Preparation And Application Of Rare Earth-loaded Red Mud Adsorbent

Industrial and domestic wastewater, if not treated and drained off directly, will have aserious effect on our lives and human health. It is an economical and effective way to removecontaminants from wastewater by using adsorption method. The red mud generated in thealumina refining process is a hazardous solid waste and the annual production is very large.This paper summarized the present situations of red mud at home and abroad, especially theuse as an absorbent. On this basis, red mud as a carrier, type of adsorbent was prepared,namely rare earth-loaded red mud adsorbent.In this thesis, using the adsorption properties of red mud and rare earth, the preparationprocess and conditions of Ce-loaded red mud and La-load red mud absorbents were studied.Meanwhile the removal effect of phosphorus, fluoride and phenol from wastewater by thosetwo absorbents were also studied.The main parts of the experiment: First, the effects of acid-modified concentration,contact time, cerium concentration and calcination temperature were investigated, obtainingthe optimizing conditions of Ce-loaded red mud absorbent. The effects of lanthanum nitrate,reaction temperature, reaction time and solid-liquid ration were investigated, obtaining theoptimizing conditions of La-loaded red mud absorbent by hydrothermal synthesis. Second,the process of removal phosphorus and fluoride by Ce-loaded red mud absorbent and phenolby La-loaded red mud absorbent was studied. There was a variety of conditions effect theadsorption such as pH, dosage, adsorption time. By the study, we can get the optimizingconditions. The results show that the removal rate of phosphorus is more than97%, fluoride isabout95%, phenol is about85%. Third, through the analysis of adsorption kinetics andthermodynamics, we could get the degree of difficulty and the saturation adsorption capacity.The results show that adsorption kinetics of those three contaminants in line with Lagergren’ssecond order kinetics, and the absorbents are easy to adsorb those three contaminants, withthe saturation adsorption capacity for phosphorus reach24.75mg/g at35℃, for fluoride reach 22.94mg/g at25℃. Fourth, The absorbents were characterized by means of IR, SEM andEDX.On the basis of adsorption of red mud, the rare earth-loaded red mud adsorbent furtheroptimized adsorption effect， good results had achieved on removal contaminants inwastewater. The preparation of the two absorbents is simple and easy operation, which willprovide a good reference value in practical application.