硼掺杂还原氧化石墨烯吸附六价铬的动力学和热力学研究  

Kinetic and thermodynamic studies on the adsorption of Cr(Ⅵ)by B-RGO

作　　者：陈锋 马路路 张谋 郭世浩 徐子豪 马培[1] 刘帅霞[1] Chen Feng;Ma Lulu;Zhang Mou;Guo Shihao;Xu Zihao;Ma Pei Liu;Shuaixia(School of Resource and Environment,Henan University of Engineering,Zhengzhou 451191)

机构地区：[1]河南工程学院资源与环境学院,郑州451191

出　　处：《化工新型材料》2020年第7期139-144,149,共7页New Chemical Materials

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

摘　　要：以氧化石墨烯为碳源,硼酸为硼源,采用水热法一步制得硼掺杂还原氧化石墨烯(B-RGO),利用扫描电镜、X射线衍射和红外光谱表征其物理性能,并首次研究其对Cr(Ⅵ)的吸附动力学和热力学。结果表明,B-RGO中B含量为7.16at%,为纳米片状无序结构碳,表面存在含氧和含硼官能团,可以提供更多的活性吸附位点,因而其对Cr(Ⅵ)的吸附性能优于RGO和GO。测试发现,其动力学符合准二级动力学模型,相关系数R^2为0.992,化学吸附起主导作用;粒子内扩散模型表明,吸附的速率由膜扩散和内扩散共同控制。不同温度下的吸附等温线更符合Langmuir等温式,最大吸附量为119mg/g(318K),0<RL<1,说明B-RGO吸附Cr(Ⅵ)为有利吸附。热力学参数ΔG^0<0,ΔH^0>0,ΔS^0>0,表明B-RGO吸附Cr(Ⅵ)的过程是自发的、吸热的熵增反应。Boron-doped reduced graphene oxide(B-RGO)was prepared by one pot hydrothermal method using graphene oxide(GO)and boric acid as the carbon precursor and boron source.The physical properties of B-RGO were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD)and fourier transform infrared spectrum(FT-IR),and its adsorption kinetics and thermodynamics for Cr(Ⅵ)were also studied for the first time.The results showed that B-RGO was nanosheet-like disordered structure carbon,the content of B in B-RGO was 7.16 at%.The surface had oxygen-containing and boron-containing functional groups,which could provide more active adsorption sites.Thus,the adsorption performance of Cr(Ⅵ)by B-RGO was superior to that of RGO and GO.The adsorption kinetics fitted well to the pseudo-second-order model,and the correlation coefficients R^2 was 0.992,suggesting that the adsorption of Cr(Ⅵ)by B-RGO was dominated by chemisorption.The intra-particle diffusion model showed that the rate-controlled step was governed by both film-diffusion and intra-particle diffusion.The adsorption isotherms at different temperatures were more consistent with the Langmuir isotherm,with a maximum adsorption quantity of 119 mg/g(318 K).Moreover,0<R_L<1,indicating that the adsorption of Cr(Ⅵ)by B-RGO was a favorable process.The thermodynamic parametersΔG^0<0,ΔH^0>0,ΔS^0>0,manifesting that the adsorption process was spontaneous,endothermic and randomness.

关 键 词：硼掺杂还原氧化石墨烯 吸附 六价铬 动力学 热力学 

分 类 号：X703.1[环境科学与工程—环境工程]