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The not-homogenous microplastics (MPs) distribution in freshwaters results in distinct microbial communities. Yet knowledge regarding plastisphere in metabolic pathways and element cycling behaviors remains limited. In this study, we collected MPs from 15 sampling sites in the Taihu Lake in China, and found that MPs were widely distributed in this freshwater lake, and dominantly composed of fibrous polyethylene terephthalate. Based on the metagenomic analysis, we found that MPs were colonized by Bacteroidia, Alpha - Proteobacteria, and Bacilli as a filter, but depleted in Verrucomicrobiae. Potential pathogens of plant eudicots and monocots were significantly enriched in plastisphere. Predicted functional profiles involved in the metabolism of other amino acids, biosynthesis of other secondary metabolites, and glycan biosynthesis and metabolism were overrepresented in plastisphere. Regarding elemental cycling, functional genes related to nitrogen fixation and nitrification showed 39.6% and 67.5% decline in plastisphere, whereas the genes involved in denitrification and nitrate reduction were significantly enriched. For sulfur cycles, the plastisphere exhibited higher sulfate reduction and sulfur oxidation system activities. Additionally, the taxonomic compositions and predicted functions in the plastispheres were mainly driven by the stochastic processes, while the deterministic processes were more important for the planktonic communities. The distinctions in the microbial composition, the predicted functionality, and the underly mechanisms between plastisphere and planktonic communities illustrated the unique ecology of the new anthropogenic-related plastisphere ecosystems. [Display omitted] • Distinctive microbial communities were found between MPs and waters in Taihu Lake. • Potential pathogens of eudicots and monocots significantly enriched in plastisphere. • Microbiome and predicted functions on MPs were mainly driven by stochastic process. • MPs may induce N and S cycles by enriched denitrification and sulfate reduction. [ABSTRACT FROM AUTHOR]

The interaction of ciprofloxacin chlorination products (CIP-CPs) with bacteria in drinking water distribution systems (DWDSs) was investigated. The piperazine ring of CIP was destroyed by chlorination. Among of CIP-CPs, by the bacterial role, 7.63% of the derivative with two carboxylic groups went through decarboxylation to form desethylene ciprofloxacin, and then loss of C 2 H 5 N group generated aniline compound. Furthermore, 12.3% of the aniline compound, 7.60% of chlorinated aniline compound and 1.35% of defluorinated product were bio-mineralized. Therefore, the chlorine and bacteria played synergistic effects on transformation of CIP-CPs in DWDSs, contributing to the obvious decrease of genotoxicity in effluents. Correspondingly, the TEQ 4-NQO decreased from 667 μg/L to 9.41 μg/L. However, compared with DWDSs without CIP-CPs, the relative abundance of mexA and qnrS increased 1-fold in effluents and the relative abundance of qnrA and qnrB increased 3-fold in biofilms in DWDSs with CIP-CPs. mexA and qnrS positively correlated with Hyphomicrobium , Sphingomonas and Novosphingobium (p < 0.05), while qnrA and qnrB positively correlated with Shewanella and Helicobacter (p < 0.05), indicating the increase of antibiotic resistance genes (ARGs) came from the growth of these bacterial genera by transformation of CIP-CPs in DWDSs. These results suggested that biotransformation of antibiotics might increase ARGs risk in DWDSs. [ABSTRACT FROM AUTHOR]

Highlights: [•] Heavy metals removal from MSWI fly ash with BES and electrolysis was confirmed. [•] 98.5% of Cu(II), 95.4% of Zn(II) and 98.1% of Pb(II) removal were achieved in reactors. [•] BESs can remove some heavy metals in fly ash with energy saving. [Copyright &y& Elsevier]

Highlights: [•] Feasibility of natural limonite as iron catalyst in BES-Fenton system was confirmed. [•] With natural limonite, 96% of PNP removal efficiency was achieved within 6h. [•] PNP removal efficiency is kept above 94% for 7 periods with adding limonite only once. [ABSTRACT FROM AUTHOR]

Abstract: Aluminum-modified hydroxyapatite (Al-HAP) was prepared and characterized using XRD and BET analyses. Al-HAP possessed higher defluoridation capacity (DC) of 32.57mgF−/g than unmodified hydroxyapatite (HAP) which showed a DC of 16.38mgF−/g. The effect of Al/Ca atomic ratio in Al-HAP, solution pH and co-existing anions was further studied. The results indicated that the adsorption data could be well described by the Langmuir isotherm model and the adsorption kinetic followed the pseudo-second-order model. The pH changes during the adsorption process suggested that the surface of Al-HAP was the adsorption sites. The more adsorption sites were formed on Al modified HAP, which possessed abundant surface hydroxyl groups, resulting in higher efficiency of F− removal. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated in order to understand the nature of adsorption process. The results revealed that the adsorption reaction was a spontaneous and endothermic process. [Copyright &y& Elsevier]

Abstract: Ag–AgBr was deposited onto mesoporous alumina (MA) and titanium-doped MA by a deposition–precipitation method. The photocatalytic activity and the dissolution of Ag+ from different catalysts were investigated during the photodegradation of 2-chlorophenol (2-CP) and phenol in ultrapure water and tap water with visible-light irradiation. With the increase in doped titanium, the Ag+ dissolution decreased with a decrease in the photocatalytic activity. Ag–AgBr/MA-Ti1 was considered the better catalyst for practical applications because its Ag+ dissolution was minimal (0.4mgL−1 in ultrapure water and 5μgL−1 in tap water), although its photoactivity was slightly less than that of Ag–AgBr/MA. The dissolution of Ag+ was related to a charge–transfer process based on the study of cyclic voltammetry analyses under a variety of experimental conditions. The results suggested that several types of anions in the water, including CO3 2−, SO4 2−, and Cl−, could act as electron donors that trap the photogenerated holes on Ag nanoparticles to facilitate electron circulation; this would decrease the release of Ag+. Our studies indicated that the catalyst had a higher activity and stability in water purification. [Copyright &y& Elsevier]

Abstract: Based on energetic analysis, a novel approach for copper electrodeposition via cathodic reduction in microbial fuel cells (MFCs) was proposed for the removal of copper and recovery of copper solids as metal copper and/or Cu2O in a cathode with simultaneous electricity generation with organic matter. This was examined by using dual-chamber MFCs (chamber volume, 1L) with different concentrations of CuSO4 solution (50.3±5.8, 183.3±0.4, 482.4±9.6, 1007.9±52.0 and 6412.5±26.7mg Cu2+/L) as catholyte at pH 4.7, and different resistors (0, 15, 390 and 1000Ω) as external load. With glucose as a substrate and anaerobic sludge as an inoculum, the maximum power density generated was 339mW/m3 at an initial 6412.5±26.7mg Cu2+/L concentration. High Cu2+ removal efficiency (>99%) and final Cu2+ concentration below the USA EPA maximum contaminant level (MCL) for drinking water (1.3mg/L) was observed at an initial 196.2±0.4mg Cu2+/L concentration with an external resistor of 15Ω, or without an external resistor. X-ray diffraction analysis confirmed that Cu2+ was reduced to cuprous oxide (Cu2O) and metal copper (Cu) on the cathodes. Non-reduced brochantite precipitates were observed as major copper precipitates in the MFC with a high initial Cu2+ concentration (0.1M) but not in the others. The sustainability of high Cu2+ removal (>96%) by MFC was further examined by fed-batch mode for eight cycles. [Copyright &y& Elsevier]

Abstract: The photodegradation of three antibiotics, oxytetracycline (OTC), doxycycline (DTC), and ciprofloxacin (CIP) in UV and UV/H2O2 process was investigated with a low-pressure UV lamp system. Experiments were performed in buffered ultrapure water (UW), local surface water (SW), and treated water from local municipal drinking water treatment plant (DW) and wastewater treatment plant (WW). The efficiency of UV/H2O2 process was affected by water quality. For all of the three selected antibiotics, the fastest degradation was observed in DW, and the slowest degradation occurred in WW. This phenomenon can be explained by R OH,UV, defined as the experimentally determined l exposure per UV fluence. The R OH,UV values represent the background l scavenging in water matrix, obtained by the degradation of para-chlorobenzoic acid (pCBA), a probe compound. In natural water, the indirect degradation of CIP did not significantly increase with the addition of H2O2 due to its effective degradation by UV direct photolysis. Moreover, the formation of several photoproducts and oxidation products of antibiotics in UV/H2O2 process was identified using GC–MS. Toxicity assessed by Vibrio fischer (V. fischer), was increased in UV photolysis, for the photoproducts still preserving the characteristic structure of the parent compounds. While in UV/H2O2 process, toxicity increased first, and then decreased; nontoxic products were formed by the oxidation of l. In this process, detoxification was much easier than mineralization for the tested antibiotics, and the optimal time for the degradation of pollutants in UV/H2O2 process would be determined by parent compound degradation and toxicity changes. [ABSTRACT FROM AUTHOR]

Abstract: Iron oxides coated on Fe0 core–shell nanospheres (nIOCI) were synthesized through the reduction of ferrous sulfate aqueous solution by sodium borohydride at ambient atmosphere. The catalyst was highly effective for the degradation of humic acid (HA) in the presence of H2O2 and UVA at neutral pH. Under deoxygenated conditions in the dark, the generation of hydroxyl radicals in aqueous nIOCI dispersion verified its galvanic cell-like performance, which enhanced the interfacial electron transfer and led to its higher reactivity. By the total organic carbon, the absorbance of UV254, FTIR, the molecular weight distribution and the chemical fractional character analysis, the degradation process of HA was shown to proceed by the disappearance of aromaticity, the increase of hydrophilic fraction and aromatic ring openings into CO2 and small organic acid. The treated HA showed much lower reactivity toward chlorine and the disinfection byproduct (DBP) formation potential was also greatly reduced. Moreover, it was found that the DBP formation potential more depended on the structure of the intermediates of HA degradation than TOC removal. [Copyright &y& Elsevier]

Porous Cu-doped alumina (P-Cu-Al 2 O 3) has been synthesized using ammonium chloride as a green gaseous template. The unique pore-forming agent endows the catalyst a large surface area and homogenous pore structure. According to the characterization results by multi-technologies, the highly dispersed framework Cu+/Cu2+ was incorporated in octahedral sites with the formation of the Cu-O-Al bonds. Compared with bulk Cu-doped Al 2 O 3 (B-Cu-Al 2 O 3), more surface acidic oxygen-containing groups and Lewis acid sites existed in P-Cu-Al 2 O 3 , resulting in the production of surface adsorbed •OH, which is helpful for the removal of surface adsorbed organic intermediates. In addition, O 2 more easily participate in surface reaction to promote the •OH generation in P-Cu-Al 2 O 3 system than that in B-Cu-Al 2 O 3. As a result, the representative endocrine disruptor bisphenol A can be more efficiently mineralized by P-Cu-Al 2 O 3. This work provides a facile route to develop porous active heterogenous Fenton-like catalysts and a unique perspective to insight into the structure-activity relationship. ga1 • Uniformly porous Cu-Al 2 O 3 is successfully synthesized by a facile gas-templated method. • More Lewis acid sites and oxygen-containing groups existed at P-Cu-Al 2 O 3 surface. • P-Cu-Al 2 O 3 is highly effective for pollutant removal in Fenton-like reaction. • Free and surface adsorbed •OH were vital active species in P-Cu-Al 2 O 3 /H 2 O 2 system. • O 2 participated in surface reaction to promote the •OH generation in the system. [ABSTRACT FROM AUTHOR]

In contaminated soils, arsenic (As) often co-exists with copper (Cu). However, its effects on As accumulation and the related mechanisms in As-hyperaccumulator Pteris vittata remain unclear. In this study, P. vittata plants were exposed to 50 µM As and/or 50 µM Cu under hydroponics to investigate the effects of Cu on plant growth and As accumulation, as well as gene expression related to arsenic uptake (P transporters), reduction (arsenate reductases), and translocation and sequestration (arsenite antiporters). After 14 d of growth and compared to the As treatment, the As concentration in P. vittata fronds increased by 1.4-times from 793 to 1131 mg·kg−1 and its biomass increased by 1.2-fold from 18.0 to 21.1 g·plant−1 in the As+Cu treatment. Copper-enhanced As accumulation was probably due to upregulated gene expressions related to As-metabolisms including As uptake (1.9-fold in P transporter PvPht1;3), translocation (2.1–2.4 fold in arsenite antiporters PvACR3/3;2) and sequestration (1.5–2.0 fold in arsenite antiporters PvACR3;1/3;3). Our results suggest that moderate amount of Cu can help to increase the As accumulation efficiency in P. vittata , which has implication in its application in phytoremedation in As and Cu co-contaminated soils. [Display omitted] • 50 µM Cu enhanced plant growth and As accumulation in P. vittata. • P. vittata maintains a normal Cu level in fronds by concentrating most Cu in roots. • Cu promoted AsV uptake by upregulating P transporter PvPht1;3. • Cu upregulated AsIII antiporters PvACR3-3;3 for As translocation and sequestration. [ABSTRACT FROM AUTHOR]

Highly dispersed framework Cu+/Cu2+ containing LaAlO 3 /Al 2 O 3 (La-Cu-Al) was synthesized by a solid-liquid mixed sol-gel method. Excessive Al 2 O 3 was confirmed to be necessary for the formation of LaAlO 3. The NMR, EXAFS, FTIR and element mapping results revealed that Cu+/Cu2+ preferred to substitute octahedral Al sites and bonded by Cu-O-Al in the lattice of LaAlO 3. Compared to La 2 CuO 4 , CuAl 2 O 4 and other reported Fenton-like catalysts, La-Cu-Al was more efficient to mineralize refractory pollutants at a wide pH range of 4.0–10.0. More single electrons around Cu center and octahedral Cu+ were confirmed to be responsible for the effective reduction of H 2 O 2 into powerful •OH. Moreover, organic pollutants as electron donors could interact with surface Cu to accelerate Cu2+/Cu+ cycle and affect O-O bond of H 2 O 2 on La-Cu-Al surface, further promoting the reduction of H 2 O 2 into •OH. These processes resulted in the high H 2 O 2 utilization and the highly efficient removal of pollutants on La-Cu-Al. [Display omitted] • Cu-LaAlO3/Al2O3 (La-Cu-Al) was fabricated by a solid-liquid mixed sol-gel method. • Cu preferred to substitute lattice octahedral Al sites of LaAlO3 with Al–O–Cu bond. • La-Cu-Al shows superior activity and stability for the pollutants removal. • More single electrons and octahedral Cu+ were responsible for more •OH generation. [ABSTRACT FROM AUTHOR]

Abstract: Layered birnessite-type manganese oxides (Na-OL-1) were prepared via a redox reaction involving MnO4 − and Mn2+ under markedly alkaline conditions. According to the XRD analysis, the resulting material exhibited a well-crystallized octahedral layer (OL) structure with several different phases, including β-MnOOH, α-MnOOH and γ-Mn3O4. The catalyst was highly effective for the decolorization and degradation of methylene blue (MB) in the presence of H2O2 at neutral pH. The tested MB was completely decolorized in Na-OL-1 suspension by the fraction dosing of H2O2 (556.5mM at the beginning and then 183.8mM at 40min). Based on the studies of electron spin resonance and the effect of radical scavengers, the 1O2 and O2 − were the main reactive oxygen species (ROS) in the reaction. It was found that both oxygen and ROS were generated from the decomposition of H2O2 in Na-OL-1 suspension, wherein the decomposition pathways were proposed. The generation of H2O2 in Na-OL-1 suspension at air atmosphere indicated that the existence of multivalent manganese oxides greatly enhanced the interfacial electron transfer, leading to the high activity of Na-OL-1. [Copyright &y& Elsevier]

In common advanced oxidation processes, excess reagents and energy are often added to the reaction system to maintain the continuity of the reaction. These additions result in a large waste of resources and energy, which has become a bottleneck in the development of water treatment technology. In this study, we propose a new strategy to solve this problem based on a novel dual-reaction-center (DRC) Fe-ZnS quantum dots (Fe–ZnS QDs) catalyst that forms a non-equilibrium surface with an electron-polarized distribution. Through experimental and theoretical studies, it was verified that the activation of trace amounts of H 2 O 2 could break the energy barrier for pollutants to transfer electrons. The dissolved oxygen (DO) in the reaction system could be activated by gaining energy on the surface of the Fe–ZnS QDs catalyst, and was converted to 1O 2 to attack organic pollution. In addition, the pollutants themselves supplied electrons to H 2 O 2 through the surface of the Fe–ZnS QDs catalyst to generate more •OH radicals for pollutant degradation, thus providing two fast paths for pollutant degradation. The system could drive the reaction through a trace amount of H 2 O 2 , thereby activating DO to generate 1O 2 while effectively using the energy of pollutants. Therefore, the proposed system offers a new direction for the development of environmentally-friendly catalysts and greatly reduces the consumption of resources and energy. [Display omitted] • Fe–ZnS QDs is successfully developed as a Fenton catalyst for the first time. • The surface of ZnS QDs is regulated by trace Fe to form a non-equilibrium surface with an electron-polarized distribution. • The Fe–ZnS QDs/H 2 O 2 system exhibits excellent activity for pollutants degradation. • Inert oxygen species in reaction system are easily activated to 1O 2 to attack pollutants. [ABSTRACT FROM AUTHOR]

The biofilm stress response of biological activated carbon (BAC) was investigated under prolonged exposure to sulfadiazine and 2,4-Dichlorophenoxyacetic acid, simulating complex emerging organic contaminants (EOCs) that are mainly involved in the formation of nitrogenous disinfection byproducts (N-DBPs) and antibiotic resistance genes (ARGs). Under trace complex EOCs condition (2 µg/L), N-DBP precursors and abundance of ARGs increased significantly in BAC effluent. The total formation potential of haloacetonitriles (HANs) and halonitromethanes (HNMs) was 751.47 ± 2.98 ng/L, which was much higher than the control group (440.67 ± 13.38 ng/L without EOCs). Similarly, the relative abundance of ARGs was more than twice that in the control group. The complex EOCs induce excessive extracellular polymeric substance secretion (EPS), thereby causing more N-DBP precursors and stronger horizontal gene transfer. Metagenome analysis revealed that functional amino acid and protein biosynthesis genes were overexpressed compared to the control group, causing more EPS to be secreted into the external environment. Complex EOCs promote Cobetia , Clostridium, and Streptomyces dominance, contributing to the production of N-DBP precursors and ARGs. For the first time, in addition to the direct hazards of the EOCs, this study successfully revealed the indirect water quality risks of complex EOCs from the microbial stress response during BAC treatment. Synergistic regulation of EOCs and microorganisms is important for tap water security. [Display omitted] • Trace complex emerging organic contaminants exacerbated the risk of DBPs and ARGs after BAC treatment. • Excessive EPS secretion contributed to DBP precursors and horizontal gene transfer. • The amino acid/protein-encoding functional genes overexpressed to counteract micropollutants stress. • Cobetia , Clostridium, and Streptomyces were the dominant bacterial genera associated with DBPs and ARGs. • The indirect effect of micropollutants on microbial stress response should receive more attention. [ABSTRACT FROM AUTHOR]

High energy consumption is impedimental for eliminating refractory organics in wastewater by current technologies. Herein, we develop an efficient self-purification process for actual non-biodegradable dyeing wastewater at pilot scale, using N-doped graphene-like (CN) complexed Cu-Al 2 O 3 supported Al 2 O 3 ceramics (HCLL-S8-M) fixed-bed reactor without additional input. About 36% chemical oxygen demand removal was achieved within 20 min empty bed retention time and maintained stability for almost one year. The HCLL-S8-M structure feature and its interface on microbial community structure, functions, and metabolic pathways were analyzed by density-functional theory calculation, X-ray photoelectron spectroscopy, multiomics analysis of metagenome, macrotranscriptome and macroproteome. On the surface of HCLL-S8-M, a strong microelectronic field (MEF) was formed by the electron-rich/poor area due to Cu-π interaction from the complexation between phenolic hydroxy of CN and Cu species, driving the electrons of the adsorbed dye pollutants to the microorganisms through extracellular polymeric substance and the direct transfer of extracellular electrons, causing their degradation into CO 2 and intermediates, which was degraded partly via intracellular metabolism. The lower energy feeding for the microbiome produced less adenosine triphosphate, resulting in little sludge throughout reaction. The MEF from electronic polarization is greatly potential to develop low-energy wastewater treatment technology. [Display omitted] • An efficient pilot-scale self-purification process for actual dyeing wastewater was developed. • The COD of dyeing wastewater was effectively removed and maintained stability for one year. • The superior performance was attributed to surface microelectric fields (MEF). • The MEF drived the electrons of the adsorbed pollutants to the microorganisms. • The adsorbed-dyes electrons were transferred though EPS and direct extracellular transfer. [ABSTRACT FROM AUTHOR]

Few-layered Bi 4 O 5 I 2 nanosheets (FL-Bi 4 O 5 I 2) were synthesized by intergrowth with Bi 2 O 2 CO 3 under room temperature. The photoactivity of FL-Bi 4 O 5 I 2 was 2.5 and 9.5 times higher than that of Bi 4 O 5 I 2 nanoflakes (NF-Bi 4 O 5 I 2 , about 30 nm thickness) and standard visible-light-driven N-TiO 2 , respectively. Moreover, FL-Bi 4 O 5 I 2 exhibited a wide pH application range (3.0 – 10.0) and excellent photostability. The characterization results showed FL-Bi 4 O 5 I 2 was consisted of 5 – 8 layers with thickness of 4 – 7 nm and enclosed by {1 0 − 1} facets. The ultrathin characteristics could accelerate the charge transfer to the surface due to the shortened transport distance. Compared to NF-Bi 4 O 5 I 2 , surface oxygen vacancies and the more negative CB potential were formed on FL-Bi 4 O 5 I 2. The photogenerated electrons were confirmed to be captured by surface oxygen vacancies to effectively reduce surface adsorbed O 2 into HO 2 •/O 2 •–, leaving more h+ to oxidize organic pollutants. This process was further facilitated by the more negative CB potential of FL-Bi 4 O 5 I 2 , resulting in the highly efficient removal of pollutants. [Display omitted] • Few-layered Bi 4 O 5 I 2 were formed by intergrowth with Bi 2 O 2 CO 3 at room temperature. • FL-Bi 4 O 5 I 2 was enclosed by {1 0−1} facets with surface oxygen vacancies. • Surface oxygen vacancies as electron traps promoted the efficient reduction of O 2. • HO 2 •/O 2 •– and holes were involved in the photocatalytic degradation process. • Organic pollutants were efficiently degraded by the surface adsorption and oxidation process. [ABSTRACT FROM AUTHOR]

The mechanism of the effects of Fe 2+ aq on the reduction of NO 3 − by Fe 0 was investigated. The effects of initial pH on the rate of NO 3 − reduction and the Fe 0 surface characteristics revealed Fe 2+ aq and the characteristics of minerals on the surface of Fe 0 played an important role in NO 3 − reduction. Both NO 3 − reduction and the decrease of Fe 2+ aq exhibited similar kinetics and were promoted by each other. This promotion was associated with the types of the surface iron oxides of Fe 0 . Additionally, further reduction of NO 3 − produced more surface iron oxides, supplying more active sites for Fe 2+ aq , resulting in more electron transfer between Fe 2+ and surface iron oxides and a higher reaction rate. Using the isotope specificity of 57 Fe Mossbauer spectroscopy, it was verified that the Fe 2+ aq was continuously converted into Fe 3+ oxides on the surface of Fe 0 and then converted into Fe 3 O 4 via electron transfer between Fe 2+ and the pre-existing surface Fe 3+ oxides. Electrochemistry measurements confirmed that the spontaneous electron transfer between the Fe 2+ and structural Fe 3+ species accelerated the interfacial electron transfer between the Fe species and NO 3 − . This study provides a new insight into the interaction between Fe species and contaminants and interface electron transfer. [ABSTRACT FROM AUTHOR]

Nanoscale LaFeO 3 was prepared via sol–gel method and characterized by XRD, FTIR and N 2 adsorption/desorption experiment. The results indicated that, LaFeO 3 had a typical perovskite structure with a BET area of 8.5 m 2 /g. LaFeO 3 exhibited excellent Fenton activity and stability for the degradation of pharmaceuticals and herbicides in water, as demonstrated with sulfamethoxazole, phenazone, phenytoin, acyclovir and 2,4-dichlorophenoxyacetic acid, 2-chlorophenol. Among them, sulfamethoxazole (SMX) could be completely removed in LaFeO 3 –H 2 O 2 system after reaction for 120 min at neutral pH. Based on the ATR–FTIR analysis, the surface complex of LaFeO 3 and H 2 O 2 was formed, which was important and essential for the enhanced Fenton reaction by accelerating the cycle of Fe 3+ /Fe 2+ . Hence, more OH and O 2 − /HO 2 − were then produced in LaFeO 3 –H 2 O 2 system, resulting in more efficient removal of refractory organic compounds. Based on the surface interaction of LaFeO 3 and H 2 O 2 , a heterogeneous Fenton reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]

Herein, a novel BiOBr photocatalyst with partial surface modification by graphitized C (BiOBr-C g) was synthesized through a hydrothermal method with hydrothermal carbonation carbon (HTCC) as a slow-releasing carbon source and characterized by experimental and theoretical methods. BiOBr-C g exhibited excellent visible-light photocatalytic performance toward various refractory pollutants, such as bisphenol A, ibuprofen, ciprofloxacin, 2,4-dichlorophenoxyacetic acid, and diphenhydramine. The characterization results demonstrate that a strong molecular orbital interaction occurs between graphitized C and BiOBr, resulting in the formation of a new surface valence band on graphitized C. This not only promotes the oxidation of pollutants by surface holes but also reduces the recombination of carriers during the bulk phase transfer process, thereby increasing the number of photogenerated carriers. Intriguingly, the analytical results for degradation intermediates and other characterization techniques demonstrate that the pollutants adsorbed on the graphitized C of BiOBr-C g can be directly excited through light irradiation and react along the organic radical degradation pathway in addition to pollutant degradation by holes and HO 2 •/O 2 •-. [Display omitted] • A novel BiOBr photocatalyst (BiOBr-C g) partly coated by graphitized C with HTCC as a slow-releasing carbon source. • The surface valence band derived from graphitized C reduces the recombination of e-/h+ during bulk phase transfer process. • The pollutant adsorbed on BiOBr-C g promotes direct transfer of excited electrons along organic radical degradation pathway. • Pollutant adsorption plays a role of molecular modification to facilitate the generation of more HO 2 •/O 2 •-. [ABSTRACT FROM AUTHOR]

Abstract: A type of mesoporous ZrO2 was synthesized and its phosphate removal potential was investigated in this study. The adsorption isotherm, pH effect, ionic strength effect and desorption were examined in batch experiments. The adsorption data fitted well to the Langmuir model with which the maximum P adsorption capacity was estimated to be 29.71mgP/g. The amount of phosphate adsorbed increased rapidly in the first 5h and slowly towards the end of the run, suggesting the possible monolayer coverage of phosphate ions on the surface of the adsorbent. The phosphate adsorption tended to increase with a decrease of pH and an increase of ionic strength. A phosphate desorbability of approximately 60% was observed with 0.5M NaOH, which indicated a relatively strong bonding between the adsorbed PO4 3− and the sorptive sites on the surface of the adsorbent. The immobilization of phosphate probably occurs by the mechanisms of ion exchange and physicochemical attraction. Due to its high adsorption capacity, this type of Zirconium oxide has the potential for application to control phosphorus pollution. [Copyright &y& Elsevier]

A novel metal-free catalyst consisting of typical flower-like graphitized polyimide (g-PI) is first synthesized via an enhanced hydrothermal polymerization process, and it exhibits excellent performance for pollutant removal through peroxymonosulfate (PMS) activation over a wide pH range (3−11). The catalyst is especially effective for attacking the endocrine disruptor bisphenol A (BPA), which can be completely degraded in a short time. Based on the results of characterization, g-PI is consisted of abundant aromatic frameworks with π conjugates based on C-O-C linkages and N-hybrid rings, which play essential roles in the subsequent degradation of pollutants. In the g-PI/PMS/BPA system, BPA (rich in π bonds) is preferentially adsorbed to the catalyst surface through π-π interactions, accompanied by a decrease in its activation energy to produce surface-adsorbed BPA*. This species can be directly attacked and degraded by PMS without the need for the radical processes, which saves the energy required for the intermediate activation process of PMS. On the other hand, the electrons obtained from pollutants are rapidly transferred to the O center, driving PMS activation to generate free radicals. The synergetic interface process offers excellent potential for practical wastewater purification. [Display omitted] • g-PI is synthesized by graphitization of metal-free polyimide (PI). • g-PI/PMS system shows excellent activity in degrading organic pollutants. • Pollutants are preferentially adsorbed on the surface of g-PI through π-π interactions. • Surface-adsorbed species can be directly oxidized by PMS without the need for radical processes. [ABSTRACT FROM AUTHOR]

d-g-C 3 N 4 -Fe composites was prepared via a self-assembly and calcination process. According to measurements and density functional theory (DFT) computations, the complexation of iron and pyridinic N of g-C 3 N 4 (Fe‒N) occurred with Fe(III)-π interaction, causing more oxygen vacancies (OVs) with more electrons in iron oxides. In the catalyst air-saturated suspension, the adsorbed pollutants complexed surface Fe(III) through their hydroxyl group donated electrons to around OVs, reducing the surface Fe(III) to Fe(II) and were destructed by Fe(III)-π interaction of the complexation. The addition of H 2 O 2 mainly acted as acceptor being reduced •OH at the OV centers, causing higher degradation rate of pollutants due to both •OH and the surface reaction. However, for the adsorbed hydrophobic pollutants onto the sites of peripheral structure in g-C 3 N 4 , H 2 O 2 was mainly decomposed into O 2 by the synergistic effect of iron species and OVs. Therefore, the catalyst exhibited high Fenton-like efficiency for the degradation of hydroxyl-containing pollutants and hydrophobic pollutants mixing with the former. Our results demonstrate that the Fe(III)-π interaction could carry out the oxidation of pollutants on the catalyst surface, decreasing the consumption of H 2 O 2 , and the role of OVs depends on pollutant adsorption patterns. ga1 • Fe‒N complexation formed between g-C 3 N 4 and iron oxide in d-g-C 3 N 4 -Fe. • More oxygen vacancies produced in iron oxide of d-g-C 3 N 4 -Fe. • Degradation of organics was performed from the surface oxidation rather than •OH. • d-g-C 3 N 4 -Fe shows excellent activity for hydroxyl-containing pollutants degradation. • Efficiency of H 2 O 2 depended on the synergistic effect of OVs and pollutant adsorption. [ABSTRACT FROM AUTHOR]

• C and O dual-doped g-C 3 N 4 was generally synthesized via copolymerization. • C and O dual doping induces electronic structure reconfiguration in CN-AA 0.3. • CN-AA 0.3 exhibits good reactivity and stability in non-photochemical PMS activation. • Electron-poor C and electron-rich O atoms serve as active sites for PMS activation. • PMS activation over CN-AA 0.3 involves simultaneous PMS oxidation and reduction. Earth-abundant, environmental-benign and durable catalysts are of paramount importance for remediation of organic pollutants, and graphitic carbon nitride (g-C 3 N 4) is a promising nonmetallic material for this application. However, the catalytic oxidation on g-C 3 N 4 suffers from low efficiency because of its chemical inertness if not irradiated with light. Herein, we develop a facile copolymerization strategy for the synthesis of carbon and oxygen dual-doped g-C 3 N 4 using urea as g-C 3 N 4 precursor and ascorbic acid (AA) as carbon and oxygen sources, which induces electronic structure reconfiguration. By replacing AA with other organic precursors, a series of C and O dual-doped g-C 3 N 4 are successfully prepared, demonstrating the generality of the developed methodology. As a demonstration, the C and O dual-doped g-C 3 N 4 using AA as the organic precursor (CN-AA 0.3) exhibits pronouncedly enhanced catalytic activity in peroxymonosulfate (PMS) activation for organic pollutant degradation without light irradiation compared with pristine g-C 3 N 4 and single oxygen-doped g-C 3 N 4. Experimental and theoretical results revealed the electron-poor C atoms and electron-rich O atoms as active sites for PMS activation in terms of simultaneous PMS oxidation and reduction. This work offers a universal approach to synthesize nonmetal dual-doped g-C 3 N 4 with reconfigured electronic structure, stimulating the development of g-C 3 N 4 -based materials for diverse environmental applications. [ABSTRACT FROM AUTHOR]

Simultaneous solar hydrogen production and organics degradation is achieved by an unassisted, hybrid tandem photocatalytic fuel cell based on a highly-active silicon-doped TiO 2 nanorod array with enhanced electronic properties. • A high-active STNR with homogenously distributed silicon in TiO 2 matrix is prepared. • A notably enhanced J sc of ˜0.76 mA cm−2 at 0.2 V vs Ag/AgCl is achieved for STNR. • A HTPFC is assembled by adhering Si PVC at the back of STNR as monolithic photoanode. • A removal ratio of 94.3% for TC is obtained by HTPFC in 1.5 h operation. • An H 2 generation rate of ˜28.8 μmol h−1 cm−2 is also achieved during degradation. A novel, unassisted, hybrid tandem photocatalytic fuel cell (HTPFC) is constructed by adhering a silicon solar cell (SSC) to the back of a highly-active silicon-doped TiO 2 nanorod array (STNR) for efficient solar hydrogen production coupled with organic compound degradation. The STNR with vertically arranged nanorods is prepared by a facile hydrothermal method and has improved charge transport properties and donor density due to the homogenously distributed silicon in the TiO 2 matrix. As a result, the STNR has a notably enhanced photocurrent density that is as high as ˜0.76 mA cm−2 at 0.2 V vs Ag/AgCl, which is ˜271% of the photocurrent density of undoped sample. By combining the intriguing features of the STNR and SSC, the HTPFC shows a superior performance for tetracycline degradation and hydrogen production, with a removal ratio of 94.3% after 1.5 h of operation and an average hydrogen generation rate of ˜28.8 μmol h−1 cm−2. Compared to conventional PFCs, HTPFCs have improved light absorption and charge transfer, owing to the synergistic effect between the STNR and SSC. The results also indicate that the HTPFC is highly flexible, adaptable, and stable when treating wastewaters with various organics, and a wide range of pH values and salinities. [ABSTRACT FROM AUTHOR]

• N-doped porous carbon was prepared via transformation from graphitic carbon nitride. • N-doped porous carbon (NC 1.0) possesses ultrahigh N content up to 33.75 at%. • NC 1.0 exhibits excellent reactivity and stability for peroxymonosulfate activation. • DFT calculations reveal PMS activation involving PMS reduction and oxidation. • Singlet oxygen (1O 2) is the main reactive oxygen species in the NC 1.0 /PMS system. Nitrogen-doped carbon materials are proposed as promising metal-free catalysts for persulfate-mediated catalytic oxidation process, yet the nitrogen content in the final carbon products is typically low. Moreover, controversies remain in the unambiguous identification of active sites in nitrogen-doped carbons for persulfate activation. Here we report the facile synthesis of nitrogen-doped carbon material via one-step pyrolysis of urea and D-mannitol, which simultaneously combine ultrahigh nitrogen content (up to 33.75 at%) with apparent porous structure via transformation from graphitic carbon nitride. With this strategy, the highly nitrogen-doped porous carbon (NC 1.0) exhibits excellent catalytic activity toward peroxymonosulfate (PMS) activation for oxidation of organic pollutants. Both experiments and density functional theory (DFT) calculations, for the first time, revealed that the electron-rich graphitic N and electron-deficient carbon atom adjacent to graphitic N in NC 1.0 served as active sites for PMS reduction and oxidation toward the generation of hydroxyl radical (OH) and singlet oxygen (1O 2), respectively, in which PMS oxidation was the main reaction in the course of PMS activation rendering 1O 2 the dominant reactive oxygen species (ROS) in the NC 1.0 /PMS system. More importantly, NC 1.0 presents robust stability in PMS activation, superior to most reported nitrogen-doped carbon-based catalysts, offering great promise for practical environmental remediation. [ABSTRACT FROM AUTHOR]

• Effect of biofiltration with CAC on DBPs and pathogenic bacteria were investigated. • CAC resulted in higher biological removal of DOC and DBPs precursors. • Less microbial biomass, metabolites and smaller microbial clusters were detected in the effluent of CAC. • The EPS in CAC exhibited superior characteristics on improvement of water quality. • CAC maintained the safety of water quality continually in downstream DWDSs. The change of water quality was investigated in pilot-scale ozone-biological activated carbon (O 3 -BAC) filters using an emerging coconut shell-based granular activated carbon (CAC) or traditional granular activated carbon (GAC), respectively. More dissolved organic carbon (DOC) and disinfection by-products (DBPs) precursors were removed, meanwhile, less microbes, less metabolites and smaller microbial clusters were detected in the effluent of CAC compared with GAC. Sequentially, lower DBPs formation and higher disinfection efficiency were achieved in drinking water distribution systems (DWDSs). Furthermore, it was observed that extracellular electron transfer was enhanced in the attached biofilms of CAC, hence improving the microbial metabolic activity and biological removal of DOC. The results were attributed to the strong interaction of extracellular polymeric substances (EPS) with highly graphitized CAC. In addition, CAC resulted in totally different EPS in attached biofilms with superior characteristics including stronger viscosity, higher flocculating efficiency, mechanical stability and numerous binding sites for bacterial cells. Consequently, a wide range of compact interconnected biofilms formed on the surface of CAC and exhibited certain binding effect for microbial flocs and metabolites. Therefore, CAC resulted in higher microbial metabolic activity and lower release of microbes and metabolites, which was beneficial to maintain water quality safety in downstream DWDSs. [ABSTRACT FROM AUTHOR]

• nZVCu-Cu(II)-rGO is developed via an annealing reduction process for first time. • Nanoscale Cu(0) and Cu(II) are generated on rGO along with C-O-Cu formation. • Dual reaction centers form around Cu(II) and aromatic rings of rGO due to π→Cu. • Nanoscale Cu(0) accelerate the electron transfer of the dual reaction center system. • Pollutants are efficiently degraded by two ways: as electron donors and attacked by radicals. Nanoscale zero-valent copper combined with Cu(II)-doped reduced graphene oxide hybrid (nZVC-Cu(II)-rGO) is synthesized through an annealing reduction process, and it shows very high activity and efficiency for removing refractory organic compounds with H 2 O 2. The conversion rate for the organic pollutant in this system is ∼77 and ∼13 times higher than that in the graphene oxide (GO) and reduced graphene oxide (rGO) systems, respectively. The characterization shows that nanoscale Cu(0) and Cu(II) are generated on the rGO surface during the annealing process and they are accompanied by the C O Cu bonding formation between the rGO substrate and the Cu(II) species in nZVC-Cu(II)-rGO, which induces cation–π interactions on the surface, resulting in the reinforced electron-rich micro-centers formation around the nZVC-enhanced Cu(II) species and electron-poor micro-centers on rGO-aromatic rings. The generation of nanoscale Cu(0) consolidates the polarization of the dual reaction micro-centers and greatly accelerates the electron transfer of the system, thus promoting H 2 O 2 reduction to OH in the electron-rich micro-centers. Pollutants can obviously replace H 2 O 2 as the electron donors of the system and are efficiently oxidized and degraded in the electron-poor micro-centers, with their own electron energy being fully utilized in the nZVC-Cu(II)-rGO Fenton-like system. [ABSTRACT FROM AUTHOR]