摘要
This study highlights introducing the rare earth metal cerium(Ce(Ⅳ))into the structure of magnetite(Fe_(3)O_(4))to achieve enhanced adsorptive properties for the removal of chromium(Cr(VI))from an aqueous medium.Different ratios of Ce(Ⅳ)were introduced into the iron oxide matrix,termed FeCe-5,FeCe-10,and FeCe-20.Their numerical values correspond to the nominal content of the dopant element added to the synthesis medium.The solid materials were characterized for morphology and chemical structure,and N_(2)physical adsorption/desorption measurements were performed.The solid materials doped with Ce(IV)have a high surface area compared to Fe_(3)O_(4),and the solid material with the highest content of the dopant ion(Ce(IV))has a 4-fold greater surface area.This increase in the dopant content in the iron oxide structure leads to a total chromium removal of 93.3%.Isotherms studies on the solid materials show that chromium adsorption follows the Langmuir model.The adsorption capacity to Fe_(3)O_(4)is 12.59 mg/g and FeCe-10 is 22.49 mg/g at 35℃.By fitting the kinetic and isothermal models,it is found that for the Fe_(3)O_(4)and FeCe-10 materials Cr(VI)removal occurs in very different ways,attributed to the different surface areas and compositions of the oxide,with the formation of the goethite(α-FeOOH)phase.The FeCe-10reuse process was performed and the removal capacity the Cr(VI)is reduced after the first cycle.This result is attributed to a strong and irreversible adsorption of Cr(VI)on the FeCe-10.
基金
the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq)and Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES)
Programa de Pós-Graduacao em Agroquímica/UFLA(PPGAQ)
Programa de Pós-Graduacao Multicêntrico em Química/UFLA(PPGMQ-MG)
Centro de Prospeccao Química(CAPQ-UFLA)。
