摘要
应用平衡吸附法,研究了不同pH值、离子强度、类胡敏酸浓度和接触时间条件下,黑土、白浆土及蒙脱石对类胡敏酸(HLA)的吸附作用.结果表明:随着HLA浓度的增加,土壤及蒙脱石对HLA的吸附量增加.黑土、白浆土及蒙脱石对HLA的吸附等温线均为L型,其吸附不可逆性表现为白浆土>蒙脱石>黑土.通过Langmiur方程计算,蒙脱石、白浆土对HLA达到吸附平衡时的最大吸附量分别为764.7、790.3mg·g-1,而黑土为35.27mg·g-1.Freundlich方程可以很好地描述白浆土、蒙脱石对HLA的吸附和解吸等温线,而Temkin方程可以很好地描述黑土对HLA的吸附和解吸等温线.同时,3种材料的吸附自由能ΔG°<0,吸附热Qm>0,表明其对HLA的吸附是自发的、放热的过程.随着pH的升高,黑土、白浆土及蒙脱石对HLA的吸附量减少;随离子强度的增加,黑土、白浆土及蒙脱石对HLA的吸附量增大.黑土、白浆土及蒙脱石对HLA的吸附动力学过程划分为快反应和慢反应阶段,其中,蒙脱石、白浆土对HLA的吸附动力学过程用一级动力学方程拟合的效果最好,而对黑土而言,用Elovich方程描述更合适.
Adsorption-desorption of organic fertilizer-isolated HLA on bulk soils and montmorillonite were studied as a function of pH, ionic strength, HLA concentrations and contact time by the batch equilibrium method. The results showed that adsorption of HLA on bulk soils and montmorillonite increased with the increase of initial HLA concentrations. The adsorption isotherms were all L type. The adsorption irreversibility of HLA decreased in the order of albic luvisol 〉 montmorillonite 〉 black soil. Based on the Langmuir equation, the maximum HLA adsorption capacity of montmorillonite, albic luvisol and black soil were 764.7, 790.3 and 35.27 mg·g^-1, respectively. Freundlich equation fitted the equilibrium data better for albic luvisol and montmorillonite, while Temkin equation for black soil. Thermodynamic parameters （ΔG°） revealed that the adsorption of HLA on bulk soils and montmorillonite was spontaneous and exothermic process. Adsorption of HLA on montmorillonite, black soil and albic luvisol decreased with the increase of initial pH from 3 to 8, and increased with the increase of initial ionic strength from 0 to 0.31 mol·L^-1. Adsorption kinetics of HLA on bulk soils and montmorillonite consisted of a rapid reaction from 0 to 60 min, followed by a slow one from 60 to 360 min. The kinetics process of HLA adsorption on montmorillonite and albic luvisol could be best described by the first-order kinetic equation, while the adsorption kinetics of HLA on black soil could be best described by the Elovich equation.
出处
《环境科学学报》
CAS
CSCD
北大核心
2013年第5期1332-1340,共9页
Acta Scientiae Circumstantiae
基金
松辽平原农牧结合循环技术集成与示范项目(No.2012BAD14B05)
东北与黄淮海粮食主产区适应气候变化技术研发与应用项目(No.2013BAC09B01)
现代农业(肉牛)产业技术体系专项经费项目(No.CARS-38)~~
关键词
土壤
矿物
类胡敏酸
吸附解吸
影响因素
soil mineral humic-like acid adsorption-desorption affecting factors
