Abstract: The treatment of heavy metal chromium(Ⅵ) ions in wastewater was investigated by static adsorption method using the adsorbent of nanoscale humic acid. Experiments were systematically conducted to study the affecting factors, including amounts of nanoscale humic acid, adsorption temperature, oscillating time, and solution pH value. The specific surface area and pore diameter were characterized by the N₂ adsorption-stripping, and the static equilibrium adsorption isotherm and adsorption kinetics curves were also obtained respectively. The results showed that adsorption rate and adsorption capacity using nanoscale humic acid could reach 97.5% and 157.52mg/g respectively, under the following conditions:50g/L of nanoscale humic acid, adsorption temperature at 30℃, oscillating time 20min and pH value at 5.0. The specific surface area and pore diameter was 150.6m²/g and 6.5nm respectively. The Langmuir model provided good correlations of the experimental data; the thermodynamics parameters of adsorption system indicated spontaneous, exothermic and entropy increasing process; and kinetic data was well fitted by the pseudo-first order model. After the adsorption material was continuously recycled four times, it still remained a good adsorption performance.

Key words: nanoscale humic acid, chromium ion, thermodynamics, kinetics, adsorption, reusable ability

摘要： 采用静态吸附法系统研究了纳米腐殖酸对重金属铬的吸附, 考察了吸附剂用量、吸附温度、振荡时间、溶液pH值等因素对纳米腐殖酸吸附含铬废水的影响;用N₂吸附-脱附实验表征吸附剂的比表面积及孔径;绘制了静态吸附等温线及吸附动力学曲线。实验结果表明:最优吸附条件为纳米腐殖酸加入量50g/L, 吸附温度30℃, 振荡时间20min, 溶液pH=5.0, 得到吸附率及吸附量分别为97.5%和157.52mg/g;其比表面积及平均孔径分别为150.6m²/g和6.5nm;纳米腐殖酸对铬离子的吸附符合Langmuir模型, 为单分子层吸附, 吸附过程是自发且放热过程;吸附过程动力学符合准一级动力学方程;连续循环使用4次后, 对铬离子的吸附量无明显改变, 表明吸附剂具有重复使用性。

关键词: 纳米腐殖酸, 铬离子, 热力学, 动力学, 吸附, 重复使用性