壳聚糖包衣石英砂去除地下水中硒(Ⅳ)的试验

Study on Removal of Selenium (Ⅳ) in Groundwater by Chitosan-Coated Quartz Sand

目的为含硒地下水的处理找到一种环保、经济、高效的新型吸附剂.方法采用壳聚糖对石英砂进行改性处理,制备壳聚糖包衣石英砂.通过静态试验考察pH值、吸附时间、反应温度、Se(Ⅳ)初始质量浓度等因素对Se(Ⅳ)去除率的影响.结果当Se(Ⅳ)初始质量浓度为50μg/L时,pH值为3、反应时间为35min、反应温度为15℃的条件下,投加40g/L的吸附剂可使Se(Ⅳ)的质量浓度降至8.66μg/L,达到《生活饮用水卫生标准》(GB5746-2006)的要求.结论壳聚糖包衣石英砂能够有效去除地下水中的硒(Ⅳ).壳聚糖包衣石英砂吸附硒(Ⅳ)以单分子层吸附为主,基本符合Langmuir和Freundlich等温方程,其中Langmuir等温吸附曲线对试验数据拟合的相关性相对较好.

This paper focuses on a new, environmentally friendly, economical and efficient adsorbent, which was developed to remove selenium （ Ⅳ ） from groundwater. It was methodologically adopted that chitosan was loaded on the surface of quartz sand to produce chitosan-coated quartz sand. The results on pH, adsorption time, reaction temperature and initial mass concentration of selenium （ Ⅳ ）, which effect the removal rate of selenium（ Ⅳ）, were investigated by static experiments. They show that under the conditions of pH value of 3 ,adsorption time of 35 min,reaction temperature of 15 ℃ ,when the initial mass concentration of selenium （ Ⅳ ） is 50 μg/L, dosaging 40 g/L, adsorbent can make the mass concentration of selenium （ Ⅳ ） reduce to 8.66 μg/L, which meets the requirement of Sanitary Standard for Drinking Water（GB5746-2006）. The conclusion could be reached that chitosan-coated quartz sand can efficiently remove selenium （ Ⅳ ） from groundwater. Monolayer adsorption is the primary adsorption mechanism of chitosan-coated quartz sand adsorbing selenium（ Ⅳ ）, which basically consistent with Langmuir and Freundlich isotherm equation, especially the correlation of Langmuir adsorption isotherm curve fitting of test data is relatively better.