Application of magnesium modified corn biochar for phosphorus removal and recovery from swine wastewater

• Published in: International journal of environmental research and public health Vol. 11; no. 9; pp. 9217 - 9237
• Main Authors: Fang, Ci, Zhang, Tao, Li, Ping, Jiang, Rong-feng, Wang, Ying-cai
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 05.09.2014; MDPI
• Subjects: Adsorption; Animals; Charcoal; Charcoal - chemistry; Corn; Magnesium; Magnesium - chemistry; Phosphorus - chemistry; Phosphorus removal; Sus scrofa; Waste Disposal, Fluid - methods; Waste Water - analysis; Waste Water - chemistry; Water Pollutants, Chemical - chemistry; Water treatment; Zea mays - chemistry
• ISSN: 1660-4601; 1661-7827; 1660-4601
• DOI: 10.3390/ijerph110909217

The recycling of lost phosphorus (P) is important in sustainable development. In line with this objective, biochar adsorption is a promising method of P recovery. Therefore, our study investigates the efficiency and selectivity of magnesium modified corn biochar (Mg/biochar) in relation to P adsorption. It also examines the available P derived from postsorption Mg/biochar. Mg/biochar is rich in magnesium nanoparticles and organic functional groups, and it can adsorb 90% of the equilibrium amount of P within 30 min. The Mg/biochar P adsorption process is mainly controlled by chemical action. The maximum P adsorption amount of Mg/biochar is 239 mg/g. The Langmuir-Freundlich model fits the P adsorption isotherm best. Thermodynamics calculation shows ∆H > 0, ∆G < 0, ∆S > 0, and it demonstrates the P adsorption process is an endothermic, spontaneous, and increasingly disordered. The optimal pH is 9. The amounts of P adsorbed by Mg/B300, Mg/B450, and Mg/B600 from swine wastewater are lower than that adsorbed from synthetic P wastewater by 6.6%, 4.8%, and 4.2%, respectively. Mg/biochar is more resistant to pH and to the influence of coexisting ions than biochar. Finally, postsorption Mg/biochar can release P persistently. The P release equilibrium concentrations are ordered as follows: Mg/B600 > Mg/B450 > Mg/B300. The postsorption Mg/B300, Mg/B450, and Mg/B600 can release 3.3%, 3.9%, and 4.4% of the total adsorbed P, respectively, per interval time.