Application In Wastewater Treatment Research Articles

Engineering cellulose aerogel composites for mercury ion sequestration and aquatic real time monitoring based on the immobilization of metal-organic frameworks.

Industrial wastewater effluents containing elevated levels of mercury are a significant menace to both the ecosystem and human health. Despite the advent of metal-organic frameworks (MOFs) as promising adsorbents, their application in treatment of industrial wastewater has been impeded by the challenges associated with handling their powdered form. In this work, we introduce a straightforward method for fabricating MOF composite cellulose aerogels (5MM-101@CA). The resulting adsorbent showed a high adsorption capacity of 409.84 mg/g for Hg (II), with over 75 % removal efficiency maintained after five consecutive adsorption-desorption cycles. Furthermore, the material exhibited high sensitivity for the real-time detection of Hg (II), with a detection limit as low as 6.89×10-8 M. The adsorbent also showed remarkable fluorescence stability for up to a week, indicative of its excellent optical performance. Dynamic adsorption demonstrated the adsorbent's ability to sustain continuous and stable system operation without compromising adsorption efficiency. These findings underscore the effectiveness of post-synthetic modification (PSM) technology in enhancing the performance of MOFs, while highlighting the utility of low-cost cellulose as an effective carrier. Thus, the composite material developed in this work is promising as it not only maximizes the adsorption capabilities of MOFs but also circumvents the risk of secondary pollution.

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.

PE/PP fibrous adsorbents with bifunctional groups of tertiary amine and phosphate prepared by electron beam induced co-grafting for heavy metal adsorption of both cationic and anionic forms in acidic conditions.

A novel fabric adsorbent having bifunctional groups of tertiary amine and phosphate was prepared by co-graft polymerization of 2-diethylaminoethyl methacrylate (NMA) and 2-hydroxyethyl methacrylate phosphate (PMA) onto a polyethylene/polypropylene nonwoven fabric (PE/PP NF) under low-energy electron beam acceleration. The process involved pre-irradiating the fabric and immersing it in the comonomer solution for grafting. The kinetics of radiation-induced graft polymerization at a total dose of 100 kGy was investigated. For pre-irradiation at 100 kGy, the optimum condition offering highest degree of grafting was at 12 wt% of NMA, 8 wt% of PMA and 4 h of reaction time. The adsorption of anions using hydrogen chromate (HCrO4−) or Cr(VI) and cations using lead (Pb(II)), cadmium (Cd(II)) and copper (Cu(II)) in aqueous solution was carried out. The results demonstrated that the bifunctional adsorbent was able to adsorb both heavy metal anionic and cationic ions from water. The co-grafted adsorbents with tertiary amine and phosphate were able to adsorb 85% Cr(VI) anion and 29% Pb(II) cations from mixed Cr(VI) and Pb(II) solution at pH 3.0 and 71% Pb(II), 13% Cd(II) and 31 % Cu(II) from mixed Pb(II), Cd(II) and Cu(II) solution at pH 5.0. The unique achievement of this study is its hypothesis that a bifunctional adsorbent can be prepared from radiation-induced graft polymerization of two different monomers onto NF, along with proof that the prepared bifunctional adsorbent can actually absorb both cationic or anionic heavy metals forms. Additionally, the adsorbent's preparation offers a rapid and straightforward one-step grafting technique. Therefore, the new bifunctional adsorbents can remove heavy metal ions in aqueous solution, either in the cation or anion form, thus offering highly promising applications in industrial wastewater treatment.

Intensification of flocculation efficiency in multi-stage reactors by optimizing the multi-cone segment configuration

Flocculation is widely used in water treatment, and creating an optimal environment for floc growth is essential to enhancing flocculation efficiency. In this paper, we developed a multi-stage flocculation reactor (MFR) with strong, moderate, and weak mixing zones. Specifically, multi-cone structures with varying diameter ratios (DR) were incorporated in the moderate zone to promote floc growth. Computational simulations revealed that an MFR with a DR of 0.5 generated a uniform and symmetric flow field, reducing zero-velocity zones and forming distinct vortices within cones. This environment facilitated gradual floc growth while minimizing breakage. When applied to treating fracturing flowback fluid, a complex and challenging wastewater, the MFR produced larger and denser flocs, with an average chord length of 180 μm and a fractal dimension of 1.7170. These flocs exhibited high viscoelasticity, with a strength factor of 68.22 and a recovery factor of 47.77, indicating superior shear resistance and recovery ability after breakage. Consequently, the MFR achieved COD and turbidity removal rates of 92.05% and 93.61%, respectively, outperforming a stirred flocculation reactor, which achieved rates of 72.29% and 83.53% for the same parameters. Additionally, the MFR demonstrated excellent pollutant removal efficiency for both mineral processing wastewater and dyeing wastewater. With gradually decreasing energy along the flow direction, the MFR provided appropriate mixing intensities for different stages of floc growth, promoting efficient formation. These findings underscore the MFR’s potential as a highly effective solution for wastewater treatment applications.

Adsorption Properties of Fishbone and Fishbone-Derived Biochar for Cadmium in Aqueous Solution

Cadmium (Cd) contamination in aquatic ecosystems is a serious global environmental issue. Biochar derived from agricultural wastes has recently attracted remarkable attention as it is used as an absorbent in combating heavy metal contamination of water bodies. In the present study, the absorption efficacy of fish bone (FBM) and fishbone-derived biochar prepared at 200 °C, 400 °C, 600 °C, and 800 °C (referred to as B200, B400, B600, and B800, respectively) for the Cd ion (Cd2+) in aqueous solution was investigated. The results showed that high-temperature pyrolysis could optimize the pore structure and specific surface area of FBM, and Cd2+ successfully adsorbed onto FBM and fishbone-derived biochar. High-temperature pyrolysis significantly increased the FBM adsorption capacity for Cd2+ by 49.5–135.1%, with the optimal pyrolysis temperature being 600 °C. Furthermore, the kinetic data of FBM and fishbone-derived biochar for Cd2+ were in better alignment with the pseudo-second-order model, their adsorption isotherms were better in accordance with the Langmuir models, and the thermodynamic analysis showed that the adsorption process was monolayer and favorable adsorption. Moreover, the potential adsorption mechanisms of Cd2+ on FBM and fishbone-derived biochar might be related to pore filling, ion exchange, complexation with oxygen functional groups, and precipitation with the minerals on the biochar surface. Fishbone-derived biochar has significant potential for wastewater treatment and agricultural waste applications.

Engineering Charge Transfer Characteristics in ZnO NRs/Ag2O NPs p-n Heterojunctions: Toward Highly Efficient and Recyclable Photocatalysts.

Staggered gap p-n heterojunction ZnO nanorods/Ag2O nanoparticles, a paradigm of photocatalysts, were developed via engineering the hydrothermal and coprecipitation method. Under simulated sunlight, the photocatalytic characteristics of ZnO/Ag2O(Zn/A) heterojunctions with varying mole ratios (from 8:1 to 8:4, named Zn/A-1-Zn/A-4) were systematically evaluated through the degradation of methylene blue (MB). The influence of key experimental variables, including photocatalyst concentration, MB concentration, and solution pH, on the photocatalyst performance was further analyzed. The incorporation of Ag2O enhanced visible-light absorption, improved electron-hole separation efficiency, and significantly improved the photocatalytic recyclability of the Zn/A heterojunctions. Additionally, metallic Ag generated during photodegradation was found to enhance the photocatalytic activity further. Kinetic studies indicated that the photocatalytic degradation of MB followed pseudo-first-order kinetics, with the Zn/A-3 heterojunction showing the highest photocatalytic activity, achieving a degradation rate constant (k) of 0.028 min-1. Scavenger experiments confirmed that •OH radicals, holes (h+), and superoxide radicals (•O2-) were the primary reactive species involved in the degradation process. The photocatalytic mechanism was identified as a Z-scheme charge transfer system, facilitating efficient charge separation. Moreover, the Zn/A-3 heterojunction exhibited remarkable recyclability, retaining >91% of the photocatalytic activity after five cycles. This study demonstrates the potential of Zn/A heterojunctions for practical applications in industrial wastewater treatment using solar energy.

Development of novel reduced graphene oxide/metalloporphyrin nanocomposite with photocatalytic and antimicrobial activity for potential wastewater treatment and medical applications.

This research investigates a novel nanocomposite material composed of reduced graphene oxide (rGO) and nickel-5,15-bisdodecylporphyrin (Ni-BDP) nanoparticles for the effective removal of methyl orange (MO), a harmful synthetic dye, from water. The structure and composition of the synthesized rGO/Ni-BDP nanocomposite were characterized using high-resolution transmission electron microscopy (HR-TEM), Raman spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and ultraviolet-visible (UV-Vis) spectroscopy. The study demonstrates the material's efficacy as both a catalyst and adsorbent for MO removal. Optimal performance was observed at pH 3.0, where the positively charged nanocomposite surface facilitated strong interactions with negatively charged MO molecules, leading to enhanced photocatalytic activity. Under these conditions, 0.01g of the nanocomposite achieved an impressive 86.2% MO removal efficiency. Furthermore, the study explored the reusability of the rGO/Ni-BDP nanocomposite in repeated cycles of photocatalytic MO degradation under visible light irradiation. While exhibiting some decrease in efficiency over five cycles, the nanocomposite maintained a respectable degradation rate even after multiple uses. Finally, the antimicrobial properties of the nanocomposite were evaluated against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria exhibiting a zone of inhibition measuring 23mm and 26, respectively. The minimum inhibitory concentration (MIC) values of 2.50µg/ml and 1.25µg/ml for Escherichia coli and Staphylococcus aureus, respectively. The results revealed significant antibacterial activity, demonstrating the broad-spectrum efficacy of the rGO/Ni-BDP nanocomposite. This research underscores the potential of the rGO/Ni-BDP nanocomposite as a versatile material for environmental remediation and antibacterial applications.

Facile Synthesis of Polypyrrole-Decorated RGO-CuS Nanocomposite for Efficient Nickel Removal from Wastewater

Efficient wastewater treatment, particularly the removal of heavy metal ions, remains a challenging priority in environmental remediation. This study introduces a novel sandwich-structured nanocomposite, RGO-CuS-PPy, composed of reduced graphene oxide (RGO), copper sulfide (CuS), and polypyrrole (PPy), synthesized via a straightforward hydrothermal method. The unique combination of RGO, CuS, and PPy offers enhanced adsorption capacity for Ni(II) ions due to RGO’s high surface area and CuS’s active binding sites, supported by PPy’s structural stability contributions. This study is among the first to explore this specific nanocomposite architecture for Ni(II) removal, achieving an adsorption capacity of 166.67 mg/g and a high removal efficiency of 94.9% within 210 min for 55 mg/L of Ni(II) concentration at pH 6 and adsorbent dose of 3 mg/15 mL. The kinetic analysis shows the best fitted time-dependent experimental data with the pseudo-second-order model, indicating chemisorption. Isotherm studies confirmed the Langmuir model as the best fit, yielding a high monolayer adsorption capacity of 166.67 mg/g. Thermodynamic analysis shows the adsorption process was endothermic (ΔH° = 80.23 kJ/mol) and spontaneous (ΔG° ranging from −6.985 to −14.399 kJ/mol). Additionally, reusability tests using 0.1 M HCl for desorption demonstrated good reusability, emphasizing the RGO-CuS-PPy nanocomposite’s potential as a sustainable adsorbent for Ni(II) removal in wastewater treatment applications.

Highly Active MXene Quantum Dots/CuSe n-p Plasmonic Heterostructures for Ultrafast Photocatalytic Removal of Cr(VI) under Full Solar Spectrum.

Identifying effective plasmonic photocatalysts exhibiting robust activities across the entire solar spectrum poses a significant challenge. CuSe, with its local surface plasmon resonance (LSPR) effect, has garnered attention as a prospective plasmonic photocatalyst. However, severe charge recombination and insufficient light absorption limit its photocatalytic performance. To enhance the performance, constructing CuSe-based n-p plasmonic semiconductor heterostructures is a potential strategy. MXene quantum dots (MQDs), a kind of n-type plasmonic semiconductor with metallic conductivity and a high LSPR effect, are a promising candidate to couple with p-type CuSe. According to the complementary principle, we designed a 0D/2D MQDs/CuSe n-p plasmonic semiconductor, achieved by wrapping CuSe nanosheets with MQDs. This n-p plasmonic heterostructure exhibits a synergistic effect on an enhanced electronic field, facilitating charge transfer and separation, thereby enhancing charge excitation, carrier migration, and photothermal effect. Furthermore, optimizing the MQD loading content leads to an ultrafast photocatalytic reaction rate, achieving 100% Cr(VI) reduction efficiency within just 60 min with a reaction kinetics of 0.069 min-1, surpassing the performance of bare CuSe. Our work presents a promising approach for developing advanced n-p plasmonic heterostructures based on MQDs for wastewater treatment and other photocatalytic applications.

Computational supported experimental insights in adsorption of Congo Red using ZnO/doped ZnO in aqueous solution

The rapid growth of industrialisation has led to the discharge of harmful effluents into water bodies, severely disrupting the balance of ecosystems. The detection and removal of dyes from wastewater remains a significant challenge. In this study, we report the synthesis of zinc oxide (ZnO) and its doped derivatives through a facile chemical method, followed by comprehensive characterisation and analysis to assess their potential in various applications. The structural properties of the synthesised materials were confirmed by X-ray diffraction (XRD), which verified their crystalline nature and phase purity. Morphological analysis using field emission scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray analysis (EDAX) revealed well-defined nanostructures and uniform elemental distribution. The adsorption ability of the synthesized adsorbents was investigated through electrochemical methods, cyclic voltammetry and Tafel plots, which demonstrated enhanced conductivity and charge transfer characteristics. Additionally, theoretical studies through molecular modelling and molecular dynamic simulations were employed to elucidate the interactions between Congo red molecules and the surface of the synthesized compounds. Adsorption experiments were conducted to evaluate the efficacy of ZnO and its doped variants as adsorbents. To investigate any structural or functional changes after dye adsorption FTIR and XRD were compared, provided a deeper insight into the adsorption mechanism. This multi-faceted approach highlights the potential of ZnO-based materials for effective wastewater treatment and other environmental applications.

Amino acid functionalized carboxymethyl cellulose-based crosslinked aerogels for efficient removal of dye and metal ion from aqueous solution

In order to protect water resources and maintain sustainable development of society, it is crucial to design the adsorption materials with high adsorption capacity and environmental friendliness to effectively remove the pollutants in wastewater. In this study, amino acid functionalized carboxymethyl cellulose-based aerogels were successfully prepared by combining grafting, blending, freeze-drying and crosslinking technologies. The aerogels exhibited outstanding adsorption properties for methylene blue (MB) and lead ions (Pb (II)) with adsorption capacities of 461.68 and 304.60 mg/g, respectively. The adsorption experiment showed that the adsorption process of aerogels for MB conformed to Freundlich adsorption isotherm model and quasi-second-order kinetics model, and the adsorption process for Pb (II) conformed to Langmuir model and quasi-second-order kinetics model. Furthermore, the aerogels displayed excellent recyclability, with the removal efficiency of over 90.0 % for MB and only 14.0 % reduction for Pb (II) after 6 cycles. It is evident that the aerogels hold great potential for application in wastewater treatment, which has important practical significance for environmental protection and high-value utilization of natural polymers.

Weakly-negatively-charged loose nanofiltration membranes tailored by polyethyleneimine for dye/salt separation

Loose nanofiltration membranes with a weakly negatively charged surface were made from interfacial polymerization between natural hydrophilic polymer carboxylated chitosan (C-CS) and trimesoyl chloride (TMC) firstly and further depositing branched polyethyleneimine (PEI) on top of the surface to tailor the membrane structures and surface charge properties. This kind of membrane was exploited for dye/salt separation in textile wastewater treatment. The effects of contents and molecular weights of PEI on the morphologies, surface charge, hydrophilicity, pore size, and dye/salt separation performance of the membrane were comprehensively investigated. We found that the top layer of PEI with a moderate molecular weight is suitable to form a loose structure for dye/salt separation. The optimized membrane has a comparable high water permeability (44.4 L/m2.h.bar), a low salt rejections (2.6 % for Na2SO4, 7.7 % for NaCl, and 6.8 % for MgCl2), a relatively high dye rejection (96.9 % for Congo Red, 85.4 % for Methyl Blue, 51.1 % for Bromophenol Blue, and 48.3 % for Reactive Black 5), and an extremely high CR/Na2SO4 fractionation ratio (37.27). Moreover, the resultant membrane shows excellent anti-fouling performance after 5 cycles (50 h) of filtration. It maintains a high Congo Red rejection during a 10-day long-term run. This study shows an easy way to fabricate and adjust the properties of loose nanofiltration membranes that work well for dye/salt separation using common and low-cost polymers. It shows promising potential in the application of textile wastewater treatment and resource recovery.

Comparative analysis of the antimicrobial activity and dye degradation of metal oxides (TiO2, CdO, Mn2O3, and ZnO) nanoparticles using a green approach.

A tremendous amount of recent work has been done on different metal oxide nanomaterials for biological activities and photocatalytic dye degradation. This work used the Cissus quadrangularis leaf extract to prepare TiO2, CdO, Mn2O3, and ZnO nanoparticles using a green synthesis approach. To ascertain the physicochemical characteristics of the generated metal oxide nanoparticles, various characterisation techniques were used. The X-ray diffraction technique was used to determine the composition of the crystal and phase. Metal oxide nanoparticles have been proven to be present through surface morphological investigations using a scanning electron microscope and energy dispersive spectroscopy analysis. UV-Vis and Fourier transform infrared spectra were used for spectroscopic analysis. X-ray photoelectron spectroscopy can determine a material's elemental composition in addition to the electronicand chemicalstates of its atoms. The nanomaterial's distinct morphology, which resembles rods, rose petals, platelets, and spheres, was discovered by scanning electron microscope. Synthesized metal oxide nanoparticles have demonstrated a remarkable efficiency of 87.5-90.6% when utilized as a catalyst towards the removal of the malachite green dye under UV light irradiation. Additionally, we use the disc diffusion method to assess antibiotic efficacy against Bacillus subtilis, Candida tropicalis, and Escherichia coli. ZnO nanoparticles had the greatest zones of inhibition for 80 μL doses, measuring 26.99mm for Bacillus subtilis, 27.57mm for Escherichia coli, and 25.28mm for Candida tropicalis. The antimicrobial activity was strongly impacted by the size of the nanoparticles and increased with decreasing particle size. Overall, our research demonstrates that metal oxide nanoparticles are a promising photocatalytic agent for wastewater treatment and biological applications.

Emerging breakthroughs in membrane filtration techniques and their application in agricultural wastewater treatment: Reusability aspects

Freshwater resources are becoming limited and are rapidly getting polluted due to industrialization and urbanization. Water pollution is a pervasive global challenge both in terms of scarcity and quality. Among other sources, wastewater discharged through agricultural practices are major contributor to environmental pollution. The leading cause of contaminants is the runoff of fertilizers, herbicides, insecticides and animal waste into waterbodies. Conventional treatment methods efficiently remove large particles, organic matter, and nutrients but require extensive infrastructure and produce significant sludge. In contrast, membrane filtration offers superior purification and reuse potential by using semi-permeable membranes to selectively remove contaminants, including suspended solids and dissolved ions. This study examines membrane filtration principles and technologies, emphasizing their role in delivering high-quality effluent for discharge or reuse. The study identifies fertilizers, herbicides, and insecticides as major agricultural contaminants and highlights conventional techniques' ineffectiveness in achieving high purification levels. Membrane filtration effectively remediates a wide range of pollutants, but fouling remains a challenge, addressed by antifouling agents and advanced membrane materials in hybrid processes. The study concludes by highlighting the reusability aspect of membrane filtration in agricultural systems and the potential applications of reclaimed water. This study emphasizes the need for advanced membrane materials and integrated systems for effective utilisation of membrane filtration.

Ion-exchange formation of Ag2CO3-Ag3PO4 binary nanostructure on electrospun polyurethane nanofibers for enhanced photocatalytic degradation and antibacterial activities

In this study, a hybrid Ag2CO3-Ag3PO4/PU NFs membrane was prepared by electrospinning followed by ion-exchange methods. The obtained samples were characterized by SEM, EDS, XRD, and IR techniques. The Ag2CO3-Ag3PO4/PU NFs membrane composite exhibited excellent photocatalytic performance (100 % of the dye removal within 70 min) towards the degradation of methylene blue (MB) under visible light irradiation. This remarkable performance was mainly due to the efficient separation of the photogenerated charge carriers. In addition, the composite showed good antibacterial performance against Salmonella typhimurium and Staphylococcus aureus. The results obtained from the photocatalytic and antibacterial studies showed that the prepared material can be proposed as a multifunctional material in wastewater treatment and environmental applications.

Low-frequency contact-electro-catalysis driven by friction between the PTFE-coated fabric and dye solution

The phenomenon of contact electrification occurs when two materials with dissimilar work functions are in contact and charged. Contact-electro-catalysis may occur when electron exchange at the liquid-solid interface initiates a redox reaction. This type of catalysis, being classified as the category of mechanically-driven tribocatalysis, has been demonstrated to be able to degrade dye under high-frequency ultrasonic excitation, and is rarely realized under low-frequency friction driving. In this work, a high RhB dye decomposition ratio of 91.5 % is achieved by harnessing the ordinary low-frequency solid-liquid friction energy through the design and use of the recyclable fabric with PTFE coating as a solid friction source to agitate the dye solution. In the absence of PTFE coating, the RhB dye decomposition ratio is about 14.8 % under the same friction conditions. The enhanced contact-electro-catalysis may be attributed to the high electronegativity of PTFE coating. According to the quenching experiments with active species, it is found that both hydroxyl radical (·OH) and superoxide radical (·O2-) are these main active species induced by low-frequency solid-liquid friction. The fabric with PTFE coating after being dried and reused for 5 cycles still possesses 87.9 % RhB dye decomposition ratio. With these advantages of high decomposition ratio of organic pollution, low cost, good recyclability, and environmental friendliness, the developed low-frequency contact-electro-catalysis in this work, is potential for organic wastewater treatment application through utilizing waste solid materials to harvest the mechanical friction energy between solid waste fabrics and ordinary waterflow in future.

Luminescent Multifunctional Nanomaterials: Capacitive Removal and Enhanced Detection Efficiency of Heavy Metals Ions for Advanced Water and Wastewater Treatment Application

AbstractIn recent years, heavy metal ions pollution in the industrialized environment of the societies threaten human health that flaunt ill‐sorted blueprints in freshwater resources obviously. The paradigm of designing luminescent multifunctional nanomaterials finds directions to the strategies of synthesizing cost‐effective, green, and versatile nanomaterials not only for detection, but also removal process of heavy metal ions in large scale applications. Among them, discovering the advances of luminescent multifunctional nanomaterials provides broad types of biomaterials, polymers and porous nanoparticles that grabs focal of investigations over the past several years due to their unique advantages such as enhanced detection efficiency with lowest limit of detection (LOD), minimum ions interference in versatile removal process, fast responsivity and selectivity as outstanding as unique physicochemical properties. This review paper tries to highlight the paradigm of principles for design, development, and utilization of luminescence nanomaterials for considering fundamental detection and removal mechanisms of heavy metal ions. In particular, these nanomaterials increase the remediation quality that are tackled in detail by focusing on opportunities and challenges in the field. Finally, design methods of these nanomaterials and concentrating on empowered detection and removal efficiency for heavy metals ions highlights novel prospective and strategies for largescale applications.

Biosorption of dyes in wastewater using chitosan/polyethylene nanoparticle as adsorbent

Chitosan/low-density polyethylene (CHNP/LDPE) nanoparticles, sized at approximately 200 nm, were developed as effective adsorbents for removing dyes from wastewater. This study involved a systematic experimental investigation to evaluate the effects of several parameters: adsorbent dosage, contact time, temperature, pH, and initial dye concentration, all conducted in batch experiments at ambient temperature. The optimal adsorption conditions were identified; specifically, a pH of 5 was most effective for Methylene Blue (MB) dye, while a pH of 6 yielded the best results for Bromocresol Green (BG) dye. The highest removal efficiency was observed with an initial dye concentration of 50 mg/L and an adsorbent dosage of 0.05 mg/L. Equilibrium studies indicated that the adsorption process conformed to the Langmuir isotherm model for single systems. Notably, MB exhibited a higher adsorption capacity of 147 mg/g compared to BG’s capacity of 142.8 mg/g. These findings underscore the potential of CHNP/LDPE biocomposites as a novel biosorbent for dye removal in wastewater treatment applications, suggesting an efficient and environmentally friendly approach to managing dye pollutants.Graphical abstract

Preparation and characterization of β-cyclodextrin capped magnetic nanoparticles anchored on cellulosic matrix for removal of cr(VI) from mimicked wastewater: Adsorption and kinetic studies

Hexavalent Chromium (Cr(VI)) is essential in many industrial processes. However, it finds its way into water bodies, posing health problems, including lung cancer and the inhibition of DNA and RNA in biological systems. Several chemical and traditional water purification methods have been developed in the past, but most are expensive, tedious and ineffective. This study aimed to prepare and characterize a low-cost hybrid adsorbent, β-Cyclodextrin capped magnetic nanoparticles anchored on a cellulosic matrix (CNC-Fe3O4NP-CD). The characterization techniques confirmed the integration of CNCs, Fe3O4NP and CD into the prepared CNC-Fe3O4NP-CD nanocomposite adsorbent. The adsorbent was employed in batch adsorption experiments by varying adsorption parameters, including solution pH, adsorbent dosage, initial Cr(VI) concentration, and contact time. From the findings, the nanocomposite adsorbent achieved a maximum Cr(VI) removal efficiency of 97.45%, while the pseudo-second-order kinetic model best fitted the experimental data with high linear regression coefficients (R2 > 0.98). The Elovich model indicated that the adsorption process was driven by chemisorption on heterogeneous surface sites, with initial sorption rates surpassing desorption rates. These findings established that CNC-Fe3O4NP-CD presents high efficiency for Cr(VI) removal under acidic pH, offering the potential for optimization and application in real-world wastewater treatment.

A desert beetle-like mesh membrane by decorating superhydrophilic Fe-doped Cu-MOFs onto superhydrophobic CuC2O4 bowknot-like arrays for boosting water-in-oil emulsion separation

Inspired by the water-collecting mechanism of the back structure of the Stenocara beetle, a novel hierarchical structured mesh membrane was rationally constructed by decorating superhydrophilic Fe-doped Cu-MOFs (HKUST-1) onto superhydrophobic CuC2O4 bowknot-like arrays for enhanced separation of oil-in-water emulsions. The Fe-doped HKUST-1 particles, which accumulated in the mesh pores of the superhydrophobic membrane, served as “water-adsorption” centers to facilitate the capture, aggregation, and adsorption of tiny emulsified water droplets. Moreover, the tight packing of Fe-doped HKUST-1 particles within mesh pores not only significantly reduced the pore size, but also extended the effective range of HKUST-1 particles, thereby enhance the “capture-aggregation” process for emulsified water droplets in oil phases. This rationally-designed mesh membrane was demonstrated to efficiently separate water-in-oil emulsions prepared with different oil types, achieving the highest oil permeation flux of approximately 1200 L·m−2·h−1 and maintaining a water content in the oil phase below 57.0 mg·L−1. This study not only presents a simple and scalable strategy for developing a biomimetic anisotropic superwetting mesh membrane, but also underscores its potential industrial applications in oily wastewater treatment.