Chloride ions (Cl⁻) are traditionally considered as radical scavengers that inhibit persulfate-based advanced oxidation processes (AOPs). This study challenges this paradigm by demonstrating that Cl⁻ can be synergistically harnessed in a granular activated carbon (GAC)/sodium persulfate (PDS) system to significantly enhance toluene oxidation. The GAC/PDS/Cl⁻ system achieved 78.4% total organic carbon (TOC) removal within 150 min, representing a 25.8% enhancement over the Cl⁻-free system, with the pseudo-first-order rate constant increasing nearly threefold. Mechanistic investigations revealed a dual-pathway synergy: a radical pathway involving SO₄•⁻, •OH, ¹O₂, and O₂•⁻, and a dominant non-radical electron-transfer pathway in which GAC acts as an electron-conducting bridge, accepting electrons from both toluene and Cl⁻ and delivering them to PDS. This GAC-mediated interfacial electron transfer eliminates homogeneous competition, transforming Cl⁻ from an inhibitor into an electron donor and conductivity enhancer. Reusability tests over eight cycles showed gradual GAC deactivation, which was effectively reversed by NaOH regeneration, with regenerated GAC achieving 85.9% TOC removal—surpassing fresh material. Characterization using Brunauer-Emmett-Teller(BET), X-ray Photoelectron Spectroscopy (XPS) and Raman revealed a self-compensation mechanism: PDS oxidation etches the carbon matrix, expanding micropores and generating defects while consuming hydroxyl functional groups; alkaline regeneration restores hydroxyl groups and further increases defect density, rejuvenating active sites. Validation with real shale gas flowback water confirmed the system's practical applicability, achieving superior TOC removal (49.5%) compared to Fenton (27.0%) and Fe²⁺/PDS (46.4%), with no chlorinated byproducts detected. This work transforms Cl⁻ from an inhibitor to a promoter, offering a low-carbon, sludge-free, regeneration-enabled AOP strategy for high-salinity wastewater treatment.

Simultaneous nitrification and denitrification (SND) in one reactor has been realized with different methods in previous research. In this study, porous polymer biofilm carriers together with suspended biomass were fluidized in an airlift membrane bioreactor reactor. Limited filamentous bulking (LFB) was used to enhance SND, synthetic wastewater with mean ammonium-nitrogen concentrations of 50 mg/L was treated in the system, achieving 70% nitrogen removal. Batch experiments clearly demonstrated that nitrification was localized in the suspended biomass and attached on the carriers, while denitrification was confined within the bioparticles of the slowly degrading biocompounds. High-throughput sequencing analyses confirmed that heterotrophic nitrifying bacteria were the nitrogen-transforming functional bacteria in both the sludge and biofilm of the integrated fixed-film activated system, with Rhodobacter being the dominant genus. The LFB state-causing agent was identified as Thiothrix , which was present in the integrated fixed-film activated.

To promote the recovery of lithium resources from produced water in lithium-rich oil and gas fields, the Ce-doped layered manganese-based lithium ion-sieve spherical particle (SCHMO) has been proposed for lithium recovery in produced water of gas well in the Sichuan Basin by downflow fixed-bed adsorption. Experimental results indicated the total salt of produced water was 130.83 g/L, the CODCr was 8065.03 mg/L. By adding 2 g/L NaOH and combining it with 20%PAC and 1%PAM for flocculation and sedimentation, the significant influence of total salt on adsorption capacity can be effectively removed and adsorption capacity can be enhanced. Optimal operational conditions were observed at the flow rate of 0.81 mL/min with a height-to-diameter ratio of the fixed-bed of 1.5. The desorption of Li+ was effectively achieved by 140 mL of acid washing liquid for every 2 g of fixed-bed. Penetration curve experiments revealed the fixed-bed reached saturation at 1600 mL, 2000 mL, and 2400 mL at temperatures of 10 degrees C, 25 degrees C, and 40 degrees C, respectively. The SCHMO-FB adsorption process exhibited strong fitting results with both the Yoon-Nelson model and the Clark model. The increase in temperature could accelerated the reaction rate and enhanced the saturated adsorption capacity. The average adsorption capacity of Li+ was recorded at 17.22 mg/g in 15 cycle adsorption/desorption experiments, the Mn dissolution loss ratio remained stable at 0.4 similar to 0.6%. While SCHMO-FB cannot entirely eliminate the influence of interfering ions on Li+ recovery, it is essential to consider combined processes in industrial applications to further mitigate the impact of interfering ions.

Lithium manganese oxide (LMO) is a key material for extracting lithium from salt-lake brines, but it has problems such as structural instability and manganese dissolution during the cycling process. This review systematically examines the mechanisms of Mn loss and the Jahn-Teller effect, pinpointing key stability factors. It presents a multi-scale optimization strategy: (i) Cr, Al, Mg doping to suppress Mn3+ disproportionation and raise Mn oxidation states, strengthening the spinel lattice; (ii) advanced shaping—granulation, film casting, foaming—to boost mechanical robustness and cycle life; and (iii) novel eluents that cut Mn dissolution to <0.3%, markedly enhancing regeneration. Bridging fundamental insights with practical solutions, the review provides actionable guidance for industrial LMO deployment, while summarizing pathways toward achieving high cycling stability and adsorption efficiency for sustainable lithium recovery.

To solve the problems of poor fluidity, difficult recovery, and cycle loss of lithium manganese oxide, this study used polyvinyl butyl aldehyde (PVB) and polyethylene glycol (PEG) to construct a physical blend system, and combined with the drop-phase conversion method to prepare precursor particles. Under the optimized conditions of 10 % PVB, 7 % PEG, 40 degrees C, and a gel-powder ratio of 1:3, the porosity of spherical particles reached 65.23 %, the average particle size was 1.35 mm. Under 25 degrees C, with an initial Li-containing solution pH= 10 and a Li+ concentration of 100 mg/L, the adsorption capacity is 15.9 mg/g. This study constructed a pretreatment process of "Poly Aluminum Chloride (PAC) for Suspended Solids (SS) removal -> NaOH+PAC/Polyacrylamide (PAM) for Mg2+ removal", reducing water quality interference. In the fixed-bed system, when the feed rate was 0.53 mL/ min and the adsorbent was 0.8 g, the adsorption capacity reached 22.78 mg/g. For every 0.8 g of adsorbent desorbed with 150 mL of HCl, the Li recovery rate was 25 % and the Mn dissolution rate was less than 1 %. After 10 cycles, the adsorption capacity dropped to 18.16 mg/g. This study provided technical solutions for the industrialization of lithium manganese oxide from complex water bodies.

Foam-laden shale gas flowback water containing high surfactants and salts challenges conventional treatment. This study develops a three-stage synergistic process: iron-carbon micro-electrolysis (cleaves long-chain surfactants and eliminates foam), in-situ Fe2*-activated persulfate (PDS) pre-oxidation, and granular activated carbon (GAC)-activated PDS polishing (radical/non-radical deep mineralization). Under optimized conditions, the integrated process achieves Total Organic Carbon(TOC) removals of 61.69% for real wastewater and 88.67% for Sodium dodecylbenzene sulfonate (SDBS)-spiked synthetic water, with complete foam eradication. Mechanistic studies reveal that non-radical electron-transfer dominates in GAC/PDS, and chloride ions enhance degradation by facilitating electron transfer. The sequential pH strategy (acidic-then-alkaline) maximizes radical utilization. Compared with Fenton, the combined process shows superior oxidation performance and lower total operating cost. GAC retains 30-40% removal after seven cycles, with X-ray Photoelectron Spectroscopy(XPS) identifying C-OH as the primary persulfate activation site. This work provides an efficient, low-sludge strategy for high-salinity, foam-stable shale gas wastewater.

To address the issues of poor fluidity, significant loss during cycling, and unsuitability for industrial adsorption of lithium ion-sieve powders, the Ce4+-doped layered Mn-based lithium ion-sieve precursor (Li1.37Ce0.001Mn1.22O3) was fabricated into spherical particles, by using blend of PVB and PMMA with anti-solvent phase inversion method. The incorporation of PMMA appropriately could increase the porosity and pore size of the spherical particles, while enhancing strength and compression resistance. The porosity of SCLMO was 47.86%, with particle size range of 1.5-2.0 mm. The maximum load capacity was 627.53 N, while the maximum stress was recorded at 233.46 MPa, and the Young's modulus was 369.70 MPa. The adsorption process of corresponding lithium ion-sieve spherical particles (SCHMO) was characterized by both physical and chemical reactions, adhering to Langmuir adsorption isotherm model and following pseudo-second-order kinetics, with intraparticle diffusion being the dominant mechanism. After 15 adsorption cycles, the adsorption capacity of SCHMO for Li+ stabilized at approximately 20 mg/g, with Mn dissolution loss ratio of less than 0.5%. In experiments involving the static adsorption of Li+ from actual oil and gas field produced water, the adsorption capacity was recorded at 17.84 mg/g. The lithium ion-sieve spherical particles exhibited significant potential for further industrial applications.

This study isolated a novel halotolerant and acid-tolerant yeast, Barnettozyma hawaiiensis, from raw shale gas fracturing flowback fluid (SGFFF), demonstrating high-efficiency degradation of benzaldehyde-a representative toluene-derived aromatic intermediate. Under optimized conditions (pH 5, 20 g/L NaCl, 35 degrees C), it achieved 98.28 % benzaldehyde and 74.76 % total organic carbon(TOC) removal within 24 h. Whole-genome sequencing revealed abundant genes related to organic degradation, salt/acid tolerance, and thermostability. Gas chromatography-mass spectrometry(GC-MS) and enzymatic analysis elucidated a distinct degradation pathway involving monooxygenase and catechol 1,2-dioxygenase, leading to complete mineralization. Unlike previous halotolerant bacteria studies focusing on general organics, this work provides deep mechanistic insights into aromatic metabolism under high salinity and acidic conditions. Applied to real SGFFF, the strain achieved 37-47 % TOC removal, showcasing significant potential for enhancing bio-treatment efficacy in hypersaline wastewater.

Iron-based catalysts are widely used in the electro-Fenton technology, which are limited by strict acidic conditions. Cobalt-based catalysts can undergo Fenton-like reactions with H2O2 under neutral conditions. In this study, a CF@Co2NiOx@MgAl-LDH cobalt-based bimetallic catalyst was prepared to study 1-hydroxyethylidene-1 (HEDP) and methylisothiazolinone (MIT) degradation performance in a heterogeneous electro-Fenton system. Cobalt-based bimetallic oxides were first modified with magnesium-aluminum hydrotalcite (MgAl-LDH) and subsequently loaded onto carbon felts (CF) to reduce metal ion leaching and improve catalyst recyclability. The experimental results showed that CF@Co2NiOx@MgAl-LDH could effectively remove 93.06 % of HEDP and 92.42 % of MIT after 2 h of reaction. Removal of HEDP and MIT was still achieved at 78.62 % and 81.09 % after four cycles of experiments. Based on the catalyst characterization results, the reasons for the differences in the pollutant removal performance were analyzed and the optimal operating parameters of the CF@Co2NiOx@MgAlLDH for the removal of HEDP and MIT were investigated. This study provides a novel and sustainable strategy for the design and application of cobalt-based catalysts.

Methylisothiazolinone (MIT), a recalcitrant biocidal pollutant prevalent in industrial wastewater, demands advanced treatment strategies to address its environmental persistence. This study develops an air-lift moving bed electro-Fenton (EF) reactor integrated with iron-based heterogeneous catalysts to enhance MIT degradation. Through systematic synthesis and evaluation, carbon fiber-supported magnetite (CF@Fe3O4) was identified as the optimal catalyst, significantly enhancing reaction efficiency while minimizing sludge production. Under optimized continuous flow conditions (current of 0.7 A, ferrous concentration of 0.25 mM, aeration rate of 1.4 L/min and electrolyte concentration of 70 mM), the heterogeneous EF system achieved MIT and COD removal rates of 94.24 % and 44.08 %, respectively. Crucially, the heterogeneous system demonstrated significant operational advantages: compared to the homogeneous system (sludge yield 34.27 mg/L, specific energy consumption 0.188 kWh/gMIT), the CF@Fe3O4 system reduced sludge yield by 95.3 % (to 1.61 mg/L) and specific energy consumption by 11.8 % (to 0.1658 kWh/gMIT). An in-depth mechanism analysis revealed efficient center dot OH generation along with pollutant degradation pathways. These results confirm that the air-lift moving bed EF reactor integrated with CF@Fe3O4 catalyst achieves high performance, providing a feasible strategy for the treatment of MIT-containing industrial wastewater.

Zero-valent iron (ZVI) is the promising enhancer for sludge anaerobic digestion (AD) performance and for mitigating the proliferation of antibiotic resistance genes (ARGs). However, concerns about its size effects in shifting the behavior and risk of ARGs in sludge, during the AD process. Here, the metagenomics-based profile of ARGs, along with their potential (pathogenic) hosts in sludge were investigated, during mesophilic AD enhanced by ZVI with three different sizes. Results showed that the size of ZVI affected the profiles of ARGs, with nano-ZVI (nZVI, 50 nm) demonstrating the most significant reduction in abundance (by 45.0 %) and diversity (by 8.6 %) of total ARGs, followed by micron-ZVI (150 μm) and iron scrap (1 mm). Similar trends were also observed for high-risk ARGs, pathogens, and potential pathogenic hosts for ARGs. Notably, nZVI achieved the greatest reductions in the abundance of risk ARGs and potential pathogenic hosts (superbugs) by 58.8 % and 53.9 %, respectively. Correlation and redundancy analyses revealed that, the size of ZVI induced concentration differences in ammonium nitrogen, pH, carbonaceous matters, iron, and potential microbial hosts were the main reasons for the variation in the risk of ARGs. Moreover, the down-regulation of genes involved in oxidative stress contributed to the lower risk of ARGs in the three ZVI groups, especially in nZVI. This study provides insights into AD processes of solid wastes using ZVI enhancers.

Shale gas flowback and produced water (SGFPW) pose significant challenges to biotechnology due to their high salinity. In this study, we explored a novel method utilizing an amphiphilic copolymer of methyl methacrylate and acrylamide (p(MMA-AAM)) and powdered activated carbon (PAC) to modify poly(ether sulfone) (PES). We prepared a series of monoliths for microorganism immobilization using both thermal-induced phase separation and non-solvent-induced phase separation. Characterization of the monoliths via fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), nitrogen adsorption-desorption analysis revealed improved hydrophilicity in the p(MMA-AAM)-modified monoliths and increased specific surface area (SSA) in monoliths with PAC addition. Particularly, the highest SSA was observed for the 0.5 g PAC (0.5-PAC/PES) monolith at 235.19 m2/g. Wastewater treatment experiments demonstrated that the 0.5-PAC/PES system exhibited superior pollutant removal performance, and it achieved nearly 100 % removal of NO3 - and total nitrogen (TN) in simulated SGFPW. Besides, the removal rates of TN and total organic carbon (TOC) in actual SGFPW by the 0.5-PAC/PES system were 1.5 times and 1.3 times higher, respectively, than those achieved with suspended microorganisms. After 96 h biological treatment, the extracellular polymeric substances (EPS) content of 0.5-PAC/PES was highest, showing its positive role in enhancing microbial activity. This work introduces a new approach to immobilize microorganisms, enhancing biological activity for SGFPW treatment under high salinity conditions.

The high salinity of pickle wastewater poses significant challenges to conventional biological treatment technologies. In this study, an anoxic/oxic membrane bioreactor (A/O-MBR) system was developed through carrier selection and operational adjustment, and successfully applied to the treatment of actual pickle wastewater. Among the three tested carriers (polyurethane sponge, moving bed K1, and moving bed K3), the polyurethane sponge exhibited superior biofilm formation capacity (248 mg biofilm per gram carrier) and demonstrated higher salt tolerance across a salinity range of 0.5 % to 2.0 % NaCl, maintaining an average ammonium nitrogen (NH4+- N) removal efficiency of over 97 % even at 2 % salinity. The optimal operating conditions were determined to be a carbon-to-nitrogen ratio of 21 f 1, a hydraulic retention time of 32 h, and a reflux ratio of 400 %. Under these conditions, the system achieved average removal efficiencies of 89.56 f 4.86 % for NH4+-N, 87.84 f 4.68 % for total nitrogen (TN), and 95.81 f 0.56 % for chemical oxygen demand (COD). When treating actual pickle wastewater, the system achieved average removal efficiencies of 75.40 f 2.44 % for NH4+-N, 85.30 f 1.23 % for TN, and 97.30 f 0.28 % for COD during the stable operation phase (15-20 days). Microbial community analysis revealed that the introduction of actual wastewater led to a reduction in microbial diversity and richness. While Streptococcus and Brooklawnia remained dominant, Veillonella and Bacteroides became more prevalent following the addition of real wastewater. These findings demonstrate the effectiveness of the A/O-MBR system for pickle wastewater treatment and provide guidance for industrial application.

With appropriate cerium (Ce) doping, the layered lithium ion-sieve precursor Li1.37Ce0.001Mn1.22O3 was synthesized using hydrothermal and solid-phase calcination, which exhibited Li/Mn ratio exceeding 1, indicating a high theoretical adsorption capacity. The incorporation of Ce further stabilized the spatial configuration of the layered ion-sieve and controlled the dissolution loss ratio of manganese (Mn) to approximately 0.55%. At 25 degrees C, with pH of 9 and initial lithium-containing solution concentration of 100 mg/L, the adsorption capacity can reach around 33 mg/g. Despite the presence of interfering ions, it maintained selective adsorption of lithium (Li). The lithium adsorption process by layered lithium ion-sieve adhered to the Langmuir adsorption isotherm model, while the kinetics of adsorption conformed to pseudo-second-order kinetics. This adsorption process was characterized as spontaneous and endothermic, with higher temperatures and concentrations of lithium solutions facilitating both the adsorption process and capacity. It was found that in simulation analysis, compared to the cubic ion-sieve precursor, Li in the layered structure occupied more spatial points, resulting in a more compact stacking and increased bond energy. It alleviated the dissolution loss of Mn during the pickling process. The proximity of Ce resulted in a reduction of the charge on Mn and Li. An appropriate amount of Ce doping will enhance the valence state of Mn; however, excessive Ce doping led to the depletion of electrons from nearby Mn and Li. During pickling process, the Li surrounding Ce in the precursor were preferentially replaced by hydrogen (H) due to their lower charge.

Heavy metal pollution in soils poses a hazard to both human health and the natural ecosystems, thus it is vital to develop affordable and effective technology for the treatment of soils polluted with heavy metals. Currently, a fascinating group of technologies known as electrochemical soil treatments has received a lot of attention, owing to the advantages of their compact equipment structure, operational simplicity, rapid remediation and costeffectiveness. Although some progresses about electrochemical remediation have been achieved, there is no comprehensive review on the mechanism, advances and perspective on the role of electrochemical methods for soil contamination remediation. Herein, the working mechanism of electrochemical methods on soil remediation was clarified in detail. Further, taking As, Cd and Pb polluted soils as typical examples, the recent progress by electrochemical methods was summarized in detail. Additionally, the recent progress about remediating multicomponent heavy metal pollution by electrochemical methods was also discussed. Finally, the conclusion and future perspective were also proposed. Overall, a comprehensive review highlighted recent advancements, innovative techniques, and emerging trends in electrochemical treatment, which may provide some new un-derstandings and opportunities for soil contamination remediation.

Lithium ion-sieve with selective adsorption capacity is an important research direction in the field of recovering lithium from brine. The lithium ion-sieve precursor Li1.6Mn1.6O4 was efficiently prepared using a combination of the hydrothermal method and solid-phase calcination. Subsequently, a highly adsorbent with high adsorption capacity was obtained through a process involving pickling and Li leaching. The impact of different preparation routes and conditions on both the intermediate product LiMnO2 and the ion-sieve precursor Li1.6Mn1.6O4 were investigated. Under conditions of 25 degrees C, pH 9, and an initial Li+ concentration of 100 mg/L, the initial adsorption capacity and Mn dissolution loss are relatively optimal. After 10 cycles, the adsorption capacity stabilizes at 25-30 mg/g, However, Mn dissolution loss is unavoidable, it stabilizes between 2.0 % and 2.5 %. The selective adsorption of Li+ remains effective even in the presence of Ca2+, Mg2+, Na+, and K+ interference. Li desorption and Mn dissolution loss were investigated using density functional theory, Fukui function, electron orbital theory, and density of states. The introduction of H+ during the pickling process induced structural modifications in the ion-sieve precursor Li1.6Mn1.6O4, leading to a decrease in Mn-Mn bonds, Mn-O bonds, and Li-O distances. Initially, Li+ at each site of Li1.6Mn1.6O4 had an equal probability of being replaced by H+. Subsequent desorption occurred far away from the desorption point. The loss of Mn3+ in Li1.6Mn1.6O4 resulted in an increased electrophilic attack index at the H+ substitution site, and the 3d orbital electrons of Mn3+ migrate to the 4d and 2p orbitals to seek stability.

Mo2C@Fe3O4 and three kinds of MO2-doped Mo2C@Fe3O4 were successfully fabricated as the Mo2C@TiO2@Fe3O4, Mo2C@MoO2@Fe3O4 and Mo2C@CeO2@Fe3O4 particles for the degradation of 2-methyl-4-isothiazolin-3-one and 1-hydroxy-1,1-diphosphonoethane in a three-dimensional electro-Fenton system. The catalyst particles showed an enhancement for the catalytic activity in the system. Furthermore, the Mo2C@CeO2@Fe3O4 particles exhibited superior activity for 2-methyl-4-isothiazolin-3-one and 1-hydroxy-1,1-diphosphonoethane degradation compared to the other two particles. Based on the characterization of the synthesized particles, leaching concentration of Fe2+, generation of H_2O_2 , ∙ OH , O_2^∙ - , the reasons for the difference in pollutant degradation performance among the three type particles were comprehensively analyzed. At last, some important experimental parameters, such as particles dosage, current density and aeration intensity, which would obviously affect MIT and HEDP degradation performance were studied. Using the Mo2C@CeO2@Fe3O4 as catalytic particles, optimal 2-methyl-4-isothiazolin-3-one and 1-hydroxy-1,1-diphosphonoethane degradation rates were 97.2

The anode of two-chamber MFC was inoculated with anaerobic granular sludge (AGS) and flocculent sludge (FS), respectively. Simulated wastewater was used by adjusting different Cu2 + concentrations at concentration of 0.1 mg/L, 0.5 mg/L and 1 mg/L. Two sets of the MFC systems were maintained at a temperature of 30 +/- 2 degrees C. The power production of the AGS-MFC and the FS-MFC was promoted obviously with Cu2+ concentration of 1 mg/L, which was 707 mV and 675 mV. The Cu2+ concentration had little influence on COD removal rate of both MFC, and the COD removal rate of the AGS-MFC and the FS-MFC was 94.6 % and 94.1 % with the Cu2+ concentration of 1 mg/L. The quasi-second-order kinetic equation could well describe the Cu2+ adsorption process of the AGS-MFC and the FS-MFC, and the EDS profiles indicated that the copper element was adsorbed and fixed mainly on the surfaces of the anode biofilms. The main bacteria in the two MFC had some overlap, which were Bacilli, Anaerolineae and Ignavibacteria. With the addition of Cu2+, Bacilli replaced Betaproteobacteria as the dominant microflora in the FS, while Syntrophobacter, Petrimonas and Anaeroarcus appeared in the FS.

The occurrence of organophosphate triesters (OPEs) and organophosphate diesters (m-OPEs) in ground water is still unclear. To fill the blank, ground water samples in dry and wet seasons, surface river water and paired sediment samples were collected in Sichuan province and analyzed for 14 kinds of OPEs and 7 m-OPEs. Except Trimethyl phosphate was scarcely detected, the other OPEs were extensively found in aquatic environment. The concentrations of Ʃ14OPEs and Ʃ7m-OPEs ranged from 45.0 to 231 ng/L and from 1.25 to 62.3 ng/L in ground water and ranged from 2.20 to 1709 and from 0.08 to 35.5 ng/L in surface water, respectively. Compared to other reports, the pollution in Minjiang and Tuojiang river was at medium level. The concentration ratios and correlation analysis between OPEs and m-OPEs indicated that OPEs in ground water had three main sources, and m-OPEs mainly came from direct usage. Low ecological risk was found for surface water. The carcinogenic and non-carcinogenic risks of OPEs in surface and ground water via ingestion and dermal contact in moderate and high exposure scenarios were assessed, and results suggested the risks to human which mainly caused by Tri(2-chloroisopropyl) phosphate could be negligible.