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BACKGROUND In this study, a novel magnetic material was applied as an adsorbent for simultaneous removal of Pb(II) and Cd(II) ions from aqueous solutions. The adsorbent was synthesized using functionalized MnFe2O4 magnetic nanoparticles grafted to lamellar graphene oxide surface (MnFe2O4@SiO2‐NH2@GO) and characterized using X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis and magnetic measurements. RESULTS The adsorbent exhibited superior adsorption properties for Pb(II) and Cd(II). The maximum uptake capacity of Pb(II) and Cd(II) reached 42.48 and 18.28 mg g−1 within 30 min at 25 °C, respectively. The data for adsorption fitted well with the Langmuir isotherm and pseudo‐second‐order kinetic models, which indicated that the adsorption was via monolayer chemisorption on homogeneous sites. The calculation of thermodynamic parameters revealed spontaneous and endothermic adsorption processes accompanied by randomness increase. X‐ray photoelectron spectroscopy analysis indicated that the coordination between nitrogen atoms of amino groups and the two types of heavy metal ions was a possible adsorption mechanism. CONCLUSIONS MnFe2O4@SiO2‐NH2@GO possesses the properties of high adsorption efficiency, fast separation, high stability and easy regeneration for adsorption of Pb(II) and Cd(II) ions. Thus, the as‐prepared adsorbent is considered as a promising material for the removal of heavy metal ions and this research could offer a new means for water cleanup. © 2020 Society of Chemical Industry

Soil organic matter mineralization changed by land-use types is still not clearly understood. In this study, soils from typical land-use types including adjacent plantations of bamboo (Bam), camphor (Cam), and tea (Tea) were chosen to systematically investigate the role of organic carbon components and microbial community compositions in the organic matter mineralization in Ultisol. The mineralization of organic matter followed the sequence Bam < Cam < Tea. The higher carbon contents of labile pools were in the Cam and the Tea than that in the Bam. The carbon content of dissolved organic matter (DOM) showed the order Bam < Cam < Tea, whereas the complexity of chemical structure in DOM followed the opposite trend. The land-use types significant shifted the bacterial and fungal communities, and the relative abundances of bacterial or fungal phyla of Actinobacteria, Acidobacteria, Firmicutes, and Basidiomycota were significantly different among the land-use types. The multivariate regression tree results showed that the total organic carbon and/or the C/N ratio were dominant factors in influencing the bacterial and fungal communities. Moreover, the redundancy analysis results demonstrated that the communities of bacteria and fungi in Bam, Cam, and Tea were tightly linked to the C/N ratio, the pH and the labile pool I carbon, and the DOM, respectively. The Pearson’s correlation results revealed that the mineralization of organic matter was significantly correlated with the organic carbon components, but generally not the microbial community compositions, which implied that the organic carbon components were perhaps the major determinant in controlling the organic matter mineralization in Ultisol.

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