改性纳米蒙脱土对废水中Cr(Ⅵ)的吸附行为研究

Adsorption of Cr(Ⅵ) in wastewater by modified nano-montmorillonite

以纳米蒙脱土(MNT)、溴化十六烷基吡啶(CPB)和EDTA为原料,采用溶胶-凝胶法,制备了CPB-MNT(C-M)和CPB-EDTA-MNT(C-E-M)吸附剂,采用XRD、SEM、N2吸附-脱附和FTIR进行表征,考察其对Cr(Ⅵ)的吸附行为,并研究了吸附等温方程和吸附动力学。结果表明,经改性后,CPB和EDTA成功进入蒙脱土层间,使层间距由0.95 nm分别增大到1.69 nm和2.12 nm,单位吸附量由4.02 mg/g分别增大到7.11 mg/g和11.91 mg/g;相同条件下,对Cr(Ⅵ)去除率C-E-M(99.19%)>C-M(59.25%)>MNT(32.5%);C-E-M吸附模拟废水中Cr(Ⅵ)符合拟二级动力学和Langmuir方程,极限吸附量和Langmuir常数分别是44.41 mg/L和0.731 2;吸附机理主要是物理吸附和化学吸附。C-E-M吸附剂用于处理含Cr(Ⅵ)废水具有巨大的前景。

CPB-MNT(CM)and CPB-EDTA-MNT were prepared using sol-gel method using cetylpyridinium bromide(CPB)and disodium edetate(EDTA)as raw materials,CEM adsorbent,characterized by XRD,SEM,N 2 adsorption-desorption and FTIR,the adsorption behavior of Cr(VI)was investigated,and the modified montmorillonite was studied.Adsorption isotherms and adsorption kinetics.The results show that after the modification,the CPB and EDTA successfully enter the montmorillonite layer and the interlayer distance increases from 0.95 nm to 1.69 nm and 2.12 nm,respectively,and the unit adsorption amount increases from 4.02 mg/g to 7.11 mg/g and 11.91 mg/g respectively.Under the same conditions,the removal rate of Cr(VI)is C-E-M(99.19%)>C-M(59.25%)>MNT(32.5%);C-E-M adsorption Cr(VI)process is in line with the pseudo-secondary dynamics,the model and the Langmuir isotherm equation,the saturated adsorption capacity and the Langmuir constant were 44.41 mg/L and 0.731 2,respectively;the adsorption mechanisms were mainly physical adsorption and chemical adsorption.C-E-M adsorbent has great prospects for treating wastewater containing Cr(VI).