic environment by primary amine salts. The inorganic ions and other impurities existing in the system were all considered to research for the continuous operation of the extraction. Furthermore, the viscosities of the fresh organic phase and the recycled organic phase were determined using the extractant not only N1923 but also LK-N21, where the viscosity of the latter system increased slightly during the recycled process of the extractant. Based on the above results, the pilot and the commercial experiment were carried out. In the large-scale experiment, the vanadium was extracted and the product of 99.5 wt.% vanadium pentoxide was obtained, and the mass loss of the extractant was only 0.1%.

A comparative analysis of photocatalytic efficiency has been carried out with both TiO 2 P25 and a home-made catalyst at a solar radiation pilot plant constituted by Compound Parabolic Collector (CPC) systems. The effect of the chemical nature of three different substrates (phenol, dichloroacetic acid and pyrimethanil) and the impact of inorganic ions in natural waters, on their final photo-efficiencies was also analyzed. Subsequently, this solar photocatalytic process was applied to the photodegradation of a mixture of emerging contaminants considering the separation and recovery of catalysts by sedimentation. Although TiO 2 P25 showed better results during phenol and dichloroacetic acid photodegradation, both photocatalysts presented similar photo-efficiencies in pyrimethanil mineralization and, specially, in the treatment of emerging pollutants. The presence of high concentrations of inorganic ions in natural waters constitutes a limiting factor for solar photocatalytic activity, but this process successfully photodegraded the mixture of micropollutants (carbamazepine, ibuprofen, sulfamethoxazole, ofloxacin, flumequine) in natural water matrix using both TiO 2 catalysts, at very short irradiation times ( t 30w

Recycling of valuable secondary source of materials from spent batteries brings great opportunity for recyclers at end-of-life but a challenging issue. Peroxymonosulfate (PMS)-based advanced oxidation has been considered an efficient approach to eliminate refractory antibiotic in wastewater. In this study, a cathode material (CM) recovered from spent lithium-ion batteries (LIBs) was explored to serve as a direct catalyst to activate peroxymonosulfate for the first time. The CM catalyst included 94% LiCoO2 and 6% other substances (e.g. Co3O4) via a facile calcination process. The reactions between PMS and CM for levofloxacin hydrochloride (LFX) decomposition were investigated. Removal efficiency of LFX displayed close correlations with system parameters including CM catalyst dosage, PMS dosage, LFX concentration, pH value and inorganic ions. An optimal removal of 94% was obtained at CM-850 = 0.4 g/L and PMS = 0.5 mM within 60 min, and the first order reaction kinetic rate constant was 0.07597 min−1. Moreover, 32% total organic carbon had been removed after the reaction. In CM catalyst, the varied valence of Co2+/Co3+ underpinned PMS activation, and the SO4 − and non-radical 1O2 were of critical significance in LFX degradation. Adjacent methyl in tertiary amine of LFX molecule was the initial cleavage site. Furthermore, the CM catalysts in PMS activation exhibited prominent stability, the degradation efficiency was 80% after four catalytic cycles. Such strategy advances the development of direct recycling of spent batteries for advanced oxidation based on peroxymonosulfate.

© 2020 Elsevier B.V. Recovering lithium (Li) from natural sources such as seawater is a sustainable alternative to meet its high demands. Li recovery from seawater must be enhanced to attain economic efficiency. In this work, the potential of enhancing Li recovery from seawater by acid treated manganese oxide ion sieve (HMO) is evaluated by increasing Li concentration in seawater using direct contact membrane distillation (DCMD) and reducing competitive ions. DCMD achieved enhanced water recovery upon pre-treatment with oxalic acid (88–91%) compared to caustic soda ash (65–68%) and without pre-treatment (47–51%). Caustic soda ash required Na addition in alkaline condition for Ca removal, while, oxalic acid removed Ca in acidic condition without any inorganic ion addition. The low ion concentration in acidic condition upon oxalic acid pre-treatment enabled DCMD to concentrate seawater to high levels, increasing Li concentration by 7 times. In Li solution, HMO achieved a maximum adsorptive capacity (Langmuir Qmax) of 17.8 mg/g in alkaline condition. Multiple cycles of desorption and regeneration of HMO showed only 7–11% decline of Li uptake and minimal Mn dissolution, which, established HMO's reuse capacity. Selective Li mechanism is attributed to H/Li exchange as well as high negative surface charge of HMO. In seawater, Li uptake by HMO reduced by 44–46% due to Mg. Seawater with minimal Mg was favourable for enhancing Li uptake by HMO. Seawater treatment in stages – divalent pretreament and concentrating seawater, followed by HMO, provided a favourable scenario for attaining high quality water, selective Li recovery, and other resources – Ca and Mg.

In this study, a novel Fe2CoTi3O10-MXene (FCT-M) composite was synthesized and employed as a heterogeneous catalyst for the oxidative degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) based on peroxymonosulfate (PMS) activation. The effects of catalyst dosage, PMS dosage, pH of the initial solution, 2,4-D concentration, and the co-existing inorganic ions (HCO3− and Cl−) and humic acid (HA) were systematically evaluated. The catalyst with the Fe2CoTi3O10 loading (FCT-M-2) of 6.72% demonstrated superior catalytic performance. The results showed that around 98% of 2,4-D degraded in 15 min on using 0.2 g/L FCT-M-2 composite, 0.2 g/L PMS, and 20 mg/L 2,4-D with an initial pH of 7. The co-existence of sulfate radicals (SO4 −) and hydroxyl radicals ( OH) was confirmed based upon electron paramagnetic resonance spectroscopy and radical scavenger tests, while SO4 − was identified as the main reactive species in the FCT-M/PMS catalytic system. The superior performance of FCT-M based on PMS activation was achieved due to remarkable synergistic effect of the active sites of three transition metals (Fe, Co, and Ti) on the catalyst surface. According to the identified intermediates, a possible 2,4-D degradation pathway is proposed. Overall, this study widens the scope of employing heterogeneous catalysts towards PMS activation and sheds light on the degradation of organic pollutants in aqueous solutions.

This paper explores the applicability of electrochemical oxidation on two cytostatic drugs ifosfamide (IF) and cyclophosphamide (CF) by means of the BDD anode. The effect of the important electrochemical parameters: current density (4.8–16.0 mA cm −2 ), IF drug concentration (5–55 mg L −1 ), and initial pH (4.0–9.5) on the efficiency of the applied electrochemical process was evaluated. Both aforementioned drugs decomposed in accordance with a pseudo-first order kinetics. The obtained results indicate that the current density and initial drug concentration significantly influence the rate of electrochemical decomposition and the process efficiency for both drugs, while the pH effect is marginal. Additionally the effect of inorganic ions such as Cl − , PO 4 3− , NH 4 + , NO 3 − and HCO 3 − on the decomposition behavior of IF was also investigated. Among them Cl − and PO 4 3− ions significantly elevated the decomposition rate of the drug. To determine the degradation pathway of IF, the organic by-products, and the released inorganic ions, were identified and quantified over the entire time of electrolysis. Despite the fact that the values of coefficient rate k app of parent compounds are similar, the quality and the quantities of organic and inorganic intermediates determined during the electrolysis of IF and CF found during electrolysis was differed. The analysis of organic intermediates via LC–MS method resulted in the identification of a few products.

The work is devoted to preparation of hydrous TiO 2 adsorbent samples, their characterization, determination of adsorption isotherm types for Zn(II) and Pb(II), choosing the best adsorbent sample and measurement of its capability to purify flow of water from As(V), Bi(III), Cd(II), Co(II), Cr(VI), Pb(II), Th(IV), U(VI), V(V) and Zn(II). 10 adsorbent samples were synthesized by hydrolysis of TiOSO 4 and TiCl 4 in aqueous ammoniac, the highest surface area being 620 m 2 /g. Adsorption over TiO 2 of Zn(II) follows Sips isotherm whereas that of Pb(II) follows Freundlich isotherm, both isotherms converge into Freundlich isotherm at low concentrations. Using Pb(II) adsorption, the best TiO 2 adsorbent was chosen that has adsorption capacity 293 mg/g at concentration equal to maximum allowable concentration (MAC). This adsorbent purifies water from Co(II), Zn(II), Pb(II), U(VI), Th(IV) and Cd(II) during single pass through column to below MAC. Purification from Cr(VI), V(V), Bi(III) and As(V) required preliminary washing the adsorbent with HNO 3 solution.

Degradation of dimethyl sulfoxide (DMSO) was examined under varying parameters, including initial pH, initial Fe 2+ , initial H 2 O 2 , initial DMSO concentrations and current density. Efficiency in terms of degradation of DMSO and removal of total organic carbon (TOC) was also compared among Fenton, photo-Fenton and photoelectro-Fenton (PEF) processes. Effects of inorganic ions, namely Cl − , F − and PO 4 3 - , on DMSO degradation by the electro-Fenton (EF) process were also studied. The experimental results showed that the optimum pH was 2. The DMSO degradation in the double-cathode EF reactor reached 100% when current density and Fe 2+ concentration exceeded 1.5 A and 2.0 mM, respectively. During DMSO degradation, application of electricity by EF process obtained a higher DMSO degradation rate compared to UV-assisted Fenton process. The DMSO degradation rate after 20 min was 2.5 times higher in the PEF process than in the Fenton process. Between 20 min and 120 min, the DMSO degradation rates of the Fenton, photo-Fenton, single-cathode EF, double-cathode EF and PEF processes differed by 34%, 50%, 62%, 57% and 59%, respectively. The rate constant of double-cathode EF process was six times higher than the conventional Fenton process. The order of inhibiting effects of inorganic ions on DMSO degradation was PO 4 3 - > F − > Cl − .

The photocatalytic inactivation of Escherichia coli was studied with combustion synthesized TiO 2 photocatalysts in the presence of visible light. A series of 400 W lamps irradiating in the visible region of the solar spectrum was used. The effect of various parameters, such as catalyst loading, light intensity, presence of inorganic ions, addition of hydrogen peroxide and pH, on the photocatalytic inactivation of E. coli was investigated. Photolysis alone had a small effect on inactivation while the dark experiment resulted in no inactivation and Ag/TiO 2 showed the maximum inactivation. At a catalyst loading of 0.25 g/L, all the combustion synthesized catalysts showed better inactivation of E. coli compared to commercial Degussa P-25 (DP-25) TiO 2 catalyst. An improved inactivation was observed with increasing lamp intensity and addition of H 2 O 2 . A negative effect on inactivation was observed by addition of inorganic ions such as HCO 3 − , SO 4 2−, Cl − , NO 3 − , Na + , K + , and Ca 2+ . The photocatalytic inactivation of E. coli remained unaltered at different pH of the solution. The inactivation of E. coli was modeled with power law kinetics and was observed to follow first order kinetics.

Removal of pharmaceutical Carbamazepine (CBZ) compound from municipal wastewater has become an issue from the human health and environmental risks point of view, due to its latent recalcitrance and toxicity properties. This study investigated the photodegradation performance of a sequential batch annular slurry photoreactor (SB-ASP) system for the removal of CBZ compound from secondary municipal wastewater. Two different immobilised TiO(2) photocatalysts, namely anatase titanate nanofiber and mesoporous TiO(2) impregnated kaolinite catalyst were applied in the SB-ASP system. Various modes of sequential batch reactor (SBR) cycles, presence of effluent organic matter (EOM) and inorganic ions, mainly nitrate and phosphate that could affect the photodegradation performance of the SB-ASP system were evaluated during the removal of CBZ. High performance size exclusion chromatography revealed that the photocatalytic reaction will preferentially compete and attack on high molecular weight EOM prior to the photodegradation of CBZ. The presence of inorganic ions was found to affect the surface fouling of immobilised photocatalysts used to a different extent, without completely retarding their photoactivity. This study also highlighted that the operation of SB-ASP system was useful to enhance the photodegradation of CBZ compound in a semi-continuous operation without constant catalyst replacement. It is foreseeable that the integration of SB-ASP system with biological treatment systems could provide an advanced treatment option for the recycling and reuse of municipal wastewater. (C) 2011 Elsevier B.V. All rights reserved.

Ammonium citrate modified spent Lentinus edodes was investigated as a novel adsorbent for Pb(II) removal from aqueous solution. The results of Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analysis showed that modification by ammonium citrate obviously changed the property of spent L. edodes that enhanced the adsorption capacity. In batch studies, pH, initial Pb(II) concentration and adsorbent dose were found to significantly affect Pb(II) removal by a two-level Plackett–Burman design. The effects of foreign substances (ion strength, inorganic ions (anions, cations) and surfactants) on Pb(II) removal were studied. The adsorption process was well described by the pseudo-second-order model. The adsorption equilibrium data followed the Langmuir model and gave the maximum adsorption capacity of 59.17 mg/g at 35 °C. The adsorption mechanism was found to be dominated by ion exchange and electrostatic attraction on exterior, accompanying with the intraparticle diffusion transporting adsorbed Pb(II) from exterior to interior. The adsorbent could be regenerated by 0.1 M HNO 3 , which led only a tiny decrease in adsorption capacity after three adsorption–desorption cycles.

NiFe2O4 powders as microwave catalyst were prepared by chemical precipitation method, and characterized by XRD technologies. Their catalytic activities towards the degradation of brilliant green (BG) solutions were investigated under microwave irradiation (MW). The effects of pH, addition amount of catalysts on the degradation efficiency of BG were studied. Moreover, the degradation mechanism of BG was also analyzed. And the degradation process was investigated by UV–vis, FT-IR, TOC, HPLC and Ion chromatogram techniques. The experimental results indicated that the degradation percentage of BG could reach up to 97%, corresponding to 91% of TOC removal, and BG was degraded into inorganic ions such as NO2−, NO3− under microwave irradiation time 2.0 min. It indicates that NiFe2O4 could act as an efficient catalyst in the microwave degradation process, and there exist synergistic effects of MW and NiFe2O4 on the degradation of BG. With the advantages of low cost and rapid processing, this novel MW/NiFe2O4 composite could gain a promising application in treatment of various dyestuff wastewaters on a large scale.

As fresh water consumption in pulp and paper industry processes is reduced, dissolved and colloidal substances (DCS) gradually accumulate, which has a serious adverse impact on the production and quality of the paper product. Using laboratory simulations of the recycling filtration process of papermaking, we have studied changes in different water quality parameters with the increasing amount of water recycling to describe the accumulation of DCS. The accumulation factors (AFs) and release factors (RFs) of the different water quality parameters are also analyzed. The results indicate that the accumulation of DCS, the ultraviolet absorbance factor (UV 280 ) and the concentration of the main inorganic ions increase in line with the increasing number of times the water is recycled. Comparing the AFs of the different water quality parameters, colloidal substances and dissolved lignin are the contaminants that accumulate most in the recycling water. The AF of the Al 3+ in inorganic ions is the largest, at 10–20 times that of other ions. According to the RFs, the release rate of the colloidal substances and the dissolved lignin decreases with the increasing number of times the water is recycled. Dissolved and colloidal lignins were more affected by the contamination load increasing in the water than the other pollutants were. The release rates of calcium and magnesium were higher than the other inorganic pollutants analyzed. The major influence of the inorganic pollutant load of the water on the release rate comes from aluminum.