Granular ferric hydroxide adsorbent for phosphate removal: demonstration preparation and field study
Bei Zhao1, Yu Zhang2, Xiaomin Dou3
1Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China E-mail: zhangyu@rcees.ac.cn; Technology Institute of Beijing Waterworks Group Co., Ltd, Beijing 100012, China.
Summary
Ferric hydroxide (FHO) granules effectively remove phosphate from wastewater. This stable, regenerable adsorbent offers high capacity, demonstrating its potential as an assist technology for effluent treatment.
Area of Science:
- Environmental Chemistry
- Materials Science
- Water Treatment
Background:
- Phosphate pollution from secondary effluents is a significant environmental concern.
- High phosphate adsorption capacity materials are needed for efficient water treatment.
Purpose of the Study:
- To prepare and characterize granular ferric hydroxide (FHO) for phosphate removal.
- To evaluate the performance of granular FHO in treating municipal wastewater effluents.
Main Methods:
- Industrial-scale precipitation of FHO followed by drum granulation with poly(vinyl alcohol).
- Langmuir adsorption isotherm analysis to determine maximum adsorption capacities.
- Column studies for continuous phosphate removal from secondary effluents.
Main Results:
- Optimal binder/FHO ratio determined for stable granular adsorbent production.
- Granular FHO exhibited high Langmuir maximum adsorption capacities (56.18 mg g⁻¹ at pH 7.0).
- Over 90% phosphate removal achieved in continuous flow columns for over two months, with reduced turbidity and CODMn.
Conclusions:
- Granular FHO is a stable and effective adsorbent for phosphate removal from secondary wastewater effluents.
- The material demonstrates high adsorption capacity and regenerability, suitable for practical water treatment applications.
- Energy dispersive X-ray analysis confirmed the availability of active sites for phosphate adsorption within the granular structure.
