竹炭对水相中镉(Ⅱ)的吸附行为及机理

Adsorption Behavior and Mechanism of the Bamboo-Charcoal for Cd(Ⅱ)in Aqueous Solution

研究竹炭对水相中Cd^2＋的吸附行为．研究接触时间、pH、投料量、吸附温度和溶液中镉的初始浓度对吸附的影响．结果表明：竹炭能有效地除去水相中的镉（Ⅱ）；在pH=3．0～6．5的范围内竹炭对镉均有较大的吸附，其最佳酸度为pH=5．7；吸附温度升高，吸附量减小，说明吸附是放热过程．动力学研究表明：竹炭对镉的吸附拟用准一级动力学处理；并测定不同粒径竹炭对镉吸附的表观速率常数．研究表明Freundlich等温吸附模型能较好地描述吸附过程．用水和微波加热的方法对吸附后的竹炭进行再生实验，竹炭的吸附能力可恢复到原来的93％以上．竹炭可作为理想的除镉吸附材料．

The adsorption behavior of the bamboo-charcoal for cadmium（ Ⅱ ）was studied in aqueous solution. Parameters studied include contact time, pH, mass of absorbent, adsorption temperature, and initial concentration of cadmium in solution. Results showed that bamboo-charcoal could effectively remove cadmium from the aqueous solution. The bamboo-charcoal showed high adsorption ability for cadmium at a wide pH range （pH = 3.0 -6. 5 ）, The optima adsorption acidity of bamboo-charcoal for Cd （Ⅱ） is pH 5.7 in the HAc-NaAc medium. Adsorption decreased with adsorption temperature increases, which means that the adsorption process is an exothermic process. Research of kinetics showed that adsorption of the bamboo-charcoal for cadmium can deal with pseudo first-order reactions. The apparent adsorption rate constants were determined at different sizes. The adsorption behavior of the bamboo-carbon for cadmium （ Ⅱ ） obeys the Freundlich isotherm model. After the adsorption the bamboo-charcoal can be regenerated quantifiably with H2O and microwave heating, the percentages of regeneration reached up to 93 %. The bamboo-charcoal is the better absorbing material for removing cadmium （ Ⅱ ）from an aqueous solution.