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[Display omitted] The rapid development of process technology has led to rapid daily industrial production, which also produced a large amount of waste liquid. At the same time, the existing treatment technology cannot keep up with the demand, resulting in the malicious destruction of the environment by wastewater, especially mercury-containing wastewater was very harmful. Effective means of removing mercury ions need to be found. With magnetic ferric oxide as the core and titanium-based metal–organic frameworks as the shell, a new type of magnetic adsorbent (BTA-MIL-125(Ti)@Fe 3 O 4) was synthesized. Materials were tested by multiple characterization methods and multiple sets of experiments. At optimal pH 6, the removal rate in 100 ppm Hg(Ⅱ) was as high as 95.8%. The theoretical adsorption capacity was 615 mg/L. Isothermal experiments, kinetic experiments and thermodynamic experiments have respectively verified that the material was a kind of adsorption material with self-emission heat based on chemical action and synergistic adsorption with Hill model. By simulating the immunity of a variety of ions (Cu, Zn, Mg, Ni, Cd), the material itself also exhibited a very high affinity for Hg(Ⅱ). The results of five high-cycle stable adsorption proved the repeatable stability of the material itself. Various characterization methods have also shown that nitrogen and sulfur-containing groups chelated with Hg(Ⅱ). All of the above was enough to show that the BTA-MIL-125(Ti)@Fe 3 O 4 was a magnetic adsorption material with excellent performance and great prospects. [ABSTRACT FROM AUTHOR]

[Display omitted] In the context of industrialization and severe wastewater pollution, mercury ions pose a major threat due to their high toxicity. However, traditional adsorbents and common metal-organic framework (MOF) materials have limited effectiveness. This study focuses on combining magnetic materials with functionalized titanium-based MOF composite (SNN-MIL-125(Ti)@Fe 3 O 4) to improve mercury ion adsorption. Through comprehensive characterization and analysis, the adsorption performance and mechanism of the material were studied. The optimal adsorption of the material was achieved at pH 5, exhibiting a pseudo-second-order adsorption model and the Hill theoretical capacity of 668.98 mg/g. Hill and Tempkin models confirmed the presence of chemical and physical adsorption sites on the material surface. Thermodynamic experiments showed a spontaneous endothermic process. Despite the presence of interfering ions, the material exhibited high selectivity for mercury ions. After four cycles, adsorption performance decreased by only 8%, indicating excellent reusability. Nitrogen- and sulfur-containing functional groups played a key role in mercury ion adsorption. In conclusion, SNN-MIL-125(Ti)@Fe 3 O 4 , as a magnetic MOF adsorption material, showed potential for effective remediation of mercury-contaminated wastewater. This study contributes to the development of efficient adsorption materials and enhances the understanding of their mechanism. [ABSTRACT FROM AUTHOR]

The urgent concerns of controlling water body eutrophication and the alleviating phosphorus shortage have led to an urgent need for action. The removal of phosphate from polluted waters and its reuse are essential for the prevention of eutrophication and for the sustainable utilization of phosphate resources. In this study, modified attapulgite with different Ca:Mg molar ratios was synthesized to facilitate the recovery of phosphate, with subsequent use of soil fertilizer. Ca–Mg modified attapulgite with the optimal ratio (ACM-5:3) exhibited an exceptional adsorption quality, achieving a maximum adsorption capacity of 63.2 mg/g. The pseudo-second-order model and Langmuir model could well describe the adsorption kinetics and isotherms, respectively. The adsorption mechanism analyses suggested that the interaction between ACM-5:3 and phosphate depended mainly on ion exchange and electrostatic attraction. Moreover, phosphate-laden-ACM-5:3 demonstrated a significant potential as a phosphorus-releasing fertilizer. It could promote corn growth by ensuring a continuous supply of phosphorus and minimizing phosphorus runoff losses. The above results suggested that ACM-5:3 was a potential adsorbent for efficient phosphate removal and recovery. [Display omitted] • Ca–Mg modified attapulgite was prepared using the co-precipitation method. • The maximum adsorption capacity of ACM-5:3 was 63.2 mg/g. • Phosphate-laden-ACM-5:3 was directly used as a slow-release phosphorus fertilizer. • Efficient recovery and reuse of phosphates was achieved. [ABSTRACT FROM AUTHOR]

To evaluate the synergetic adsorption capacity of layered double hydroxide (LDH) and photocatalytic reduction property of TiO 2 for aqueous Cr(VI), the Fe 3 O 4 -ZnAl-LDH and TiO 2 composites (FLT) were prepared via sol-gel method. The removal efficiency of FLT composites for Cr(VI) changed with the mass ratio of Fe 3 O 4 -LDH/TiO 2 , and the optimal ratio was 20% (FLT-2). The adsorption efficiencies of 100 mg FLT-2 were 74% and 64% for 20 and 50 mg/L Cr(VI) solution, and the total removal ratios of Cr(VI) were all over 97% after UV irradiation. The experimental data of adsorption kinetic, adsorption isothermal, and photocatalytic reduction were consistent with the pseudo-second-order, Langmuir, and first-order reaction equations, respectively. From the X–ray photoelectron spectra analysis, FLT composites adsorbed Cr(VI) directly via surface complexation, also reduced aqueous Cr(VI) to Cr(III). The photocurrent and electrochemical impedance spectroscopy of FLT composites indicated the photo-induced electron-hole pairs were separated effectively. The regeneration results show that the FLT composites had good stability and reusability after five consecutive cycles. Therefore, FLT composites are promising materials in the disposal of wastewater containing Cr(VI). [ABSTRACT FROM AUTHOR]

In spite of recent progress in developing hollow micro/nanostructures, the synthesis of three-dimensional adsorbents with high adsorption efficiency and capability on the basis of these structures still remains a great challenge. Herein, we demonstrate a facile hydrothermal strategy to synthesize uniformly dispersed hollow CuWO 4 spheres. The as-prepared CuWO 4 spheres with unique mesoporous structure show favorable selective adsorption for cationic dyes and good recyclability. The adsorption capacity of hollow CuWO 4 towards methylene blue (MB) reaches 59.82 mg g −1 . Furthermore, the hollow CuWO 4 spheres present enhanced photoelectrochemical performance under visible light illumination. This strategy of acquiring specifically functionalized materials from smart design and simple chemical process has opened up wide opportunities on the fabrication of alternative absorbents and photoelectrodes based on CuWO 4 substrate. [ABSTRACT FROM AUTHOR]

[Display omitted] • CAL and PPy-CAL were prepared using hydrothermal and in situ polymerization methods. • The theoretical adsorption capacity of CAL-PPy for Cr(VI) was nearly twice than that of CAL. • CAL-PPy removed 100 mg/L of aqueous Cr(VI) efficiently and quickly. • Mechanisms included electrostatic attraction, anion exchange, complexation, and reduction. To efficiently remove high concentrations of hexavalent chromium (Cr(VI)), calcium–aluminum-layered double hydroxide (CaAl-LDH, denoted as CAL), and polypyrrole-modified CAL (CAL-PPy) were prepared by hydrothermal and in situ polymerization methods, respectively. The chemical structure, morphology, and elemental results indicated that the chain-like polypyrrole was decorated with hexagonal CAL. The specific surface area of CAL-PPy increased from 8.746 m2/g to 24.24 m2/g. The adsorption performances of CAL and CAL-PPy for aqueous Cr(VI) were investigated using batch equilibrium experiments. The decontamination process of aqueous Cr(VI) (100 mg/L) reached the equilibrium state within 50 min, and the kinetic data met the pseudo-second-order kinetic equation. The Langmuir model described the isothermal data properly, and the obtained theoretical adsorption capacity of CAL for Cr(VI) at 318 K was 34.06 mg/g, while that of CAL-PPy was 66.14 mg/g. The removal mechanisms involved electrostatic attraction, surface complexation, anion exchange, and reduction to low-toxicity Cr(III). Therefore, CAL and CAL-PPy have underlying applications in treating real wastewater containing Cr(VI). [ABSTRACT FROM AUTHOR]

The “universal adsorption theory” (UAT) extends the principle of corresponding states for gas compressibility to describe the excess density of an adsorbed phase at comparable reduced conditions. The UAT helps to describe experimental trends and provide predictive capacity for extrapolation from one adsorption isotherm to that of a different adsorbate. Here, we extend the UAT to a flexible metal–organic framework (MOF) as a function of adsorbate, temperature, and pressure. When considered via the UAT, the adsorption capacity and GO pressure of multiple gases to Cu(dhbc) 2 (4,4′-bpy) [H 2 dhbc = 2,5-dihydroxybenzoic acid, bpy = bipyridine] show quantifiable trends over a considerable temperature and pressure range, despite the chemical and structural heterogeneity of the adsorbent. Exceptions include quantum gases (such as H 2 ) and prediction of maximum capacity for large and/or polar adsorbates. A method to derive the heat of gate opening and heat of expansion from experimental trends is also presented, and the parameters can be treated as separable and independent over the temperature and pressure range studied. We demonstrate the relationship between the UAT and the common Dubinin analysis, which was not previously noted. [ABSTRACT FROM AUTHOR]

A novel chromium (VI) ion-imprinted polymer (Cr(VI)-IIP) was prepared using surface ion imprinting technique on graphene oxide-mesoporous silica (GO-MS) nanosheets with 3-(2-amino ethyl amino) propyl trimethoxysilane as the functional monomer. The prepared Cr(VI)-IIP was characterized by Fourier transform infrared spectroscopy, scanning electronic microscopy, X-ray diffraction and thermogravimetric analysis. The prepared Cr(VI)-IIP was then applied to remove Cr(VI) ions from aqueous solution. The influences of functional monomer amount, contact time, initial Cr(VI) concentration, solution pH and temperature, on the adsorption performance of Cr(VI)-IIP were investigated. Adsorption experiments revealed that the sorption equilibrium was achieved within 5 min with a high adsorption capacity up to 438.1 mg g −1 , and the adsorption process followed pseudo-second-order kinetic model and Freundlich adsorption isotherm model. The Cr(VI)-IIP exhibited superior selectivity for Cr(VI) with respected to Cr(III), Mo(VI), PO 4 3− , SO 4 2− and NO 3 − . Moreover, Cr(VI)-IIP showed good reusability in five adsorption/desorption cycles. Results indicated that the synthesized Cr(VI)-IIP possessed excellent potential applications for the treatment of wastewaters containing Cr(VI). [ABSTRACT FROM AUTHOR]