改性生物炭对Ni~(2+)和Cu~(2+)的吸附

以废弃松木屑为原料制备了生物炭,采用六亚甲基四胺(HMTA)和/或CO2对其进行改性,并将其用于水中Ni2+和Cu2+的吸附。表征结果显示,以HMTA和CO2共同改性的生物炭BC1的表面积最小但表面含氧官能团含量最高。实验结果表明:生物炭经改性后,其吸附性能明显提高,且以BC1为最优;在不调节溶液p H、初始重金属离子质量浓度为50 mg/L、吸附剂加入量分别为2.0 g/L和1.0 g/L、吸附时间分别为360 min和240 min的优化条件下,BC1对Ni2+和Cu2+的去除率分别达到99.81%和95.88%;改性生物炭对Ni2+和Cu2+的吸附过程可以用Langmuir等温吸附模型来描述,而其吸附动力学具有拟二级动力学方程特征。

Adsorption of Ni2+ and Cu2+ on modified biochar

The biochar was prepared using waste pine sawdust as raw material and modified with hexamethylene-tetramine(HMTA) and/or CO2. The modified biochars wereused for adsorption of Ni2+ and Cu2+ from solution. The characterization results show that the biochar BC1 modified with HMTA and CO2 is displayed the smallest specific surface area but the highest content of oxygen functional group. The experimental results show that:The adsorption performance of the biochar is obviously improved after modification,and that of BC1 is the best;Under the conditions of original solution pH,initial heavy metal ion mass concentration 50 mg/L,adsorbent dosage 2.0 g/L and 1.0 g/L, adsorption time 360 min and 240 min respectively,the removal rate of Ni2+ and Cu2+ are reached99.81% and 95.88% respectively;The adsorption process can be described by Langmuir isothermal model,and the kinetic data fit the pseudo-second-order kinetics equation well.