碳纳米管溶胶对水中微量Cd^2＋与Cu^2＋吸附的研究

Adsorption of Cd^(2+) and Cu^(2+) in micropolluted water on carbon nanotubes sol

采用强酸表面氧化法对碳纳米管进行处理,制备稳定具有高效吸附性能的碳纳米管溶胶,用于去除水中低质量浓度重金属Cd2+,Cu2+。研究表明,在实验的pH值为2.5—9.5,对Cd2+的去除,吸附起主要作用,优化的pH值为6.0;对Cu2+的去除,pH<6.7时,吸附起主要作用,在pH>6.7时,金属离子沉淀是主要的去除原因,在pH=9.5时,达到最大去除率。在相同碳纳米管溶胶投加质量浓度情况下,对Cd2+的吸附去除率远远大于对Cu2+的去除。碳纳米管溶胶对Cd2+,Cu2+的吸附等温线呈线性,对Cd2+的吸附性能优于对Cu2+的吸附性能。

The carbon nanotubes （CNTs） sol with a steady and high-efficient adsorption performance was prepared by using strong acid surface oxidation for removal of low mass concentration of Cd^2＋ , Cu^2＋ in water. The results show that when pH value is 2.5-9.5, the removal of Cd^2＋ is mainly due to adsorption, with the optimized pH value is 6 ; when pH 〈 6.7, the removal of Cu^2＋ is mainly due to the adsorption ; when pH 〉 6.7, the removal of Cu^2＋ is mainly due to Cu （OH） 2 precipitation, with the optimized pH value is 9.5. Under the same mass concentration, the CNTs sol has much better adsorption properties for removal of Cd^2＋ than for that of Cu^2＋. The adsorption isotherm of Cd^2＋ and Cu^2＋ to CNTs sol is linear and the removal efficiency of Cd^2＋ is higher than that of Cu^2＋.