Synthesis of Core-Shell Magnetic Fe3O4@poly(m-Phenylenediamine) Particles for Chromium Reduction and Adsorption

Induced structural changes of humic acid by exposure of polystyrene microplastics: A spectroscopic insight

The occurrence of microplastics (MPs) as emerging contaminants in the environment may cause changes in water or sediment characteristics, and further affect their biogeochemical cycles. Thus, insights into the interactions between dissolved organic matter (DOM) and MPs are essential for the assessment of environmental impacts of MPs in ecosystems. Integrating spectroscopic methods with chemometric analyses, this work explored the chemical and microstructural changes of DOM-MP complex to reveal the mechanism of DOM-MP interaction at a molecular level. MPs were found to interact with the aromatic structure of DOM via π-π conjugation, then be entrapped in the DOM polymers by the carboxyl groups and C=O bonds, constituting a highly conjugated co-polymer with increased electron density. This induced the fluorescence intensity increase in DOM. The interaction affinity of DOM-MP was highly dependent on the MP size and solution pH. This work offers a new insight into the impact of MP discharge on environment and may provide an analytical framework for evaluating MP hetero-aggregation and the roles of MPs in the transportation of other contaminants. Furthermore, the integrated methods used in this work exhibit potential applications in exploring the fragmentation processes of MPs and formation of secondary MPs under natural conditions.

Efficient removal of Cr(VI) from water by quaternized chitin/branched polyethylenimine biosorbent with hierarchical pore structure

A novel chitin-based biosorbent (QCP) was synthesized by cross-linking quaternized chitin and branched polyethylenimine with the aid of epichlorohydrin for efficient removal of Cr(VI) from water. Because it possessed both quaternary ammonium groups and amino groups as well as the hierarchical pore structure, QCP presented a maximum adsorption capacity of 387.7 mg/g according to the Langmuir isotherm at 25 °C. The biosorption of QCP achieved the equilibrium within 40 min and followed the pseudo-second-order kinetic model. QCP worked well even in the solution with high pH and high content of competing anions and, it exhibited an excellent reusability. The main Cr(VI) uptake mechanism was confirmed to be electrostatic attractions between Cr(VI) anions and quaternary ammonium groups as well as the protonated amino groups, and followed by partial reduction of Cr(VI) to Cr(III) by amines and hydroxyls. This work may provide a potential for Cr(VI) removal by chitin-based biosorbents.

Fluidized bed reaction towards crystalline embedded amorphous Si anode with much enhanced cycling stability

The fluidized bed reaction route was introduced for the first time to prepare amorphous–crystalline silicon anode materials with excellent cycle stabilities.

Chromium (Ⅵ) removal from aqueous solutions through powdered activated carbon countercurrent two-stage adsorption

To exploit the adsorption capacity of commercial powdered activated carbon (PAC) and to improve the efficiency of Cr(VI) removal from aqueous solutions, the adsorption of Cr(VI) by commercial PAC and the countercurrent two-stage adsorption (CTA) process was investigated. Different adsorption kinetics models and isotherms were compared, and the pseudo-second-order model and the Langmuir and Freundlich models fit the experimental data well. The Cr(VI) removal efficiency was >80% and was improved by 37% through the CTA process compared with the conventional single-stage adsorption process when the initial Cr(VI) concentration was 50 mg/L with a PAC dose of 1.250 g/L and a pH of 3. A calculation method for calculating the effluent Cr(VI) concentration and the PAC dose was developed for the CTA process, and the validity of the method was confirmed by a deviation of <5%.

Highly efficient Pb(ii) and Cu(ii) removal using hollow Fe3O4@PDA nanoparticles with excellent application capability and reusability

The easily synthesized Fe₃O₄@PDA material showed excellent performance for Pb(ii) and Cu(ii) elimination from wastewater, and its adsorption mechanism was revealed.

One-pot synthesis of arginine modified hydroxyapatite carbon microsphere composites for efficient removal of U(VI) from aqueous solutions

Uranium was not only the main source of nuclear energy but also one of the long-lived radionuclide. Herein, a novel arginine modified hydroxyapatite carbon microsphere composites (defined as C@HAp/Arg) obtained promptly via a one-step mild hydrothermal method, was applied to remove U(VI) from aqueous solutions. Based on the characterization of transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), the synthesized C@HAp/Arg presented globular morphology and abundant functional groups (e.g., COO^-), which were beneficial to its combination with U(VI). The interaction mechanism and removal capability of U(VI) on C@HAp/Arg were studied by batch adsorption technique and spectroscopy analysis. The results implied that U(VI) can form strong surface complexes on C@HAp/Arg. The kinetics adsorption of U(VI) followed pseudo-second-order kinetic model with high removal efficiency (∼95% within 5h at pH 5.0). The adsorption isotherms were well fitted by Langmuir model, implying that U(VI) uptake on C@HAp/Arg was monolayer coverage. It was found that the maximum adsorption capacities of CSs, C@HAp and C@HAp/Arg toward U(VI) were calculated to be 23.16, 72.09 and 569.66mg/g, respectively, at 298.15K and pH 5.0, and thermodynamic parameters revealed that the adsorption processes of U(VI) were spontaneous and endothermic. In addition, effect of co-existed ions and CO₃^2- concentrations demonstrated that U(VI) adsorption on C@HAp/Arg was weakly interfered by foreign ions and carbonate concentrations. More importantly, the adsorption performance of U(VI) on C@HAp/Arg was still over ∼87% after five cycles. Therefore, it was noted that the versatile C@HAp/Arg could be potentially used as a powerful building block for the enrichment and disposal of U(VI) from aqueous solutions, which could efficiently reduce the potential toxicity of U(VI) in the U(VI)-contaminated water.

Bacteria-enhanced dilute acid pretreatment of lignocellulosic biomass

Pretreatment is indispensable for the large-scale and low-cost bio-products production from lignocellulosic biomass. Herein, a new bacteria-enhanced dilute acid pretreatment (BE-DAP) strategy was introduced. Cupriavidus basilensis B-8 as a potential bacterium for lignin degradation was employed. Multi-scale characterizations on the physicochemical structure of rice straw indicated that Cupriavidus basilensis B-8 could act on the lignin droplets formed in dilute acid pretreatment (DAP), and dig out these droplets to recover cracks and holes on rice straw surface, leaving an opened and porous structure for the easy access of enzyme to inner cellulose. Eventually, the enzymatic digestibility of RS was increased by 35-70% and 173-244% in BE-DAP compared to DAP pretreated and untreated RS, respectively. The BE-DAP strategy, as well as its physicochemical mechanism, opened new perspectives for lignocellulose pretreatment.

Facile modification of nanoscale zero-valent iron with high stability for Cr(VI) remediation

In this study, a highly stable nanoscale zero-valent iron composite (HS-NZVI) was obtained via modifying nanoscale zero-valent iron (NZVI) with tetraethyl orthosilicate (TEOS) and hexadecyltrimethoxysilane (HDTMOS), and used for Cr(VI) remediation in aqueous solution. The obtained HS-NZVI remained stable in water without being oxidized for over 12h. After four consecutive runs, the Cr(VI) removal efficiency of HS-NZVI maintained a value of more than 82%. Moreover, the Cr(VI) removal capacity per unit weight of NZVI in HS-NZVI reached 292.8mg/g within 60min at the initial Cr(VI) concentration of 120mg/L at pH5. The Cr(VI) removal efficiency of HS-NZVI increased with decreasing solution pH, and the experimental data for Cr(VI) removal by HS-NZVI were well-described by the pseudo-first-order reaction model. Additionally, scanning electron microscope (SEM) images, X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) measurements of the product after reaction revealed that the mechanism of Cr(VI) remediation by HS-NZVI mainly involved adsorption, reduction and co-precipitation. Considering the advantages of easy preparation, excellent stability and reusability, and high Cr(VI) removal capacity as well as the magnetic recovery property, HS-NZVI is expected to have notably promising applications for the remediation of Cr(VI) contaminated sites.

High-resolution analyses reveal structural diversity patterns of microbial communities in Chromite Ore Processing Residue (COPR) contaminated soils

To explore how heavy metal contamination in Chromite Ore Processing Residue (COPR) disposal sites determine the dissimilarities of indigenous microbial communities, 16S rRNA gene MiSeq sequencing and advanced statistical methods were applied. 13 soil samples were collected from three COPR disposal sites in Mouding of southwestern, Shangnan of northwestern and Yima of central China. The results of analyses of variance (ANOVA), similarities (ANOSIM), and non-metric multidimensional scaling (NMDS) showed that the structural diversity of the microbial communities in the samples with high total chromium (Cr) content (more than 300 mg kg^-1; High group) were significantly lesser than in the Low group (less than 90 mg kg^-1) regardless of their geographical distribution. But their diversity had virtually rehabilitated under the pressures of long-term metal contamination. Furthermore, the similarity percentage (SIMPER) analysis indicated that the major dissimilarity contributors Micrococcaceae, Delftia, and Streptophyta, possibly having Cr(VI)-resistant and/or Cr(VI)-reducing capability, were dominant in the High group, while Ramlibacter and Gemmatimonas with potential resistances to other heavy metals were prevalent in the Low group. In addition, the multivariate regression tree (MRT), aggregated boosted tree (ABT), and Mantel test revealed that total Cr content affiliated with Cr(VI) was the principal factor shaping the dissimilarities between the soil microbial communities in the COPR sites. Our findings provide a deep insight of the influence of these heavy metals on the microbial communities in the COPR disposal sites and will facilitate bioremediation on such site.

Fe-FeS2 adsorbent prepared with iron powder and pyrite by facile ball milling and its application for arsenic removal

Arsenic is one of the major pollutants and a worldwide concern because of its toxicity and chronic effects on human health. An adsorbent of Fe-FeS2 mixture for effective arsenic removal was successfully prepared by mechanical ball milling. The products before and after arsenic adsorption were characterized with scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The adsorbent shows high arsenic removal efficiency when molar ratio of iron to pyrite is 5:5. The experimental data of As(III) adsorption are fitted well with the Langmuir isotherm model with a maximal adsorption capacity of 101.123 mg/g. And As(V) data were described perfectly by the Freundlich model with a maximal adsorption capacity of 58.341 L/mg. As(III) is partial oxidized to As(V) during the adsorption process. High arsenic uptake capability and cost-effectiveness of waste make it potentially attractive for arsenic removal.

Stepwise Deprotonation of Magnetite-Supported Gallic Acid Modulates Oxidation State and Adsorption-Assisted Translocation of Hexavalent Chromium

Recently, a synergistic strategy involving reduction of carcinogenic Cr(VI) into less toxic Cr(III) followed by Cr(III) adsorption and subsequent separation by surface-engineered magnetite nanoparticles has emerged as a promising alternative to address the environmental hazards associated with Cr(VI)-contaminated water. Despite several previous attempts exploiting this synergy, modulating the oxidation state and translocation of Cr(VI) with high spatiotemporal precision remains a major challenge. Here, we report how Cr(VI) responds accordingly in a well-defined manner to deprotonation of gallic acid covalently immobilized on magnetite nanoparticles, which proceeds through a fixed spatial sequence of distinct stages. To the best of our knowledge, this proof-of-principle study, for the first time, demonstrates that accurate spatiotemporal control over the cascading reduction-adsorption process of Cr(VI) by magnetic adsorbents is feasible, which provides guidance for rational design of more exquisite, magnetite-supported surfaces, where a predictable, and hence controllable, synergy can manifest for Cr(VI) detoxification.

Environmental implications and applications of engineered nanoscale magnetite and its hybrid nanocomposites: A review of recent literature

This review focuses on environmental implications and applications of engineered magnetite (Fe3O4) nanoparticles (MNPs) as a single phase or a component of a hybrid nanocomposite that exhibits superparamagnetism and high surface area. MNPs are synthesized via co-precipitation, thermal decomposition and combustion, hydrothermal process, emulsion, microbial process, and green approaches. Aggregation/sedimentation and transport of MNPs depend on surface charge of MNPs and geochemical parameters such as pH, ionic strength, and organic matter. MNPs generally have low toxicity to humans and ecosystem. MNPs are used for constructing chemical/biosensors and for catalyzing a variety of chemical reactions. MNPs are used for air cleanup and carbon sequestration. MNP nanocomposites are designed as antimicrobial agents for water disinfection and flocculants for water treatment. Conjugated MNPs are widely used for adsorptive/separative removal of organics, dyes, oil, arsenic, phosphate, molybdate, fluoride, selenium, Cr(VI), heavy metal cations, radionuclides, and rare earth elements. MNPs can degrade organic/inorganic contaminants via chemical reduction or catalyze chemical oxidation in water, sediment, and soil. Future studies should further explore mechanisms of MNP interactions with other nanomaterials and contaminants, economic and green approaches of MNP synthesis, and field scale demonstration of MNP utilization.

Facile preparation of magnetic mesoporous MnFe2O4@SiO2-CTAB composites for Cr(VI) adsorption and reduction

Chromium-contaminated water is regarded as one of the biggest threats to human health. In this study, a novel magnetic mesoporous MnFe₂O₄@SiO₂-CTAB composite was prepared by a facile one-step modification method and applied to remove Cr(VI). X-ray diffraction, scanning electron microscopy, transmission electron microscopy, specific surface area, and vibrating sample magnetometer were used to characterize MnFe₂O₄@SiO₂-CTAB composites. The morphology analysis showed that the composites displayed a core-shell structure. The outer shell was mesoporous silica with CTAB and the core was MnFe₂O₄ nanoparticles, which ensured the easy separation by an external magnetic field. The performance of MnFe₂O₄@SiO₂-CTAB composites in Cr(VI) removal was far better than that of bare MnFe₂O₄ nanoparticles. There were two reasons for the effective removal of Cr(VI) by MnFe₂O₄@SiO₂-CTAB composites: (1) mesoporous silica shell with abundant CTA⁺ significantly enhanced the Cr(VI) adsorption capacity of the composites; (2) a portion of Cr(VI) was reduced to less toxic Cr(III) by MnFe₂O₄, followed by Cr(III) immobilized on MnFe₂O₄@SiO₂-CTAB composites, which had been demonstrated by X-ray photoelectron spectroscopy results. The adsorption of Cr(VI) onto MnFe₂O₄@SiO₂-CTAB followed the Freundlich isotherm model and pseudo-second-order model. Tests on the regeneration and reuse of the composites were performed. The removal efficiency of Cr(VI) still retained 92.4% in the sixth cycle. MnFe₂O₄@SiO₂-CTAB composites exhibited a great potential for the removal of Cr(VI) from water.

Synthesis of a core–shell magnetic Fe3O4–NH2@PmPD nanocomposite for efficient removal of Cr(vi) from aqueous media

The magnetic Fe₃O₄–NH₂@PmPD composites show outstanding Cr(vi) removal performance due to the abundant nitrogen-containing functional groups.

Photocatalytic removal of hexavalent chromium by newly designed and highly reductive TiO2 nanocrystals

Hexavalent chromium Cr(VI), a highly toxic oxyanion, widely occurs in drinking water supplies. This study designed and synthesized a new type of highly reductive TiO₂ nanocrystals for photochemical Cr(VI) removal, via the thermal hydrolysis of TiCl₄ in the presence of diethylene glycol (DEG). Surface analyses and hydroxyl radical measurements suggested that DEG was chemically bonded on TiO₂ surface that resulted in an internal hole-scavenging effect and a high electron-releasing capacity, making it advantageous to conventional TiO₂ materials. Upon UV irradiation, the synthesized TiO₂ photocatalyst exhibited fast Cr(VI) reduction kinetics in diverse water chemical conditions. Fast elimination of Cr(VI) was achieved on a time scale of seconds in drinking water matrices. The removal of Cr(VI) by reductive TiO₂ exhibited a three-stage kinetic behavior: an initial fast-reaction phase, a lag phase resulting from surface precipitation of Cr(OH)_3(s), and a final reaction phase due to surface regeneration from oxidation-reduction induced ripening process. The lag phase disappeared in acidic conditions that prevented the formation of Cr(OH)_3(s). The catalyst exhibited extremely high electron-releasing capacity that can be reused for multiple cycles of Cr(VI) removal in drinking water treatment.

Chelating magnetic nanocomposite for the rapid removal of Pb(ii) ions from aqueous solutions: characterization, kinetic, isotherm and thermodynamic studies

Fe₃O₄@GMA–AAm nanocomposite as a novel adsorbent with high adsorption capacity for rapid removal of Pb²⁺ from aqueous media was synthesized.

Novel fungal hyphae/Fe3O4 and N-TiO2/NG composite for adsorption and photocatalysis

A new strategy enables TiO₂ particles to be suspended in solution by constructing a three-layer structure of FH, FH/Fe₃O₄, and FH/N-TiO₂/NG.

Facile synthesis of tea waste/Fe3O4nanoparticle composite for hexavalent chromium removal from aqueous solution

A tea waste/Fe₃O₄composite was prepared through chemical co-precipitation approach and was used for Cr(vi) removal, involving an adsorption-coupled reduction mechanism.

Study on the mechanism of copper-ammonia complex decomposition in struvite formation process and enhanced ammonia and copper removal

Heavy metals and ammonia are difficult to remove from wastewater, as they easily combine into refractory complexes. The struvite formation method (SFM) was applied for the complex decomposition and simultaneous removal of heavy metal and ammonia. The results indicated that ammonia deprivation by SFM was the key factor leading to the decomposition of the copper-ammonia complex ion. Ammonia was separated from solution as crystalline struvite, and the copper mainly co-precipitated as copper hydroxide together with struvite. Hydrogen bonding and electrostatic attraction were considered to be the main surface interactions between struvite and copper hydroxide. Hydrogen bonding was concluded to be the key factor leading to the co-precipitation. In addition, incorporation of copper ions into the struvite crystal also occurred during the treatment process.

Highly Flexible and Porous Nanoparticle-Loaded Films for Dye Removal by Graphene Oxide-Fungus Interaction

Highly flexible and porous films with the ability to load various nanoscale adsorbents are of particular importance in the purification field. Herein, we report the sustainable and large-scale fabrication of a porous and flexible hybrid film based on the graphene oxide/hyphae interaction at a relatively low temperature of 130 °C. Under identical conditions, such films cannot be constructed with solely graphene oxide or hyphae. Moreover, through the addition of nanoscale building blocks [e.g., nanoscale poly(m-phenylenediamine) (PmPD) adsorbents] in the interaction process, the nanoparticles can be in situ loaded into the film. According to FTIR and XPS analyses, the film formation mechanisms mainly involve redox and cross-linking reactions between graphene oxide and fungus hyphae. In a proof-of-concept study, a PmPD nanoparticle-loaded hybrid film was used as a superior key component to build a flow-through adsorption device that displayed a promising adsorption performance toward dye pollutants.

Effect of silicate on arsenic fractionation in soils and its accumulation in rice plants

Four rice genotypes, two hybrid and two indica, were selected to investigate the effects of silicate (Si) application on arsenic (As) accumulation and speciation in rice and As fractionation in soil. There were significant differences in root, straw and grain biomass among genotypes (p < 0.05), and Si application significantly increased root (p < 0.05) and grain biomass (p < 0.001). Silicate addition reduced the proportion of As associated with well-crystallized hydrous oxides of Fe and Al and residual phases, whilst increasing the proportions of specifically-sorbed As and As associated with amorphous and poorly-crystalline Fe and Al hydrous oxides. Furthermore, the results indicated that the fraction proportions of non-specifically sorbed, specifically-sorbed, and associated with amorphous and poorly-crystalline hydrous oxides of Fe and Al in rhizosphere soils, were greater than non-rhizosphere soils. Silicate application had a significant effect decreasing total As concentrations in root (p < 0.005), straw (p < 0.05) and husk (p < 0.001) of rice plants. The effect of Si on reducing As accumulation in rice leaves was revealed by SXRF. Indica genotypes transported and accumulated less As than hybrid genotypes. Both percentage and concentration of iAs were lower in indica genotype XFY-9 than in hybrid genotype XWX-12. Silicate reduced iAs and DMA by 21% and 58% in grain (polished) respectively. DMA may have a greater translocation capacity from straw to grain (polished) than inorganic As. The study provides the potential for understanding As uptake mechanisms in rice and mitigating the health risks posed by As contamination in paddy fields.

Enhanced photo-Fenton-like process over Z-scheme CoFe2O4/g-C3N4 Heterostructures under natural indoor light

Low-cost catalysts with high activity and stability toward producing strongly oxidative species are extremely desirable, but their development still remains a big challenge. Here, we report a novel strategy for the synthesis of a magnetic CoFe₂O₄/C₃N₄ hybrid via a simple self-assembly method. The CoFe₂O₄/C₃N₄ was utilized as a photo-Fenton-like catalyst for degradation of organic dyes in the presence of H₂O₂ under natural indoor light irradiation, a green and energy-saving approach for environmental cleaning. It was found the CoFe₂O₄/C₃N₄ hybrid with a CoFe₂O₄: g-C₃N₄ mass ratio of 2:1 can completely degrade Rhodamine B nearly 100 % within 210 min under room-light irradiation. The effects of the amount of H₂O₂ (0.01-0.5 M), initial dye concentration (5-20 mg/L), solution pH (3.08-10.09), fulvic acid concentration (5-50 mg/L), different dyes and catalyst stability on the organic dye degradation were investigated. The introduction of CoFe₂O₄ on g-C₃N₄ produced an enhanced separation efficiency of photogenerated electron - hole pairs by a Z-scheme mechanism between the interfaces of g-C₃N₄ and CoFe₂O₄, leading to an excellent activity as compared with either g-C₃N₄ or CoFe₂O₄ and their mixture. This study demonstrates an efficient way to construct the low-cost magnetic CoFe₂O₄/C₃N₄ heterojunction as a typical Z-scheme system in environmental remediation.

Aerosol-Assisted Self-Assembly of Reticulated N-Doped Carbonaceous Submicron Spheres for Effective Removal of Hexavalent Chromium

This Research Article described a facile one-step method to prepare reticulated N-doped carbonaceous submicron spheres. Through a simple aerosol-assisted technology, glucosamine sulfate used as a carbon source was aerosolized and carbonized to functionalized carbonaceous submicron spheres. The electrostatic attraction between protonated amino groups and sulfate in the aerosol droplets induced a self-assembly and led to the formation of reticular structure, avoiding the use of templates. Compared to bare carbonaceous materials produced from glucose, reticulated N-doped carbonaceous spheres exhibit higher efficiency in the removal of Cr(VI), where the doping of element nitrogen led to electrostatic attraction between protonated nitrogen and chromium ions, and reticulated structure created relatively higher surface area and pore volume, facilitating materials to contact with Cr(VI) ions. XPS characterization proved these novel N-doped carbonaceous materials could effectively transform Cr(VI) to less toxic Cr(III) because of the surface reducing groups. For the practical application, several factors including the initial pH, materials dosage and recycle numbers on the removal performance were studied.

Efficient adsorption of both methyl orange and chromium from their aqueous mixtures using a quaternary ammonium salt modified chitosan magnetic composite adsorbent

A quaternary ammonium salt modified chitosan magnetic composite adsorbent (CS-CTA-MCM) was prepared by combination of Fe3O4 nanoparticles. Various techniques were used to characterize the molecular structure, surface morphology, and magnetic feature of this composite adsorbent. CS-CTA-MCM was employed for the removal of Cr(VI) and methyl orange (MO), an anionic dye, from water in respective single and binary systems. Compared with chitosan magnetic adsorbent (CS-MCM) without modification, CS-CTA-MCM shows evidently improved adsorption capacities for both pollutants ascribed to the additional quaternary ammonium salt groups. Based on the adsorption equilibrium study, MO bears more affinity to CS-CTA-MCM than Cr(VI) causing a considerable extent of preferential adsorption of dye over metal ions in their aqueous mixture. However, at weak acidic solutions, Cr(VI) adsorption is evidently improved due to more efficient Cr(VI) forms, i.e. dichromate and monovalent chromate, binding to this chitosan-based adsorbent. Thus chromium could be efficient removal together with MO at suitable pH conditions. The adsorption isotherms and kinetics indicate that adsorptions of Cr(VI) and MO by CS-CTA-MCM both follow a homogeneous monolayer chemisorption process. This magnetic adsorbent after saturated adsorption could be rapidly separated from water and easily regenerated using dilute NaOH aqueous solutions then virtually reused with little adsorption capacity loss.

Electrospun nanofibrous polyethylenimine mat: a potential adsorbent for the removal of chromate and arsenate from drinking water

A nanofibrous adsorbent for sub-ppm level chromate and arsenate removal from drinking water has been fabricated via an electrospinning technique.

A novel hollow capsule-like recyclable functional ZnO/C/Fe3O4 endowed with three-dimensional oriented recognition ability for selectively photodegrading danofloxacin mesylate

The functional ZnO/C/Fe₃O₄ exhibits high photocatalytic activity and possesses good selectivity.

Pathway of zinc oxide formation by seed-assisted and controlled double-jet precipitation

ZnO can be well formed in a short time at room temperature via seed-assisted and controlled double-jet precipitation.

Microstructured macroporous adsorbent composed of polypyrrole modified natural corncob-core sponge for Cr(vi) removal

A high-performance, cost-effective and spongy adsorbent is rationally designed for Cr(vi) removal based on polypyrrole modified corncob-core natural microsheets.

Core-Shell Ferromagnetic Nanorod Based on Amine Polymer Composite (Fe3O4@DAPF) for Fast Removal of Pb(II) from Aqueous Solutions

Heavy metal ion removal from wastewater constitutes an important issue in the water treatment industry. Although a variety of nanomaterials have been developed for heavy metal removal via adsorption, the adsorption capacity, removal efficiency, and material recyclability still remain a challenge. Here, we present novel Fe3O4@DAPF core-shell ferromagnetic nanorods (CSFMNRs) for the removal of Pb(II) from aqueous solutions; they were prepared by the facile surface modification of twin-like ferromagnetic Fe3O4 nanorods using a 2,3-diaminophenol and formaldehyde (DAPF)-based polymer. The crystallinity and structure of the Fe3O4 nanorods were confirmed via X-ray diffraction (XRD). Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) revealed the core-shell morphology and composition of the materials. Pb(II) removal using the prepared Fe3O4@DAPF CSFMNRs was assessed, and comparable adsorption capacities (83.3 mg g(-1)) to the largest value were demonstrated. A thermodynamic study of the adsorption clearly indicated that the adsorption was exothermic and spontaneous. Due to the ferromagnetic properties with a high saturation magnetization value (56.1 emu g(-1)) of the nanorods, the nanorods exhibited excellent reusability with one of the fastest recovery times (25 s) among reported materials. Therefore, the Fe3O4@DAPF CSFMNRs can serve as recyclable adsorbent materials and as an alternative to commonly used sorbent materials for the rapid removal of heavy metals from aqueous solutions.

Rational design of nanomaterials for water treatment

The ever-increasing human demand for safe and clean water is gradually pushing conventional water treatment technologies to their limits. It is now a popular perception that the solutions to the existing and future water challenges will hinge upon further developments in nanomaterial sciences. The concept of rational design emphasizes on 'design-for-purpose' and it necessitates a scientifically clear problem definition to initiate the nanomaterial design. The field of rational design of nanomaterials for water treatment has experienced a significant growth in the past decade and is poised to make its contribution in creating advanced next-generation water treatment technologies in the years to come. Within the water treatment context, this review offers a comprehensive and in-depth overview of the latest progress in rational design, synthesis and applications of nanomaterials in adsorption, chemical oxidation and reduction reactions, membrane-based separation, oil-water separation, and synergistic multifunctional all-in-one nanomaterials/nanodevices. Special attention is paid to the chemical concepts related to nanomaterial design throughout the review.

Synthesis of graphene oxide decorated with core@double-shell nanoparticles and application for Cr(vi) removal

A novel graphene oxide composite, namely Fe₃O₄@SiO₂@ chitosan/GO nanocomposite (MSCG) was synthesized for decontamination of Cr(vi) from aqueous solution.

A novel tetraethylenepentamine functionalized polymeric adsorbent for enhanced removal and selective recovery of heavy metal ions from saline solutions

A novel tetraethylenepentamine functionalized polymeric adsorbent with polymethacrylate–divinylbenzene as the substrate was facilely prepared for the enhanced removal and selective recovery of Cu(ii) and Ni(ii) from saline solutions.

Core–shell structured Fe3O4@SiO2@CdS nanoparticles with enhanced visible-light photocatalytic activities

Uniform core–shell structured Fe₃O₄@SiO₂@CdS is synthesized by a facile chelating-assistant growth route, which enhances the photocatalytic activities.