不同热解温度龙虾壳生物炭特征及对Zn2+的吸附机制  

Influence of Pyrolysis Temperature on Characteristics and Zn2+ Adsorptive Mechanism of Crayfish Shell Biochars

作　　者：马洁晨 汪新亮 张学胜 李玉成 郑刘根 王宁 MA Jie-chen;WANG Xin-liang;ZHANG Xue-sheng;LI Yu-cheng;ZHENG Liu-gen;WANG Ning(School of Resources and Environmental Engineering,Anhui University,Heifei 230601,China)

机构地区：[1]安徽大学资源与环境工程学院环境科学研究所

出　　处：《生态与农村环境学报》2019年第7期900-908,共9页Journal of Ecology and Rural Environment

基　　金：国家自然科学基金(41172121);国家水体污染控制与治理科技重大专项(2017ZX07603)

摘　　要：为研究不同热解温度条件下生物炭的理化性质及对Zn^2+的吸附特性和机理,以龙虾壳为生物质原料,采用限氧慢速热解法在300、400、500和600℃条件下制备龙虾壳生物炭,分别记作LS300、LS400、LS500和LS600。采用扫描电镜能谱仪(SEM-EDS)、傅里叶变换红外光谱仪(FTIR)、X射线衍射仪(XRD)等对龙虾壳生物炭进行表征,并结合批量吸附实验分析其对Zn^2+的吸附特性和机理。结果表明:随着热解温度的升高,龙虾壳生物炭产率降低,灰分含量升高,pH增大,孔径增大,芳香性增强;4种生物炭吸附动力学遵循准二级动力学模型,LS600在7 h时达到吸附平衡,其他3种均在24 h时达到平衡;LS600的吸附等温线更符合Langmuir模型,LS300、LS400和LS500的等温吸附过程更符合Freundlich模型,LS600对Zn^2+的吸附效果最好,最大吸附容量可达462.50 mg·g^-1;龙虾壳生物炭对Zn^2+的吸附机理包括阳离子交换、沉淀作用、与含氧官能团络合及与π电子配位。In order to investigate the physicochemical properties of biochar at different pyrolysis temperatures and underlying adsorption mechanism of Zn^2+on biochar.Crayfish shell biochar were prepared at 300,400,500,600℃by the limited oxygen slow pyrolysis(LS300,LS400,LS500 and LS600).The original biochar and zinc-loaded biochar were characterized by using scanning electron microcopy with energy spectrum analysis(SEM-EDS),Fourier transform infrared spectroscopy(FTIR)and X-ray diffraxtion(XRD).Then,the Zn^2+adsorption property and mechanism of crayfish shell biochar was proposed based on the results of adsorption experiment and characterization.Results indicated that the higher the pyrolysis temperature,the yield of crayfish shell biochar decreased,while the ash content,pH,the pore diameter,and the aromaticity were increased.The adsorption kinetics was well fit to the pseudo-second order model.For LS600,adsorption equilibrium was reached at 7 h,and adsorption equilibrium of the other three types biochar were reached at 24 h.The isothermal adsorption of LS600 was well consistent with the Langmuir isotherm model,and LS600 displayed the best adsorption effect on Zn^2+,with its adsorption rate up to 462.50 mg·g-1.Isothermal adsorption of LS300,LS400 and LS500 were well described by Freundlich isotherms model.The adsorption mechanism of crayfish shell biochar on Zn^2+mainly includes cation exchange,the surface complexation of oxygen-containing functional groups,the combination ofπelectrons and precipitating action.

关 键 词：龙虾壳 生物炭 吸附 ZN^2+ 

分 类 号：X52[环境科学与工程—环境工程] X799