FeCl_3改性柚子皮吸附去除水中的砷

Adsorption removal of arsenic in aqueous solution by FeCl_3-modified pomelo peel

以生物质废弃物柚子皮为主要原料,通过在柚子皮粉中加入FeCl_3进行改性,将该改性产物用于吸附去除水中的砷。该改性柚子皮的制备条件为柚子皮粉:FeCl_3质量比为50∶1,常温下加水混合均匀,在(85±2)℃条件下烘24 h后粉碎。当水中砷离子浓度为1.5~30 mg·L^(-1),pH值为2~9,吸附剂投加量为10 g·L^(-1),吸附反应温度为20℃的条件下,吸附反应30 min后达到平衡,去除率最高达到96.19%,单位吸附量q最大值为1.86 mg·g^(-1)。该吸附反应符合Freundlich等温方程,该去除机制可能以金属沉淀、静电吸附、絮凝作用和共沉淀作用为主。研究表明该改性吸附材料可自动调节废水pH值,操作简单,无二次污染,考虑用作中等浓度含砷废水的预处理,有利于生物质废弃物的资源化利用。

A newly modified biomass adsorbent of powdered pomelo peel-FeCl_3 has been synthesized and shows great potential as a treatment for arsenic polluted water. The presynthesized powder mixture of the pomelo peel and FeCl3 at a mass ratio of 50 ∶ 1 was stirred in the water under the room temperature for a few minutes and then dried at 85 ℃ for 24 h. The adsorbent experiment was conducted under the following conditions： an arsenic concentration of 1. 5 to 30 mg·L^-1,a pH value of 2 to 9,an adsorbent dosage of 10 g·L^-1,a temperature of 20℃,and a maximal balance time of 30 min. The result shows the highest adsorption efficiency of 96. 19% and the maximum unit adsorption capacity（ q） of 1. 86 mg·g^-1,which could be explained by the isothermal equations of Freundlich. The discussed reaction mechanism may consist of the main chemical adsorption and some physical adsorptions in the water,such as complexation,flocculation,and precipitation. Due to our adsorbent＇s obvious advantages of an automatic-control of the pH value,an ease of operation,and a lack of secondary pollutants,the FeCl3-modified pomelo peel adsorbent is likely to be an ideal material in the treatment of moderately arsenic-polluted waste and in the resource utilization of biomass materials.