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采用惰性电解质滴定法和静态吸附实验,研究了磁性海泡石表面零电荷点和吸附Cd2+特性.实验结果表明,海泡石经过磁改性后所对应的pHpzc值由8.0升高到8.5,吸附体系pH的提高,有利于对重金属阳离子Cd2+的吸附.在pH值大于3时,磁性海泡石对Cd2+吸附量和去除率随pH值的升高而增大且趋于稳定,其吸附量为16.10 mg.g-1,约为海泡石的3.9倍,去除率为98%,约为海泡石的2.2倍.磁性海泡石对Cd2+的吸附量与离子强度有较大的相关性,随离子强度的增加而减小;对Cd2+的吸附量随反应温度的升高而增加,吸附等温式符合Langmuir方程.吸附机理以表面配合吸附和表面沉淀为主.
The properties of zero charge and adsorption of Cd2 + on magnetic sepiolite surface were studied by means of inert electrolyte titration and static adsorption experiments.The experimental results show that the corresponding pHpzc value of magnetic sepiolite increases from 8.0 to 8.5, The increase of pH value of the system is beneficial to the adsorption of heavy metal cation Cd2 + .The adsorption and removal rate of Cd2 + by magnetic sepiolite increases and tends to be stable with the increase of pH, 16.10 mg.g-1, about 3.9 times the sepiolite, the removal rate of 98%, about 2.2 times the sepiolite. Magnetic sepiolite Cd2 + adsorption capacity and ionic strength have a greater correlation, With the increase of ionic strength, the amount of Cd2 + adsorbed increased with the increase of reaction temperature, and the adsorption isotherm fitted Langmuir equation.The adsorption mechanism was dominated by surface adsorption and surface precipitation.