微波辅助HNO_3改性竹炭对Cu^(2+)的吸附性能

Adsorption of Cu^(2+) on HNO_3 modified bamboo charcoal prepared with microwave heating

以竹炭为原料,采用HNO3(NA)作为改性药剂,通过微波辅助加热的方法对竹炭进行改性;运用Boehm滴定、扫描电子显微镜(SEM)、电子能谱(EDAX)和红外光谱(FTIR)对改性竹炭进行了表征;考察了pH、时间、温度和离子强度等对改性竹炭吸附Cu2+的影响.研究结果表明,微波辅助硝酸改性使得竹炭表面的羧基、酚羟基、内酯基等酸性含氧官能团的数量有所增加;改性竹炭对Cu2+吸附更符合Langmuir等温方程,吸附为自发的吸热过程;吸附动力学符合准二级动力学方程;溶液离子强度增大不利于其对Cu2+的吸附.

In this study,the bamboo charcoal was modified with HNO3 using microwave as an assistant heating method.The bamboo charcoal before and after modification were characterized by Boehm titration,scanning electron microscope（SEM）,energy dispersive X-Ray analysis（EDAX） and fourier transform infrared spectrometer（FTIR）.The effects of pH,reaction time,temperature and ionic strength on the adsorption capacity of Cu（Ⅱ） were investigated.Boehm titration,EDAX and FTIR analysis demonstrated that the contents of surface acid oxygen functional groups such as carboxyl,phenolichydroxyl and lactone,which played a significant role in the adsorption of Cu2＋ onto modified bamboo charcoal,increased with HNO3 modification.The rates of adsorption were found to conform to the pseudo-second-order kinetic model.Langmuir isotherm was more suitable to describe the adsorption reaction of bamboo charcoal than Freundlich isotherm.The adsorption of Cu2＋ onto BC-9NA was an endothermic and spontaneous process.Iron strength in solution had obviously negative effect on the adsorption.