摘要
酸性含镉[Cd(Ⅱ)]废水通常采用吸附法进行除Cd(Ⅱ);生物炭对重金属具有较好的亲和力,但原始生物炭的比表面积较小及活性位点有限,活化能够增大生物炭的孔隙结构。本文以城市污泥为合成生物炭的前驱体,采用低成本且无二次污染的磷酸二氢钾与其共热解制备改性污泥生物炭(PBC),考察了混合比对PBC吸附性能的影响,还对PBC进行了单因素试验、动力学试验、等温吸附试验、FTIR表征分析等,得出以下主要结论。PBC孔隙结构发达且石墨化程度高,在磷酸二氢钾与城市污泥混合比例为1∶1时,PBC具有最佳的Cd(Ⅱ)去除率,在溶液pH值4~7范围内,Cd(Ⅱ)去除率均保持在98%以上;在温度25℃、投加量1 g·L^(-1)以及溶液Cd(Ⅱ)浓度为10~200 mg·L^(-1)时,PBC对Cd(Ⅱ)的最大吸附能力为132.77 mg·g^(-1);共存离子Na^(+)、Ca^(2+)和Mg^(2+)对PBC去除Cd(Ⅱ)的影响忽略不计,而Pb^(2+)、Zn^(2+)及Cu^(2+)对PBC去除Cd(Ⅱ)存在抑制作用;PBC对Cd(Ⅱ)的去除行为符合拟二级动力学模型和Langmuir模型,这说明PBC对Cd(Ⅱ)的去除是一种单一且均匀的化学吸附;PBC对Cd(Ⅱ)的去除机理包括络合、Cd(Ⅱ)-π相互作用及共沉淀。
Acidic Cd(Ⅱ)-containing wastewater is commonly treated by adsorption for the removal of Cd(Ⅱ).Biochar exhibits a strong affinity for heavy metals;however,raw biochar generally has a relatively low specific surface area and limited active sites.Activation can enhance the pore structure of biochar.In this study,municipal sludge was used as the precursor for biochar synthesis,and potassium dihydrogen phosphate(KH2PO4),a low-cost and environmentally friendly agent that causes no secondary pollution,was co-pyrolyzed with the sludge to produce phosphate-modified sludge biochar(PBC).The effect of the mixing ratio on the adsorption performance of PBC was investigated.In addition,single-factor experiments,adsorption kinetics,isotherm studies,and FTIR analyses were conducted,leading to the following main conclusions:PBC possesses a well-developed pore structure and a high degree of graphitization.When the mass ratio of KH2PO4 to municipal sludge was 1:1,PBC exhibited the highest Cd(Ⅱ)removal efficiency,maintaining a removal rate above 98%within a solution pH range of 4-7.Under conditions of 25℃,an adsorbent dosage of 1 g·L^(-1),and an initial Cd(Ⅱ)concentration of 10-200 mg·L^(-1),the maximum adsorption capacity of PBC for Cd(Ⅱ)reached 132.77 mg·g^(-1).The coexisting ions Na^(+),Ca^(2+),and Mg^(2+)had negligible effects on Cd(Ⅱ)removal by PBC,whereas Pb^(2+),Zn^(2+),and Cu^(2+)exhibited inhibitory effects.The adsorption behavior of PBC toward Cd(Ⅱ)followed the pseudo-second-order kinetic model and the Langmuir isotherm model,indicating that the removal process was dominated by monolayer chemical adsorption.The mechanisms involved in Cd(Ⅱ)removal by PBC included complexation,Cd(Ⅱ)-仔interactions,and co-precipitation.
作者
刘巧会
谢芳
卢许佳
杨江峰
许良全
谭维佳
LIU Qiaohui;XIE Fang;LU Xujia;YANG Jiangfeng;XU Liangquan;TAN Weijia(School of Engineering,Zhengzhou Technology and Business University,Zhengzhou 45400,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 611756,China;The 3th Engineering Co.,Ltd.,The Second Public Bureau of China Communications,Xi'an 710016,China;China Construction Eighth Engineering Bureau Co.,Ltd.,Shanghai 200135,China;College of Geological Engineering and Survey,Chang'an University,Xi'an 710054,China)
出处
《中国有色冶金》
北大核心
2025年第4期128-138,共11页
China Nonferrous Metallurgy
基金
国家重点研发计划“农业面源和重金属污染农田综合防治和修复技术研发”(2017YFDO800501)。
关键词
酸性含Cd(Ⅱ)废水
除镉
城市污泥
磷酸二氢钾
热解
磷酸盐改性污泥生物炭(PBC)
吸附性能
吸附机理
acidic Cd(Ⅱ)-containing wastewater
cadmium removal
municipal sludge
potassium dihydrogen phosphate
pyrolysis
phosphate-modified sludge biochar(PBC)
adsorption performance
adsorption mechanism
