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Bismuth-based photocatalytic technology has been a promising way to degrade contaminants in the aqueous system. In this work, a direct Z-scheme BiOCl/Bi3NbO7 heterojunction with a different molar ratio of Bi and Nb elements was fabricated through a facile in situ growth method. The structural and photoelectric characteristics of these as-prepared samples were investigated by SEM, XPS, TEM, XRD, BET, UV-vis DRS, PL, EIS and TPC. The photocatalytic activity was evaluated by the degradation of RhB, and its mechanism was analyzed by the active species trapping experiments and DFT calculation. The results showed that compared with other as-prepared samples, BN-4 had the highest activity for RhB degradation with the value of the rate constant (k) being 0.01664 min−1. The reason that might be those different molar ratios of Bi and Nb elements in BiOCl/Bi3NbO7 heterojunction would impact the interface structure. And an appropriate molar ratio of that could bring a lower interface resistance that enhances the photocatalytic activity. The •OH and •O2− were the main active substances during the RhB photocatalytic process, and a reasonable degradation pathway was proposed. [ABSTRACT FROM AUTHOR]

Functionalized graphene oxide was an important candidate for removing heavy metal pollution. However, its difficult separation, low mechanical strength, and secondary pollution were restricted. In our study, polyvinyl alcohol/functionalized graphene oxide macroporous composite spheres (PVA/GO-SH) were prepared by wrapping sulfhydryl-functionalized graphene oxide (GO-SH) in polyvinyl alcohol (PVA) to solve the above problems. The experiments showed that the removal rates of Cu2+ and Pb2+ by 1 g L−1 PVA/GO-SH were 86.59% and 94.7%, and the equilibrium adsorption capacities were 84.42 mg g−1 and 218.62 mg g−1, respectively. The isothermal equation calculation showed that the adsorption was monomolecular layer adsorption. Kinetic and thermodynamic results showed that adsorption follows a second-order reaction kinetic model, and the more high temperature, the more favorable the adsorption. At a flow rate of 2.0 mL min−1, 80 mg L−1 of Cu2+ solution, and 100 mg L−1 of Pb2+ solution could be adsorbed entirely, with volumes of 1960 mL and 2480 mL, respectively. After five adsorption–desorption cycles, the adsorption rate achieved more than 75% of the initial adsorption rate. The composite sphere maintained an excellent spherical shape without damage, which had good stability. In conclusion, PVA/GO-SH has potential practical value. [ABSTRACT FROM AUTHOR]