摘要
在微波辐射条件下,用ZnCl2改性小麦秸秆制备吸附剂处理含Cd2+废水,研究了吸附剂投加量、初始pH、吸附时间、温度对水溶液中Cd2+的去除率与吸附量的影响;通过动力学、热力学模型拟合、扫描电镜(SEM)和红外光谱(FTIR)分析,探讨其吸附机理。结果表明,改性小麦秸秆是一种具有潜在利用价值的Cd2+吸附剂,在投加量为4 g/L、初始pH为6,温度为298 K条件下处理100 mg/L的Cd2+废水,去除率达92.11%,吸附量为22.33 mg/g,吸附达到平衡的时间约为120 min;吸附动力学可以用准2级动力学方程描述;等温吸附模型符合Langmuir方程,293、303、313K温度条件下的饱和吸附量分别可达61.31、63.74和66.83 mg/g;结合SEM和FTIR谱图分析推断,改性小麦秸秆吸附Cd2+主要发生在吸附剂表层,吸附过程以化学吸附为主。
In order to solve the problem of chromium-contaminated wastewater, mircrowave-ZnCl2 modified wheat straw was prepared as a kind of Cd2＋ sorbent. Effects of sorbent dosage, initial pH, contact time and temperature on removal rate and adsorption capacity of Cd2＋ were studied. The sorption mechanism was investigated by kinetic and isotherm model simulation, scanning electron and infrared spectroscopy analysis. The results showed that the modified wheat straw has a good potential as a Cd2＋ adsorbent, and the removal rate and the adsorption capacity were 92.11% and 22.33 mg/g, respectively, under the condition of sorbent dosage of 4 g/L, initial pH of 6 and temperature of 298 K. The adsorption equilibrium achieved after about 120 min. The adsorption dynamics could be well described with pseudo-second-order kinetic equation and the adsorption isotherm fits Langmuir equation. The saturation adsorption capacities from Langmuir model were 61.31, 63.74 and 66.83 mg/g under the temperature of 293, 303 and 313 K, respectively. Combining SEM images and FTIR spectrogram, it was inferred that the adsorption mainly happened on the surface of the sorbent, and the main adsorption process was chemical adsorption.
出处
《水处理技术》
CAS
CSCD
北大核心
2013年第4期15-19,共5页
Technology of Water Treatment
基金
中国科学院西部行动计划项目"晋陕蒙能源基地受损生态系统恢复重建关键技术与示范"(KZCX2-XB3-13)
关键词
改性小麦秸秆
镉
吸附
动力学
等温吸附模型
modified wheat straw
Cd
adsorption
kinetics
isothermal adsorption model
