Magnetic aminated lignin/CeO2/Fe3O4 composites with tailored interfacial chemistry and affinity for selective phosphate removal

Magnetic field-assisted adsorption of phosphate on biochar loading amorphous Zr-Ce (carbonate) oxide composite

For metal-based phosphate adsorbents, the dispersity and utilization of surface metal active sites are crucial factors in their adsorption performance and synthesis cost. In this study, a biochar material modified with amorphous Zr-Ce (carbonate) oxides (BZCCO-13) was synthesized for the phosphate uptake, and the adsorption process was enhanced by magnetic field. The beside-magnetic field was shown to have a better influence than under-magnetic field on adsorption, with maximum adsorption capacities (123.67 mg P/g) 1.14-fold greater than that without magnetic field. The beside-magnetic field could also accelerate the adsorption rate, and the time to reach 90% maximum adsorption capacity decreased by 83%. BZCCO-13 has a wide range of application pHs from 5.0 to 10.0, with great selectivity and reusability. The results of XPS and ELNES showed that the "magnetophoresis" of Ce3+ under the magnetic field was the main reason for the enhanced adsorption performance. In addition, increased surface roughness, pore size and oxygen vacancies, enhanced mass transfer by Lorentz force under a magnetic field, all beneficially influenced the adsorption process. The mechanism of phosphate adsorption by BZCCO-13 could be attributed to electrostatic attraction and CO32-dominated ligand exchange. This study not only provided an effective strategy for designing highly effective phosphate adsorbents, but also provides a new light on the application of rare earth metal-based adsorbent in magnetic field.

Magnetic Hyperporous Elastic Material with Excellent Fatigue Resistance and Oil Retention for Oil-Water Separation

Oily wastewater has caused serious threats to the environment; thus, high-performance absorbing materials for effective oil-water separation technology have attracted increasing attention. Herein, we develop a magnetic, hydrophobic, and lipophilic hyperporous elastic material (HEM) templated by high internal phase emulsions (HIPE), in which free-radical polymerization of butyl acrylate (BA) and divinylbenzene (DVB) is employed in the presence of poly(dimethylsiloxane) (PDMS), lecithin surfactant, and modified Fe3O4 nanoparticles. The adoption of the emulsion template with nanoparticles as both stabilizers and cross-linkers endows the HEM with biomimetic hierarchical open-cell micropores and elastic cross-linked networks, generating an oil absorbent with outstanding mechanical stability. Compressive fatigue resistance of the HEM is demonstrated to endure 2000 mechanical cycles without plastic deformation or strength degradation. By exploiting the synergistic effect of hierarchical structures and low-surface-energy components, the resulting HEM also possesses excellent and robust hydrophobicity (water contact angle of 164°) and good oil absorption capacity, in which Fe3O4 nanoparticles lead to convenient magnetically controlled oil recyclability as well. Notably, the unique biomimetic microporous structure demonstrates superior oil retention capacity (>95% at 1000 rpm and >60% at 10,000 rpm) over the state-of-the-art porous materials for a diverse variety of oils to reduce the risk of secondary oil leakage, along with good recoverability by squeezing owing to the excellent compression resilience. These excellent performances of our HEM provide broad prospects for practical applications in oil-water separation, energy conversion, and smart soft robotics.

Construction of 3D network aluminum sludge-based hydrogel beads: combination of macroization, amino functionalization, and resource utilization

An aluminum sludge-based composite material was constructed against the problems of phosphorus pollution and the waste of aluminum sludge resources. Utilizing metal Ce doping and hydrogel microbeads with pore preparation, the adsorption performance of the original sludge was improved. Meanwhile, the macroscopic body was constructed, and on this basis, polyethyleneimine (PEI) was introduced to complete the amino functionalization further to enhance the adsorption of phosphorus by the adsorbent, and NH-CeAIS-10 microbeads were successfully prepared. In adsorption, microbeads with larger specific surface area and richer functional groups are better choice compared to original sludge. The results of SEM, BET, FT-IR, and XPS analyses indicate that the adsorption of phosphorus by the microbeads is mainly achieved through electrostatic interactions, ligand exchange, and the formation of inner-sphere complexes. According to the Langmuir model, the maximum phosphorus adsorption capacity of NH-CeAIS-10 was 29.56 mg g-1, which was four times higher compared to native aluminum sludge. This also confirms the significant enhancement of phosphorus adsorption through the modification of aluminum sludge. Besides, in dynamic adsorption column experiments, the material exhibited up to 99% removal in simulated wastewater for up to 30 days, demonstrating the great adsorption potential of NH-CeAIS-10 in engineering applications.

Chitosan Biocomposites with Variable Cross-Linking and Copper-Doping for Enhanced Phosphate Removal

The fabrication of chitosan (CH) biocomposite beads with variable copper (Cu2+) ion doping was achieved with a glutaraldehyde cross-linker (CL) through three distinct methods: (1) formation of CH beads was followed by imbibition of Cu(II) ions (CH-b-Cu) without CL; (2) cross-linking of the CH beads, followed by imbibition of Cu(II) ions (CH-b-CL-Cu); and (3) cross-linking of pristine CH, followed by bead formation with Cu(II) imbibing onto the beads (CH-CL-b-Cu). The biocomposites (CH-b-Cu, CH-b-CL-Cu, and CH-CL-b-Cu) were characterized via spectroscopy (FTIR, 13C solid NMR, XPS), SEM, TGA, equilibrium solvent swelling methods, and phosphate adsorption isotherms. The results reveal variable cross-linking and Cu(II) doping of the CH beads, in accordance with the step-wise design strategy. CH-CL-b-Cu exhibited the greatest pillaring of chitosan fibrils with greater cross-linking, along with low Cu(II) loading, reduced solvent swelling, and attenuated uptake of phosphate dianions. Equilibrium and kinetic uptake results at pH 8.5 and 295 K reveal that the non-CL Cu-imbibed beads (CH-b-Cu) display the highest affinity for phosphate (Qm = 133 ± 45 mg/g), in agreement with the highest loading of Cu(II) and enhanced water swelling. Regeneration studies demonstrated the sustainability and cost-effectiveness of Cu-imbibed chitosan beads for controlled phosphate removal, whilst maintaining over 80% regenerability across several adsorption-desorption cycles. This study offers a facile synthetic approach for controlled Cu2+ ion doping onto chitosan-based beads, enabling tailored phosphate oxyanion uptake from aqueous media by employing a sustainable polysaccharide biocomposite adsorbent for water remediation by mitigation of eutrophication.

PDMS/magnetic lignin sponge for oil/water separation

Recyclable, non-toxic, and degradable biological substrates contribute significantly to super-wetting surfaces. In this work, we prepared magnetic micro-nano super-hydrophobic surfaces through a robust solution with magnetic modified lignin particles as the supporting structure. A novel PDMS (polydimethylsiloxane)/magnetic lignin particle (lignin@Fe3O4)/PDA sponge composite was fabricated. Through dopamine (DA) self-polymerization, covalent deposition of magnetic lignin (ML), and PDMS silane modification, the magnetic super-hydrophobic polyurethane sponge composite (Sponge-P) was synthesized so that the Fe3O4 nanoscale microspheres wrapped with microscale lignin magnetic particles adhered to the sponge surface tighter and were barely dislodged. The as-prepared Sponge-P displayed excellent flexibility and a water contact angle of up to 152.2°. The super-hydrophobic sponge prepared with the proposed method was acid-base stable (pH = 2-12), self-cleaning, and suitable for high-salinity seawater. The magnetic super-hydrophobic sponge has good oil-water separation ability and can absorb 43 times its own weight of oil. In the meantime, due to the introduction of magnetic materials into lignin, we not only constructed micro-nanostructures to improve the surface super-hydrophobicity, but also made Sponge-P have the function of magnetic recovery, which has a unique advantage in treating oily wastewater.

High efficient adsorption of W(VI) with a novel lignin-based biosorbent functionalized with Zn2+ and polyamine

Functionalized lignin-based biosorbent has become popular in wastewater treatment and extraction of valuable metals. Amination and metallization modification can effectively improve the adsorption performance of adsorbent. Zn2+/polyamine lignin for adsorption of W(VI) was synthesized by quaternization, amination and metallization from lignin with 3-chloro-2-hydroxypropyl trimethylammonium chloride, tetraethylenepentamine and ZnCl2. The adsorbent was characterized by SEM-EDS, FTIR and XRD. The adsorption performance of Zn2+/polyamine lignin for W(VI) was investigated in batch system. The adsorption mechanism was revealed by zeta potential, SEM-EDS and FTIR and XPS. It was shown that Zn2+/polyamine lignin exhibited great adsorption capacity at pH of 2, 25 °C, oscillation rate of 400 r/min, initial tungsten concentration of 700 mg·L-1 and adsorption time of 720 min. The maximum adsorption capacity of 0.5 g·L-1 Zn2+/polyamine lignin for W(VI) reached 488.28 mg·g-1. The adsorption followed Langmuir model and quasi-second-order kinetic model, indicating that the adsorption was monolayer homogeneous chemisorption. W(VI) was adsorbed through electrostatic attraction of hydrogen bond and Zn2+, ion exchange with Cl- and coordination with -NH2. The adsorption capacity reduced by only 6.47 % after seven cycles of adsorption-desorption, which indicated that Zn2+/polyamine lignin had a great application prospect.

Efficient removal of phosphate from aqueous media using magnetic bimetallic lanthanum‑iron-modified sulfonylmethylated lignin biochar

The use of lignin carbon as an adsorbent for the adsorption of phosphates from wastewater is a promising technology. However, most lignin carbon-based adsorbents still suffer from low adsorption efficiency and poor selectivity. Herein, a novel FeLaO3-modified sulfomethylated lignin (SL) biochar adsorbent (FLO@CSL) was prepared for phosphate removal. The development of this adsorbent took into consideration the strong affinity of lanthanum (La) and iron (Fe) (hydro) oxides for phosphate and the excellent carrier properties of lignin-based biochar. As the core of FLO@CSL, FeLaO3 active sites are highly dispersed on the surface of SL biochar. Besides, doping of Fe(III) not only imparts magnetic properties to FLO@CSL, thereby effectively improving the separation efficiency of the adsorbent, but also enhances the phosphate adsorption performance. Performance studies revealed that FLO@CSL exhibits remarkable adsorption selectivity and substantial phosphate-adsorption capacity. Notably, the maximum adsorption capacity was found to be 137.14 mg P g-1. Phosphate adsorption on the FLO@CSL surfaces proceeds via chemisorption in a single layer, and ligand exchange plays an important role in determining the adsorption behaviour. Because of its exceptional selectivity, remarkable adsorption capacity and outstanding magnetic separation efficiency, FLO@CSL is a highly promising adsorbent material for effectively treating phosphates in wastewater.

Hydrothermal Synthesis of a Technical Lignin-Based Nanotube for the Efficient and Selective Removal of Cr(VI) from Aqueous Solution

Aminated lignin (AL) was obtained by modifying technical lignin (TL) with the Mannich reaction, and aminated lignin-based titanate nanotubes (AL-TiNTs) were successfully prepared based on the AL by a facile hydrothermal synthesis method. The characterization of AL-TiNTs showed that a Ti-O bond was introduced into the AL, and the layered and nanotubular structure was formed in the fabrication of the nanotubes. Results showed that the specific surface area increased significantly from 5.9 m2/g (TL) to 188.51 m2/g (AL-TiNTs), indicating the successful modification of TL. The AL-TiNTs quickly adsorbed 86.22% of Cr(VI) in 10 min, with 99.80% removal efficiency after equilibration. Under visible light, AL-TiNTs adsorbed and reduced Cr(VI) in one step, the Cr(III) production rate was 29.76%, and the amount of total chromium (Cr) removal by AL-TiNTs was 90.0 mg/g. AL-TiNTs showed excellent adsorption capacities of Zn2+ (63.78 mg/g), Cd2+ (59.20 mg/g), and Cu2+ (66.35 mg/g). After four cycles, the adsorption capacity of AL-TiNTs still exceeded 40 mg/g. AL-TiNTs showed a high Cr(VI) removal efficiency of 95.86% in simulated wastewater, suggesting a promising practical application in heavy metal removal from wastewater.

Preparation and Characterization of an Invasive Plant-Derived Biochar-Supported Nano-Sized Lanthanum Composite and Its Application in Phosphate Capture from Aqueous Media

Invasive plants pose a great threat to natural ecosystems owing to their rapid propagation and spreading ability in nature. Herein, a typical invasive plant, Solidago canadensis, was chosen as a novel feedstock for the preparation of nano-sized lanthanum-loaded S. canadensis-derived biochar (SCBC-La), and its adsorption performance for phosphate removal was evaluated by batch adsorption experiment. The composite was characterized by multiple techniques. Effects of parameters, such as the initial concentration of phosphate, time, pH, coexisting ions, and ionic strength, were studied on the phosphate removal. Adsorption kinetics and isotherms showed that SCBC-La shows a faster adsorption rate at a low concentration and SCBC-La exhibits good La utilization efficiency than some of the reported La-modified adsorbents. Phosphate can be effectively removed over a relatively wide pH of 3-9 because of the high pH _pzc of SCBC-La. Furthermore, the SCBC-La shows a strong anti-interference capability in terms of pH value, coexisting ions, and ionic strength, exhibiting a highly selective capacity for phosphate removal. Additionally, Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) measurements reveal that hydroxyl groups on the surface of SCBC-La were replaced by phosphate and manifest the reversible transformation between La(OH)₃ and LaPO₄. Considering its high adsorption capacity and excellent selectivity, SCBC-La is a promising material for preventing eutrophication. This work gives a new method of pollution control with waste treatment since the invasive plant (S. canadensis) is converted into biochar-based nanocomposite for effective removal of phosphate to mitigate eutrophication.

Pyrolysis of Ca/Fe-rich antibiotic fermentation residues into biochars for efficient phosphate removal/recovery from wastewater: Turning hazardous waste to phosphorous fertilizer

Ca/Fe-rich antibiotic fermentation residues (AFRs), a type of hazardous waste, can be regarded as recyclable biomass and metal resources. However, concurrent detoxification and reutilization of biomass and metals resources from AFRs have never been reported before. In this study, Ca/Fe-rich vancomycin fermentation residues were pyrolyzed into biochar to adsorb phosphate for the first time. The residual vancomycin and antibiotic resistance genes were completely decomposed during pyrolysis. The resultant Ca/Fe-rich biochar exhibited excellent performance at adsorbing phosphate without further modifications. The process had rapid kinetics and a maximum adsorption capacity of 102 mg P/g. Ca and Fe were the active sites, whereas different mechanisms were observed under acidic and alkaline conditions. Surprisingly, HCO₃^- enhanced phosphate adsorption with an increase of adsorption capacity from 43.9 to 71.0 mg/g when HCO₃^- concentration increased from 1 to 10 mM. Furthermore, actual wastewater could be effectively treated by the biochar. The phosphate-rich spent biochar significantly promoted seed germination (germination rate: 96.7 % vs. 80.0 % in control group, p < 0.01) and seedling growth (shoot length was increased by 57.9 %, p < 0.01) due to the slow release of bioavailable phosphate, and thus could be potentially used as a phosphorous fertilizer. Consequently, the hazardous waste was turned into phosphorous fertilizer, with the additional benefits of detoxifying AFRs, reutilizing biomass and metal resources from AFRs, controlling phosphate pollution, and recovering phosphate from wastewater.

A Recyclable Magnetic Aminated Lignin Supported Zr-La Dual-Metal Hydroxide for Rapid Separation and Highly Efficient Sequestration of Phosphate

The application of lignin-based adsorbents in the efficient removal of phosphate from wastewater has attracted much attention and been intensively studied in recent years. However, most currently reported lignin-based adsorbents are difficult to recover and recycle. Herein, we have developed a recyclable, nanostructured bio-adsorbent, poly(ethyleneimine) (PEI)-modified lignin (LG) integrated with Fe3O4 and Zr-La dual-metal hydroxide (LG-NH2@Fe3O4@Zr-La), by the Mannich reaction followed by the chemical coprecipitation method. Multilayer adsorption existed on the surface of LG-NH2@Fe3O4@Zr-La based on the isotherm fitting curve, and its adsorption capacity reached 57.8 mg P g−1, exhibiting a higher phosphate uptake than most reported metallic oxide-based composites. The adsorption process was dominated by inner-sphere complexation of ligand-exchange and electrostatic interactions. Moreover, LG-NH2@Fe3O4@Zr-La exhibited excellent selectivity against coexisting anions, and the adsorption was more efficient under acidic conditions. When the phosphate concentration was 2.0 mg P L−1, the removal efficiency of phosphate reached 99.5% and the residual concentration was only 10 μg P L−1, which meets the United States Environmental Protection Agency (USEPA) standard for eutrophication prevention. In addition, the LG-NH2@Fe3O4@Zr-La displayed excellent reusability, maintaining 91.8% of removal efficiency after five cycles. Importantly, owing to the magnetic properties of the loaded Fe3O4, the resulting composite could be separated within 30 s under an external magnetic field. Thus, the separable and recyclable biobased magnetic adsorbent developed in this work exhibited promising application in phosphate capture from real sewage. This research study provides a new perspective for lignin valorization in lignocellulose biorefineries and establishes an approach for developing an economical and efficient bio-adsorbent for phosphate removal from wastewater.

A magnetically recyclable lignin-based bio-adsorbent for efficient removal of Congo red from aqueous solution

It has been always attractive to design a sustainable bio-derived adsorbent based on industrial waste lignin for removing organic dyes from water. However, existing adsorbent strategies often lead to the difficulties in adsorbent separation and recycling. Herein, we report a novel magnetically recyclable bio-adsorbent of Mg(OH)₂/Fe₃O₄/PEI functionalized enzymatic lignin (EL) composite (EL-PEI@Fe₃O₄-Mg) for removing Congo red (CR) by Mannish reaction and hydrolysis-precipitation. The Mg(OH)₂ and PEI functionalized EL on the surface act as active sites for the removal of CR, while the Fe₃O₄ allows for the easy separation under the help of a magnet. As-obtained EL-PEI@Fe₃O₄-Mg forms flower-like spheres and has a relatively lager surface area of 24.8 m² g^-1 which is 6 times that of EL. The EL-PEI@Fe₃O₄-Mg exhibits a relatively high CR adsorption capacity of 74.7 mg g^-1 which is 15 times that of EL when initial concentration is around 100 mg L^-1. And it can be easily separated from water by applying an external magnetic field. Moreover, EL-PEI@Fe₃O₄-Mg shows an excellent anti-interference capability according to the results of pH values and salt ions influences. Importantly, EL-PEI@Fe₃O₄-Mg possesses a good reusability and a removal efficiency of 92 % for CR remains after five consecutive cycles. It is illustrated that electrostatic attraction, π-π interaction and hydrogen binding are primary mechanisms for the removal of CR onto EL-PEI@Fe₃O₄-Mg. This work provides a novel sustainable strategy for the development of highly efficient, easy separable, recyclability bio-derived adsorbents for removing organic dyes, boosting the efficient utilization of industrial waste lignin.

A innovative stepwise strategy using magnetic Fe3O4-co-graft tannin/polyethyleneimine composites in a coupled process of sulfate radical-advanced oxidation processes to control harmful algal blooms

A novel co-graft tannin and polyethyleneimine co-coating magnetic composite (TP@Fe₃O₄) was prepared in the study. On this premise, an unique stepwise efficient strategy based on magnetic flocculation and Sulfate radical (SO₄^•-)-advanced oxidation processes (S-AOPs) for eliminating Microcystis aeruginosa (M. aeruginosa) and algal organic matters (AOMs) was presented. Due to the high positive charge of TP@Fe₃O₄, a > 99 % high algae removal rate was obtained at a modest TP@Fe₃O₄ dosage of 100 mg/L at pH = 8.0 with a short separation time of 5 min. Further, peroxymonosulfate (PMS) treatment was employed as a pre-oxidation method to lower cell stability and promote M. aeruginosa removal by subsequent TP@Fe₃O₄ flocculation. The PMS/TP@Fe₃O₄ system successfully cuts the optimum dose of TP@Fe₃O₄ in half (50 mg/L) without causing obvious cell damage. Following algal fast magnetic separation, ultraviolet (UV) was introduced to activate PMS to totally degrade AOM and microcystin. Response surface methodology (RSM) demonstrated that UV/PMS oxidation removed > 80 % of DOC and > 94 % of microcystin under optimal conditions. SO₄^•- was the main radical species that aided in the elimination of AOM. This is the first study to use magnetic flocculation in conjunction with AOPs to mitigate harmful algal blooms, which can enable the non-destructive eradication of M. aeruginosa while also efficiently degrading AOMs.

Recent advances in developing innovative sorbents for phosphorus removal-perspective and opportunities

Phosphorus is an essential mineral for the growth of plants which is supplied in the form of fertilizers. Phosphorus remains an inseparable part of developing agrarian economics. Phosphorus enters waterways through three different sources: domestic, agricultural, and industrial sources. Rainfall is the main cause for washing away a large amount of phosphates from farm soils into nearby waterways. The surplus of phosphorus in the water sources cause eutrophication and degradation of the habitat with an adverse effect on aquatic life and plants. Phosphate elimination is necessary to control eutrophication in water sources. Among the different methods reported for the removal and recovery of phosphorus: ion exchange, precipitation, crystallization, and others, adsorption standout as a sustainable solution. The current review offers a comparative assessment of the literature on novel materials and techniques for the removal of phosphorus. Herein, different adsorbents, their behaviors, mechanisms, and capacity of materials are discussed in detail. The adsorbents are categorized under different heads: iron-based, silica-alumina-based, calcium-based, biochar-based wherein the metal and metal oxides are employed in phosphorus removal. The ideal attribute of adsorbent will be the utilization of spent adsorbents as a phosphate plant food and a soil conditioner in agriculture. The review provides the perspective on the current research with potential challenges and directives for possible research in the field.

Phosphate Removal from Wastewater by Magnetic Amorphous Lanthanum Silicate Alginate Hydrogel Beads

It is of both fundamental and practical importance to develop effective adsorbents for removing phosphate from aqueous solutions continuously. In this study, magnetic amorphous lanthanum silicate alginate hydrogel beads (MALS-B) were prepared and used for phosphate removal. Mesoporous silica materials with highly ordered and hexagonal channel structures were synthesized from natural mineral rectorite (REC) at room temperature. On this basis, amorphous lanthanum silicate (ALS) was synthesized by theone-pot method using a silicon source from REC and a commercial lanthanum source. Further, MALS-B were synthesized from sodium alginate (SA) with ALS and Fe3O4 as the incorporated adsorbable and magnetic nanoparticles via a simple cross-linking method in CaCl2 solution. The synthesized hydrogel beads were characterized by various techniques. ALS and Fe3O4 existed relatively independently in MALS-B, where ALS provided adsorption sites and Fe3O4 provided magnetism. They played a synergistic role in phosphate removal. The saturation magnetization value of MALS-B was 17.38 emu/g, enabling theirfacile separation from aqueous solutions after phosphate adsorption. MALS-B exhibited a preferable adsorption capacity of 40.14 mg P/g for phosphorus compared to other hydrogel beads based on adsorption experiments. More significantly, MALS-B exhibited excellent selectivity for phosphate in aqueous solutions with various interfering ions and possessed a high affinity to phosphate in a wide pH range. MALS-B showed the treatment volume of 480 BV when effluent phosphate concentration was below 0.5 mg/L in fixed-bed column adsorption. The adsorption mechanism was also revealed. Our work demonstrates that MALS-B can serve as a promising adsorbent for continuous phosphate adsorption.

Biochar/Mg-Al spinel carboxymethyl cellulose-La hydrogels with cationic polymeric layers for selective phosphate capture

Recently, biochar-related phosphate sorbents have been extensively investigated and achieved significant progress; however, there is still much room for enhancement on capturing performance and recovery of powdery ones after sorption. Herein, a new kind of adsorbent, in which biochar/Mg-Al spinel encapsulated in carboxymethyl cellulose-La hydrogels with cationic polymeric layers, was fabricated, aiming for integrating multi-advantages of each component for enhanced phosphate capture. Batch static experiments were correlated to the phosphate adsorption performance of the adsorbent. The maximum phosphate adsorption capacity of the adsorbent was 89.65 mg P/g at pH = 3. The Langmuir isotherm model and the pseudo-second-order kinetic model fitted well with the adsorption behavior of the adsorbent. More importantly, this composite adsorbent that integrated with biochar, Mg-Al spinel, cationic polymeric components exhibited favorable selectivity over coexisting anions (Cl^-, SO₄^2-, HCO₃^- and NO₃^-) and performed good reusability after five consecutive cycles. By virtue of the bead-like feature, fixed-bed column experiments demonstrated that the Thomas model fitted the breakthrough curves well under varied experimental conditions. The adsorption mechanism of phosphate on the designed composite adsorbent with multi-components could be described as the electrostatic attraction, ligand exchange and inner-sphere complexation, which might account for the efficient phosphate capturing performance.

Enhanced phosphate remediation of contaminated natural water by magnetic zeolitic imidazolate framework-8@engineering nanomaterials (ZIF8@ENMs)

The efficient enrichment and reutilization of phosphate from natural water still remains a daunting challenge to satisfy the increasingly stringent phosphate discharge criteria. In response to this problem, the presented study successfully synthesizes a series of magnetic zeolitic imidazolate framework-8@engineering nanomaterials (ZIF8@ENMs) via a two-step hydrothermal and coprecipitation method by facilely growing ZIF8 and/or Fe₃O₄ on various functional ENMs. Structure morphology, chemical composition and hysteresis curve characterizations demonstrate the successful formation of magnetic Fe₃O₄-ZIF8@ENM. Amongst the prepared magnetic ZIF8@ENMs hybrids, the Fe₃O₄-ZIF8@ENMs possessing massive hydroxyl groups is demonstrated to harvest the maximum adsorption capacity of 441.7 mg g^-1 under neutral condition. Such-acquired adsorption capacity evidently surpass state-of-the-art adsorbents. Systematic assessment of the chemical condition effects on phosphate removal, revealing its conspicuous merits of robust pH independence (94.63-98.20%), high selectivity pinpointing phosphate within complex cations, ease-of-separation and satisfactory recycle. The outstanding performance of magnetic ZIF8@ENMs are mainly derived from the formed strong ZnOP, FeOP and electrostatic interactions between phosphate and adsorbents. Along this line, designing magnetic MOFs-based hybrids towards phosphate are anticipated to be promising avenues for advanced treatment of phosphate-like contaminants and efficient recycle in practical applications.

Preparation of resin-based composites containing Ce and cationic polymers with abundant promotional affinity sites for phosphate capture

A new type of composite, D301-Ce+, for efficient and selective phosphate removal.