Pollutant Removal Efficiency Research Articles

Inhibition of denitrification and enhancement of microbial interactions in the AGS system by high concentrations of quinoline

Quinoline represents a highly toxic and structurally stable nitrogen-containing heterocyclic compound in coking wastewater, posing a potential threat to human beings and the ecological environment. In this study, we investigated the impact of gradually elevating quinoline concentration on pollutant removal efficiency, sludge characteristics, microbial community and their interactions in the aerobic granular sludge (AGS) system. The results demonstrated that AGS was capable of effectively degrading quinoline, with a final removal rate of 90 mg/L quinoline reaching 98.54 ± 0.28%. Notably, the denitrification process was significantly impeded in the presence of 90 mg/L quinoline, with the Phase D effluent displaying a notably high NO3--N concentration of 37.09 ± 21.81 mg/L, primarily attributed to the reduced abundance of norank_f_A4b bacteria. As the quinoline concentration increased, the sludge particle size diminished from 3.46 to 2.60 mm, while the settling performance deteriorated significantly, escalating from 31.29 ± 1.63 mL/g to 62.32 ± 2.87 mL/g. Meanwhile, the protein (PN) content in EPS gradually increased (from 19.87 ± 0.88 mg/g MLVSS to 51.22 ± 3.21 mg/g MLVSS), while the polysaccharide (PS) content fluctuated. Quinoline profoundly modified microbial community composition and structure, with deterministic processes dominating community assembly. Network analysis indicated intensified and complex microbial interactions at 90 mg/L quinoline, characterized by significantly higher positive correlations. In addition, rare taxa (RT) dominated the network nodes, with 74 of 93 key species belonging to RT, highlighting their pivotal roles in sustaining system functions and strengthening microbial connections. This study provides new insights into the effects of quinoline on microbial community structure and interactions in AGS system.

Enhanced Photodegradation of Imidacloprid Using ZnO@Ca‐Alginate Composites: Optimization of pH and pHzcp for Effective Water Treatment

AbstractThis research focused on the photodegradation of the insecticide imidacloprid (IM) via a ZnO@Ca‐Alginate composite catalyst to address water contamination issues, particularly in agricultural areas such as Palestine. The composite was synthesized and characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), energy dispersive X‐ray (EDX), thermogravimetric analysis (TGA), and Fourier transform infrared (FT‐IR) spectroscopy, confirming the presence of ZnO. Photocatalytic experiments under simulated solar light revealed significant IM degradation, with a 50 % reduction in 40 minutes, an 80 % reduction in 2 hours, and up to 94 % in 3 hours. The degradation efficiency was influenced by the point of zero charge (pHzcp) and solution pH, with optimal performance under neutral to slightly basic conditions. UV‐visible spectrophotometry, high‐performance liquid chromatography (HPLC), and total organic carbon (TOC) analyses verified complete IM mineralization, yielding CO₂, Cl−, and NO₃− after 3 hours. The ZnO@Ca‐Alginate composite demonstrated high reusability, highlighting its potential for treating pesticide‐contaminated water. This study emphasizes the need for efficient pollutant removal technologies in regions where agricultural pollutants are prevalent.

Laccase‐Copper Nanohybrids as Highly Active Catalysts for Bio‐degradation

AbstractPhenolic contamination is one of the crucial concerns for the safety of drinking water. Enzymatic degradation is a green and efficient manner for phenolic compounds removal from water. However, enzymatic degradation of phenolic pollutants in water is limited as a result of the low activity, stability and reusability of the enzyme. Herein, we propose a novel strategy to degrade phenolic pollutants in water by using an enzyme‐metal hybrid catalyst constructed by in situ formation of ultrafine Cu nanoparticles on the cross‐linked Laccase aggregates. The designed Cu/Lac CLEAs showed excellent performance on phenolic pollutants removal due to the cooperative catalysis between Lac CLEA and Cu NPs and the enrichment of phenolic pollutants in hybrid catalyst. The degradation efficiency of 2,4,6‐trichlorophenol catalyzed by Cu/Lac CLEAs was improved by 33 % compared to the Lac CLEAs, while Cu NPs barely catalyzed the degradation process of phenolic pollutants. The Cu/Lac CLEAs hybrid catalyst exhibit high catalytic activity at room temperature in a wide pH range of 5–8, making the degradation of phenolic pollutants more practically operational. In other words, this study develops a novel hybrid catalyst for the efficient removal of pollutants from water.

Use of native macrophyte Echinodorus subalatus for grey water treatment applying alternative bed substrate in constructed wetlands

ABSTRACT Two vertical flow constructed wetland (VFCW 1 and VFCW 2) with native macrophyte Echinodorus subalatus (Mart.) were operated. In VFCW 1, the substrates used were ceramic brick, washed sand, seashells (Anomalocardia brasiliana), and ceramic brick and sand in VFCW 2. The system was operated for 74 days, in batches, with cycles of 168 h, and fed with synthetic grey water. The presence of seashells in VFCW 1 was a differential factor (p < 0) for the removal of anionic surfactant (94.09 ± 7.77%), COD (88.43 ± 5.43%) and total phosphorus (45. 98 ± 9.86%) when compared to VFCW 2. The Langmuir isotherm was used to calculate the substrate adsorption capacity for total phosphorus, anionic surfactant, and COD. The results showed that adsorption on support materials was not the primary mechanism of pollutants removal. From 16S sequencing, it was observed that phylum Firmicutes was the most abundant (96.5%), followed by phylum Proteobacteria (3.5%). The results suggest that using seashells as an alternative substrate improved pollutant removal efficiency.

New Perspective for the Prediction of Pollutant Removal Efficiency in Constructed Wetlands: Using a Genetic Algorithm-Assisted Machine Learning Model

New Perspective for the Prediction of Pollutant Removal Efficiency in Constructed Wetlands: Using a Genetic Algorithm-Assisted Machine Learning Model

Characteristics of Nitrogen Removal from an Integrated Fixed-Film Activated Sludge (IFAS) System and the Relationship Between Activated Sludge and Biofilm Interactions

In order to investigate the enhancement mechanism of modified three-dimensional elastic filler (MTEF) on the nitrogen removal performance of the integrated fixed-film activated sludge (IFAS) process, and to clarify the interactions between competition and synergy between activated sludge and biofilm in the IFAS system, an IFAS reactor (T2) filled with MTEF was employed for the study, while a sequencing batch reactor activated sludge process (SBR) reactor (T1) was utilized for comparison. IFAS and SBR reactors were operated over an extended period at ambient temperature to assess the enhancement of pollutant removal performance with the addition of the filler to investigate the competitive dynamics between activated sludge and biofilm under varying influent water qualities (C/N, N/P, and organic loading), and to analyze the synergistic relationship between activated sludge and biofilm at the microbial level using high-throughput sequencing technology. The results demonstrate that throughout the entire operational phase, reactor T2 exhibited superior pollutant removal efficiency. Compared to reactor T1, reactor T2 achieved an average increase in the removal rates of COD, ammonia nitrogen, and total nitrogen by 13.07%, 12.26%, and 28.96%, respectively. The findings on the competitive dynamics between activated sludge and biofilm indicate that the nitrification volumetric load of the IFAS system is significantly higher than that of a pure activated sludge system, suggesting that the IFAS system possesses enhanced nitrification capabilities. Furthermore, when dealing with wastewater characterized by low C/N ratios and high phosphorus pollution, or under substantial organic loads, the biofilm holds a competitive edge and the IFAS system exhibits improved stability. High-throughput sequencing data reveal that the microbial community structures in activated sludge and biofilm can influence each other, thereby enabling the IFAS system to effectively enrich denitrification-related functional microbial populations. Additionally, the biofilm has a certain enhancing effect on the expression levels of nitrogen metabolism-related functional genes in the activated sludge phase microorganisms, indicating that, in addition to competitive interactions, there is also a synergistic effect between the biofilm and activated sludge.

Enhancing photocatalytic water treatment efficiency via nitrogen Self-Doping and Hive-Like Structuring in isotype homojunctions of g-C3N4 generated from Thiourea-Melamine copolymerization

The combination of overpopulation and rapid industrial progress has led to a pronounced increase in water contamination. Photocatalysis emerges as a viable solution for mitigating water pollution, and graphitic carbon nitride (g-C3N4) is considered as a particularly promising photocatalyst due to its advantageous properties, such as low cost, and high chemical stability. Nonetheless, the effectiveness of g-C3N4 is often compromised by its limited surface area and substantial recombination of photogenerated charge carriers. To address these challenges, in this work, we propose a systematic approach to develop photocatalytically efficient surface structures and intimate isotype homojunctions through the copolymerization of various g-C3N4 precursors. A range of photocatalysts, each with distinctly tailored morphologies and homojunctions, was produced and their photocatalytic performance was assessed through the removal efficiencies of model pollutants, bisphenol A (BPA), and methylene blue (MB), with each at a concentration of 10 mg L-1. The enhanced photocatalytic activity observed in the optimized sample is primarily attributed to its significantly increased surface area, which is ten times greater than that of standard g-C3N4, and a marked reduction in charge recombination, which is four times lower, facilitated by the intimate homojunction. Thus, this work will open the door to the synthesis of various highly efficient photocatalysts for application in the photodegradation of diverse pollutants, consequently mitigating adverse environmental effects.

Sulfonate-Bonded Conjugated Microporous Polymer Hollowed-Out Spheres to Capture Fluoroquinolone Antibiotics and Cationic Dyes from Wastewater.

Developing adsorbent materials for the efficient removal of multiple organic pollutants in water is of importance technological significance. In the present work, a kind of conjugated microporous polymer (CMP) with a hollow sphere structure was constructed by applying SiO2 nanoparticles as a template and 1,3,5-triethynylbenzene (TEB) and 2,7-dibromocarbazole (27-DBCZ) as building blocks via the Sonogashira-Hagihara cross-coupling reaction. In order to further improve the dispersibility of the as-resulting CMPs in water, hydrophilic CMPs (H-S-CMPs) were obtained by a sulfonation modification. The adsorption performance of H-S-CMPs on dyes and antibiotics was investigated, which was based on different experimental parameters such as the initial concentration, contact time, temperature, pH, and adsorbent dose. The adsorption isotherm, kinetics, and thermodynamics were also studied, and the possible adsorption mechanism of H-S-CMPs was discussed. The experimental results illustrated that the adsorption process of H-S-CMPs on dyes and antibiotics is more consistent with the Langmuir isotherm model and the pseudo-second-order kinetic model. The maximum adsorption capacities of H-S-CMPs for rhodamine B (RhB), methylene blue (MB), ciprofloxacin, and norfloxacin were 206.2, 324.7, 222.2, and 216.9 mg/g, respectively, which were determined according to the Langmuir isothern model. In addition, the adsorption mechanism of H-S-CMPs may be attributed to the synergistic effects of hydrogen bonding, electrostatic attraction, π-π stacking, and pore filling. After 5 cycles, H-S-CMPs still maintained good stability, and their removal rate of dyes could reach more than 70%. Notably, this polymeric hollow microsphere has been less extensively investigated as an adsorbent for the removal of dyes and antibiotics. As a result, based on the designable flexibility of CMPs and the unique structure of hollow microspheres, the material holds great promise for wastewater treatment in the presence of multiple pollutants.

Conversion of waste polystyrene into porous adsorbents for efficient removal of hazardous pollutants: Adsorption properties and adsorption mechanism

Herein, the porous adsorbent material (PS-SAS) was prepared by introducing a large number of carboxyl groups on the benzene ring of waste polystyrene (WPS) by Friedel-Crafts acylation reaction using succinic anhydride as the modifying group, followed by further alkaline modification, and was used for the removal of hazardous dye and heavy metal ion. The chemical structure and surface morphology of the prepared adsorbent were assessed via Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), optical microscope (OM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The prepared adsorbent gave highly efficient separation performance towards malachite green (MG) and Cu2+ with corresponding maximum sorption capacities of 2231 mg/g and 156 mg/g at 298 K. The experimental data indicated that the sorption process followed the Langmuir adsorption isotherm and the pseudo-second-order kinetic model. Moreover, thermodynamic studies also demonstrated that the sorption process occurred spontaneously. The adsorption mechanisms of the adsorbent for MG include hydrogen bonding, electrostatic attraction, n-π interactions, and π-π interactions, while for Cu2+ via electrostatic attraction, ion exchange, and complexation. Furthermore, the selective adsorption, regeneration, dynamic sorption, and simulated wastewater experiment demonstrated that the adsorbent is a promising adsorbent. And phytotoxicity test proved that the prepared adsorbent can effectively reduce the toxicity of dye and metal ions. In summary, the transformation of waste polystyrene into an adsorbent represents a promising solution for water purification.

An assessment of in vitro lead (Pb) bioaccumulation of Dianthus chinensis L. (Chinese pink).

Heavy metals (HM) also known as potentially toxic elements (PTEs), are well-known environmental pollutants, among which lead (Pb) is a widespread and hazardous soil contaminant. Its removal from soil sediments is often difficult to achieve. In this study, in vitro experiments were conducted to investigate the bioaccumulation capability of Dianthus chinensis L. in solid and liquid Murashige and Skoog (MS) medium supplemented with varying concentrations (0, 10, 100, and 200µM) of Pb as lead nitrate [Pb(NO3)2] for 30days. The objectives of the study were to assess the efficiency of the selected plant as a bio-accumulator in the in vitro system and to obtain data on morphological, biochemical, and molecular changes during Pb salt-induced stress. Significant growth patterns of initial growth promotion up to 100µM lead nitrate supplemented medium were observed, with maximum shoot length and biomass production along with remarkable lead bioaccumulation. Molecular studies on in vitro raised plantlets confirm the high degree of genetic uniformity (98.3%) of the selected plants after a considerable duration (30days) of Pb exposure. Biochemical parameters revealed significant stress effects, including a 284% reduction in total chlorophyll content, altered carotenoid, and proline level during the study. The experiment revealed the high tolerance capacity of D. chinensis to Pb salt and its bioaccumulation potential (397.33mg/kg). This increases the possible use of such an ornamental and floriculture plant as a prospective candidate for the efficient removal of soil Pb pollutants, as they can remediate soils, coupled with aesthetic and profitable outcomes for the growers.

Dissolved organic matter-mediated adsorption behavior of benzophenones on functionalized covalent triazine frameworks

Adsorption is a highly efficacious technique for the remediation of organic micropollutants (OMPs). However, the presence of dissolved organic matter (DOM) frequently impedes adsorbent process, with insufficient attention given to this influence. This study systematically evaluates the adsorption performance of covalent triazine frameworks (CTFs) functionalized with electron-donating or electron-withdrawing groups for benzophenones (BPs). The adsorption capacities of SO3H-CTF, OH-CTF, and NH2-CTF for BPs were 512.11 μmol/g, 1356.27 μmol/g, and 1421.85 μmol/g, respectively. The adsorption mechanism is predominantly governed by π-π electron donor–acceptor (EDA) interactions, supplemented by hydrogen bonding, particularly in hydroxyl-containing BPs, with electrostatic interactions being relatively negligible. Functionalization with − OH and − NH2 groups increased the electron density in π-conjugated regions, enhancing BPs adsorption capacity, whereas − SO3H modification, due to its electron-withdrawing nature, acted as a π electron acceptor. Importantly, the mediating role of humic acid (HA) in the adsorption process was investigated. The CTF-BPs-HA ternary system can either inhibit/enhance π-π EDA interactions between π-electron donor/acceptor and BPs by adsorbing onto the CTF materials. The HA-mediated system primarily affects the film diffusion stage, with minimal impact on pore diffusion and inner surface adsorption. The oxygenated functional groups in HA slightly enhanced hydrogen bonding within the adsorption system, with negligible influence on electrostatic interactions. In the presence of HA, the overall adsorption capacity of SO3H-CTF decreased by 67.0 %, while that of OH-CTF and NH2-CTF increased by 120.9 % and 55.3 %, respectively. This study elucidates the electronic behavior modifications of functionalized CTFs during BPs adsorption and underscores the significant role of HA in interaction mechanisms, providing theoretical guidance for the design of advanced adsorbents to enhance pollutant removal efficiency.

A Two-Phase Hydrogenation Membrane for Contaminants Reduction at High Hydrogen Reagent Utilization Efficiency.

Heterogeneous hydrogenation is surging as a promising strategy for selective removal of water pollutants, yet numerous efforts rely on catalyst design to advance catalytic activity. Herein, we enhanced the mass transfer and the utilization of hydrogen reagent through construction of a two-phase flow-through membrane reaction device (Pd/SiC-MR). Pd/SiC-MR displays high efficiency and selectivity toward removal of multiple pollutants. For instance, rapid (∼0.35 s) and exclusive hydrogenation (>99%) of carbon-chlorine bond in organohalogens were realized at high water flux (220 L/m2/h). More importantly, the two-phase Pd/SiC-MR reaction system achieved 31.4% utilization of hydrogen reagent, 1-3 orders of magnitude higher than those by classical slurry or fixed-bed reactor. The high hydrogenation performance is attributed to the close proximity of the hydrogen source, reactive hydrogen atom, and pollutant under high molecular collision frequency in membrane pores. Our study opens an approach for improved hydrogen reagent utilization while reserving the high pollutant removal efficiency through altering operating conditions, beyond complex material design limitations in hydrogenation water purification.

Stormwater runoff volume reduction and pollutant removal efficiency via bioretention cell using rock wool as the media

ABSTRACT Bioretention cells have been widely used in stormwater management. Media plays an important role in stormwater runoff reduction and pollutant removal. A novel bioretention media of rock wool has been proposed, and its effect on stormwater runoff reduction was investigated via a laboratory-scale experiment. The results showed that compared with the conventional bioretention (CB) using medium sand as media, the volume capture ratio of annual rainfall (VCRAR) of the rock wool bioretention (RWB) was 2.66–5.5% higher, and the peak flow reduction rate was 2.97–11.32% higher. The removal efficiency rates of the RWB on COD, NH4+ -N, TN, and TP were 25–30%, 10–31%, 20–40%, and 5–14% higher than the CB, respectively. The removal efficiency of the RWB on botht Pb and Zn was &amp;gt;99%. The microbial high-throughput sequencing results showed that the RWB can provide a better breeding environment for Bacteroides and Actinobacteria, which is conducive for the removal of pollutants. The RWB had a better stormwater runoff volume reduction rate and pollutant removal efficiency than the CB, therefore, it could be used as a better media for bioretention cells to improve stormwater management efficiency by using rock wool, obtained from construction waste, as the media.

Pollution resistance and removal efficiency of mesophytic plants of polluted water bodies

With the development of cities and economic growth, the eutrophication of urban park landscape water has become a hot topic in environmental governance and research at home and abroad. Using indoor water pollution simulation experiments, the decontamination and pollution resistance performance of six aquatic plants were studied. The research results found that all six aquatic plants can reduce the pH value of eutrophic water bodies. The pH of the Lythrum salicaria L. (Q) and Iris tectorum Maxim (Y) treatment systems was the lowest which are 7.34 and 7.48, respectively. They were significantly lower than the control group (CK). The content of nitrogen and phosphorus elements were reduced by six types of plants in the wastewater. After the completion of the experiment, the total nitrogen (TN) removal efficiency of Y was as high as 66.2%, and its content decreased from 9.49 to 3.21 mg/l. The removal rates of total phosphorus (TP) by six types of plants ranged from 59.1 to 81.3% and they were significantly higher than the CK. Among them, the removal rate of TP in wastewater by Y treatment exceeded 80%, which is superior to other plants and significantly different from CK. After the completion of the experiment, the content of chlorophyll a (chl a) in the water treated with Y was the lowest (6.6 mg/l). It was significantly lower than the other treatments (P&lt;0.05). The contents of chl a in Y decreased by 37.1% compared to the initial level. Compared to CK, it is 54.1% lower and the content of chl a in CK showed an increasing trend with time delay. Overall analysis shows that the microsystems formed by the six plants all have a certain improvement effect on water quality, effectively inhibiting the proliferation of algae in eutrophic water bodies. Among them, planting iris has the best effect. Bangladesh J. Bot. 53(3): 757-763, 2024 (September) Special

Assessment of carbon efficiency in wastewater treatment plants through Stochastic non-parametric data envelopment analysis (StoNED): Insights from Spanish facilities

Evaluating the carbon efficiency (CE) of wastewater treatment plants (WWTPs) is crucial for guiding these facilities towards carbon neutrality. Nevertheless, enhancing carbon performance ought not to be pursued to the detriment of pollutant removal efficiency. In this study, the CE of WWTPs is calculated as a composite index that integrates carbon emissions with the volume of pollutants removed from wastewater, including organic matter, suspended solids, nitrogen, and phosphorus. To achieve this, the Stochastic Non-parametric Envelopment of Data (StoNED) method is employed. This approach, distinct from the commonly used Data Envelopment Analysis (DEA), accounts for both empirical data and random variations in the estimation of CE, thereby enhancing the reliability of the CE evaluation. The study assesses the CE of 109 Spanish WWTPs, finding that none of them are fully carbon efficient. This involves that all plants have potential to reduce greenhouse gas emissions without sacrificing pollutant removal efficiency. The average CE of the WWTPs is 0.529, indicating a possible reduction in carbon emissions by approximately 0.076 kg of CO2 equivalent per cubic meter of wastewater treated. The analysis also reveals that neither the volume of wastewater treated nor the type of reactor used for secondary treatment has a significant impact on the CE of the facilities. The CE metric proposed in this study serves as an important decision-support tool for advancing towards the carbon neutrality of wastewater treatment processes. By providing a more comprehensive understanding of the environmental performance of WWTPs, it helps identifying areas for improvement and guiding policy and operational decisions.

Palygorskite-mediated simultaneous nutrient removal and antibiotic degradation from aquaculture wastewater in lab-scale constructed wetlands

In this study, palygorskite was employed as a substrate in laboratory-scale constructed wetlands (CWs) over a period of 180 days to investigate the removal efficiency of pollutants from mariculture wastewater under high loads of enrofloxacin (ENR) stress. The results indicated that the incorporation of palygorskite into CWs resulted in average effluent concentrations of total phosphorus (TP), total nitrogen (TN), chemical oxygen demand (COD), and ENR reaching 0.07 ± 0.00 mg/L, 1.07 ± 0.06 mg/L, 11.57 ± 1.04 mg/L, and 0.047 ± 0.002 mg/L, respectively. The removal efficiencies reached 96.45 ± 0.04 %, 94.62 ± 0.27 %, 88.61 ± 1.22 %, and 91.14 ± 5.00 % respectively, with phosphorus removal significantly surpassing that reported for similar CWs. This superior performance was mainly attributed to the strong binding mechanisms between phosphorus and the metal oxides and hydroxides leached from the palygorskite. The palygorskite stimulated the secretion of extracellular polymeric substances (EPS), accelerated biofilm establishment, and enhanced the relative abundance of key functional bacteria associated with carbon, nitrogen, and antibiotic removal, thus achieving rapid denitrification and efficient organic matter removal. Monitoring of metals (Ca, Fe, Mn, and Cu) in the CWs effluent suggested that their presence was insufficient to affect cytoplasmic enzyme activity or cause oxidative stress damage to plants. In conclusion, palygorskite serves as an environmentally friendly, high-nutrient removal alternative, apt as a substrate for CWs.

Enhanced remediation of real agricultural runoff in surface-flow constructed wetlands by coupling composite substrate-packed bio-balls, submerged plants and functional bacteria: Performance and mechanisms

Import of agricultural runoff containing nutrients considerably contributes to eutrophication of receiving water bodies. Surface-flow constructed wetlands (SFCWs) are commonly applied for agricultural runoff purification, but the performance is usually unsatisfactory. In this study, suspended bio-balls filled with zeolite and iron-carbon (Fe-C) composite substrates, submerged macrophyte (Ceratophyllum demersum) and functional denitrifying bacteria were collectively added into SFCW microcosms to enhance the remediation efficiency for real agricultural runoff with high nutrient concentrations and low content of bioavailable organic matter. The bio-ball added SFCWs achieved notably higher pollutant removal efficiencies (21.1%, 80.2% and 47.5% for chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP), respectively) than the control (COD: 6.9%, TN: 64.4%, TP: 27.9%), because of the versatile functions of filling materials for pollutant removal. C. demersum plantation (COD: 44.2%, TN: 82.8% and TP: 53.7%) and functional bacteria inoculation (COD: 51.8%, TN: 85.8% and TP: 55.1%) further enhanced the efficiency of the SFCWs for agricultural runoff remediation. Bio-ball addition and C. demersum plantation significantly increased the humification degree and reduced the molecular weight of dissolved organic matter (DOM) in the agricultural runoff. Moreover, the two intensification measures also notably reduced organic and nitrogen contents in the wetland sediment. Remarkable distinction in bacterial community distribution patterns was observed in the SFCW sediment and filling substrates in bio-balls. Keystone genera including Clostridium_sensu_stricto_1 and Bacillus in the zeolite, Sphingomonas and Exiguobacterium in the Fe-C substrates and Sediminibacterium in the sediment might be critical for agricultural runoff remediation in the SFCW microcosms. The study highlights a high potential of the intensified SFCWs by these coupling measures for agricultural runoff remediation.

Characterization optimization of synthesis Chitosanclay/benzoin/Fe3O4 composite for adsorption of Thionine dye by design expert study

A novel composite material, magnetic chitosan-clay/benzoin/Fe3O4 (CS-CY/Benz/Fe3O4), was synthesized for effectively removing thionine dye (TH) from water solutions. The structural integrity and suitability of CS- CY/Benz/Fe3O4 composite for adsorption purposes were validated through extensive characterization techniques including BET, XRD, FTIR, and SEM. The adsorption efficiency was optimized through a Box–Behnken design (BBD) employing response surface methodology (RSM), focusing on variables such as adsorbent dose (A: 0.02–0.08 g), solution pH (B: 4–10), temperature (C: 30–60 °C), and time (D: 5–30 min). Experimental results revealed a maximum TH removal of 99% with significant interactions between temperature (C) and time (D) (p-value = 0.0001). The optimal conditions for TH removal were determined as pH ~ 5.91, adsorbent dosage of 0.08 g, temperature of 54.34 °C, and time of 29.7 min. The investigation of kinetics revealed that the adsorption process conformed to a pseudo-second-order (PSO) model, while the equilibrium data were effectively described by the Freundlich isotherm model. At a temperature of 333.15 K and a TH concentration of 350 mg/L, the adsorption capacity was determined to be 660.86 mg/g. The mechanism of adsorption encompassed various interactions such as electrostatic attractions, n–π interactions, hydrogen bonding, and Yoshida H-bonding. Particularly, the CS-CY/Benz/Fe3O4 composite demonstrated strong magnetic responsiveness, enabling straightforward separation from water using an external magnetic field after adsorption. Particularly, the CS-CY/Benz/Fe3O4 composite demonstrated strong magnetic responsiveness, enabling straightforward separation from water using an external magnetic field after adsorption. This research contributes important findings to the advancement of magnetic chitosan-based composites for efficient removal of TH dye pollutants from water environments.

Performance comparison of modified polyethersulfone membrane with graphene oxide and molybdenum disulfide for effective filtration of urban surface water

In the current water treatment scenario, membrane filtration is a crucial technology due to its ability to effectively remove pollutants, ensuring clean and safe water. However, a significant challenge to its widespread application is membrane fouling, which reduces membrane efficiency and service life. Various membrane modifications have been studied to enhance fouling resistance. In this work, the effect of adding graphene oxide (GO) and molybdenum disulfide (MoS2) nanoparticles for the fabrication of mixed polyethersulfone (PES) membranes was evaluated. The modified membranes were evaluated for pollutant removal efficiency and fouling resistance using model humic acid solutions and surface water samples. The PES-GO membranes demonstrated significantly improved hydrophilicity, up to 43% reduction in protein deposition, and an average flux recovery ratio (FRR) of 63%, superior to the control PES membrane, resulting in reduced fouling and sustained high permeability. Nevertheless, although PES-MoS2 exhibited high rejection rates of dissolved organic matter and UV254, they also showed higher foulant adsorption and lower FRR, likely due to the development of a colloidal fouling when treating more complex water matrices. Attenuated Total Reflectance Fourier-Transform Infrared (ATR-FTIR) analysis confirmed the deposition of organic foulants, with polysaccharides and proteins identified as major contributors to fouling. These findings suggest that while GO-enhanced PES membranes offer improved water treatment performance, modifications with MoS2 require careful consideration of feedwater composition. Future work should focus on optimizing nanoparticle integration and evaluating membrane effectiveness for diverse water sources.

CaO composite improves the conversion efficiency of free radicals in the catalytic activation of permonsulfate by Cu-based oxides

The advanced oxidation technology based on persulfate has excellent performance in the efficient removal of refractory organic pollutants in water bodies, among which the heterogeneous catalytic activation system has been studied extensively due to its characteristics of convenient operation, low energy consumption, and no secondary pollution. Many studies have been focused on improving the overall oxidation efficiency of target substrates in heterogeneous catalytic oxidation systems. Herein, a series of bimetallic composite oxides (CaOMOx) (M = Cu, Fe, Ni, etc.) were prepared by combining inert metal oxides—CaO with various transition metal oxides, and were used for permonosulfate (PMS) activation. Among them, the introduction of CaO has the most obvious effect on the catalytic efficiency of CaOCuO/PMS system. Almost 100 % of benzothiazole (BTH) was degraded within 40 min at 0.3 g/L PMS and 0.15 g/L CaOCuO. The mechanism study showed that the introduction of CaO significantly increased the content of oxygen vacancies (OVs) on CaOCuO, and thus promoted the formation of surface hydroxyl groups to strengthen the adsorption capacity for PMS. In addition, the introduction of CaO enhanced the reducibility of Cu species and thus promoted the transformation of Cu2+ to Cu+, ensured the continuous and rapid generation of SO4•-, thereby promoting the improvement of oxidation efficiency. Our study provides a novel strategy for improving the conversion efficiency of free radical in heterogeneous persulfate catalytic oxidation systems.