Baskan Meltem Bilici, Pala Aysegul
Department of Environmental Engineering, Dokuz Eylul University, Buca, Izmir, Turkey.
J Hazard Mater. 2009 Jul 30;166(2-3):796-801. doi: 10.1016/j.jhazmat.2008.11.131. Epub 2008 Dec 11.
Arsenic contamination of drinking water is a serious problem in many parts of the world. The precipitation/coprecipitation method was used for arsenic removal from drinking water by ferric chloride, ferric sulfate and ferrous sulfate as coagulant. A Box-Behnken statistical experiment design method was used to investigate the effects of major operating variables such as initial arsenate concentration (10-1000 microg L(-1)), coagulant dose (0.5-60 mg L(-1)) and pH (4-9) were investigated. Experimental data were used for determination of the response functions coefficients. Predicted values of arsenate removal obtained using the response functions were in good agreement with the experimental data. Fe(III) ions were more effective and economic than Fe(II) ion due to required lower coagulant dose and pH. In the low initial arsenate concentrations, the highest arsenate removal efficiency was required high ferric chloride and ferric sulfate dose of 50 and 40 mg L(-1), while in the high initial arsenate concentrations, the highest arsenate removal efficiency was provided at low ferric chloride and ferric sulfate dose of 37 and 32 mg L(-1), respectively. This study showed that Box-Behnken design and response surface methodology was reliable and effective in determining the optimum conditions for arsenic removal by coagulation and flocculation.
饮用水中的砷污染是世界许多地区面临的一个严重问题。采用沉淀/共沉淀法，以氯化铁、硫酸铁和硫酸亚铁作为混凝剂去除饮用水中的砷。运用Box-Behnken统计实验设计方法，研究了初始砷酸盐浓度（10 - 1000 μg L⁻¹）、混凝剂剂量（0.5 - 60 mg L⁻¹）和pH值（4 - 9）等主要操作变量的影响。实验数据用于确定响应函数系数。使用响应函数获得的砷酸盐去除预测值与实验数据吻合良好。由于所需的混凝剂剂量和pH值较低，Fe(III)离子比Fe(II)离子更有效且经济。在低初始砷酸盐浓度下，最高砷酸盐去除效率需要50和40 mg L⁻¹的高氯化铁和硫酸铁剂量，而在高初始砷酸盐浓度下，分别在37和32 mg L⁻¹的低氯化铁和硫酸铁剂量下可提供最高砷酸盐去除效率。本研究表明，Box-Behnken设计和响应面方法在确定混凝沉淀去除砷的最佳条件方面是可靠且有效的。
