科研之友
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摘要
Cadmium content in the environment if exceeded would cause significant harm to human health. In this study, a FeSO4 and magnetism modified method was used to prepare an eggshell magnetic adsorbent (BC-FM) to adsorb cadmium in water. Through material characterization and a series of experiments on the adsorption of Cd2+, the adsorption characteristics and mechanism were studied. Characterization showed that the specific surface area and total pore volume of BC-FM were increased after modification, and the magnetic functional group Fe-O (gamma-Fe2O3) was successfully attached to the surface of BC-FM. Compared with the original adsorbent (BC), the adsorption capacity of BC-FM was greatly improved, and their equilibrium adsorption capacities were respectively 4.82 and 47.33 mg g-1. Pseudo-second-order kinetics equation and Langmuir adsorption isotherm fit the adsorption process well. pH and the presence of Mg2+, Pb2+, Cu2+ and Zn2+ had great influence on its capacity to absorb Cd2+. The main adsorption mechanisms were surface adsorption, strong electrostatic interaction and complexation of oxygen-containing functional groups and compounds containing Fe. BC-FM was easy to separate from water and has good reuse performance. After 5 cycles of adsorption-desorption, the adsorption capacity of Cd2+ still reached 81.9% of that of fresh adsorbent.
