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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。
Under the condition of microwave irradiation, ZnCl2-modified wheat straw was used to prepare adsorbent to treat Cd2 + -containing wastewater. The effects of dosage of sorbent, initial pH, adsorption time and temperature on the removal rate and adsorption capacity of Cd2 + in aqueous solution were studied. Learning, thermodynamic model fitting, scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) analysis to explore the adsorption mechanism. The results showed that the modified wheat straw was a potentially useful Cd2 + adsorbent with 100 mg / L Cd2 + wastewater treated at a dosage of 4 g / L, an initial pH of 6 and a temperature of 298 K. Removal of Cd2 + The adsorption rate was 92.11%, the adsorption capacity was 22.33 mg / g and the adsorption equilibrium time was about 120 min. The adsorption kinetics could be described by quasi-second order kinetic equation. The isothermal adsorption model was in accordance with Langmuir equation, 293,303,313 K The results showed that the adsorption capacity of Cd2 + on wheat straw was mainly adsorbed on the surface of adsorbent, and the adsorption was dominated by chemisorption on the basis of SEM and FTIR spectroscopy.