硼掺杂多孔碳球吸附Cd(Ⅱ)的热力学和动力学  

Thermodynamics and Kinetics of the Adsorption of Bivalent Cadmium by Boron-doped Porous Carbon Spheres

作　　者：陈锋 郭世浩 刘佩 邓弘勇 张继伟[1] 马路路 马培[1] 刘帅霞[1] CHEN Feng;GUO Shi-hao;LIU Pei;DENG Hong-yong;ZHANG Ji-wei;MA Lu-lu;MA Pei;LIU Shuai-xia(School of Resource and Environment,Henan University of Engineering,Zhengzhou 451191,China)

机构地区：[1]河南工程学院资源与环境学院,郑州451191

出　　处：《科学技术与工程》2020年第4期1544-1550,共7页Science Technology and Engineering

基　　金：国家自然科学基金青年基金(41401549);河南省科技发展计划(152102310323);河南省高等学校重点科研项目(19A610004);河南工程学院博士基金(D2017011);2019年度河南省青年人才托举工程(2019HYTP012)。

摘　　要：以蔗糖为碳源、硼酸为硼源,采用水热法和化学活化法制备出硼掺杂多孔碳球(boron-doped porous carbon spheres,B-PCS),利用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射(XRD)、傅里叶红外光谱(FTIR)和比表面积(BET)对B-PCS进行物理表征分析,探究B-PCS吸附Cd(Ⅱ)的热力学和动力学。结果表明,B-PCS为球状无定型结构的碳材料,直径为1~6μm,比表面积达672.2 m^2·g^-1,孔体积为0.356 cm^3·g^-1,且表面含有大量的含氧和含硼官能团,这些特性可以为Cd(Ⅱ)提供更多的活性吸附位点,有利于提高B-PCS对Cd(Ⅱ)的吸附性能。动力学符合准二级动力学模型,B-PCS对Cd(Ⅱ)的吸附为化学吸附控制过程,内扩散和Boyd模型表明粒子内扩散不是控制吸附速率的唯一因素。Freundlich方程能更好地模拟吸附等温线,最大理论吸附量为41.5 mg·g^-1,0<R L<1,说明B-PCS吸附Cd(Ⅱ)为有利吸附。吉布斯自由能(ΔG^0)小于0,焓变(ΔH^0)大于0,熵变(ΔS^0)大于0,表明B-PCS吸附废水中的Cd(Ⅱ)为自发、吸热、熵增的过程。Boron-doped porous carbon spheres(B-PCS)were prepared by the hydrothermal and chemical activation method using sucrose and boric acid as the carbon precursor and boron source in this work.The physical properties of B-PCS were characterized by scanning electron microscopy(SEM),energy disperse spectroscopy(EDS),X-ray diffraction(XRD),Fourier transform infrared spectrum(FTIR),and Brunauer-Emmett-Teller(BET).Its adsorption kinetics and thermodynamics for Cd(Ⅱ)were also investigated.Results show that B-PCS is spherical carbon materials with amorphous structure and the diameter of sphere is 1~6μm.The specific surface area and pore volume are 672.2 m^2·g^-1 and 0.356 cm^3·g^-1 respectively,and the surface has abundant oxygen-containing and boron-containing functional groups.These features can provide more active adsorption sites for Cd(Ⅱ),thus improving the adsorption properties of Cd(Ⅱ)by B-PCS.The adsorption kinetics fits well to the pseudo-second-order model,suggesting that the adsorption of Cd(Ⅱ)by B-PCS is dominated by chemical adsorption process.The internal diffusion and Boyd model show that the internal diffusion of particles is not the sole rate-controlling step.Freundlich equation can simulate the adsorption isotherm better,and the maximum theory adsorption quantity is 41.5 mg·g^-1.Furthermore,R L is between 0 and 1,indicating that the adsorption of Cd(Ⅱ)by B-PCS is a favorable process.The thermodynamic parametersΔG^0 is negative,ΔH^0 andΔS^0 are positive,manifesting that the adsorption process of Cd(Ⅱ)by B-PCS is spontaneous,endothermic and randomness.

关 键 词：吸附 硼掺杂 多孔碳球 热力学 动力学 镉 

分 类 号：TQ132.44[化学工程—无机化工]