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Graphical abstract Abstract In this work, the magnetic alginate microsphere of Fe 3 O 4 /MgAl-LDH (Fe 3 O 4 /LDH-AM) was prepared by immobilizing the Fe 3 O 4 /LDH with calcium alginate (CA) and was used to remove Cd2+, Pb2+, and Cu2+ from aqueous solutions. The obtained Fe 3 O 4 /LDH-AM was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller surface area determination. The results indicated that the surface groups of the alginate and LDH were retained and so was the crystal structure in the alginate microsphere. The adsorption performance of the Fe 3 O 4 /LDH-AM for Cd2+, Pb2+, and Cu2+ in aqueous solutions was evaluated by batch and column adsorption experiments. The effects of adsorption conditions, kinetics, isotherms, mechanisms, and potential applications were investigated. The adsorption kinetic data conformed to the pseudo-second-order kinetic equation, and the isotherm data fit well with the Freundlich and Langmuir isotherm models. The adsorption mechanism of Cd2+, Pb2+, and Cu2+ by the Fe 3 O 4 /LDH-AM entailed complexation and precipitation. The experimental breakthrough curves were correlated with the Thomas model. Moreover, the Fe 3 O 4 /LDH-AM displayed superior regeneration and reusability. These results suggest that the Fe 3 O 4 /LDH-AM is an efficient adsorbent for the removal of heavy metals and can be effectively employed in practical applications. [ABSTRACT FROM AUTHOR]

Abstract: RMn2O5 (R=La, Pr, Nd, Tb, Bi) crystallites were prepared by a mild hydrothermal method and characterized by powder X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and magnetic measurement. The formation of manganates was sensitive to the alkalinities and Mn-containing precursors of the reaction mixtures. This family of manganates is isostructural and has a space group of Pbam. The magnetic measurements for RMn2O5 showed an antiferromagnetic transition. The strong irreversibility between the ZFC and FC curves indicated a helicoidally magnetic structure below 40K. The max d.c. susceptibilities of LaMn2O5+ δ (δ=0.01, 0.06, 0.08, 0.16, 0.17) were found to be variable and the excess oxygen (δ) in the compounds was influenced by the alkalinity used in the hydrothermal synthesis. [Copyright &y& Elsevier]

Abstract: Two pure light rare earth iron garnets Pr3Fe5O12 and Nd3Fe5O12 single crystals were synthesized under mild hydrothermal conditions and structurally characterized by single crystal and powder X-ray diffraction methods. Both compounds crystallize in cubic space group Ia3̄d with lattice parameters a=12.670(2)Å for Pr3Fe5O12 and a=12.633(2)Å for Nd3Fe5O12, respectively. The synthesis of compounds was studied with regard to phase evolution and morphology development with hydrothermal conditions. We proposed the formation mechanisms and formulated a reasonable explanation for their growth habits. Ferrimagnetic Curie temperatures which have been inferred from thermo-magnetization curves were 580K for Pr3Fe5O12 and 565K for Nd3Fe5O12, and the transitions of long range order were also evidenced by differential scanning calorimetry method. The result of magnetic properties has shown that moments of the large radius Pr3+ and Nd3+ ions are parallelly coupled with net moments of iron ions. [Copyright &y& Elsevier]

Abstract: Two novel polyoxometalate derivatives, {X IVWVI 10WV 2O40[Cu(en)2(H2O)]3} [X=V (1), Si (2); en=ethylenediamine], have been hydrothermally synthesized and characterized by elemental analyses, IR, UV–Vis, XPS, EPR, TG and single crystal X-ray diffraction analyses. They represent the first classical Keggin polyoxoanion supported by three transition metal complex moieties, which further act as the neutral molecular unit for the construction of the interesting three-dimensional supramolecular frameworks. The magnetic properties of 1 have also been studied in the temperature range of 4–300K, and its magnetic susceptibility obeys the Curie–Weiss law, showing antiferromagnetic coupling. [Copyright &y& Elsevier]

As a recycling use of waste activated sludge (WAS), we used high-temperature pyrolysis of WAS to support bimetallic Fe–Mn with nitrogen (N) co-doping (FeMn@N–S), a customized composite catalyst that activates peroxysulphate (PS) for the breakdown of tetracycline (TC). First, the performance of TC degradation was evaluated and optimized under different N doping, pH, catalyst dosages, PS dosages, and contaminant concentrations. Activating PS with FeMn@N–S caused the degradation of 91% of the TC in 120 min. Next, characterization of FeMn@N–S by XRD, XPS and FT-IR analysis highlights N doping is beneficial to take shape more active sites and reduces the loss of Fe and Mn during the degradation reaction. As expected, the presence of Fe–Mn bimetallic on the catalyst surface increases the rate of electron transfer, promoting the redox cycle of the catalyst. Other functional groups on the catalyst surface, such as oxygen-containing groups, accelerated the electron transfer during PS activation. Free radical quenching and ESR analysis suggest that the main contributor to TC degradation is surface-bound SO 4 •−, along with the presence of single linear oxygen (1O 2) oxidation pathway. Finally, the FeMn@N–S composite catalyst exhibits excellent pH suitability and reusability, indicating a solid practicality of this catalyst in PS-based removal of antibiotics from wastewater. [Display omitted] • A Fe/Mn bimetallic sludge-based catalyst (SBC) was fabricated. • N doping contributed to high porosity and more active sites for SBC. • SO 4.•− and 1O 2 are the main active substances. • N doping reduces the loss of Fe–Mn bimetallic during the degradation reaction. • FeMn@N–S exhibits excellent adsorbability, stability and reusability. [ABSTRACT FROM AUTHOR]