In the present study, the sorption ability of three metal ions, lead, cadmium, copper, from aqueous solution by tea waste was investigated. Sorption of the evaluated toxic metals by tea waste was pH-dependent, and kinetic data for three metal ions not only indicated a quick sorption process but also were excellently represented by the pseudo-second-order model with all correlation coefficients R 2 > 0.97. In addition, the sorption processes of three metal ions by tea waste in different temperatures could be described satisfactorily by both Langmuir and Freundlich isotherms. According to calculated results by the Langmuir equation, the maximum removal capacities of Pb(II), Cd(II), and Cu(II) were 33.49, 16.87, and 21.02 mg/g, respectively. Fourier transform infrared (FT-IR) analysis of the tea waste samples laden with different metals indicated that multiple functional groups were involved in the sorption of metal ions, and the carboxyl group (CO) and bonded−OH group were primary binding sites in lead and cadmium removal, while the −CN stretching and the carboxyl group were primary binding sites in copper removal. All the results reported strongly implied the potential of tea waste as an economic and excellent bioadsorbent for removal of metal ions from contaminated waters.
The nano goethite and nano alumina were synthesized to investigate the effect of nanoscale size on adsorption-desorption of U(VI) from aqueous solution. It was determined that the site densities of nanoparticles are higher than a-alumina and goethite, whereas slight effect of carbonate on adsorption of U(VI) onto nanoparticles was observed. The maximum adsorption capacities of nano alumina and nano goethite were *151 and 79 mg/g, respectively. The batch desorption indicated stronger binding affinity of U(VI) for nanoparticles as compared to non-nanoparticles, which were consistent with the results of surface complexation modeling assuming weak and strong sites for nanoparticles while weak sites for a-alumina and goethite.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.