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Fluoride contamination in groundwater is a worldwide problem that is related to human health. Zirconium-based adsorbents possess satisfactory selective defluoridation capacities. However, narrow efficiency pH range, easy aggregation and difficult separation are the main obstructions in practical application. In this study, the branched polyethyleneimine (bPEI) modified hydrous zirconium oxide (HZO)/polyacrylonitrile (PAN) nanofibers (NFs) are synthesized by immobilizing bPEI-HZO into PAN nanofibers via electrospinning. The resultant bPEI-HZO/PAN NFs exhibit a wide working pH range and an excellent adsorption capacity toward fluoride (67.51 mg·g−1) even at neutral condition, indicating non-negligible superiority in the practical application of groundwater defluoridation. This enhanced adsorption performance along with extended wider working pH range are ascribed to the optimization of the adsorbents from both composition and structure. Compositionally, the modification of bPEI improves the surface property of HZO, and thus increases fluoride capacity in alkaline groundwater. Structurally, electrospinning conquers the drawbacks of nano-adsorbents for both easy aggregation and difficult separation. In addition, the effect of co-existing ions was further investigated and the X-ray photoelectron spectroscopy (XPS) as well as fourier transform infrared spectrum (FTIR) measurements were used to clarify the fluoride adsorption mechanism. Furthermore, the dynamic adsorption and regeneration performance were accomplished through the fixed-bed column experiment. All the results indicated that bPEI-HZO/PAN NFs are promising materials for defluoridation from groundwater.

The rational design of active and sustainable heterogeneous catalysts towards advanced oxidation process (AOPs) is of great significance for water remediation. Here, we synthesized Fe0/graphitized carbon composite catalysts for efficient removal of bisphenol A (BPA) by activating peroxymonosulfate (PMS). The Fe0/graphitized carbon composites were obtained by the pyrolysis of iron-tannic modified cotton, where tannic acid (TA) is an eco-friendly and low-cost polyphenol that can strongly form complexes with iron ions. The introduction of iron could significantly regulate the graphitization of carbon by changing the pyrolysis temperature. The combination of Fe0 and graphitized carbon can endow Fe-TCs with an enhanced adsorption ability due to strong complexation between Fe0 and BPA. The pyrolysis of iron-tannic modified cotton may serve as a novel strategy to design an efficient low-toxic metal-carbon catalyst for sulfate radical based processes in water remediation.

Fractionation of dyes and salts is a great challenge in high salinity wastewater from the textile industry. In this work, a high performance loose nanofiltration membrane (LNM) was fabricated to fractionate the dyes and salts in the solution via green rapid coating (GRC) process on polyethersulfone (PES) substrate. The organic solvent-free GRC process was achieved within 10 min based on the crosslinking between polyethylenimine (PEI) and tannic acid (TA). The resultant LNM performance was optimized by altering the coating parameters including the TA concentration and the coating time. The microstructure, surface properties and dye/salt separation performance of the LNM were demonstrated by characterizations and filtration experiments, respectively. With the co-existence of dye and salt, the optimized LNM exhibited desirable permeability (40.6 LMH·bar−1) and dye rejection (99.8% for 0.1 g/L Congo Red) as well as low salt rejection (6.1% for NaCl and 2.2% for Na2SO4). Furthermore, it was observed that even under 60 g/L of salt content, the satisfying rejection of CR (99.3% in Na2SO4 and 97.6% in NaCl) and high permeation of salts (98.9% for Na2SO4 and 97.9% for NaCl) can still be maintained. Moreover, the LNM showed incredible stability during the filtration process (10 h) towards dye/salt aqueous mixture. The PEI-TA/PES LNM exhibited promising application potential in dye/salt separation.

Protecting the staff on site from exposure risk to toxic industrial chemicals (TICs) in an efficient way is of great significance. However, simultaneous removal of multicomponent TICs with different physical and chemical properties is a challenge for porous carbon materials. In this work, Cu-carbon beads with tailored porous structure and chemical property were synthesized via phase inversion-carbonization (PIC) route. The in-situ introduction of copper species was accomplished via coupling solidification-reduction of copper species and PIC process. The obtained Cu-carbon beads possessed uniform spherical shape (Φ1.3 mm) with good mechanical strength, developed porous structure and abundant chemical groups. Three kinds of TICs with different chemical properties, i.e. benzene (nonpolar), ethanol (polar) and H2S (inorganic), were selected as probes to evaluate the simultaneous elimination performance of Cu-carbon beads. The optimized Cu-beads-3 exhibited excellent performance for multicomponent TICs with capacities of 491.9 mg benzene/g, 192.1 mg ethanol/g and 76.2 mg H2S/g, representing 74.0, 60.3 and 99.2% capacities compared with monocomponent TICs. The enhanced adsorption of H2S were ascribed to chemisorption of copper species and basic groups on Cu-carbon beads. These results indicated that Cu-carbon beads would be a promising candidate for the simultaneous elimination of TICs with different chemical properties.

The solidification/stabilization of municipal solid waste incineration (MSWI) fly ash is required before it enters a landfill, and water is needed in this process. At the same time, a large quantity of Ca(OH)2 is consumed during copper smelting wastewater treatment. The purpose of this study was to utilize both MSWI fly ash and copper smelting wastewater in a co-processing process. The elements Cr, Cu, Pb, and As were selected to study the stability of the co-processing products. The effects of H2SO4 and As in copper smelting wastewater on the stability of the co-processing products were studied. A TCLP leaching procedure and a BCR sequential extraction procedure were conducted to evaluate the stability of the co-processing products. H2SO4 (0–50 g/L) in simulated copper smelting wastewater had no significant influence on the stability of Cr and Cu; however, it enhanced the stability of Pb and As in the co-processing products. The stability of Cu and Pb increased with the content of As (0–5000 mg/L) in simulated copper smelting wastewater, while the stability of Cr and As decreased. When the co-processing products came into contact with the landfill leachate, the leaching of Cu was promoted. The co-processing products helped to reduce the concentration of Pb and As in landfill leachate. The results indicated that a chelating agent is needed to enhance the stabilization of Cu.

Due to highly recalcitrant and toxicological nature of halogenated organic compounds, conventional anaerobic dehalogenation is often limited by low removal rate and poor process stability. Besides, the reduction intermediates or products formed during dehalogenation process, which are still toxic, required further energy-intensive aerobic post-treatment. In this study, an up-flow electricity-stimulated anaerobic system (ESAS) was developed by installing cathode underneath and anode above to realize simultaneous anaerobic debromination and mineralization of 4-bromophenol (4-BP). When cathode potential was −600 mV, high TOC removal efficiency (98.78 ± 0.96%), complete removal of 4-BP and phenol could be achieved at 4-BP loading rate of 0.58 mol m−3 d−1, suggesting debrominated product of 4-BP from cathode (i.e., phenol) would be utilized as the fuel by the bioanode of ESAS. Under high 4-BP loading rate (2.32 mol m−3 d−1) and low electron donor dosage (4.88 mM), 4-BP could be completely removed at acetate usage ratio as low as 4.21 ± 1.42 mol acetate mol−1 4-BP removal in ESAS, whereas only 13.45 ± 1.38% of 4-BP could be removed at acetate usage ratio as high as 31.28 ± 3.38 mol acetate mol−1 4-BP removal in control reactor. Besides, electrical stimulation distinctly facilitated the growth of various autotrophic dehalogenation species, phenol degradation related species, fermentative species, homoacetogens and electrochemically active species in ESAS. Moreover, based on the identified intermediates and the bacterial taxonomic analysis, possible metabolism mechanism involved in enhanced anaerobic debromination and mineralization of 4-BP in ESAS was proposed.

Water flooding in the microporous cathode is poisonous but inevitable for oxygen reduction reaction (ORR) in electro-Fenton (EF) processes. To meet this challenge, a facile modification was reported to stabilize performance of cathode through the infiltration process, which selecting superior CB-PTFE electrode as backbone and dimethyl silicon oil (DMS) as maturation layer. Characterized by FE-SEM, EDS, BET, XRD, the matured cathode was proved to be wrapped uniformly by DMS. Electrochemical performances of cathodes were evaluated by CA, CV, EIS and CP measurements in oxygen “starvation” condition. These results proved that the maturation layer improved the electrocatalysis on 2 e − ORR, the service lifetime from 1.68 h to 18.34 h, the working range of current density from 70 to 110 A m−2 and reduced the oxygen diffusion resistance from 74.23 to 8.07 Ω. Besides, H2O2 generation and oxygen utilization of 2%DMS cathode respectively reached 126.7 mg L−1 and 83.49% in 60 min, which were rarely influenced by pH and aeration rate even after water flooding process. 2%DMS layer served as the accelerated oxygen transport channel can explain the enhanced oxygen transport. The simulated contaminated solution containing a fungicide-flutriafol (FTF) was obtained 100% removal in about 40 min and 48.88% TOC removal in 2 h. The lifetime tests revealed much more stable decay of FTF under the broader operational condition.

This study introduces the application of the Fe(III)/flue gas desulfurization gypsum (FGDG) system to remove EDTA-chelated Pb(II). Systematic experiments were conducted to explore the possibility of removing EDTA-chelated Pb(II) and the crucial factors of the removal process, as well as to determine the underlying removal mechanism. The results showed that the removal reaction was a quick process, with the removal rate exceeding 90% after 1 min. The system removed 97.35% of EDTA-chelated Pb(II), reducing its concentration from 700 mg/L to 18.81 mg/L. EDTA-chelated Pb(II) can be most effectively removed at pH 2. This system had a high removal rate from 50 mg/L to 1000 mg/L of EDTA-chelated Pb(II), particularly at 700 mg/L when the removal rate reached 97.35%. When the molar ratio of Fe(III)/Pb(II) was greater or smaller than 1:1, an inhibitory effect on removal was observed. TOC and UV–Vis analyses indicated that ferric ions replaced lead ions, resulting in the conversion of the EDTA-chelated Pb(II) to EDTA-chelated Fe(III). Surface structure, crystalline phase and elemental distribution were analyzed to explore the transformation of substances. The results indicated that FGDG coprecipitated with free lead ions to form lead sulfate. Overall, the rapid and efficient removal performance with cost-effective characteristics makes the Fe(III)/FGDG system a potentially attractive method for the removal of EDTA-chelated Pb(II)in wastewater.

The degradation of organic contaminants under high salinity condition is still a challenge for environmental remediation due to the inhibiting effect resulted from the side reactions between radicals and anions. Here, we demonstrate the non-radical oxidation process via peroxymonosulfate (PMS) activation by metal-free carbon catalyst for efficiently decomposing bisphenol A (BPA) in saline water. The nitrogen-doped graphitic carbon (NGC700) exhibits excellent catalytic activity for depredating BPA at acid and neutral pH. Based on the scavenger experiments and electron paramagnetic resonance (EPR) analyses, the mechanism of catalytic oxidation was elucidated as the non-radical pathway, and singlet oxygen was identified as the primary reactive species. Experiments on the influence of anions (5–500 mM) further show that the inhibiting effect was overcame due to the non-radical process. Interestingly, Cl− markedly facilitated the catalytic performance by generating HOCl in the catalytic process. The results highlight leveraging the non-radical pathway dominated by singlet oxygen to conquer the inhibitory effect of anions in NGC700/PMS system, which represents a crucial step towards environmental remediation under high salinity condition.

Development of efficient catalysts for peroxymonosulfate (PMS) activation and further understanding its mechanism on organic pollutants degradation is of significant importance for advanced oxidation processes (AOPs). Herein, hollow (Co, Mn)3O4 catalysts were synthesized by calcination of Co, Mn containing metal-organic frameworks (MOFs) and further used to evaluate the effectiveness of organic pollutants (Bisphenol A (BPA), atrazine (ATZ), and diethyl phthalate (DEP)) degradation by PMS activation. The PMS utilization efficiency in (Co, Mn)3O4/PMS system (36.4%) was estimated to be 28.0% and 43.8% higher than that of Co3O4/PMS and Mn5O8/PMS system, respectively. Notably, the metal leaching in (Co, Mn)3O4/PMS system was significantly suppressed. The utilization efficiency also reveals an inverse proportionality relationship with BPA mineralization but decreases with increasing initial pH value. A synergy between oxides of Co and Mn was perceived to enhance PMS utilization efficiency and BPA degradation. The results indicate enhanced catalytic performance with (Co, Mn)3O4 compared to Co3O4 derived from Co-MOF and other reported catalysts, with 99% of BPA degradation within 4 min. The oxidation mechanism was then proposed based on the electron paramagnetic resonance (EPR) and XPS results. Our findings might have contributed to designing heterogeneous catalysts for efficient PMS utilization in AOPs.

Effective removal of Sb(III) and Sb(V) has long been an urgent task for protecting human health and environment. In this study, novel magnetic mesoporous FeMn binary oxides (MMFMs) were fabricated via calcinating the Mn encapsulated carboxymethyl cellulose-Fe(III) hydrogel, and the structure of MMFMs were closely related to the Fe:Mn ratio. Owing to the mesoporous structure together with synergistic effect of FeMn binary component, the MMFMs exhibited excellent mass transfer and adsorption ability to Sb(III) and Sb(V). MMFM

Well dispersed nanocatalysts on porous substrate with macroscopic morphology are highly desired for the application of heterogeneous catalysis. Traditional fabrication process suffers from multiple steps for controlling the structure on nanocatalysts and matrix or both. Herein, we report a facile strategy for the synthesis of millimeter-sized hierarchical porous carbon beads (HPCBs) which containing well dispersed hollow-nano carbon boxes for peroxymonosulfate catalysis. Specially, the precursors of HPCBs were prepared by phase inversion method, which involving introduction of zeolitic imidazolate framework (ZIF-8) nanocubes into polyacrylonitrile (PAN) solutions followed by solidification of the mixture. After pyrolysis, nitrogen doped and hierarchical porous HPCBs with diameter of about 1.2 mm were obtained. The merits of our synthesis strategy lie in that synchronizes the hollow microstructure evolution with the shaping of ZIF-8 nanocubes into millimeter scale beads. Attribute to its special structure feature and the appropriate chemical composition, the resultant millimeter-sized HPCBs exhibit enhanced catalytic performance by activation of peroxymonosulfate (PMS) for tetracycline degradation. The degradation efficiency of TC is up to 85.1% within 120 min, which is 18% higher than that of ZIF8-Solid/PAN carbon bead (SPCBs). In addition, the possible decomposition pathways, main reactive oxygen species, and reasonable enhanced mechanism for the HPCBs/PMS system are systematically investigated by quenching experiments, electron paramagnetic resonance (EPR) and liquid chromatography-mass spectrometry (LC-MS). This work addresses the issue of easy aggregation and recycling of carbon materials in industrial productions and extends the prospects of carbon materials in engineering applications.

Acceleration of Fe3+/Fe2+ cycle and simultaneous reduction of particle size with enhanced stability is extremely important for iron-based heterogeneous Fenton catalysts. In this work, Fe0-Fe2O3 composite nanoparticles embedded ordered mesoporous carbon hybrid materials (Fe0-Fe2O3/OMC) were rationally designed as efficient heterogeneous Fenton catalysts. Because of the confinement and reduction of OMC, highly dispersed Fe0-Fe2O3 active species with diameter of ∼8 nm were generated by an optimized carbothermic reduction process. In addition, Fe0-Fe2O3/OMC possesses ordered mesoporous structure with uniform mesopore, high surface area and pore volume. For comparison, two other catalysts, including solely Fe0 nanoparticles supported on ordered mesoporous carbon (Fe0/OMC) and solely Fe2O3 nanoparticles supported on ordered mesoporous carbon (Fe2O3/OMC) were also prepared. The Fenton catalytic performance of synthesized catalysts was evaluated by using H2O2 as oxidizing agent to degrade Acid Orange II (AOII). The results show that almost 98.1% of 100 mg L−1 AOII was removed by Fe0-Fe2O3/OMC in condition of neutral pH and nearly room temperature, which is much higher than those of compared catalysts. The enhanced catalytic activity of Fe0-Fe2O3/OMC for AOII removal is due to the efficient electron transfer between the Fe0 and iron oxide and the accelerated Fe3+/Fe2+ cycle. The stability and reusability of the catalyst was also investigated, which showed a good performance even after five consecutive runs. The as-synthesized catalyst is proved to be an attractive candidate in heterogeneous Fenton chemistry and practical application.

To enhance the antibacterial property and chlorine resistance, organic nanospheres, polypyrrole (PPy), were innovatively incorporated into the polyamide (PA) layer for fabricating thin film nanocomposite (TFN) membranes. Owing to the improved hydrophilicity and compatibility between the PPy nanospheres and the PA layer, the obtained TFN membranes exhibited significant water flux enhancement without sacrificing salt rejection. Under the optimal PPy dosage (0.006 wt%), TFN membranes showed a high water flux of 42.19 L/(m2 h), which was 118.0% higher than that of the pristine membrane. Remarkably, the chlorine resistance of TFN membranes was strengthened after the incorporation of PPy nanospheres, as evidenced by the less decreased salt rejection, as compared with the TFC and commercial RO membrane. In addition, the positively charged PPy nanospheres immobilized in the PA layer endow the TFN membranes with improved biocidal activity, which was much higher than that of the pristine membrane. This study shows that incorporating organic nanospheres into the PA layer is an effective strategy to develop new TFN membranes with enhanced performance for advanced water purification.

Enhanced biodegradation of high-strength pyridine was successfully achieved in the inner loop anoxic/oxic-dynamic membrane bioreactor (A/O-DMBR) in this study. Due to the key role of dynamic membrane in biomass retention, NH4+ released from pyridine biodegradation could be effectively nitrified to NO3− in oxic zone, which was then recirculated into the anoxic zone to serve as electron acceptor for pyridine biodegradation. Acetate dosage adversely affected pyridine biodegradation, due to the competitive effect of acetate towards NO3−. Increase of recirculation ratio positively affected pyridine biodegradation, due to high availability of NO3− at high recirculation ratio. At influent pyridine concentration as high as 1500 mg L−1, effluent turbidity was well maintained below 10 NTU, indicating excellent biomass retention performance of the dynamic membrane. Microbial community analysis confirmed the enrichment of specific functional species in both anoxic and oxic zones. Stable performance during 260 days’ operation confirmed the potential of A/O-DMBR for full-scale application.

In this study, bioaugmentation potential of 1H-1,2,4-triazole (TZ) degrading strain namely Shinella sp. NJUST26 and tricyclazole (TC) degrading strain namely Sphingomonas sp. NJUST37 was evaluated in a bench-scale activated sludge tank. The performance of the bioreactor demonstrated the feasibility of bioaugmentation by NJUST26 and NJUST37 in terms of almost complete TC and TZ removal, significant COD and TOC removal, as well as toxicity reduction. The effect of influent pH, hydraulic retention time (HRT) and triazole fungicide concentration was investigated in order to reach an optimal treatment performance. The bioaugmented process after the inoculation of NJUST26 and NJUST37 could maintain stable performance in terms of TZ, TC, COD and TOC removal from the wastewater. High-throughput sequencing analysis suggested that higher diversity and significant shifts in bacterial community structure were achieved after the inoculation of NJUST26 and NJUST37. However, both NJUST26 and NJUST37 lost their dominance during long-term operation, despite of the key role of the inoculation of NJUST26 and NJUST37 in the formation of effective microbial community.

A highly ordered three-dimensional macro-porous PbO2 (3D porous PbO2) electrode has been prepared for electrochemical oxidation of nitrogen-heterocyclic compounds. The 3D porous PbO2 electrode was fabricated by templated electrochemical deposition method with TiO2 nanotube arrays as substrate and SnO2-Sb as intermediate layer. The morphology and composition characterization of the 3D porous PbO2 electrode was performed by field emission scanning electron microscopy and X-ray diffraction, which revealed a uniform distribution of highly ordered macro-porous β-PbO2 structure. The Brunner−Emmet−Teller analysis suggested the electrode possessed large specific surface area of 37.39 m2·g−1. Electrochemical measurements indicated the electrode had a favourable oxygen evolution potential of 1.89 V and inner voltammetric charge of 14.48 mC·cm−2, which were higher than that of conventional PbO2 electrode. Furthermore, the electrochemical oxidation and TOC removal percentage of pyrrole, pyrazole and tetrazole obtained by 3D porous PbO2 electrode were 93.4%, 72.7%, 61.2% and 66.7%, 57.3%, 38.6% respectively, which were also superior to conventional PbO2 electrode. The intermediates were detected and analyzed by high-performance liquid chromatography, gas chromatography-mass spectrometer, and ion chromatography to propose a degradation pathway of pyrrole, pyrazole and tetrazole. Finally, quantum chemical calculation was introduced in this study by density function theory method, which is consistent with the experimental detection.

Porous matrix immobilization is considered as an effective approach to address the engineering challenges during practical application of nanoadsorbent. In this work, solid and hollow hydrous Zirconium (IV) oxide (ZrO2·nH2O, SHZO and HHZO) nanoparticles were enwrapped into millimeter-level beads by polyethersulfone through a mild liquid-liquid phase inversion technique. The beads possess asymmetric and hierarchical structure with an exterior porous surface dense layer and numerous inner interpenetrating finger-like channels, which promote the transportation of molecule and prevent the leaching of nanoadsorbents. As compared to SHZO beads, HHZO beads exhibited higher efficient adsorption capacity toward Pb (II) (104 mg·g−1), which could remain at 94% of HHZO nanoparticles. The effects of pH, the stability of adsorbents and coexisting ionic are further explored in detail. The Pb (II) removal mechanism is further studied by the EDS mapping, XPS, FTIR measurements, further indicating the surface hydroxyl groups played a key role in the adsorption process. Fixed-bed column sorption experiment and in situ regeneration were conducted so as to examine the practical application of the beads. Therefore, this kind of beads indicated the potential practical application in industrial wastewater treatment.

In order to develop an effective bioaugmentation strategy for the removal of highly toxic and recalcitrant tricyclazole from wastewater, a tricyclazole degrading strain was firstly successfully isolated and identified as Sphingomonas sp. NJUST37. In batch reactors, 100 mg L−1 tricyclazole could be completely removed within 102 h, which was accompanied by significant biomass increase, TOC and COD removal, as well as toxicity reduction. Chromatography analysis and density functional theory simulation indicated that monooxygenation occurred firstly, followed by triazole ring cleavage, decyanation reaction, hydration reaction, deamination, dihydroxylation and final mineralization reaction. Tricyclazole biodegradation condition by NJUST37 was optimized in terms of temperature, pH, tricyclazole concentration and additional carbon and nitrogen sources. After the inoculation of NJUST37 into a pilot-scale powdered activated carbon treatment tank treating real fungicide wastewater, tricyclazole removal efficiency increased to higher than 90%, demonstrating the great potential of NJUST37 for bioaugmentation particularly on tricyclazole biodegradation in practice.

MXene, as an emerging group of two-dimensional layered material, attracted more and more attention due to its extraordinary physical properties. In this study, a sandwich-like Co3O4/MXene (CMs) composite was prepared via a one-step heating method and used as a novel catalyst to activate peroxymonosulfate (PMS) for Bisphenol A (BPA) degradation. The sample (CM-20%) achieved an efficient catalytic activity with 95% removal of BPA at 20 mg/L within 7 min. Meanwhile, the parameters in the degradation process were optimized. In particular, CM-20% obtained excellent BPA removal efficiency in a wide pH range (4–10). Anions like NO3− and Cl− had a slight negative effect while HCO3− had a great negative effect on catalytic activity in CM-20%/PMS system. Notably, the catalyst exhibited a good performance after 5 consecutive runs and the leached cobalt ion was negligible. Electron paramagnetic resonance (EPR) analysis and quenching tests identified SO4 − and OH were the reactive species. The pathway of degradation was also detected by analyzing its intermediates using LC-MS. This work provides a new field of MXene composite material for PMS remediation of organic pollutant and widens the application of MXene in environmental remediation field.

Considering the highly toxic by-products generation and environmental friendliness, the adsorption process is a suitable solution as the end of pipe treatment for refractory organics in coking wastewater. Nitrogen-doped micro-mesoporous carbon prepared by carbonization and KOH activation of urea-formaldehyde resin (UFCA) realized effective adsorption of quinoline, phenol and pyridine in coking wastewater. Among them, UFCA-900 has large specific surface area (SBET=1469.94 m2·g-1) and excellent adsorption properties: the adsorption removal rate of quinoline reached 98.40% about 16 min, and the maximum adsorption capacity of quinoline was 721.90 mg·g-1 at 318 K, the adsorption capacity of phenol and pyridine at 298 K were 341.59 mg·g-1 and 225.08 mg·g-1, respectively. The adsorption kinetics of UFCA-900 obeyed the pseudo-second-order model, and the adsorption process was endothermic. The membrane adsorption reactor demonstrated efficient adsorption, well separation, and negligibly irreversible membrane fouling. The adsorption mechanism included electrostatic interactions, π-π interactions and hydrogen bonds. Regeneration test proved that the removal rate of the chemically regenerated UFCA-900 was similar to the fresh adsorbent after six cycles. Taken together, a simple strategy for in-situ nitrogen-doped porous carbon has been developed and the resultant composite UFCA-900 has promising application prospect in coking wastewater treatment.

In this study, ozonation catalyst nano-MnO2 blended polyvinylidene fluoride (PVDF) membrane was fabricated via phase inversion method and applied to membrane bioreactors (MBR), and then coupled with in-situ ozonation to study the anti-biofouling performance and reveal its mechanism. Results showed that, compared with pristine PVDF membrane (MBR_M0), 0.75 wt% and 1.00 wt% nano-MnO2 modified PVDF membrane (MBR_M0.75 and MBR_M1.00) could mitigate the membrane biofouling rate. Meanwhile MBR_M1.00 coupled with in-situ ozonation could increase the membrane cleaning cycle to 1.5 and 2.7 times, compared with MBR_M0 and MBR_M0.75 without in-situ ozonation. The possible mechanisms included that the nano-MnO2 modification coupled with in-situ ozonation directly removed the biofouling on the membrane surface, improved the hydrophilicity of the membrane surface and enhanced the chemical oxidation and biodegradation of membrane biofouling contaminants in the sludge mixture. The results of this work provide a new strategy for the control of membrane biofouling in MBR to treat industrial wastewater.

Industrial wastewater containing organic ligands and heavy metals is considered a serious public health threat, and its treatment and purification have become challenging tasks. Moreover, the organic-chelated heavy metals formed by common organic ligands and free heavy metals can cause many problems and concerns because of their poor biodegradability, high solubility, and extreme stability. In this study, aluminum-containing ferrihydrite (Fh-Al) adsorbents of different composition molar ratios were prepared and utilized to remove typical EDTA-Cr(III) in an aqueous system, and the associated removal mechanism was examined. The experimental results show that adding Al not only enhances the removal rate of EDTA-Cr(III) by the Fh-Al adsorbent in a wide pH range (pH = 3–9) but also increases the maximum adsorption capacity of EDTA-Cr(III). In addition, the specific surface area of Fh-Al can be increased by adding aluminum with different molar ratios, thus promoting its adsorption performance for EDTA-Cr(III). Furthermore, surface complexation and electrostatic attraction were proposed as possible mechanisms of EDTA-Cr(III) adsorption by Fh-Al. This study shows that Fh-Al-6 adsorbent can adsorb common EDTA-chelated heavy metals (such as EDTA-Pb, EDTA-Cr, EDTA-Cu and EDTA-Cd) in one step, with maximum adsorption capacities of 41.47, 32.33, 16.51 and 31.27 mg/g at pH = 3. The Fh-Al-6 adsorbent can be reused after being regenerated in a 2 g/L Na2SO4 solution. This study provides new expectations for treating wastewater containing organic groups and heavy metals.

Efficient decontamination of Sb(V) from water has long been an urgent task owing to its grave threat to human health. Herein, Y-based MOFs (MOF-Y and NH2-MOF-Y) were synthesized for effective adsorption of Sb(V) from aqueous solution, and the stability of the Y based MOFs were estimated. Kinetic and isotherms results indicated that the pseudo-second order kinetic (R2 > 0.90) and Langmuir isotherm models (R2 > 0.97) quite well described the adsorption of Sb(V) on Y-based MOFs, revealed that the uptake of Sb(V) on Y-based MOFs were followed by a monolayer chemical adsorption process. The maximum adsorption capacities of Sb(V) calculated from the Langmuir model were 161.3 and 151.5 mg/g for MOF-Y and NH2-MOF-Y, respectively. The Y-based MOFs exhibited strong water and chemical stability, it could be utilized for removal Sb(V) under wide pH range and various concentration of Sb(V). The spent adsorbents could be successfully regenerated by NaCl (5 mol/L) solution for further utilization without damaging the crystal structure of Y-based MOFs. X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS) results revealed that the formation of inner-sphere Y-O-Sb complex between Y-oxo-clusters and Sb(V) was the dominant adsorption mechanism, while the co-precipitation of Y^(+3) and Sb(V) was also partially contributed the Sb(V) adsorption. High stability together with high Sb(V) adsorption capacity and excellent recyclability endow the Y-based MOFs as promising adsorbents for Sb(V) removal from wastewater. Refereed/Peer-reviewed

The interfacial compatibility between fillers and polymers essentially influences the separation performance of mixed matrix membranes (MMMs). In this work, an one-pot synthesized functional layer veiled zeolite imidazolate frameworks-67 (VZIF-67) was used as an efficient nanofillers to fabricate MMMs via physical blending with 6FDA-Durene polyimide. Benefiting from the CO2 affinity from functional layer and the intrinsic characteristics of porous nanofillers, significant enhancement on separation performance was observed on the resultant MMMs. Specifically, the optimized VZIF-67 MMMs (30 wt% loading) exhibited CO2/CH4 selectivity of 32.5 with CO2 permeability of 1210 Barrer, which is 1.7 and 1.5 times higher than those of the control membrane, respectively. More importantly, the surface organic attribute and abundant amine groups of VZIF-67 reinforced the interfacial compatibility between the nanofillers and polymer matrix, leading to a doubled CO2/CH4 selectivity compared with the ZIF-67 MMMs. Overall, the performance of the VZIF-67 membrane toward CO2/CH4 separation surpasses the 2008-updated Robeson upper bound. These results indicate the functionalization strategy on porous nanofillers is a promising approach to fabrication of high performance of MMMs.

The application of bioelectrochemical system (BES) for recalcitrant contaminant removal is a promising strategy for wastewater treatment but is limited to the low cathodic reduction efficiency. In this paper, a new approach using polypyrrole as nitrogen source has been utilized for the fabrication of nitrogen-doping graphene (NG) modified graphite felt (GF) electrodes. The results of the Raman spectrum and X-ray photoelectron spectroscopy confirmed that the nitrogen species, i.e., pyridinic N, pyrrolic N and graphitic N, in the NG sheets could be conveniently controlled by tuning the pyrolysis temperature from 300 to 600 °C during carbonization process. Cyclic voltammetry and electrochemical impedance spectra measurements verified that the catalytic activity and electron transfer efficiency of the ‘as prepared’ electrodes were greatly improved. Due to the synergistic effect of pyrrolic N and graphitic N, the 4-nitrophenol reduction efficiency of the modified cathode increased 2.1 times higher than that of blank GF cathode in the BES system.

In this study, a pyridine-degrading strain namely NJUST30 was isolated from aerobic granules capable of degrading pyridine and was identified as Paracoccus sp. At incubation temperature of 30 °C, initial pH of 7.0 and initial pyridine concentration of 500 mg L−1, complete pyridine removal could be achieved within incubation period as short as 54 h. Pyridine biodegradation profile by NJUST30 could be well fitted by the first-order decay kinetic model, suggesting the recalcitrant nature of pyridine and the inhibitory effect of pyridine towards NJUST30. Major intermediates during pyridine biodegradation by NJUST30, including 2,4-dihydroxy-2H-pyridine-3-one, 2-carbonyl-succinic acid, 1,2-dihydro-pyridin-2-ol, piperidin-2-ol and 4-formylamino-butyric acid were identified through HPLC/MS. Based on these intermediates, a distinct pyridine biodegradation pathway via hydroxylation, pyridine ring cleavage, carbonylation and carboxylation was revealed for the first time.

Simultaneous pyridine biodegradation and nitrogen removal were successfully achieved in a sequencing batch reactor (SBR) based on aerobic granules. In a typical SBR cycle, nitritation occurred obviously after the majority of pyridine was removed, while denitrification occurred at early stage of the cycle when oxygen consumption was aggravated. The effect of several key operation parameters, i.e., air flow rate, influent NH4+-N concentration, influent pH and pyridine concentration, on nitritation, pyridine degradation and total nitrogen (TN) removal, was systematically investigated. The results indicated that high air flow rate had a positive effect on both pyridine degradation and nitritation but a negative impact of overhigh air flow rate. With the increase of NH4+ dosage, both nitritation and TN removal could be severely inhibited. Slightly alkaline condition, i.e., pH7.0-8.0, was beneficial for both pyridine degradation and nitritation. High pyridine dosage often resulted in the delay of both pyridine degradation and nitritation. Besides, extracellular polymeric substances production was affected by air flow rate, NH4+ dosage, pyridine dosage and pH. In addition, high-throughput sequencing analysis demonstrated that Bdellovibrio and Paracoccus were the dominant species in the aerobic granulation system. Coexistence of pyridine degrader, nitrification related species, denitrification related species, polymeric substances producer and self-aggregation related species was also confirmed by high-throughput sequencing.

Simultaneous removal of multi-component pollutants from atmosphere is crucial for personal protection. Herein, porous carbon spheres (PCSs) with 1.2 mm diameter were prepared through the phase inversion route followed by carbonization using g-C3N4 and PVDF as precursors. The structure and chemical property of PCSs can be tailored via controlling the content of g-C3N4 due to its dual-function of template and nitrogen source. The resultant PCSs possess high surface areas, rich nitrogen content and favorable micro/meso/macro hierarchical porous structure, which are highly desired for simultaneous removal of benzene and H2S. The dynamic adsorption behaviors for benzene and H2S were investigated to examine the protective performance. Owing to the abundant porous structure and chemical polarity, PCSs extend the protective performance for H2S under retention of adsorption performance for benzene. The promotion on adsorption performance for H2S from mixture could be attributed to the change of electron distribution on nitrogen atom caused by the adsorbed benzene. The adsorption kinetic confirmed the enhancement on mass transfer ascribed to meso/macro hierarchical porous structure. These results revel that PCSs would be a promising adsorbent in personal protective equipment for VOCs and TICs.

The electrode material with high electrosorption capacity and fast electrosorption rate is highly desired in capacitive deionization (CDI) process. To meet this demand, the nitrogen-doped cluster-like porous carbons (NCPCs) with hierarchical hollow nanoarchitecture were rationally prepared by carbonizing the polydopamine/nano-ZnO composite and employed as CDI electrodes. The resultant NCPCs possess an interconnected hierarchical structure with a hollow cavity, nitrogen-doping property, high specific surface, large pore volume and good wettability. All these merits can ensure a huge accessible electrosorption interface for the very quick diffusion of ions so that achieve an excellent CDI performance. Particularly, the sample carbonized at 900 °C (NCPC-900) with the optimal porous structure and chemistry composition exhibits the highest electrosorption capacity of 11.98 mg g− 1 in 100 mg L− 1 NaCl solution. Besides, the NCPC-900 electrode shows a good cycle stability over 20 electrosorption-desorption cycles. These results render that the NCPCs have the great potential as the electrode material for high performance CDI desalination.

A series of novel blend ultrafiltration (UF) membranes have been successfully prepared from commercial poly (ether sulfone), lab-synthesized sulfonated poly (aryl ether sulfone) (SPAES, 1 wt%) and copper nanoparticles (0 ∼ 0.4 wt%) via immersion precipitation phase conversion. The micro-structure and separation performance of the membranes were characterized by field emission scanning electron microscopy (SEM) and cross-flow filtration experiments, respectively. Sodium alginate, bovine serum albumin and humic acid were chosen as model organic foulants to investigate the antifouling properties, while E. coil was used to evaluate the antibacterial property of the fabricated membranes. By the incorporation with SPAES and copper nanoparticles, the hydrophilicity, antifouling and antibacterial properties of the modified UF membranes have been profoundly improved. At a copper nanoparticles content of 0.4 wt%, the PES/SPAES/nCu(0.4) membrane exhibited a high pure water flux of 193.0 kg/m2 h, reaching the smallest contact angle of 52°, highest flux recovery ratio of 79% and largest antibacterial rate of 78.9%. Furthermore, the stability of copper nanoparticles inside the membrane matrix was also considerably enhanced, the copper nanoparticles were less than 0.08 mg/L in the effluent during the whole operation.

Arsenic-contaminated water has significant adverse impacts on human health and ecosystems. We developed a new adsorptive membrane by modifying the porous support layer of a phase inversion formed membrane for arsenic removal. Iron oxide (Fe3O4) microspheres were immobilized in the support layer of the membrane by reverse filtration, followed by dopamine polymerization. The prepared adsorptive membrane was compared with a virgin membrane without Fe3O4 microspheres and a Fe3O4 blended membrane in terms of membrane structures and separation performance. The adsorptive membrane prepared by our new method had comparable water permeability and rejection performance with the virgin membrane without Fe3O4 microspheres, but higher rejection performance and dynamic adsorption capacity than the membrane prepared by the conventional blending method. Both static and dynamic adsorption modes were used to evaluate the adsorption performance of the membranes. Our new adsorptive membrane also had excellent regeneration performance. After three regeneration cycles, the membrane was still capable of treating more than 2 tons of As-contaminated water/m2. The adsorptive membrane of 1 m2 could treat over 7 tons of water to the drinking water standard in terms of arsenic concentration during three regeneration cycles. Therefore, our adsorptive membrane may pave a new way for arsenic removal from water and ensuring drinking water security.

In this work, we have fabricated a kind of N-doped hierarchal carbon fiber web by electrospinning hollow mesoporous carbon spheres (HMCSs) into fibrous structure. The as-synthesized carbon fiber web with novel mulberry-like morphology, thus denoted as MC-FW, possesses micro/meso/macroporous porosity, large surface area, high conductivity and multi-level structure, which are highly desired for supercapacitor electrode materials. The electrochemical measurements demonstrate that the designed MC-FW shows high capacitance (298.6 F g−1), favorable capacitance retention (71.0%) and long cycle life (97.3% capacitance retention after 5000 cycles). Notably, the capacitance of 298.6 F g−1 for MC-FW is higher than the capacitance reported so far for many hollow carbon spheres and carbon fibers, which may contribute to the synergistic effect between the merits of HMCSs (e.g. micro/meso/macroporous hierarchal structure, large surface area, high pore volume) and advantages of 1D carbon fiber (e.g. large aspect ratio and high conductivity). It is believed that this distinctive carbon fiber web may show promising prospects as advanced energy storage materials and catalyst.

Flue gas desulphurization (FGD) gypsum is an abundant waste generated from coal-fired power plants. This study evaluated the potential application of hydroxyapatite (F-HAP) derived from FGD gypsum for immobilization of lead (Pb) and copper (Cu) in water and soil. MINTEQ software was employed to determine the species distribution of Pb(II) and Cu(II) at different solution pH conditions. The factors that affect sorption behavior such as pH effect, sorption kinetics, thermodynamics, and isotherms were investigated using batch tests. Various kinetics and isotherms models were used to fit the obtained data. The experimental results showed that the amount of Pb(II) and Cu(II) adsorbed on F-HAP increased as the pH increased from 2.0 to 6.0, and adsorption was enhanced with the rise in temperature. The predicted maximum adsorption capacities were found to be 1.376 and 0.460. mmol/g for Pb(II) and Cu(II), respectively. The values of mean free energy (E) obtained from Dubinin-Radushkevich (D-R) model implied that the chemical reaction, which was stronger than ion exchange governed the process of Pb(II) adsorption, while the adsorption of Cu(II) was mainly ascribed to ion exchange. XRD analysis revealed that the final solid obtained after Pb(II) immobilization was mainly mixed of pyromorphite and F-HAP, while the final solid acquired after Cu(II) immobilization still consisted of a single phase of F-HAP. On the other hand, application of F-HAP in contaminated soil effectively reduced the leachable and exchangeable Pb and Cu, reflecting that F-HAP is a potential material for remediating environmental pollution with Pb and Cu. This study realized the potential of a modified geochemical waste material towards remediation of metal contaminated soils, providing very useful and valuable information for other similar solid wastes, such as paper sludge and phosphogypsum. Refereed/Peer-reviewed