【摘要】 采用响应面优化(Box-Behnkendesign,BBD)法对茶树菇废菌体吸附水中Cr(Ⅵ)的过程进行了优化,并设定pH值、Cr(Ⅵ)初始浓度、反应时间、摇床转速和吸附剂用量为5个影响因子,Cr(Ⅵ)吸附率为响应值,对吸附过程的热力学特征及吸附机理进行了研究.结果表明,对废菌体吸附Cr(Ⅵ)有显著影响的因素是pH值、Cr(Ⅵ)初始浓度和吸附剂用量;废菌体对Cr(Ⅵ)吸附的最佳条件为pH=1.19,Cr(Ⅵ)初始浓度为148.58mg·mL-1,反应时间为89.02min,摇床转速为180.12r.min-1,吸附剂用量为10.90g.L-1,在此条件下,实测Cr(Ⅵ)的吸附率达96%以上.用Langmuir、Freundlich及Dubinin-Raduskevich吸附等温模型对吸附过程进行拟合发现,Langmuir模型可以很好地反映茶树菇废菌体对Cr(Ⅵ)的吸附特性,在298K时最大吸附量为46.95mg·g-1.对表观热力学参数ΔG、ΔS及ΔH的计算表明,废菌体对Cr(Ⅵ)吸附为吸热的自发过程,并且吸附过程增加了体系的混乱度.最后结合FTIR图对吸附机理进行了探讨,结果表明,废菌体对Cr(Ⅵ)具有良好的吸附效果,可用于处理含铬废水,达到以废治废的目的.更多还原

【Abstract】 The Box-Behnken design methodology,including five factors:pH,initial Cr(Ⅵ)concentration,contact time,stirring speed and adsorbent dosage,was employed to study the removal of chromium(VI)from aqueous solution by waste Agrocybe aegerita(Black poplar mushroom).The thermodynamic characteristics and mechanism of the adsorption process were also studied.The pH,initial Cr(Ⅵ)concentration and adsorbent dosage were the three key factors influencing the uptake of Cr(Ⅵ).The optimal adsorption conditions were pH 1.19,initial Cr(Ⅵ)concentration 148.58 mg·L-1,contact time 89.02 min,stirring speed 180.12 r·min-1 and adsorbent dosage 10.90 g·L-1,and under these conditions,the removal of Cr(Ⅵ)was above 96%.Langmuir,Freundlich and Dubinin-Radushkevick isotherms were applied to fit the adsorption equilibrium data and the adsorption process.The Langmuir isotherm adsorption model best reflected the adsorption characteristics.The adsorption capacity of the biosorbent was 46.95 mg·g-1.Apparent thermodynamic parameters,such as ΔG,ΔS and ΔH were calculated and showed that the adsorption process was endothermic and spontaneous,while the entropy of the system increased.Finally,the removal mechanism is discussed by deduction from FTIR spectra.The results of this study show that waste Agrocybe aegerita is a good absorbent for removing chromium(VI)from wastewater,which is a strategy of controlling waste by waste.更多还原