LUO Hai-cui1, ZHOU Yue-fei1*, PI Hui-yu1, YANG Jian-ming2, XIE Qiao-qin1, CHEN Tian-hu1
(1. Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, School of Resources & Environmental Engineering, Hefei University of Technology, Hefei 230009, China;
2. Zhejiang Huayuan Pigment Co., Ltd., Deqing 313220, China)
Abstract:Nanosized and porous hematite and maghemite, which have respective specific surface areas of 85.74 m2/g and 22.65 m2/g, were prepared through calcination of synthetic goethite in order to explore their adsorption efficiencies of Sb(Ⅲ) through static experiments. Results show that the adsorption efficiencies of Sb(Ⅲ) of hematite, maghemite, and goethite are subsequently decreased. Especially, those of hematite and maghemite are obviously higher than that of goethite. The adsorption of Sb(Ⅲ) on surfaces of 3 kinds of minerals is a rapid chemical process, in which the adsorption equilibrium can almost be reached within 2 hours. It accords with the pseudo-second-order adsorption kinetic reaction model and the Freundlich isothermal adsorption model. It is a spontaneous endothermic reaction which is beneficially facilitated by the increase of temperature. The saturated adsorption capacities for the goethite, hematite, and maghemite at 45℃ and pH value of 7.0 are 16.04, 50.44, and 33.53 mg/g, respectively. The pH value of solution has little effect on the adsorption efficiencies of Sb(Ⅲ) by hematite and maghemite. However, the increase of ph value of solution will result in the decrease of the adsorption efficiency of Sb(III) by goethite. Anions of CO32-, SiO44-, PO43-, and humic acids will restrain the Sb(Ⅲ) adsorption by the hematite, maghemite, and goethite through the competition of adsorption sites with Sb(Ⅲ), though such restraint is efficient only under high anion concentration condition. It is considered that maghemite is a better material than goethite and hematite for treating Sb(Ⅲ)-bearing waste water because it has much more surface active sites and stronger magnetic recovery ability than others.
Keywords: Goethite; hematite; maghemite; Sb(Ⅲ); adsorption
ACTA MINERALOGICA SINICA Vol.41, No.6, 2021, page 697-703
