微波辅助(NH_4)_2S_2O_8改性竹炭对Cu^(2+)的吸附性能

Adsorption of Cu^(2+) on (NH_4)_2S_2O_8 modified bamboo charcoal prepared with microwave heating

以竹炭为原料,采用(NH4)2S2O8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、扫描电镜(SEM)、电子能谱(EDAX)和傅里叶红外光谱(FTIR)对改性竹炭进行表征;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。结果表明,微波辅助(NH4)2S2O8改性使得竹炭表面的酚羟基、内酯基、羧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。

The bamboo charcoal was modified by（NH4）2S2O8 with microwave as 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 Cu2＋ were investigated.Boehm titration,EDAX and FTIR analysis demonstrated that the contents of carboxyl,phenol hydroxyl and lactones groups were increased after（NH4）2S2O8 modification,these surface acid oxygen functional groups played a significant role in the adsorption of Cu2＋ onto modified bamboo charcoal.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-1.0APS was endothermic and spontaneous processes,higher temperature favored the adsorption process.Iron strength in solution had obviously negative effect on the adsorption.