巯基乙胺改性蛭石对水体中Ag(I)的吸附性能研究

用巯基乙胺(MEA)来改性天然蛭石,并利用FTIR、BET、TG-DSC等手段对蛭石和改性蛭石进行表征,分析结果显示MEA成功负载到蛭石上.同时,研究改性蛭石对Ag+的吸附性能,结果表明,经过巯基乙胺改性后蛭石的吸附能力得到较大提升Ag+的去除率从20%提升到79%,吸附大约在200min达到平衡,吸附剂最佳投加量为2g/L左右,pH值在6~12范围内都有较好的吸附效果.Langmuir等温吸附模型和准二级动力学模型能够很好的解释VER和MEA-VER对Ag+的吸附过程.VER和MEA-VER对Ag+的吸附机理主要有电荷吸附和配位吸附.

Efficient removal of silver from aqueous solution with vermiculite modification by 2-aminoethanethiol

In this study, raw vermiculite has been modified by 2-aminoethanethiol (MEA) to obtain organo-vermiculite as adsorbent for the removal of silver ions in aqueous solution. The physicochemical properties of the raw and modified vermiculites were analyzed by Fourier transform infrared (FTIR) spectroscopy, thermogravimetry-differential scanning calorimetry (TG-DSC) and BET analysis, which indicated that MEA was successfully grafted onto the vermiculite. Additionally, batch adsorption experiments involving initial pH, adsorbent dosage, time and temperature demonstrated that the adsorption capacity of Ag+ onto MEA-VER was improved highly compared with that of raw vermiculite. The optimum adsorbent dosage was 2.0g/L, the adsorbents presented a high removal efficiency of Ag+ in a wide range of initial pH values (6-12). The kinetics studies showed that the adsorption process was described well with pseudo-second-order model and the equilibrium was achieved at about 200min of contact time. The adsorption isotherm of Ag+ onto vermiculites fitted the Langmuir model well. All these results indicated that the adsorption process onto vermiculites was taken place mainly by coordination and electrostatic adsorption .