摘要
以城市污水厂富磷剩余污泥为研究对象,考察高温热解制备生物炭吸附剂对水中Pb(Ⅱ)的去除效果.研究表明,随着热解温度升高,制备的生物炭对Pb(Ⅱ)的吸附能力增强;在相同热解温度下,生污泥生物炭对Pb(Ⅱ)的吸附能力比消化污泥生物炭大.采用700℃热解1 h制备生污泥生物炭以研究对Pb(Ⅱ)吸附的影响因素,结果显示:吸附180 min达到吸附平衡;富磷污泥生物炭对Pb(Ⅱ)的去除率随pH增加而升高;生物炭投加量增加,对Pb(Ⅱ)去除率上升,而单位吸附容量迅速减小.污泥生物炭对Pb(Ⅱ)的吸附符合准二级反应动力学,Langmuir模型比Freundlich模型能更好地拟合等温吸附线.在pH 5.0、吸附时间3 h、生物炭投加量20 g.L-1条件下,对Pb(Ⅱ)的最大吸附量为34.5 mg.g-1,表明富磷污泥生物炭可以作为一种廉价的吸附剂.
Phosphorus-rich excess sludge from municipal wastewater treatment plant was pyrolyzed to produce biochar as an adsorbent for lead（Pb（Ⅱ））removal in aqueous solutions.The results showed that Pb（Ⅱ） adsorption capacity of this phosphorus-rich sludge biochar increased with pyrolytic temperature.Biochar derived from raw sludge had higher sorption capacity than the one from anaerobic digested sludge carbonized under same temperatures.Batch experiments were conducted using phosphorus-rich sludge biochar produced by 700 ℃ and 1.0 h pyrolyzation to investigate the Pb（Ⅱ） sorption reaction.The results indicate that adsorption reached equilibrium after 3 hours reaction.Pb（Ⅱ） removal rate of sludge biochar increased with solution pH.Pb（Ⅱ） adsorption onto sludge biochar can be described by pseudo-second-order kinetics model.Langmuir model fits sorption isotherm better than Freundlich model.The maximum sorption capacity of the biochar was 34.5 mg · g-1 at pH 5.0,reaction time 3 h,and adsorbent dose 20 g · L-1 which is higher than previously reported value.We suggest that phosphorus-rich sludge biochar can be used as a cheap adsorbent for low concentration heavy metal removal in water.
出处
《环境化学》
CAS
CSCD
北大核心
2012年第9期1375-1380,共6页
Environmental Chemistry
基金
重庆市自然科学基金(CSTC
2011BB7098)
中央高校基本科研业务费科研专项"研究生科技创新基金"(No.CDJZR10210003)
重庆大学大型仪器设备开放基金(2010121548)资助
