微波辅助氢氧化钠改性竹炭对水溶液中铜离子的吸附

Adsorption of copper (Ⅱ) from aqueous solution onto bamboo-carbons modified by microwave-induced sodium hydroxide

以竹炭为原料,NaOH为改性药剂,采用微波辅助加热的方法对竹炭进行改性,并利用SEM、EDAX、BET、FTIR、pHzpc和Boehm滴定等方法对改性前后的竹炭进行表征.考察了溶液pH、吸附时间、温度和离子强度等对改性竹炭吸附Cu2+的影响.结果表明微波辅助NaOH改性提高了竹炭的比表面积,增加了其表面含氧官能团和总碱基的数量;改性竹炭吸附Cu2+的最佳pH值约为5,吸附过程符合拟二级动力学模型,Langmuir吸附等温方程比Freundlich方程更适合描述Cu2+在改性竹炭上的吸附行为,吸附为放热的物理吸附过程.

Bamboo-carbon was modified with NaOH via microwave assistant heating. The physicochemical properties of the bamboo-carbons before and after modification were characterized by SEM, EADX, BET, FTIR, pHzpc and Boehm titration, respectively. The effects of the initial pH, contact time, temperature and ion strength on the adsorption capacity of Cu （Ⅱ） were investigated in a batch-adsorption technique. The results showed that the specific surface area, the number of surface oxygen-containing functional groups and basic groups of the bamboo carbon increased after the modification. The optimum pH value for adsorption of Cu （Ⅱ） was about 5. The kinetic study demonstrated that the adsorption process followed the second-order kinetic equation. The adsorption of Cu （Ⅱ） onto modified carbon fitted Langmuir isotherm better than Freundlich isotherm, which was an endothermic and physical process in nature.