Wastewater Treatment Research Articles

Efficiency and Ecotoxicity of Activated Biochar in the Treatment of Artificial Wastewater Contaminated by Pharmaceuticals

Pharmaceuticals are emerging contaminants of global concern due to potential ecotoxicity and persistence in wastewater. Since conventional wastewater treatment plants are not designed to remove micropollutants and the removal efficiency varies compound-specifically, pharmaceuticals pose a risk in the recipient aquatic environments. Adsorption by solid materials such as activated biochar has been suggested to offer a practical removal method. However, not much is known about the environmental risks of the adsorbents used in wastewater treatment. This study aimed to study the efficiency of activated biochar (ACB) to remove low and high concentration of specific pharmaceuticals including diclofenac (DI), tetracycline (TE), and cephalexin (CEP) from Milli-Q water (MQ) and artificial wastewater (AWW). Furthermore, the study evaluated the ecotoxicity of these pharmaceuticals, as well as pristine ACB and ACB loaded with pharmaceuticals (ACB-LP), in both MQ and AWW using Daphnia magna. The adsorbate concentration and matrix affected ACB’s removal efficiency. Weaker adsorbent-adsorbate interactions and mass transfer resistance at lower adsorbate concentrations, along with interactions between wastewater constituents and pharmaceuticals were the leading factors contributing to this reduction. These experimental observations indicate practical considerations for using adsorbents in operational wastewater settings. Furthermore, ACB-LPs generally exhibited lower toxicity compared to ACB, attributed to the saturation of free binding sites and reduced adhesion to daphnids. This study highlights the importance of examining the environmental risks of adsorbent materials used in wastewater treatment, particularly given their anticipated future use.

Surface modification of bentonite and montmorillonite as novel nano-adsorbents for the removal of phenols, heavy metals and drug residues.

Montmorillonite (Mt) is one of the eco-friendly and low-cost nano-adsorbents for water and wastewater treatment. Interactions of Mt. with various modifiers such as surfactants and polymers make it an ideal adsorbent with good selectivity for the removal of phenols, heavy metals and drug residues from water and wastewater. Surface modification can improve the adsorption potential of Mt. due to increasing the number of adsorption sites and functional groups to remove a wide variety of contaminants. This paper shows a general overview of the structure, adsorptive characteristics, and applications of Mt. and modified Mt. (m-Mt). Also, recent progress made in using of natural and modified bentonite and Mt. for removing phenols, heavy metals and pharmaceuticals from water and wastewater are explained. Furthermore, it discusses the strategies used to increase the adsorption capacity of Mt. by surface modification with cationic surfactants, acids, and polymers. This article delivers an exploration of the current uses of bentonite and Mt. for water and wastewater treatment and encouraging results obtained in this review could aid in the application Mt. and m-Mt for the recovery of high added value compounds and removal of contaminants from aquatic systems.

Enrichment and catalysis effect of 2D/2D g-C3N4/Ti3C2 for promoting organic matter degradation and heavy metal reduction in plasma systems: Unveiling the promotion and redox mechanism.

This work proposes a novel plasma-assisted 2D/2D g-C3N4/Ti3C2 system for treatment of organics-heavy metals composite wastewater. Unlike traditional materials in plasma system, 2D/2D g-C3N4/Ti3C2 not only improved the mass transfer efficiency of plasma by gathering both reactive species and pollutants onto the surface, but also induced photocatalytic reactions. Besides, the higher specific surface area and faster carrier separation rate can enhance the oxidation and reduction activity, and then promoted organic matter degradation and heavy metal reduction. Remarkably, the removal efficiency of sulfamethoxazole (SMX) and Cr(VI) increased by 16.5% and 73.1% respectively when introducing 2D/2D g-C3N4/Ti3C2. Roles of·OH,·H,·O2-, 1O2, e-, and h+ in SMX oxidation and Cr(VI) reduction are clarified. The primary aggregated·OH and 1O2 dominate the degradation of SMX. The influencing factors, synergistic mechanism between plasma and catalyst, and redox mechanism were clarified. This work provides a breakthrough idea for treatment of organics-heavy metals composite wastewater.

A novel Zobellella endophytica W14 strain for nitrogen removal from hypersaline wastewater through simultaneous nitrification and denitrification.

To address the challenges associated with biological treatment of high-salinity wastewater, a novel salt-tolerant strain, Zobellella endophytica W14, was isolated. This strain exhibited heterotrophic nitrification-aerobic denitrification (HN-AD) capabilities. Strain W14 could grow and remove ammonium in high-salinity environments with salinity levels ranging from 0 to 11% (w/v). At 5% salinity, strain W14 demonstrated high removal efficiencies for nitrite, ammonium, and nitrate (100%, 99.58%, and 98.85%, respectively), when these compounds were provided as the single source of nitrogen. In cases of mixed nitrogen sources, total nitrogen removal efficiency of strain reached 95.22%. The nitrogen balance analysis confirmed the utilization of nitrogen sources by strain W14 through both assimilation and dissimilation. Through the amplification of functional genes involved in nitrogen metabolism (i.e., hao, napA, nirS, and nosZ), the nitrogen metabolism pathway of strain W14 was predicted to be: NH₄⁺ → NH₂OH → NO₂⁻ → NO₃⁻ → NO₂⁻ → NO → N₂O → N₂. The study reveals that the novel W14 strain can efficiently remove total nitrogen from high-salinity wastewater and has significant potential for biological treatment of such wastewater.

Efficient degradation of emerging organic pollutants via activation of peroxymonosulfate over Fe-N co-doped carbon materials: Singlet oxygen and electron-transfer mechanisms

Singlet oxygen (1O2) is widely recognized as an effective reactive species for the targeted oxidation of organic contaminants. However, producing 1O2 with high selectivity and efficiency remains a significant challenge. This study describes the synthesis of a N-C-loaded Fe catalyst (Fe/NC) loaded with nitrogen-doped carbon materials. The Fe/NC catalyst efficiently produces 1O2 via the activation of peroxymonosulfate (PMS), demonstrating exceptional degradation capabilities for p-chlorophenol (4-CP). Compared to the control samples of nitrogen-doped carbon (NC) and Fe/NC-x under identical conditions, the Fe/NC/PMS produced a significantly greater degradation rate (0.794min-1) for 4-CP (50mg⋅L-1) within 14min. The content of zinc was regulated to enhance the degradation of 4-CP. The durability of the catalyst was tested with a fixed-bed flow reactor, maintaining almost 100% removal efficiency over 36h on stream. The 4-CP degradation within this system was shown to be a non-radical process predominated by 1O2 and electron transfer, as shown by electrochemical methods, quenching studies, and electron paramagnetic resonance test (EPR). Moreover, Fe/NC demonstrated exceptional resistance to pH changes (3-10), natural organics, and inorganic ions while degrading organic contaminants. The degradation process of 4-CP over the Fe/NC catalyst was examined using liquid chromatography-mass spectrometer. The results of the phytotoxicity evaluation indicated a significant decrease in their toxicity within the Fe/NC/PMS/4-CP system. The satisfactory activity, stability, and universality enabled Fe/NC to serve as a promising candidate for PMS activation. This study presents a novel approach for the selective production of 1O2, enabling targeted pollutant degradation in wastewater treatment.

Cost-Effective multifunctional bilayer structural hydrogel evaporator for stable solar desalination and wastewater treatment

Cost-Effective multifunctional bilayer structural hydrogel evaporator for stable solar desalination and wastewater treatment

Anaerobic oxidation of methane coupled to reductive immobilization of hexavalent chromium by “Candidatus Methanoperedens”

The anaerobic oxidation of methane (AOM) carried out by anaerobic methanotrophic archaea (ANME) plays an important role in mitigating methane emissions from aqueous environments and has applications in bioremediation and wastewater treatment. Previous studies showed that AOM could be coupled to chromate reduction. However, the specific responsible microorganisms and the biochemical mechanisms are unclear. Herein, we showed that a consortium dominated by ANME “Candidatus Methanoperedens” was able to couple AOM to the reduction of Cr(VI) to Cr(III) at a stoichiometry close to the theoretical ratio. Quantitative distribution analysis of Cr(III) products suggested Cr(VI) was predominantly reduced via the extracellular respiratory pathways. Further Cr(III)-targeted fluorescent visualization combined with single-cell electron microscopic imaging suggested that Cr(VI) was reduced by “Ca. Methanoperedens” independently. Biochemical mechanism investigation via proteomic analysis showed proteins for nitrate reduction under nitrate-reducing conditions were significantly downregulated in Cr(VI)-reducing incubation. Instead, many multiheme cytochrome c (MHCs) were among the most upregulated proteins during the Cr(VI) reduction process, suggesting MHC-governed pathways for extracellular Cr(VI) reduction. The significant upregulation of a formate-dependent nitrite reductase during Cr(VI) reduction indicated its potential contribution to the small proportion of Cr(VI) reduction inside cells.

Clean energy production and wastewater treatment by Exophiala dermatitidis: first findings

A single-chamber microbial fuel cell (MFC) was constructed to evaluate the capacity of Exophiala dermatitidis EXF-8193 as an electron-donor microorganism. The working electrodes were made of unidirectional carbon fiber and the voltage generation was evaluated for 120h. The maximum voltage value reached was 176mV after 93hours of operation. At the same time, the degradation of the Basic Blue 9 (BB9) was studied and a 70% decolorization was achieved in 120h. Optimization studies were conducted to maximize the electrical energy produced. In the first stage, the individual influence of the variables: carbon source, shape and area of the anode was analyzed. It was obtained that glucose, a T-shaped anode and an anodic area of 12 cm2 provided the best voltage values, generating 175.8 ± 0.57mV, 175.8 ± 0.57mV and 310.53 ± 1.22mV, respectively. In the second stage of the investigation, multiparametric optimization was carried out using the Response Surface Methodology (RSM) with a Box Behnken experimental design. A second-order model was the best fit, with R2 = 91.7. Finally, the MFC operation was optimized, with 284mV being the most favorable voltage when the cell is operated maintaining the optimal conditions for each parameter.

Tetracycline degradation for wastewater treatment based on ozone nanobubbles advanced oxidation processes (AOPs) – Focus on nanobubbles formation, degradation kinetics, mechanism and effects of water composition

Presence of pharmaceuticals, especially antibiotics, in industrial and domestic effluents causes serious damage to the environment. Classic wastewater treatment processes, in particular conventional biological treatment methods, are not sufficient to rapidly eliminate antibiotics. Typically, Advanced Oxidation Processes (AOPs) based on activation of hydrogen peroxide, ozone or persulfate for production of particular type of radical species or singlet oxygen are used. A one of cutting-edge technologies to increase effectiveness of AOPs based on ozone are nanobubbles based processes. Thus, this paper focuses on utilization of ozone in the form of nanobubbles for degradation of tetracycline (TC). The effects of several reaction parameters, such as antibiotic concentration, ozone intake, pH, presence of salts, were investigated. This study revealed that the presence of ozone nanobubbles had a substantial positive impact on the degradation of TC. This improvement may be attributed to the enhanced mass transfer and the production of reactive radicals that occur during the collapse of the nanobubbles. Identification of radical species revealed a significant contribution of hydroxyl radicals in the degradation of the antibiotic. AOP process based on O3 nanobubbles was most (•OH) and superoxide (O2–) effective with 100 % degradation efficiency of 100 mg/L TC within 20 min at 8 mg/L concentration of ozone. Based on identified by LC-MS intermediates a degradation mechanism has been described. Degradation of TC and intermediates transformations included methylation, hydroxylation, ring-opening steps as well as cleavage of C-N bonds. This research introduces a novel technique combining nanobubbles with advanced oxidation processes (AOPs), which is anticipated to provide enhanced efficiency and environmental sustainability.

Simultaneous nitrification and denitrification framework for decentralized systems: Long-term study utilizing rope-type biofilm media under field conditions

This research introduces a novel approach to achieve simultaneous nitrification-denitrification (SND) under dynamic load conditions using a cost-effective rope-type biofilm technology. The approach represents a significant advancement in wastewater treatment, particularly beneficial for remote and decentralized communities. The biofilm-based SND process was developed using a pilot-scale flow-through reactor by implementing upstream carbon management with constant-timer-based aeration control versus dynamic-sensor-based aeration control strategies. The findings indicate that adding an upstream anaerobic pretreatment process to handle excess carbon plays a substantial role in achieving a sustainable SND process under a dynamic load environment using simple aeration on-off control. The most optimal nitrification performance of 0.32 g NH3-N/m2/d (89 % removal) was achieved under a 1-hour ON/30-minute OFF aeration. The process sustained an average bulk liquid DO of 5.16 mg/L and 3.80 mg/L during the aeration ON and OFF periods, respectively, facilitating a 0.13 g N/m2/d (41 %) total inorganic nitrogen (TIN) removal, notably, implementing advanced aeration strategies driven by DO, NH3, and NO3 sensors enhanced TIN removal efficiency to 72 %. The nitrification performance remained comparable (89 % removal), resulting in 3 and 10 mg N/L effluent ammonia and TIN concentration, respectively. Additionally, utilizing two multivariate approaches accounting for 82 % and 64 % of the variance, this study discerned patterns in monitored variables and performance. Additionally, the analysis underscored the difference of bulk liquid DO levels in the biofilm versus suspended systems inhibiting the SND process. Distinct bacterial communities were established in biofilms under aerobic, anaerobic, and SND conditions, with the SND reactor showing a hierarchy of functional group and enzymes, enriched sequentially from heterotrophs to denitrifiers, nitrifiers, and anammox bacteria. These innovations underline the potential of tailored control strategies to enhance a passive biofilm-based SND process efficiency under dynamic conditions, providing scalable solutions for diverse target water quality demands in remote communities and decentralized systems.

Characterizing persistent organic pollutants in seawater at a multifunctional international harbor influenced by industrial riverbank activities.

The objective of this study is to comprehensively characterize persistent organic pollutants (POPs) in seawater at Kaohsiung Harbor, focusing on their concentrations, partitioning behaviors, and profiles in both particle and liquid phases. We analyzed 100L seawater for each sample, finding total dioxin-like toxicity (PCDD/Fs+PCBs + PBDD/Fs) ranging from 0.00936 to 0.167pg WHO-TEQ/L, with PCDD/Fs accounting for 68% of total toxicity. POPs predominantly appeared in the particle phase, observed in over 80% of samples, except for PCBs. The observed correlations between particulate matter (PM) and chlorinated POPs at sites receiving river effluents suggest shared pollution sources. The liquid partition of PCDD/Fs, PCBs, and PBDEs in the seawater shows an inverse relationship with log Kow and a direct proportionality with solubility, particularly above 0.1μg/L. Furthermore, PBDEs in seawater can transform into PBDD/Fs upon UV light exposure, highlighting another potential pathway for the persistence and spread of these harmful contaminants in the environment. These findings emphasize the need for field-based investigations to assess PBDF formation in aquatic environments and underscore the importance of stronger mitigation strategies, including better wastewater treatment and stricter discharge regulations to reduce POPs in marine ecosystems.

Research progress of simultaneous nitrogen and phosphorus removal adsorbents in wastewater treatment

Research progress of simultaneous nitrogen and phosphorus removal adsorbents in wastewater treatment

Proactive Monitoring of Changes in the Microbial Community Structure in Wastewater Treatment Bioreactors using Phospholipid Fatty Acid Analysis

Diverse microbial community structures (MCS) in wastewater treatment plants (WWTPs) are vital for effectively removing nutrients and chemicals from wastewater. However, the regular monitoring of MCS in WWTP bioreactors remains unattractive owing to the skill and cost required for deploying modern microbial molecular techniques in the routine assessment of engineered systems. In contrast, low-resolution methods for assessing broad changes in the MCS, such as phospholipid fatty acid (PLFA) analysis, have been used effectively in soil studies for decades. Despite using PLFA analysis in soil remediation studies to capture the long-term effects of environmental changes on MCS, its application in WWTPs, where the microbial mass is dynamic and operational conditions are more fluid, remains limited. In this study, microbial communities in a controlled pilot plant and 12 full-scale activated sludge plants (ASPs) were surveyed over a two-year period using PLFA analysis. This study revealed that changes in the MCS in wastewater bioreactors could be detected using PLFA analysis. The MCS comprised 59% Gram-negative and 9% Gram-positive bacteria, 31% fungi, and 1% actinomycetes. The abundances of Gram-negative bacteria and fungi were strongly inversely correlated, with an R2 = 0.93, while the fatty acids cy17:0 and 16:1ω7c positively correlated (R2 = 0.869). Variations in temperature, solid retention time, and WWTP configuration significantly influenced the MCS in activated sludge reactors. This study showed that WWTP bioreactors can be routinely monitored using PLFA analysis, and changes in the bioreactor profile that may indicate imminent bioreactor failure can be identified.

Synergistic flocculation performance and underlying mechanisms of a novel bioflocculant flocan with coagulant iron salt

Flocculation is an integral part of wastewater treatment units and various flocculants have been employed to strengthen the flocs formation and produce clean water. Natural polysaccharides have been employed as eco-friendly bioflocculants for the treatment of turbid water. In the study, flocan is a named exopolysaccharide (EPS) isolated from a coastal mudflat with a high yield of 8.3g/L. Flocan consisted of glucose, mannose, galactose, and glucuronic acid in a molar ratio of 2:3:1:1, along with pyruvate modifications. As the bioflocculant agent, flocan exhibited more than 85% removal efficiency in kaolin suspension in terms of a concentration of 10mg/L at pH 3. The addition of iron salts with flocan showed high flocculation efficiency in acidic kaolin suspension (99.37%) and acidic coal wastewater (99.44%). The carboxyl/hydroxyl groups and branched structure of flocan provided ionic interactions and promoted higher bridging between bioflocculants and negatively charged particles. Coagulants FeCl3 enhanced the flocculating activity via neutralizing and stabilizing the residual negative charge of functional groups. Treatment with EDTA decreased the ionic interactions and reversed the flocculation significantly. Compared with the current bioflocculants, the superior production, low dosage, and excellent flocculating activity implied that flocan showed great potential in acidic wastewater treatment industrially. The coagulants/bioflocculants combination appears to be a promising and sustainable technology for wastewater flocculation.

Modified gum ghatti based hybrid hydrogel nanocomposite as adsorbent material for dye removal from wastewater

A hybrid hydrogel nanocomposite based on the polysaccharide-gum ghatti, has been made and evaluated as an adsorbent material for wastewater treatment. The nanocomposite is composed of a network of gum ghatti-graft-poly(2-acrylamido-2-methylpropane sulfonic acid) with magnetite nanoparticles embedded within. This functional material Ggh-g-PAMPS/Fe3O4 has been characterized by FTIR, TGA, SEM, EDS, XRD, BET and VSM techniques. The presence of magnetite nanoparticles imparted superparamagnetic property to the adsorbent material enabling its easy separation after use with an external magnet. The characterization data indicated mesoporous nature of the nanocomposite adsorbent with mean pore diameter of 4.9 nm. The nanoparticles imparted high surface area to the adsorbent material the value being 4.7 m2g−1 based on nitrogen adsorption experiments. The suitability of the material as an adsorbent for removal of cationic dyes from water was checked with two cationic dyes namely, rhodamine 6G and methylene blue. The maximum adsorption capacity of the nanocomposite Ggh-g-PAMPS/Fe3O4 towards rhodamine 6G and methylene blue were observed to be 403.2 and 427.8 mg g−1 respectively from their individual solutions of concentration 500 mg L−1. The pH dependence on swelling and surface charge indicated medium of pH of 7.0 as the ideal condition for effective adsorption. Freundlich isotherm model and pseudo second order kinetic model are observed to be the most befitting models to describe adsorption. Further, the thermodynamic studies revealed the adsorption to be a spontaneous and endothermic process. The desorption study portrayed the reusability of the adsorbent material. The excellent adsorption performance and magnetic nature of the developed nanocomposite suggests its potential application as an adsorbent material in wastewater treatment.

Downstream Effects of the Pandemic? Spatiotemporal Trends of Quaternary Ammonium Compounds in Suspended Particulate Matter of German Rivers

During the SARS-CoV-2 pandemic, the preventive use of antimicrobials such as quaternary ammonium compounds (QACs) surged worldwide. As cationic and surface-active biocides, QACs are only partly removed during wastewater treatment and may cause adverse ecological effects in the downstream environment. To understand the environmental consequences of increased disinfectant use during the pandemic, we investigated spatiotemporal QAC concentration trends in the suspended particulate matter (SPM) of three diverse German rivers. Covering pooled annual SPM samples from 2006-2021 and monthly samples from 2018-2021 collected by the German Environmental Specimen Bank, 31 QACs were quantified by high performance liquid chromatography–mass spectrometry.∑QAC concentrations in annual samples differed by more than tenfold between rivers in the order Saar (average 6.7µg/g) > Rhine (0.9µg/g) > Mulde (0.3µg/g). The strongest potential pandemic imprint was however observed in the Mulde (+67%) and Rhine (+22%). Besides pandemic dynamics, also seasonal variation and mineral content of SPM tentatively affected QAC concentrations. Exceedance of predicted no-effect concentrations for sediment suggest ecotoxicological risks for long-chained QACs already before the pandemic. Our study thus highlights the importance of monitoring the environmental effects of antimicrobial use during pandemics and calls for an urgent minimization of non-essential applications. Environmental implicationThe SARS-CoV-2 pandemic caused a global surge in disinfectant use, including quaternary ammonium compounds (QACs). This raises concerns about their environmental residues, aquatic toxicity and contribution to the (co)selection of antimicrobial resistance in pathogens. To assess these ecotoxicological risks, we investigated spatiotemporal QAC concentration trends in suspended particulate matter of German rivers. While seasonal and spatial fluctuations exceed a potential pandemic “imprint” by a factor of 10, concentrations of some QACs reach ecotoxicological effect levels. This highlights the need to consider particle-associated QAC concentrations, the widespread use of QAC, as well as the environmental implications of chemical public health interventions.

Three birds with one stone: Preparation of multifunctional Fe-MOF/PAN nanofiber membranes for wastewater treatment

In this research, a new NH2-MIL-88B(Fe)/polyacrylonitrile nanofiber membrane (NPNFM) was synthesized utilizing a straightforward electrospinning technique. The morphological characteristics and performance of nanofiber membranes were finely tuned via adjusting the dosage of NH2-MIL-88B(Fe) (NM88B, the “stone”). The prepared NPNFM exhibits superhydrophilicity/underwater superoleophobicity, coupled with outstanding photo-Fenton self-cleaning ability (the first two “birds”). This membrane efficiently and swiftly facilitated the separation of various surfactant-stabilized emulsions under gravitational force, achieving a separation efficiency and flux of up to 99.5 % and 350.3 L m-2h−1, respectively. The fouling on the membrane surface can be rapidly decomposed, attributing to the superior photo-Fenton activity of NM88B. Furthermore, the organic dye methylene blue (MB) was degraded by 97.4 % within 40 min under the catalytic influence of the membrane. The nanofiber membrane has good mechanical properties and its tensile strength is about 2.3 times that of the original membrane attributing to the good compatibility between NM88B and the membrane matrix (the third “bird”). This study proposed new Fe-MOF-based photo-Fenton multifunctional membranes with the characteristics of environmental stability and high efficiency in wastewater treatment fields.

Effluent Quality Soft Sensor for Wastewater Treatment Plant with Ensemble Sparse Learning-Based Online Next Generation Reservoir Computing

Real-time monitoring of key quality variables is essential and crucial for stable and safe operations of wastewater treatment plants (WWTPs). Next generation reservoir computing (NG-RC) has recently garnered significant attention in quality prediction, such as COD and BOD, as an effective alternative to traditional reservoir computing (RC), then is able to act as a data-driven soft sensor to twin a hardware sensor for quality variable measurements. Unlike RC, NG-RC does not require random sampling matrices to define the weights of recurrent neural networks and has fewer hyperparameters. However, NG-RC is usually used online but trained offline, thus leading to model degradation under dynamic scenarios. This paper proposes a sparse online NG-RC approach to meet the real-time requirements of WWTPs and mitigate the impact of measurement noise on the model. First, inspired by the Woodbury matrix identity, an incremental strategy is designed, using sequentially arriving data blocks to learn the output weights of NG-RC online. Then, an ensemble sparse strategy is combined to alleviate overfitting issues of the prediction model. Moreover, a soft sensor based on the ensemble sparse online NG-RC is developed to perform real-time prediction of quality indicators in wastewater treatment processes. Finally, two datasets from actual WWTPs are used to validate the effectiveness of the proposed model.

The synergistic effect of Co atomic clusters and single atoms facilitates the fenton-like reaction on A- and R-TiO2

The regulation of single atom (SA) sites is crucial for the promotion of advanced oxidation processes (AOPs). Here A- and R-TiO2 with Co mixed sites (clusters and single atoms, CS) were prepared to degrade sulfamethoxazole (SMX) by activating peroxymonosulfate (PMS). Co CS/A-TiO2+PMS system can completely remove SMX within 14 min under secondary effluent and dark conditions, and its rate constant (0.4926 min-1) was 4.4, 3.2 and 2.5 times higher than that of Co SA/R-TiO2, Co SA/A-TiO2 and Co CS/R-TiO2 systems, respectively. Experiments and calculations verified that the electron configuration of Co SA was optimized by Co clusters, facilitating the adsorption, conversion and desorption of PMS by Co SA, leading to the enhancement of Fenton-like activity. Co CS/A-TiO2 catalytic sponges exhibited exceptional degradation performance in microreactor treatment experiment. This work reveals the synergistic effect between SA and clusters at atomic level and provides an all-purpose strategy (catalytic sponge) for the recovery of non-magnetic catalysts in wastewater treatment.

Utilization of Ziziphus spina-christi leaf extract-loaded chitosan nanoparticles in wastewater treatment and their impact on animal health

Ziziphus leaf extract (ZEX), chitosan nanoparticles (CS NPs) and Ziziphus leaf extract loaded chitosan nanoparticles (ZEX-CS NPs) were prepared in this study and after chemical analysis and characterization, they were used in wastewater purification. The study also aimed to establish, using an animal model, the feasibility of employing treated water in drinking applications. ZEX-CS NPs were prepared by ionic gelation method. About 25 male Sprague Dawley rats (10 weeks and 170-200 g) were divided into five groups (5 rats/group): group I received tape water; group II received untreated wastewater, group III received ZEX treated wastewater, group IV received CS NPs treated wastewater and group V received ZEX-CS NPs treated wastewater. ZEX-CS NPs have a size of 73 nm, hydrodynamic size of 85.81 nm and zeta potential of −33.68 mV. In addition, ZEX-CS NPs have stronger antioxidant and anti-inflammatory activity with moderate anti-coagulant activity and weaker cytotoxicity than ZEX and CS NPs. Group II showed a significant elevation in the kidney function parameters, oxidative stress and cytokine levels when compared to the other groups, in addition; no significant differences were found in all measured parameters between the rats of group I and V. ZEX-CS NPs were effective in wastewater purification.