竹炭对水相中硝酸盐的吸附行为及其机理研究

Adsorption behavior and mechanism of the bamboo-carbon for nitrate in aqueous solution

采用分光光度法研究竹炭对硝酸盐的吸附特性。试验发现,竹炭对硝酸盐的吸附在50min后达到平衡,吸附动力学过程遵守准二级速率方程;竹炭粒径对吸附也有影响,粒径越小,平衡吸附量越大;在25℃下,以Langmuir方程、Freundlich方程和Temkin方程分别对竹炭吸附氯仿的等温线进行拟合,拟合效果以Langmuir方程最好,相关性达到0.9989;不同温度Langmuir拟合结果表明,参数q∞、KL随着温度上升呈线性下降,温度上升不利于竹炭对硝酸盐的吸附;pH值对吸附效果也有影响,pH值为2.0时,竹炭对硝酸盐的吸附效果最佳。

Adsorption behavior and mechanism of the bamboo-carbon for nitrate in aqueous solution was studied in this paper.Research of kinetics showed that adsorption of the bamboo-carbon for nitrate can deal with pseudo second-order reactions and absorption equilibrium time is about 50 min.Absorption of nitrate is decreased by the increase of size of bamboo-carbon.Absorption of nitrate by bamboo-carbon at 25 ℃ could be described more exactly by langmuir equation（R2=0.998 9） than freundlich equation and temkin equation.The parameters q∞,KL is decreased by the increase of absorption temperature.Therefore,the absorption of nitrate on bamboo-carbon is decreased.The absorption performance of bamboo-carbon was also affected by absorption pH.Results showed that the optima adsorption acidity of bamboo-carbon for chloroform is pH 2.0.