Adsorption removal of phosphate from aqueous solution by active red mud
Chang-jun Liu1, Yan-zhong Li, Zhao-kun Luan
1State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. liuchangjun@china.com
Journal of Environmental Sciences (China)
|December 8, 2007
Summary
Red mud effectively removes phosphate pollutants. Acid-heat treatment at 80°C yielded the highest phosphate removal, demonstrating its potential for wastewater treatment.
Area of Science:
- Environmental Science
- Materials Science
- Chemical Engineering
Background:
- Red mud, a waste product from alumina refining, contains high levels of TiO2 and Fe2O3.
- These components are active in adsorbing anionic pollutants, presenting an opportunity for waste valorization.
Purpose of the Study:
- To investigate the efficiency of red mud in phosphate removal.
- To explore the impact of heat and acid-heat treatments on red mud's adsorption capabilities.
- To determine optimal conditions and adsorption mechanisms for phosphate removal.
Main Methods:
- Red mud samples were activated using heat treatment (700°C) and acid-heat treatment (80°C, 0.25 mol/L HCl).
- Phosphate adsorption experiments were conducted under varying pH conditions.
- Adsorption data were analyzed using the Langmuir isotherm model.
Main Results:
- Acid-heat treated red mud showed superior phosphate removal compared to heat-treated samples.
- Optimal conditions for phosphate removal were identified as pH 7.
- Maximum adsorption capacities were 202.9 mgP/g for acid-heat activated red mud and 155.2 mgP/g for heat-activated red mud.
Conclusions:
- Red mud, particularly when activated by acid-heat treatment, is a highly effective adsorbent for phosphate removal.
- The adsorption process is pH-dependent and follows Langmuir isotherm behavior.
- Activated red mud offers a sustainable solution for treating phosphate-contaminated wastewater.
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