High Removal Efficiency Research Articles

Development of New Biosorbent Based on Crosslinked Chitosan Beads with High Brilliant Blue FCF Removal Efficiency

Effluents containing synthetic anionic dyes can pose a risk to ecosystems, and they must be treated before their release to the environment. Biosorption, a simple and effective process, may be a promising solution for treating these effluents. In this work, chitosan beads were crosslinked with epichlorohydrin to produce a highly stable and performant biosorbent to remove Brilliant Blue FCF dye. The biosorbent was characterized by determining the functional groups on its surface, as well as its elemental composition, crystallinity, and surface morphology. Crosslinking with epichlorohydrin significantly improved the biosorption capacity of chitosan beads. A maximum biosorption capacity of 600 mg/g corresponding to 99% removal efficiency was observed at pH 3.0, a biosorbent dose of 0.5 g/L, an initial dye concentration of 300 mg/L, a contact time of 10 h, and a temperature of 323 K. The biosorption of Brilliant Blue FCF dye in chitosan beads crosslinked with epichlorohydrin was well described by the Langmuir isotherm and followed an adsorption kinetic of pseudo second order. The thermodynamic parameters indicate a spontaneous biosorption process. The presence of anions such as NO3− and SO42− could interfere with the biosorption of Brilliant Blue FCF on the chitosan crosslinked beads, but Cl− did not interfere in biosorption process. Over three biosorption/desorption cycles, the biosorbent showed a removal efficiency of 97% and a desorption rate of over 98%. Chitosan is available worldwide and is a low-cost biomaterial, presenting high potential to be used as a biosorbent to treat industrial effluents containing anionic compounds, such as dyes.

Composite Treatment Module for Removing Acidity and Metal (Loid)S from Acid Rock Drainage

This study evaluates a two-stage approach for remediating acid rock drainage (AMD) generated from an abandoned coal mine site. The method combines the adsorption and chemical precipitation properties of drinking water treatment residue (WTR) in a continuous flow-through fluidized filter bed with hydroponic phytoremediation using Vetiver grass to remove dissolved metal(loid)s. In the first stage, the filter demonstrated exceptionally high removal efficiencies for several metals, including up to 99.67% of Al (<1 mg/L), 99.46% of Fe (<2 mg/L), and 92.48% of As. Significant removal efficiencies were also achieved for Zn (69.24%) and Cu (62.85%). However, relatively low removal efficiencies were observed for Mn (12.50%), Ni (26.74%), and Co (21.36%). Additionally, the system effectively reduced acidity, increasing the pH from 2.67 to a near-neutral level of 6.13. The second stage, a 30-day Vetiver grass treatment, further reduced Mn concentrations by 56.9%, improving upon the limited Mn removal observed in the fluidized filter column. This underscores the complementary role of hydroponic phytoremediation in enhancing the overall metal removal process. This innovative and cost-effective system demonstrates significant potential for AMD remediation, achieving simultaneous removal of metal(loid)s and neutralizing acidity in contaminated mine water.

Optimizing biochar-based column filtration systems for enhanced pollutant removal in wastewater treatment: A preliminary study.

This study aims to test the efficiency of biochar-based substrates in removing chemical and bacteriological pollutants from wastewater and to determine the optimal percentage of biochar (BC) to implement for large-scale filters (e.g., constructed wetlands). So, a preliminary test was conducted on a lab column scale for wastewater treatment of decanted wastewater using column filtration systems (CFS) integrated with BC (BC-based CFSs) at different concentrations (0%, 10%, 25%, and 50%). The BC used here was produced from exhausted olive pomace (pyrolised at T 590°C, residence time of 2h and a heating rate of 10°C min-1). The results revealed that the BC incorporated into the CFS improved the efficiency of nitrogen species removal (total nitrogen (TN) 64-65%, total kjeldahl nitrogen (TKN) 75%-77%, organic nitrogen (ON) 78%-87%, and NH4+-N 57%-69%); phosphorus species (total phosphorus (TP) 39%-44%, PO43- 38%-42%); total and soluble chemical oxygen demand (TCOD (44%-56%), and SCOD (33%-51%) respectively); and total suspended solids (TSS) 87%-92%, compared to the control filter (CFS0). Bacteriological analysis focused on faecal bacteria indicators, including total coliforms (TC), faecal coliforms (FC), faecal streptococci (FS), as well as the pathogen Staphylococcus (SP) and total aerobic mesophilic flora (TAMF). The highest removal efficiencies were observed for CFS10. Based on this preliminary study, the efficiency of CFS in removing pollutants from wastewater is optimal with a small amount of BC (10%) from both water quality and economic points of view.

High-Efficiency Catalytic Ozonation Degradation of Ni Complex Wastewater Using Mn-N Codoped Active Carbon Catalyst.

With the rapid development of electroless nickel (Ni) plating industry, a large amount of Ni complex wastewater is inevitably produced, which is a serious threat to the ecological environment. Herein, a novel Mn-N codoped active carbon (Mn-N@AC) catalyst with high catalytic ozonation ability was synthesized by the impregnation precipitation method and was characterized by BET, XRD, Raman, SEM, FTIR, and TPR. Meanwhile, Mn-N@AC showed excellent catalytic ozonation ability, stability, and applicability. When Ni-EDTA (TOC = 400, Ni = 58.05 mg/L) was used as simulated wastewater, the removal efficiency of TOC and total Ni reached 97.8 and 92.7%, respectively, and after three cycles, the TOC removal efficiency was still up to 93.6%. When Ni-EDTA wastewater was replaced with Ni-citrate, Ni-tartaric, and Ni-malate, the TOC removal efficiency remained above 93%. In addition, mechanistic insights by quenching experiments and EPR verified the high removal efficiency of TOC mainly attributed to indirect oxidation of ·OH and ·O2-, and the potential mechanism was proposed. The work provides insights into the deep removal of Ni complex wastewater by catalytic ozonation with low cost and high efficiency.

A Review of Sources, Hazards, and Removal Methods of Microplastics in the Environment

The prevalence of microplastics in a wide range of environmental media has attracted increasing attention worldwide. This review article provides a comprehensive and systematic review of the nature, sources, hazards, and removal methods of microplastics in the environment. In contrast to previous studies focusing on the sources and risks of microplastics in a single environment, this article comprehensively analyses atmospheric, terrestrial runoff, marine and freshwater sources of microplastics and explores the hazards they pose to the environment and the health of humans and other organisms. Microplastics cause multiple adverse effects on aquatic and terrestrial organisms through accumulation, including growth inhibition, oxidative stress, inflammation, organ damage, and germ cell abnormalities. They may also enter the food chain and affect human health. This article summarizes the latest research progress on microplastic removal technologies from biological, physical, and chemical perspectives, with high efficiency, sustainability, and degradability for biological removal and adsorption and filtration being more effective for physical removal. This provides valuable information for future research related to microplastics. We advocate for a reduction in the use of microplastics and provide references for solving the problem of microplastic pollution.

Experimental and ANN based process optimization for bioremediation of Cr6+ and Cd2+ by green adsorbent prepared from Artocarpus Heterophyllus leaves

The effective removal of toxic pollutants from water and waste water, is a challenging issue for environmental protection. In the present work, the performance of Artocarpus Heterophyllus (jackfruit) leaves have been examined for reduction of toxic Cr (VI) and Cd (II) from synthetic wastewater. Characterization of the adsorbent was made to evaluate the surface morphology and chemical composition, by Scanning Electron Micrograph (SEM) and Energy Dispersive Spectroscopy (EDS). Characteristic surface groups [Fourier Transform Infra-Red (FTIR)], surface area and surface structure [Brunauer–Emmett–Teller, (BET)] were also determined. The influences of various factors which control the removal process were studied experimentally in batch method and optimized. High removal efficiency was obtained at pH ≤ 2 for Cr (VI); and for Cd (II) it was ≥ 6. The experimental data were tested using different kinetic and isotherm models. Artocarpus Heterophyllus leaf was found suitable to remove 99.7 % Cr (VI) and 98.4 % Cd (II) from a strength of 20 mg L-1 solution at 0.5 g L-1 adsorbent concentration, at their respective favorable pHs. The reaction followed pseudo second order kinetic model for both the cases. The calculated sorption energy of 16.16 and 12.68 kJ mol-1, suggested chemical nature for both the cases. Desorption studies showed the effective reuse of Artocarpus Heterophyllus leaf for three times. The relatively high equilibrium adsorption capacity of 32.29 and 20.37 mg g-1 for Cr (VI) and Cd (II) respectively, suggested use of Artocarpus Heterophyllus leaf as a reasonably good green bio-adsorbent. The modeling of the complex adsorption process based on artificial neural network approach exhibited reliability and high degree of proficiency (R values of 0.999) in the model’s prediction and experimental data indicated its applicability in forecasting removal efficiency for both the metal ions.

High-performance cellulose acetate fibers-loaded Al[sbnd]ca layered double oxide adsorbents towards efficient elimination of anionic pollutants: Mechanism adsorption and RSM-CCD approach

In the present research, we investigate Congo red (CR) removal by layered double hydroxide and oxide AlCa on cellulose acetate (CA) fiber as anion-adsorbents in aqueous solution. The as-prepared composite was characterized by FE-SEM, XRD, FTIR, EDS-mapping and BET-BJH analyses. The CR adsorption ability on AlCa LDH/CA and AlCa LDO/CA adsorbents was evaluated. The removal property, dye adsorption and filtration properties of the AlCa LDO/CA composite were studied for removal CR based on central composite design (CCD) technique through investigating operational variables (temperature, adsorbent dosage, pH and contact time). The fabricated AlCa LDO/CA composite indicates a high removal efficiency up to 98.7 % for the CR removal in the 16 min. The data of the adsorption equilibrium were described by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms, and exhibited that AlCa LDH/CA fibers and AlCa LDO/CA fibers followed a pseudo-second-order kinetic model and Langmuir isotherm. The stability of Al-Ca-LDO/CA fibers nanocomposite was indicated that it was >95 % after eight cycles for removal of CR in the batch method on stirrer. The findings illustrated that appropriate AlCa LDO/CA fiber could be an efficient technique for CR elimination.

Odorant production surges induced by exogenous oxidative stress: An overlooked risk in PAA-based moderate preoxidation for algal-laden water.

Moderate preoxidation is feasible for odor-producing algae treatments, usually requiring trade-offs in algal removal and integrity maintenance. However, dosing oxidants may cause internal oxidative homeostasis imbalances and secondary odorous metabolite responses, adding new trade-offs for moderate treatments. Peracetic acid (PAA)/Fe processes are promising strategies in moderate treatments and thus were applied to examine how to achieve the following three trade-offs: good algal removal, no odorant increases and no releases. For algal removal, the highest removal efficiency was 71.1 %, 87.0 % and 98.1 %, respectively, in PAA/Fe(Ⅲ) separate, PAA/Fe(Ⅱ) separate and PAA/Fe(Ⅱ) simultaneous process. Odorant responses always followed a pattern of "promotion-low dosages, inhibition-high dosages", with the highest production reaching 3.91-fold of the control without PAA addition, well above odorant threshold concentrations (500 ng/L). Instant releases did not occur, yet with delayed releases observed during sludge retention in sedimentation tanks (5, 16 h). It was verified that exogenous oxidative stress stimulated odorant generation with multiple reactive species. Among them, PAA oxidant was crucial in algal removal and odorant promotion; R-O· and ·OH caused odorant generation and degradation, respectively. Overall, PAA/Fe(Ⅱ) processes were more suitable for moderate treatments, simultaneously avoiding odorant increases and allowing sludge retention. This work provides a novel perspective for moderate preoxidation, highlighting instant odorant generation and delayed releases triggered by exogenous PAA stressors.

High dye removal and H2O2 production efficiency of KOH-activated bagasse cellulose carbon aerogel-ZnO composite material

High dye removal and H2O2 production efficiency of KOH-activated bagasse cellulose carbon aerogel-ZnO composite material

Assessing the aerobic/anoxic enrichment efficiency at different C/N ratios: pilot scale polyhydroxyalkanoates production from waste activated sludge

Polyhydroxyalkanoates (PHA) can be produced using fermentation products of an excess sewage sludge fermentation process. An efficient method to enrich a PHA-producing community is an aerobic-feast/anoxic-famine enrichment strategy. The effect of different carbon to nitrogen (C/N) feed ratios of 1, 2 and 3.5 g COD/g N on the process performance was studied. The study was executed on a pilot plant scale using fermented waste activated sludge as the organic carbon source. The system's performance was monitored in terms of removing contaminants, producing PHA, and reducing N2O emissions. The results indicated that a lower C/N ratio results in lower PHA production, with PHA content in the sludge of 20, 24 and 36 % w/w for C/N ratios of 1, 2 and 3.5 g COD/g N, respectively. At the lowest C/N ratio, the highest nitrite accumulation rate (77%), nitrification efficiency (89%) and denitrification efficiency (89%) were observed, but the N2O production was also the highest (0.77 mg N2O-N/L). The long-term comprehensive monitoring carried out in this study revealed high carbon and ammonia removal efficiencies (never below 80%) despite the C/N shifts and high COD and ammonia concentrations. At the same time, the system showed relatively low PHA production and high environmental impact in terms of high gaseous N2O emission. These findings question the sustainability of the aerobic-feast/anoxic-famine enrichment strategy for PHA production in full-scale plants.

Enhanced removal of sulfonamide antibiotics in water using high-performance S-nZVI/BC derived from rice straw.

Sulfonamide antibiotics (SAs) are widely used in the biomedical field but pose an environmental risk as ecotoxic pollutants. Developing eco-friendly methods to degrade SAs into harmless compounds is crucial. In this work, biochar (BC) was prepared from rice straw via pyrolysis and used to support S-nZVI, thereby forming the S-nZVI/BC composites. The results show high SAs removal efficiency (up to 98.3%) at optimal Fe/C and Fe/S molar ratios of 3:1 and 50:1, respectively, with strong tolerance to coexisting ions. Furthermore, the effectiveness of S-nZVI/BC(Fe3/C1, Fe50/S1) sample was validated using five real wastewaters, and the results showed consistent performance, stability and reusability. Mechanistic studies revealed that S-nZVI/BC synergized with persulfate to enhance the reactivity of sulfate-free radical (SO4-·) and Fe2+. The degradation pathways of SAs, involving electrophilic substitution and nucleophilic attack, were elucidated by density functional theory (DFT) calculations. These insights were instrumental in comprehending the degradation mechanism of SAs. Additionally, the degradation dynamics of ten SAs were further analyzed using quantitative structure-activity relationship (QSAR) models and principal component analysis (PCA). Hence, this work highlights the potential of S-nZVI/BC for industrial wastewater treatment, providing insights into the degradation mechanisms and pathways of SAs.

Magnetic nanoparticle modified moss Biochar: A novel solution for effective removal of enrofloxacin from aquaculture water.

The presence of residual antibiotics in water constitutes a potential threat to aquatic environments. Therefore, designing environmentally friendly and efficient biochar adsorbents is crucial. Aquaculture by-product moss (bryophyte) was transformed into biochar, which can eliminate antibiotics from wastewater through adsorption. This study successfully fabricated moss biochar (BC) and magnetically modified moss biochar (MBC), and explored their adsorption performance for enrofloxacin (ENR). Characterization analyses revealed that the specific surface area, total pore volume, and the quantity of functional groups of the MBC were significantly larger than those of the BC. The Langmuir isotherm model suggests that the maximum adsorption capacities of BC and MBC for ENR are 7.24mgg⁻1 and 11.62mgg⁻1. The adsorption process conforms to a pseudo-second-order kinetic model. Studies carried out at different temperatures disclose the spontaneous and endothermic thermodynamic characteristics of the system. Under neutral conditions, the adsorption efficiency attains its peak. The existence of various coexisting ions in water exerts a negligible influence on the adsorption process; furthermore, when the concentration of humic acid (HA) ranges from 0 to 20mg/L, the removal rate remains above 90%. In actual water samples, the antibiotic removal rate can be as high as 96.84%. After three cycles of reuse, the structure of MBC remains unchanged while maintaining a high removal efficiency. The primary mechanisms for antibiotic adsorption by MBC involve electrostatic interactions, hydrophobic interactions, pore-filling effects, hydrogen bonding, and π-π interactions. This reusable magnetic moss biochar provides a promising research direction for effectively eliminating antibiotics from water sources.

Insights into the effects of phenolic compounds on the growth of Chlorella vulgaris: The case of olive mill wastewater.

Olive mill wastewaters (OMWW) are characterized by a large concentration of pollutants, among which polyphenols represent a large part. This study investigated the effect of different dilutions of a culture medium enriched with olive-derived phenolic compounds on Chlorella vulgaris growth and its ability to degrade each one of them. In particular, polyphenols were precisely identified and quantified by HPLC-DAD analysis, showing high removal efficiency by C. vulgaris cells. Notably, in a 20% (v/v) medium simulating OMWW, polyphenol reduction reached 83%, and COD reduction was as high as 98%, without compromising microalgae growth or biomass productivity. To further assess the scalability of this bioremediation strategy, the study also examined the performance of C. vulgaris cultivated in an unsterilized OMWW medium at the optimal concentration of 20% (v/v). The results confirmed that the proposed process could be successfully implemented under non-sterile conditions, a crucial factor for transitioning to pilot and large-scale industrial applications, with the system maintaining a polyphenol degradation efficiency of over 75% within 14days. Overall, the proposed green and potentially cost-effective process is a sustainable solution for the degradation of phenolic compounds from OMWW and the management of such high-polluting waste.

Development of Microorganisms Capable of Absorbing Environmental Pollutants through Synthetic Biological Engineering

In Indonesia, environmental pollution is a major concern, especially in industrialised and urban areas. The use of synthesised microorganisms can be an innovative solution to rehabilitate the damaged ecosystems in this region. In this research, an innovative approach based on synthetic biological engineering will be developed to create microbes that have an optimal capacity to absorb and decompose various types of environmental pollutants, such as heavy metals (Pb and Hg), hydrocarbons (benzene), and organic waste (phenol). The results show that the engineered bacteria Escherichia coli, Pseudomonas putida, Bacillus subtilis, and Alcaligenes eutrophus showed high pollutant removal efficiency (85-93%) under laboratory conditions. These results support the potential of synthetic biology technology as an innovative solutions in bioremediation of polluted environments. This research makes a real contribution to green technology innovation in environmental pollution mitigation, supporting the implementation of Sustainable Development Goals (SDGs), especially on points 6 (Clean Water) and 15 (Land Ecosystems).

Surface Modified Magnetic Nanoparticles as an Efficient Material for Wastewater Remediation: A Review

Novel methods for management of environmental quality is directly proportional to the growth of the society. This paper reviews the advanced developments in the synthesis methods, surface modifications and applications of magnetic nanoparticles (MNPs) in environmental applications such as wastewater treatment and others. Surface modifications of magnetic nanoparticles with various inorganic, organic and biomolecules such as silicon dioxide, surfactants, metals etc. enhances the properties of the nanoparticles. The present review access the use of MNPs in removing the organic and inorganic contaminants present in the water bodies. Such methods are cost-friendly, eco-friendly, sustainable and easy to access as compared to other methods or techniques. Various organic and inorganic contaminants such as dyes, heavy toxic metals, pesticides, insecticides, pharmaceuticals etc. can be adsorbed or degraded by MNPs with high removal efficiency upto >95% and recycling upto 5 cycles with a minimum time span of 15 to 25 min. The novelty of the work on surface modified magnetic nanoparticles for wastewater remediation lies in several aspects such as enhanced adsorption affinities for particular contaminants, diverse functionalizations that enables targeting wide range of contaminants, synergic effects can enhance overall remediation and magnetic recovery provides access of easy separation and minimizing waste. The need for removal of such contaminants are necessary to reduce the harmful effects on plants, human as well as to aquatic beings.

Nucleation and growth of zinc-templated mesoporous selenium nanoparticles and potential non-thermal effects during their microwave-assisted synthesis

The effects of 5.8-GHz microwave (MW) irradiation on the synthesis of mesoporous selenium nanoparticles (mSeNPs) in aqueous medium by reduction of selenite ions with ascorbic acid, using zinc nanoparticles as a hard template and cetyltrimethylammonium bromide (CTAB) as a micellar template, are examined for the first time with a particular emphasis on MW-particle interactions and the NPs morphology. This MW-assisted synthesis is compared to 2.45 GHz MW heating method and conventional hydrothermal method at around 100 °C to produce the nanoparticles of different morphology and particle size distributions. The NPs morphology is tailored by varying the temperature ramp characteristics and the MW irradiation time. Under mild synthesis conditions only spherical particles are formed. Enhancing temperature ramp rate in the presence of CTAB micelles increases the metal–semiconductor hybrid particles growth rate and promotes the formation of nanorods and branched shapes. The effect is MW frequency dependent and non-thermal to some extent. Multi-step mechanism of mSeNPs formation is proposed based on derivative UV–Vis spectrophotometry and scanning electron microscopy (SEM) data. Both the stability of the chemical composition at a single particle level and the high efficiency of zinc template removal are determined by single particle microwave plasma optical emission spectrometry (SP-MWP-OES). After Zn template removal mSeNPs can be loaded with antifungal carbamate agent, hence the application as a nanopesticide is suggested.

Design and fabrication of nanocomposite adsorbents for dairy industry wastewater treatment

The dairy industry produces a significant volume of effluents that contain various pollutants, which causes environmental issues. In this study, the fabrication and performance of nanocomposite adsorbents incorporating activated carbon (AC), calcium alginate (CA), and nanosilica, as a simple, cost-effective, and eco-friendly approach to treat dairy wastewater, aiming to enhance food processing sustainability by reducing water consumption, minimizing wastewater, and supporting the Water-Food-Environment Nexus. The nanoparticles were synthesized using sand extraction in an environmentally friendly approach with a size of 30–45 nm. Several techniques such as X-ray fluorescence (XRF), X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–VIS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to characterize the materials. Furthermore, the nanocomposite adsorbent performance and efficiency in removing chemical oxygen demand (COD) were assessed through batch experiments. The nanocomposite adsorbents’ optimal conditions were investigated through batch experiments, achieving a 99.7% COD removal in dairy wastewater treatment. The best results were obtained with a 4-h contact time, pH of 2, and nanosilica dosage of 10%, demonstrating the adsorbent’s high efficiency in organic pollutant removal. However, the adsorption isotherm, kinetic, and thermodynamic studies were carried out and the best-fitted models of isotherm, and kinetic models were Langmuir, and pseudo-second-order reaction, respectively. The thermodynamic reaction of this study is related to being endothermic.

The Effectiveness of an Anoxic-Oxic-Anoxic-Oxic Sequencing Batch Reactor System (A2/O2-SBR) to Treat Electroplating Wastewater and the Bacterial Community within the System

This study presents an examination of the effectiveness of an anoxic-oxic-anoxic-oxic sequencing batch reactor (A2/O2-SBR) for treating electroplating wastewater (EPWW). The A2/O2-SBR was monitored for 60 days and the bacterial composition in the treatment system was determined. The system consisted of four reactors, which had the following anoxic/oxic ratios: reactor-I, 0:9 h; reactor-II, 2:7 h; reactor-III, 4.5:4.5 h; and reactor-IV, 7:2 h. The combined cycle time of the reactors was 12 h, the hydraulic retention time (HRT) was five days, and the total volume of mixed liquor suspended solids (MLSS) was 2,000 mg/L. The results demonstrate the importance of an anoxic period for the treatment of heavy metals. Most of the ammonium nitrogen (NH4+-N), Total Kjeldahl nitrogen (TKN), and total nitrogen (TN) were removed during the oxic period. However, as the anoxic period increased, the amounts of TKN, nitrite nitrogen (NO2--N), nitrate nitrogen (NO3--N), and TN declined. Reactor-IV showed a high removal efficiency for heavy metals (Zn2+, 89.74%; Cd2+, 81.37%), TKN (89.20%), and TN (84.25%), and also effectively treated NH4+-N (78.84%), biochemical oxygen demand (BOD5; 93.5%), and chemical oxygen demand (COD; 84.9%). Reactor-IV showed an appropriate difference in the dissolved oxygen (DO) concentration between the anoxic period and oxic period (2.12-2.00 mg/L). The main bacterial phyla in the treatment system were Proteobacteria, Actinobacteria, and Firmicutes, while Pseudomonas vancouverensis and Cryobacterium arcticum were the most common species. The anoxic period and bacterial community have significantly demonstrated the ability to remove Zn2+ and Cd2+ for effective treatment of EPWW.

Removal characteristics of heavy metals from polluted river water purified by hybrid constructed wetlands.

Heavy metal pollution in urban rivers has become a global issue. In this study, hybrid constructed wetlands (HCWs) were used to comprehensively evaluate the effectiveness of field wetland projects in removing heavy metals, with evaluation metrics including seasonal variations, plant contributions, and structure compositions. The experimental results showed that the synergistic system of root-microorganism-substrate formed in the combined process well realized the high efficiency of heavy metal removal, in which the removal rate in the warm season was higher than that in the cold season. The average removal rates of Cu, Zn, Cr, and Pb were 44.62%, 43.12%, 40.59% and 45.18%, respectively. In the effluent, Zn and Cr can better meet the corresponding standards of the US, EU, and CN, and the biotoxicity of Cu and Pb was also greatly reduced. Compared to Cu, Cr, and Pb, the removal of Zn was less affected by influent loads and stable removal was achieved. In HCWs, the primary contribution to heavy metal removal is attributed to sediment deposition, subsequently followed by the uptake by plant roots and stems, with adsorption onto fillers being the least significant. These results of the study show that HCWs can effectively treat heavy metal pollution in water bodies, and are a highly efficient process for ecological remediation of urban river water. Most importantly, HCWs have demonstrated strong adaptability during the operation of actual ecological restoration projects. Additionally, HCWs can adjust the component structure according to the specific conditions of the process to realize the highest efficiency, which provides a new idea for urban river ecological restoration.

Z-scheme CeO2-TiO2@CNT Heterojunction for Efficient Photoredox Removal of Mix Pollutants (CPF, MB, MO, and RhB).

Z-scheme CeO2-TiO2@CNT (CTC) heterojunction is fabricated using hydrothermal method and evaluated for removing mixed pollutants (MIX-P) from ciprofloxacin (CPF) and textile contaminations. CTC demonstrated ≈99% removal efficiency against MIX-P under solar irradiation of ≈105 lumens. High removal efficiency of CTC is attributed to reduced bandgap (Eg), 2.65eV, and high specific surface area (68.193m2g-1). Lower Eg extends light absorption that generates more charge carriers and reactive species, RS (•O2 -, h+, •OH), to facilitate the photocatalytic removal process. These RS are confirmed through trapping experiments using IPA, N2, and KI. Binding energies of 282.5, 283.7, and 285eV, corresponding to Ti─C, Ti─O─C, and Ce─C bondings, indicated coupling of TiO2, CeO2, and CNT within the CTC structure. Ionic and pH tests confirmed lower photocatalytic efficiency of CTC in an alkaline environment. Photocurrent density and EIS measurements provide insights into the charge carrier dynamics, while HPLC-MS analysis offered information on degradation pathway and identification of intermediates in the removal process. DFT studies confirmed the adjustments in electronic states, structural modifications, and band alignments in agreement with experimental results. This study highlights the potential of CTC as highly effective catalyst for sustainable removal of mixed pollutants from wastewater.