Adsorption removal of phosphate from aqueous solution by active red mud
LIU Chang-jun , LI Yan-zhong , LUAN Zhao-kun , CHEN Zhao-yang , ZHANG Zhong-guo , JIA Zhi-ping
DOI:
Received September 14, 2006,Revised June 14, 2007, Accepted , Available online
Volume 19,2007,Pages 1166-1170
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Red mud is the waste of alumina industry and has high TiO2 and Fe2O3 content which are active components for the adsorption of
anion pollutants. In this study, the uptake of phosphate by red mud activated by heat treatment and acid-heat treatment was investigated.
The factors influencing the adsorption were also investigated. The result showed that the red mud sample treated using acid-heat
method at 80℃ with 0.25 mol/L HCl for 2 h achieved the highest phosphate removal. For the heat-activated red mud, the sample heated
at 700℃ for 2 h preformed better than the other heat treatment. Phosphate removal by the activated red mud was significantly pH
dependent, and pH 7 was the optimal pH for phosphate removal. The adsorption fits Langmuir isotherm model well and the maximum
adsorption capacities of the acid-heat activated red mud and the heat activated samples were 202.9 mgP/g and 155.2 mgP/g, respectively.
