摘要
为了揭示生物炭对不同重金属离子的吸附特征,以水葫芦为原料,热解得到水葫芦生物炭,并对水葫芦生物炭吸附Cu^(2+)、Pb^(2+)、Cd^(2+)和Zn^(2+)的动力学、等温学和吸附机理进行了研究。结果表明:准一级、准二级动力学模型均能很好地拟合水葫芦生物炭对Cu^(2+)、Pb^(2+)、Cd^(2+)和Zn^(2+)的吸附过程;结合颗粒内扩散模型,水葫芦生物炭对重金属离子的吸附主要发生在吸附初期,而在接近吸附平衡时,才开始由颗粒内扩散对吸附速率进行控制;Langmuir吸附模型能更好地拟合水葫芦生物炭吸附Pb^(2+)、Cd^(2+)和Zn^(2+)的过程,而水葫芦生物炭对Cu^(2+)的吸附过程则更符合Freundlich吸附模型;由Langmuir吸附模型拟合得到水葫芦生物炭对Cu^(2+)、Pb^(2+)、Cd^(2+)和Zn^(2+)的最大吸附容量(Q_(m))分别为177.66mg/g、195.24mg/g、142.59mg/g和146.14mg/g;通过对水葫芦生物炭吸附4种重金属离子前后的SEM-EDS、FTIR、XPS和XRD谱图和重金属离子特性的分析,揭示生物炭对重金属离子的吸附机理主要包括沉淀反应、静电吸附作用、表面物理吸附作用、表面络合作用和阳离子交换作用,而对于不同的重金属离子,因其特性不同,生物炭对其吸附能力也有所不同。
In order to reveal the adsorption characteristics of biochar for different heavy metal ions,water hyacinth biochar was obtained by pyrolysis with water hyacinth as raw material.The kinetics,isotherm and adsorption mechanism of Cu^(2+),Pb^(2+),Cd^(2+) and Zn^(2+) were studied.The results show that the quasi first-order and quasi second-order kinetic models can well simulate the adsorption process of Cu^(2+),Pb^(2+),Cd^(2+) and Zn^(2+) by water hyacinth biochar.Combined with the intra-particle diffusion model,the adsorption of heavy metal ions by water hyacinth biochar mainly occurs in the initial stage of adsorption,and the intra-particle diffusion controls the adsorption rate when it is close to equilibrium.The Langmuir adsorption model can better fit the adsorption process of Pb^(2+),Cd^(2+) and Zn^(2+) by water hyacinth biochar,while the adsorption process of Cu^(2+) by water hyacinth biochar is more consistent with Freundlich adsorption model.The maximum adsorption capacity(Q_(m))of Cu^(2+),Pb^(2+),Cd^(2+) and Zn^(2+) obtained with the Langmuir model are 177.66 mg/g,195.24mg/g,142.59mg/g and 146.14mg/g,respectively.Through the analysis of SEM-EDX,FTIR,XPS and XRD spectra and the characteristics of heavy metal ions before and after the adsorption of four kinds of heavy metal ions by water hyacinth biochar,it is reavealed that the adsorption mechanism of heavy metal ions by water hyacinth biochar mainly includes precipitation,electrostatic adsorption,surface physical adsorption,surface complexation,and ion exchange.For different heavy metal ions,the adsorption capacity of water hyacinth biochar is also different.
作者
周润娟
张明
ZHOU Runjuan;ZHANG Ming(School of Architecture and Engineering,Anhui Polytechnic University,Wuhu 241000,China)
出处
《安全与环境工程》
CAS
CSCD
北大核心
2022年第3期168-177,共10页
Safety and Environmental Engineering
基金
安徽省自然科学基金面上项目(2008085ME159)
安徽省级高校自然科学重点项目(KJ2021A0505)。
关键词
水葫芦生物炭
重金属离子
吸附动力学
吸附等温学
吸附机理
water hyacinth biochar
heavy metal ion
adsorption kinetics
adsorption isotherm
adsorption mechanism
作者简介
周润娟(1984-),女,博士,讲师,主要从事水环境污染综合治理方面的研究。E-mail:rjzhou@126.com;通讯作者:张明(1983-),男,博士,教授,主要从事水资源与环境系统工程方面的研究。E-mail:zhangming@ahpu.edu.cn。
