改性烟草秸秆生物炭的制备及其对重金属Cd^(2+)的吸附  

Preparation of Modified Tobacco Straw Biochar and Its Adsorption of Heavy Metal Cd^(2+)

作　　者：李会端[1] 刘志波 罗盛铃 常国琼 LI Huiduan;LIU Zhibo;LUO Shengling;CHANG Guoqiong(Department of Resources,Environment and Chemistry,Chuxiong Normal University,Chuxiong 675000,China)

机构地区：[1]楚雄师范学院资源环境与化学学院,云南楚雄675000

出　　处：《化工技术与开发》2025年第4期82-91,共10页Technology & Development of Chemical Industry

基　　金：国家自然科学基金项目(12263001);云南省基础研究计划项目(202101BA070001-181);省级大学生创新创业训练计划项目(S202311391059,S202311391043);楚雄师范学院课程思政资源库建设项目(SZZYK10)。

摘　　要：基于生物质材料的资源化利用,本文研究了改性烟草秸秆生物炭对模拟污染水体和土壤中重金属Cd^(2+)的吸附。通过限氧碳化和化学改性制备了烟草秸秆生物炭吸附剂,设计了单因素和设计响应面分析方案,以优化Cd^(2+)的吸附过程,完成吸附过程的化学分析。烟草秸秆在500℃下限氧碳化2h,再分别用KMn O_(4)溶液和Na OH溶液浸泡改性,制备了tsb-Mn和tsb-OH。基于单因素实验结果和设计响应面实验结果,拟合了各因素及交互作用对响应值影响的多元回归模型为:R=98.94-0.24A+0.43B+0.26C+0.076D+0.26AB+0.053AC-0.11AD-0.18BC+0.070BD-0.10CD-0.20A^(2)-0.11B^(2)-0.16C^(2)-0.053D^(2)。ANVOA分析模型的P值<0.0001(极其显著),相关系数R^(2)=0.9445,调整系数Adj.R^(2)=0.8891,两者的差值为0.0554,表明拟合模型可再优化。各因子及交互作用对响应值影响的主次顺序:B>C>A>D。根据多元回归模型预测的最佳吸附条件为:吸附剂用量64.88mg,Cd^(2+)初始浓度15.340mg·L^(-1),吸附温度为29.11℃,吸附时间为64.79min。验证性实验测得Cd^(2+)的吸附率为99.80%,比理论预测值99.82%略低0.02%,证明了多元回归模型的适用性和可预测性。tsb-OH和tsb-Mn对Cd^(2+)的吸附均是热力学自发的过程,符合准二级动力学方程。tsb-OH对Cd^(2+)的吸附符合Freundlich吸附类型,吸附率与溶液中残留Cd^(2+)的平衡浓度成正比。tsb-Mn对Cd^(2+)的吸附符合Langmuir吸附类型,以单分子层化学吸附为主。2种改性生物炭吸附剂tsb-OH和tsb-Mn对污染水体和土壤中的重金属Cd(Ⅱ)具有良好的吸附性能。本实验结果可为农林固体废弃物的资源化利用、重金属污染水体的防治及土壤的改良提供参考。Based on the resource utilization of biomass materials,This paper focuses on preparation of modified tobacco straw biochar and its adsorption of heavy metal Cd^(2+)in simulated polluted water and soil.Tobacco straw biochar adsorbent was prepared by oxygen limited carbonization and chemical modification.Single factor and response surface analysis schemes were designed to optimize the Cd^(2+)adsorption process and complete the chemical analysis of the adsorption process.Tobacco straw was carbonized at500℃for 2h under oxygen limitation,and tsb-Mn and tsb-OH were prepared by soaking modification with KMnO_(4)(aq) and Na OH(aq),respectively.Based on the results of the single factor experiment,a response surface experiment was designed to fit the multiple regression model of the impact of each single factor and interaction on the response value:R=98.94-0.24A+0.43B+0.26C+0.076D+0.26AB+0.053AC-0.11AD-0.18BC+0.070BD-0.10CD-0.20A~2-0.11B~2-0.16C~2-0.053D~2.The ANVOA analysis results show that P value of model is less than 0.0001(extremely significant),and the difference between the correlation coefficient R^(2)=0.9445 and the adjustment coefficient Adj.R^(2)=0.8891 is 0.0554,indicating that the fitting model can be further optimized.The primary and secondary order of the impact of each corresponding factor and interaction on the response value is B>C>A>D.The optimal adsorption conditions predicted by the multiple regression model were 64.88mg of adsorbent dosage,15.340mg/L of Cd^(2+)initial concentration,29.11℃adsorption temperature,and 64.79min of adsorption time.The confirmatory experiment measured a Cd^(2+)adsorption rate of 99.80%,which is slightly lower than the theoretical predicted value of 99.82%by 0.02%,supporting the applicability and predictability of the multiple regression model.The adsorption of Cd^(2+)by tsb-OH and tsb-Mn is a thermodynamic spontaneous process,which conforms to the quasi second-order kinetic equation.The adsorption of Cd^(2+)by tsb-OH follows the Freundlich adsorption type,and the adsorp

关 键 词：烟草秸秆 生物炭 化学改性 Cd(Ⅱ)吸附 热力学 动力学 

分 类 号：TQ424[化学工程] X703[环境科学与工程—环境工程]