Studies on fluoride and arsenic removal from power plant wastewater by polysilicate ferric aluminum sulfates

FUEL 87

Shuqin Wang, wsqhg@163.com, Yi Zhao, hgxzy@sina.com, and Qiangwei Li, liqiangwei@sohu.com. School of Environmental Science & Engineering, North China Electric Power University, Yonghua North Street 619#, Baoding, 071003, China
The fluoride and arsenic removal efficiency from model and coal-fired power plant wastewater by using polysilicate ferric aluminum sulfate (PSFAS) coagulant was studied. The effect of pH, molar ratio of (Fe + Al) to SiO2, and dosage of the coagulant on the fluoride and arsenic removal efficiency were also investigated. The species of Al( III) and Fe( III)in PSFAS were determined by the Ferron timed complex colorimetric method. The PSFAS was characterized by the infrared spectrometer (IR) and transparent electron microscopy (TEM). The fluoride and arsenic removal mechanisms of PSFAS were also discussed. Experimental results showed that PSFAS had more than 95% fluoride removal efficiency and 93% arsenic removal efficiency with a wider range of pH from 6.0 to 9.0. The active Fe and Al have the main responsibility to remove arsenic and fluoride respectively. The interaction between aluminum and ferric salt could improve the coagulating effect of PSFAS.