Pollutants In Wastewater Research Articles

Electronic structure regulation of Cu-based Ruddlesden-Popper perovskites by cobalt doping for enhanced degradation of oilfield fracturing wastewater in electrocatalytic peroxymonosulfate system

Purification of oilfield fracturing wastewater is the most challenging type of oilfield wastewater treatment. In this work, a heterogeneous electrocatalytic peroxymonosulfate (PMS) system was established to treat oilfield wastewater using Co-doping induced Cu-based Ruddlesden-Popper (RP) perovskites as catalysts. Characterization results illustrated that the obtained catalysts were generated the heterojunction of LaCoO3/La2CuO4 and the Co would transfer electrons to Cu, resulting in a higher chemical oxygen demand (COD) degradation efficiency (> 80 %) of oilfield fracturing wastewater under the neutral environment. Singlet oxygen (1O2) played the main function for COD removal with analysis results of reactive oxygen species (ROS). Experimental results and theoretical calculations indicated that the reduction effect of carbon felt (GF) cathode and the redox cycle of Cu(I)/Cu(II) and Co(II)/Co(III) accelerated the activation of PMS. Moreover, the lattice oxygen participated in the generation of ROS. Significantly, the LaCoO3/La2CuO4 heterojunction displayed a higher total density of states (TDOS) value near the Fermi level, implying their favorable electron transfer for PMS activation. This study opens new avenue for resolving the challenge of oilfield fracturing wastewater pollution.

Flower-like layered ZnO nanoflakes for cost-effective visible light-assisted photodynamic oxidation of tetracycline and bacterial disinfection

The conventional precipitation method was employed to synthesize the flower-like layered ZnO nano-flakes, characterized, and their photocatalytic potential was investigated for control of tetracycline antibiotics and high-strength pathogenic bacteria in wastewater effluent. Scanning electron microscope measurements confirm the formation of flower-like nano-flakes. Under white light, the catalytic efficiency of the ZnO nano-flakes is higher compared to blue light for the photocatalytic degradation of tetracycline, the inactivation of multidrug-resistant bacteria, and total coliforms. Under white light irradiation with the intensity of 80 mW/cm2, the ZnO nano-flakes showed the highest tetracycline degradation efficacy of 86 % within 120 min and complete inactivation of bacteria within 90 min without any additional oxygen sources. Scavenging experiments have clarified the photocatalytic mechanism of the degradation of tetracycline. The used catalyst was simply recovered by centrifugation (5 min) and could be reused without significant loss of photocatalytic activity. The remarkable efficiency and stability of the ZnO nano-flakes in this study mark a distinct approach to the development of heterogeneous photocatalysts for pollutant degradation. To evaluate the feasibility of a photocatalytic process for achieving consistent disinfection, microbial inactivation experiments were conducted using a batch-scale photocatalytic reactor with blue and white LEDs. The study targeted high-strength multidrug-resistant bacteria, including E. coli (Gram-negative) and S. aureus (Gram-positive), as well as total coliform in secondary effluent. This research clarifies the practical potential of ZnO nano-flakes for cost-effective photocatalytic oxidation treatment of wastewater pollutants.

Kinetics of the decomposition of reactive black 5 on carbon nanostructured adsorbents

Textile industry effluents, containing vast quantities of toxic organic pollutants and synthetic dyes like Reactive Black 5 (RB5), pose a significant environmental threat. RB5 contamination can harm ecosystems and human health, necessitating effective treatment for water recycling and compliance with quality standards. Traditional methods like filtration often fall short in removing dye chemicals. This study examines the efficiency of nanocarbon-based adsorbents in removing RB5 from textile industry effluents. RB5 solutions at concentrations of 10 µM, 30 µM, 60 µM and 100 µM were investigated and characterized using scanning electron microscopy (SEM) and UV-Vis spectrophotometry. Activated carbon (AC) demonstrated the highest degree of RB5 decomposition, outperforming graphene nanoplatelets (GNPs) and graphene oxide (GO) and offering a promising solution for mitigating textile wastewater pollution. Kinetic studies revealed that RB5 adsorption follows a pseudo-second-order model for all adsorbents. The rate constants were determined using PSO kinetics and they were comparable with the rate constants of prior studies, indicating the applicability of the model to the study of the kinetics of similar dye adsorption and decomposition processes.

Plasma coupled with ultrasonic for degradation of organic pollutants in water: Revealing the generation of free radicals and the dominant degradation pathways

This study explores the synergistic effects of dielectric barrier discharge (DBD) plasma coupled with ultrasound (US) in the degradation of organic pollutants in water. The optimal degradation conditions were determined to be 100W ultrasonic power, 190V DBD plasma voltage, and neutral pH. The combination of DBD plasma and US significantly enhances the generation of reactive species (·OH, ·O2-, and 1O2), leading to a 97.3% degradation efficiency of methyl orange (MO), which is 17.3% higher than DBD plasma alone. Electron spin resonance (ESR) identified ·OH, ·O2-, and 1O2 in DBD/US system, and radical scavengers were employed to elucidate their roles. The degradation process was assessed through changes in pH, conductivity, TOC and COD, with characterization and analysis via UV-Vis and LC-MS. By combining LC-MS with density functional theory (DFT) calculations, nine intermediates were identified and three degradation pathways dominated by free radicals were established. Additionally, the DBD/US system treated wastewater containing sulfamethoxazole (SMX), sulfadiazine (SDZ), tetracycline (TC), and ciprofloxacin (CIP), achieving degradation rates exceeding 80%. These findings suggest that the DBD/US coupled system holds promising potential for treating organic pollutant wastewater.

Evaluation of blue textile dye decolorization by immobilized polyphenol oxidase using pumice stone under optimum conditions

Industrial dyes are major pollutants in wastewater and river water with an initial visible concentration of 1 mg/L. Recent studies have shown the possibility of using polyphenol oxidase in catalytic biological treatment due to its ability to oxidize a large number of dyes and pollutants in wastewater and the flexibility to work in wide ranges of temperature, pH and salinity. It is easy availability as well as the low economic cost resulting from its use in biological treatments, this enzyme polyphenol oxidase was used. The findings in this study showed that the extraction of polyphenol oxidase (PPO) from potato peel was homogenized with potassium phosphate buffer (0.1 M, pH 7) at a ratio of 1:10 (weight: volume) for two min. The result of enzyme purification by ion exchange chromatography showed that the yield of this step was 64 % and the specific activity was 6541.67 U/mg. The polyphenol oxidase was immobilized covalently on the functionalized pumice stone (25.2 U/gm) compared with other methods. The characterization results demonstrated that the optimum pH for immobilized and free enzyme activity was 6.0 while the pH range of free and immobilized polyphenol oxidase stability was from 4.5 -7.0 and 3.5 - 8.5 respectively. The better temperature for free and immobilized polyphenol oxidase activity was 25 ºC, whereas the free and immobilized polyphenol oxidase was stable at 15-35 and 15-50 °C respectively. The outcomes showed that the decolorization efficiency of blue textile dye employing immobilized polyphenol oxidase reached 99.85 % after 24 hr. for 100 mg/L concentration while for other concentrations 200, 300, 400, 500 and 1000 mg/L the decolorization efficiencies were 85.96, 76.15, 72.54, 66.94 and 63.5 % respectively. Based on the results, the immobilized polyphenol oxidase on pumice stone is highly efficient in removing textile dyes at large concentrations and in different environmental conditions.

Recent advances in cadmium sulfide (CdS)-based photocatalysts

Organic compounds from different industries produce a range of problematic pollutants in wastewater. Cadmium sulfide (CdS) based photocatalyst as a typical photocatalytic material, due to its high efficiency and stability, shows great potential in the field of environmental restoration, which has strong visible light absorption, suitable band energy level and excellent electron charge transport performance. Research on degradation of organic pollutants using cadmium sulfide (CdS) based photocatalyst has made significant progress. In order to improve the rate and ability of cadmium sulfide (CdS) based photocatalyst to degrade pollutants, this paper introduces various strategies to modify the shape and structure of photocatalyst to improve its performance. In addition, the reaction conditions were optimized, and the mechanism of photocatalytic degradation was discussed. In conclusion, the research of cadmium sulfide based photocatalysts provides valuable insights for the degradation of organic pollutants and offers hope for future application in ecological environmental protection.

Industrial wastewater treatment from oil and petroleum products with carbonate sludge

In the modern world, pollution of industrial wastewater by oil and petroleum products is one of the most acute environmental problems. These pollutants have a significant negative impact on ecosystems and water quality. In this regard, there is a need to develop effective and environmentally safe methods of wastewater treatment. The aim of the study is to develop and evaluate the efficiency of using carbonate sludge as an adsorbent for removing oil and petroleum products from wastewater. The scientific and practical significance of the work lies in the proposal of an environmentally friendly treatment method that can not only improve the quality of wastewater, but also ensure the disposal of industrial waste. The use of carbonate sludge, a by-product of industry, makes the method cost-effective and reduces the environmental burden. The main results of the study showed that carbonate sludge has a high sorption capacity for petroleum products. The adsorption isotherm belongs to type I according to the Brunauer, Deming, Deming and Teller classification, which indicates the presence of monolayer adsorption on the sludge surface. It was found that the sludge is able to remove up to 95% of pollutants from wastewater. The value of the study lies in demonstrating that carbonate sludge is an effective and affordable material for solving environmental problems associated with water pollution by petroleum products. This research contributes to the development of industrial waste recycling technologies by offering a newapplication for carbonate sludge. The practical significance of this work lies in the possibility of introducing this method at industrial enterprises for wastewater treatment, which can lead to a reduction in waste disposal costs and an improvement in the environmental situation. The results of the study can be useful for enterprises of the petrochemical industry and wastewater treatment plants.

Synthesis of Copper-Doped Metal Nanoferrites for Efficient Removal of Pharmaceutical Wastewater Pollutants in Membrane Bioreactor System

Pharmaceuticals present in the aquatic environment can poison aquatic species and humans through drinking water and cause harmful bacteria to become resistant. The role of transition metal doped metal nanoferrites for the enhanced efficiency of degradation process is widely achieved. In this work, copper doped magnesium ferrite (Cu-MgFe2O4) and copper doped zinc ferrite (Cu-ZnFe2O4) nanoparticles were synthesized using a sol-gel method. X-ray diffraction (XRD) analysis confirmed the formation of the spinel structure for both samples, with crystal sizes of 16.72 nm and 59.05 nm, respectively. The magnetic properties of the samples were studied using a vibrating sample magnetometer (VSM), which revealed that the addition of Cu2+ ions has a significant impact on the magnetic properties of the nanoparticles. The saturation magnetisation (Ms), retentivity (Mr) and coercivity value (Hc) for the Cu-MgFe2O4 sample were found to be 0.18453 emu, 39.584 × 10-3 emu and 139.61 Oe, respectively, while for the Cu-ZnFe2O4 sample, the values were 0.21271 emu, 71.022 × 10-3 emu and 285.91 Oe, respectively. The impact of copper doped nanoferrites on pollutant removal from pharmaceutical wastewater using the membrane Bioreactor (MBR) system has also been accomplished. The results demonstrated the effectiveness of ferrites in reducing concentrations of heavy metals, including lead and cadmium, within acceptable ranges for inland surface water and public sewers. Furthermore, the MBR system with ferrites exhibited efficient removal of fluoride, sulphide and radioactivity, ensuring compliance with the specified standards. Although the study exhibited the potential of ferrites in pollutants removal, further optimization is necessary to achieve complete compliance with water quality standards.

An innovative strategy for polyester microplastic fiber elimination from laundry wastewater via coupled separation and degradation using TiO2-based photocatalytic membrane reactor

Microplastics (MPs) pollution, particularly from polyester microplastic fibers (PMPF) released during laundry processes, has become a significant environmental issue. This study explores an effective solution for rejecting and degrading both simulated and real PMPF in laundry wastewater using a TiO2-based photocatalytic membrane reactor (PMR). The immobilized-PMR integrates an Ag-decorated TiO2 (Ag-TiO2) catalyst onto an Al2O3 ceramic membrane, combining the photocatalytic capabilities of TiO2 with the enhanced efficiency provided by silver nanoparticles’ plasmonic effect. This setup aims to optimize PMPF degradation under ultraviolet-C (UVC) light irradiation. The performance of the immobilized-PMR was assessed with simulated and real laundry wastewater containing PMPF. Results showed that the Ag-TiO2 catalytic membrane achieved up to 99.9 % rejection of both simulated and real PMPF, and a 23.2 % degradation rate of simulated PMPF after 48 h of UVC irradiation. Detailed morphological analyses via FESEM and chemical characterization through FTIR and GC/MS confirmed substantial degradation of polyester fibers. This study demonstrates the potential of the TiO2-based immobilized-PMR as a scalable, efficient solution for mitigating fibrous MP pollution in wastewater. The approach combines photocatalytic degradation with membrane filtration, effectively rejecting and degrading fibrous MPs, thereby reducing their environmental impact.

Maximizing diclofenac bioremoval efficiency using Chlorella vulgaris strain H1 and Chlorella sorokiniana strain H2: Unveiling the impact of acetic acid on microalgae

BackgroundDiclofenac (DFC) is a commonly detected pharmaceutical pollutant in wastewater, posing environmental risks. Microalgae have emerged as potential candidates for bioremediation due to their ability to degrade pollutants. This study focuses on investigating the biodegradation potential of two newly isolated microalgae strains, Chlorella vulgaris strain H1 and Chlorella sorokiniana strain H2, towards DFC removal. The optimization of pH is crucial for enhancing the efficiency of bioremediation processes. Therefore, in addition to assessing the biodegradation potential of microalgae, this study also investigates the impact of adjusting the pH of the culture medium using acetic acid as an additional carbon source on the biodegradation process. MethodsThrough genetic analysis using 18S rDNA sequencing, the microalgae strains were identified. Various parameters including growth dynamics, chlorophyll content, cell proliferation, photosynthetic activity, and DFC biodegradation efficiency were comprehensively assessed. Additionally, the impact of incorporating acetic acid as an additional carbon source in the culture medium on the biodegradation process was examined. Significant FindingsC. sorokiniana strain H2 demonstrated superior biodegradation rates compared to C. vulgaris strain H1 across varying DFC concentrations. Specifically, C. sorokiniana strain H2 exhibited remarkable biodegradation rates of 84 %, 83.72 %, and 29.57 % for DFC concentrations of 12.5 mg L−1, 25 mg L−1, and 100 mg L−1, respectively. In contrast, C. vulgaris strain H1 showed lower biodegradation rates of 66.64 %, 29.24 %, and 1.83 % for the corresponding DFC concentrations. The study highlights the potential of C. sorokiniana strain H2 as a promising candidate for the removal of pharmaceutical pollutants like DFC from wastewater. Furthermore, the use of acetic acid as a supplementary carbon source enhanced the biodegradation efficiency, suggesting a potential strategy for optimizing bioremediation processes.

Holistic insight into the viability of employing cerium(IV) sulphate to oxidise toxic contaminants in effluent from the coal gasification process: Optimisation studies

The coal gasification (CG) process, while beneficial for producing syngas, poses environmental risks due to the production of highly toxic wastewater containing high concentrations of polycyclic aromatic hydrocarbons (PAHs), phenolics, and cyanides. This study examines the oxidation of pollutants in wastewater from a simulated underground coal gasification (UCG) process, with initial pollutant levels of pH 1.8, total cyanides 21.00 mg/L, total phenols 61.95 mg/L, heavy metals 7.68 mg/L, PAHs 2459 μg/L, and dissolved organic carbon (DOC) 148.0 mg/L. Three oxidation systems (Ce(SO4)2·4H2O, Ce(SO4)2·4H2O + H2O2, and Fenton process with FeSO4 + H2O2) were used to remove pollutants from wastewater from the coal gasification process. In the first system, the oxidising agent was Ce4+ ions, while in the second and third systems, where hydrogen peroxide was added, the oxidising agents were hydroxyl radicals. Using central composite design and response surface methodology (CCD/RSM), the most favourable oxidation conditions were identified for Ce(SO4)2·4H2O (35 min, Ce4+:C molar ratio of 5:1, pH 2.5, temp. 40 °C). For the Ce(SO4)2·4H2O + H2O2 system DOC:Ce4+:H2O2 molar ratio of 1:2:10. Results showed significant reduction in pollutants: Ce(SO4)2·4H2O reduced PAHs, phenols, cyanides, DOC, and heavy metals by 99.40 %, 99.97 %, 97.67 %, 65.34 %, and 90.01 %, respectively; Ce(SO4)2·4H2O + H2O2 achieved reductions of 99.91 %, 99.66 %, 98.14 %, 76.35 %, and 81.45 %; and the Fenton process achieved reductions of 99.91 %, 99.95 %, 95.07 %, 56.49 %, and 89.33 %. An application of alternative oxidation processes (Ce(SO4)2·4H2O and Ce(SO4)2·4H2O + H2O2) is a viable option in removing toxic pollutants with simultaneously cerium recovery.

Mitigating antibiotic pollution in wastewater by harnessing the potential of microalgae-based bioremediation technologies

Mitigating antibiotic pollution in wastewater by harnessing the potential of microalgae-based bioremediation technologies

Two Stable Pillar-Layered Zn-LMOFs for Highly Fluorescence Sensing of Inorganic Pollutants and Nitro Aromatic Compounds in Water.

Luminescent metal-organic frameworks (LMOFs) are a potential class of functional materials for the photoluminescent detection of a wide range of analytes as well as for the detection of pollutants in wastewater. Herein, by using the pillar-layered strategy, two new luminescence Zn-LMOFs (JLU-MOF222 and JLU-MOF223) were successfully solvothermal synthesized. The 2D layers are both consisting of Zn2+ and TPHC [TPHC = (1,1':2',1″-terphenyl)-3,3″,4,4',4″,5'-hexacarboxylic acid] ligands and then pillared by the different N-donor ligands to form the 3D Zn-LMOFs with fsh topology. Benefiting from the uncoordinated carboxylate sites, uncoordinated N atom, or -NH2 group in the pillaring ligands and excellent stability in pH = 2-13 aqueous phase, JLU-MOF222 and JLU-MOF223 not only can sensitively detect trace amounts of inorganic pollutants (Fe3+, Cr2O72-) and nitro aromatic compounds TNP and 2,4-DNP (TNP = 2,4,6- trinitrophenol, 2,4-DNP = 2,4-dinitrophenol) through luminescence quenching but also exhibit high selectivity of other anti-interference competing analytes. The two new Zn-LMOFs can be used as potential luminescent sensors for pollutant detection in water due to their high KSV and low limit of detection (LOD).

Photoresponse of Ti3C2Tx MXene promotes its adsorptive-reductive removal of Cr(VI) from water

MXenes, such as Ti3C2Tx, demonstrate tremendous potential as heavy metal adsorbents due to their abundant reaction sites, high hydrophilicity, controllable interlayer spacing, and inherent reduction ability. However, their structural dependent pollutant removal performances and the related mechanisms are far less studied. Therefore, the removing abilities of Cr(VI) from water on Ti3C2Tx MXenes with different structures (multilayer (ML-) and delaminated (DL-) Ti3C2Tx) synthesized via several etching techniques were evaluated. Focusing on the most effective ML- and DL-Ti3C2Tx obtained by acid/fluoride salt etching, the impacts of structural variations on the Cr(VI) removal performances were explored. Both ML- and DL-Ti3C2Tx demonstrate outstanding Cr(VI) adsorption and reduction capabilities, achieving equilibrium within 500 min with capacities of 92.7 and 205 mg/g, respectively. The differences in removal mechanisms stemed from the varying adsorption and reduction capacities of two MXenes. ML-Ti3C2Tx, with lower surface area and porosity, had low adsorption capacity but superior reduction ability, efficiently converting most Cr(VI) to Cr(III) (66.8%). Conversely, DL-Ti3C2Tx exhibited better removal efficiency but a lower capacity for reduction (45.7%). Notably, although the partial reduction of DL-Ti3C2Tx to TiO2 results in its limited chemical reduction capacity, Ti3C2Tx might serve as a co-catalyst for TiO2, boosting the photoresponsiveness of DL-Ti3C2Tx or TiO2 through Ti3C2Tx/TiO2 heterojunctions, thereby facilitating photocatalysis to realize the reduction of Cr(VI). Both Ti3C2Tx exhibited both excellent Cr(VI) removal capacity and detoxification capacity, demonstrating their high potential in treating heavy metal pollutants in wastewater.

Enhanced Pollutant Removal and Antifouling in an Aerobic Ceramic Membrane Bioreactor with Bentonite for Pharmaceutical Wastewater Treatment.

This study examined the impact of adding bentonite clay (concentration of 1.5 to 10 g/L) to a pilot-scale aerobic ceramic membrane bioreactor (AeCMBR) for treating pharmaceutical wastewater (PhWW). The hydraulic retention time (HRT) was maintained at 24 h; the dissolved oxygen was between 2 mg/L (on) and 4 mg/L (off) throughout operation. Organic and nitrogen pollution removal rates and heavy metal (Cu, Ni, Pb, Zn) reduction rates were assessed. The chemical oxygen demand (COD) removal efficiency exceeded 82%. Adsorption improved ammonia (NH4+) removal to 78%; the addition of 5 g of bentonite resulted in a 38% improvement compared with the process without bentonite. The average nitrate concentration decreased from 169.69 mg/L to 43.72 mg/L. The average removal efficiencies for Cu, Ni, Pb and Zn were 86%, 68.52%, 46.90% and 56.76%, respectively. Bentonite at 5 g/L significantly reduced membrane fouling. The cost-benefit analysis enabled us to predict that the process will meet the multiple objectives of durability, treatment performance and economic viability. The combination of an AeCMBR and bentonite adsorption has proven to be a valuable solution for treating highly polluted wastewater.

Built-In Electric Field Boost Photocatalytic Degradation of Pollutants in Wastewater.

The photocatalysis technique shows significant potential for wastewater degradation; however, the rapid recombination of photogenerated holes and electrons severely limits its photocatalytic efficiency. This situation necessitates the development of effective strategies to tackle these challenges. One well-documented approach is built-in electric field engineering in heterojunctions or composites, which has been shown to enhance electron transfer and thereby reduce the recombination of electrons and holes. This strategy has proven highly effective in significantly improving photocatalytic activity for the degradation of pollutants in wastewater. In this context, we summarize recent advancements in built-in electric field engineering in photocatalysts, highlighting the fundamentals and modifications of this approach, as well as its positive impact on photocatalytic performance in the degradation of wastewater pollutants.

Efficient Pulp and Paper Wastewater Treatment Using Green Tea-Synthesized Magnetite: Artificial Intelligence and Kinetic Analysis

The pulp and paper industry generates pollutant-laden wastewater, requiring effective treatment to prevent environmental damage and enable sustainable reuse. This study investigated the use of green tea-synthesized magnetite (GT-Fe3O4) for treating pulp and paper wastewater. Characterization techniques, including SEM, XRD, FTIR and EDX, were employed to analyze the synthesized magnetite. Batch adsorption studies were conducted to examine the optimal operating conditions, including pH, contact time, adsorbent dose, and stirring rate, for achieving the best treatment performance. The treatment focused on reducing chemical oxygen demand (COD), total suspended solids (TSS), and turbidity in the wastewater. The adsorption data were evaluated using kinetic models, with the pseudo-second-order model providing the best fit. Additionally, an artificial intelligence prediction model (AIP) with a 4–10–1 structure was employed to predict the removal efficiencies. The optimal conditions for the treatment process were determined to be a pH of 6, a contact time of 60min, a GT-Fe3O4 dose of 0.7g/L, and a stirring rate of 150rpm at room temperature. Under these conditions, the removal efficiencies for COD, TSS, and turbidity were 70.5%, 65.4%, and 38.8%, respectively. The AIP model achieved an R² value range of 0.978 to 0.982, showing high prediction accuracy. The study demonstrates that GT-Fe3O4 effectively reduces pollutants in pulp and paper wastewater.

Wide-spectrum-responsive MoS2/WS2 decorated Al-MOF nanohybrid with dual S-scheme heterojunction in facilitating sonophotocatalytic tetracycline abatement and pharmaceutical effluent treatment

The work investigates the application of a MoS2/WS2 decorated Al-MOF nanocomposite for the degradation of tetracycline (TC) in water by sonophotocatalysis. The nanocomposite revealed a dual S-scheme heterojunction that has a broad-spectrum response, resulting in a better efficiency for the degradation of TC (97%). The synergy index during sonophotocatalysis was measured to be 2.79. Moreover, the nanocomposite was effectively used to actively regulate the concentration of TC (73.2%) and other pollutants in pharmaceutical wastewater. An extensive analysis was performed to examine the impact of various significant parameters, including pH, catalyst dosage, TC concentration, and others. Sonophotocatalysis outperforms both sonocatalysis and photocatalysis, exhibiting pseudo-first-order kinetics. The improved performance can be credited to the formation of a dual S-scheme heterojunction, which facilitates the efficient transfer and separation of charge carriers that are stimulated by visible light exposure. Furthermore, the nanocomposite exhibited exceptional stability and demonstrated significant potential for being reused. The results suggest that the MoS2/WS2 decorated Al-MOF nanocomposite shows promise as a feasible choice for efficient and eco-friendly water treatment processes.

Investigation of the effect of salts on dye wastewater separation performance in TpPa-1 membrane via molecular dynamics simulation

The rapid progress in science and technology increases the demand for dyes and results in the pollution of dye wastewater. Recently, covalent organic frameworks (COFs) have been suggested as a promising candidate for wastewater treatment. The influence of inorganic salt ions on the transport and separation processes of dye wastewater is poorly understood. In this work, the transport and separation mechanisms of dyes are investigated via nonequilibrium molecular dynamics simulations (NEMD). It is found that the inorganic salts enhance the rejection rate of different dyes in TpPa-1 membranes. The fundamental reason for this phenomenon is the hindrance caused by inorganic salt ions, which change the orientation of dye molecules as they pass through the pore channels of the TpPa-1 membrane. As a result, the dye molecules show a greater tendency to form π–π interaction with the TpPa-1 membrane surface, which accelerates their adsorption.

Alginate/organo-selenium composite hydrogel beads: Dye adsorption and bacterial deactivation

Post-COVID-19, the risk and spread of germs, coupled with wastewater contamination, have become critical concerns. Wastewater contains waterborne bacteria and various contaminants like dye molecules, threatening water safety. Traditional adsorption methods address pollutant removal or pathogen inactivation separately, but a dual-action solution is increasingly essential. This study presents alginate/selenium composite hydrogel beads with the potential to simultaneously remove dyes and deactivating bacteria. Fabricated by dropping suspension droplets into a calcium ion bath, these beads were tested for dye adsorption and antibacterial efficacy. Beads with 50 wt% organo‑selenium demonstrated the highest methylene blue (MB) adsorption capacity and nearly 100 % deactivation efficiency against Pseudomonas aeruginosa, while those with 20 wt% showed no significant improvement. Mechanistic studies reveal that organo‑selenium induces stacking effects and reduces surface charges, enhancing MB adsorption and antibacterial performance. The alginate/organo‑selenium composite hydrogel beads offer a potential effective and sustainable solution for tackling the complex issue of wastewater pollutants.