Cadmium ion-imprinted polymers (Cd-IIP) were synthesized by precipitation polymerization using a complex of dithizone and cadmium as a template. The saturation adsorption capacity of the Cd-IIP is two times that of the nonimprinted polymers (Cd-NIP). Homogeneous binding sites are confirmed by the Langmuir isotherm. The adsorption kinetics fit a pseudo-secondorder model well; and the adsorption equilibrium time is only approximately 20 min. The effect of coexisting ions on the Cd(II)-IIP and NIP were investigated by competing with Pb(II), Zn(II), Co(II), and Cu(II), and the ratio of relative selectivity coefficients was greater than 1.68. Thermodynamic parameters indicated that Cd(II) adsorption over IIP and NIP was a spontaneous and exothermic process. The enthalpy changes in different temperatures and adsorption energy are lower than −20.0 and 8 kJ/mol; respectively. These indicate that the adsorption process may be dominated by physisorption. The Cd-IIP was used for five cycles with a small decrease in adsorption capacity, which validated a significant potential of Cd-IIP in wastewater treatment.

At present, the application of phytoremediation technology in the ecological remediation of heavy metal tailings is receiving more and more attention. In this study, the physiological and biochemical response and tolerance mechanism of woody plant Nerium indicum to Pb and Zn under different proportions of inorganic modifier calcium carbonate (C1: 5%, C2: 10%, C3: 15%) and organic modifier mushroom residue (M1: 10%, M2: 20%, M3: 30%) was compared. The results showed that the pH value has a trend of C group > M group > CK group and organic matter has a trend of M group > CK group > C group. Phosphatase activity and catalase activity has a trend of M group > C group > CK group, but catalase was more vulnerable to the calcium carbonate concentration. Both modifiers can promote the transformation of Pb, Zn, Cu, and Cd in tailings to more stable organic bound and residual states. However, the stabilization effect of mushroom residue is better, and its stability is Pb, Zn > Cd, Cu. Both modifiers can increase the biomass of Nerium indicum and the modification effect of mushroom residue is better than calcium carbonate. Pb/Zn content and accumulation in Nerium indicum organs showed root > stem > leaf in all groups. Compared with the CK group, the enrichment coefficient of Pb/Zn in C1 and M1 groups decreased, while the translocation factor of Pb/Zn in C1 and M1 groups increased. With the increase in modifier concentration, the enrichment coefficient increases about 1.75~52.94%, but the translocation factor decreases rapidly (20.01~64.46%). Clearly, both the calcium carbonate and mushroom residue amendment could promote the growth ability of Nerium indicum in lead–zinc tailings and strengthen the phytoremediation potential.

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Hierarchically porous reduced graphene oxide/SnIn 4 S 8 (RGO/SnIn 4 S 8 ) composites with visible-light response and strong mineralization ability were first successfully prepared by a facile low-temperature co-precipitation method, and were characterized by X ray diffraction (XRD), scanning electron microscope (SEM), Brunauer-Emmet-Teller (BET), UV-Visible spectrophotometer (UV-Vis), Raman spectra and Photoluminescence (PL) techniques. RGO/SnIn 4 S 8 composite exhibits strong absorption in UV and visible-light range. The optimized 5% RGO/SnIn 4 S 8 possesses the optimal photocatalytic degradation efficiency and the best mineralization performance with complete degradation of Rhodamine B (RhB) within 70 min and 73.17% mineralization yield within 160 min under visible-light irradiation, which is much higher than that of pure SnIn 4 S 8 . The main reactive species, which play crucial roles in the degradation and mineralization of RhB, follow the order of h + >¨O 2´>¨O H. The intermediate products of RhB degradation were analyzed by using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS), and the possible degradation pathways and mechanism were proposed. Moreover, 5% RGO/SnIn 4 S 8 exhibits excellent reusability and stability without an obvious decrease in photocatalytic activity after four consecutive photocatalytic degradation-regeneration experiments.

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