凹凸棒石/脱硅稻壳炭复合材料吸附Pb^(2+)、Cu^(2+)、Ni^(2+)的对比研究

Comparison of attapulgite / activated carbon composite for the adsorption of Pb^(2+),Cu^(2+) and Ni^(2+)

以天然稻壳和凹凸棒石为原料,通过高温炭化,制备了新型无机重金属离子吸附剂-凹凸棒石/脱硅稻壳炭(ATP/DAC)复合材料。采用Zeta电位、TEM、BET等技术对材料进行了表征。通过静态吸附法,研究了不同条件下(pH值、吸附时间、初始浓度)ATP/DAC对Pb2+,Cu2+,Ni2的吸附特性。结果表明:ATP/DAC对离子半径大的重金属有较好的吸附,吸附能力表现为:Pb2+>Cu2+>Ni2+。动力学研究表明:3种重金属离子在ATP/DAC上的吸附均遵循二级动力学方程。吸附等温线研究发现ATP/DAC对Ni2+的吸附等温线更符合Langmuir和D-R模型,Pb2+和Cu2+更适合Freundlich模型。红外光谱(FTIR)表明ATP/DAC复合材料与重金属离子之间存在化学吸附。

A novel inorganic composite was prepared from silicon-freed rick husk（DC）and attapulgite（ATP）through high temperature carbonization for adsorption of heavy metal ions. The attapulgite/active carbon（ATP/DAC）composite was characterized by the zeta electric potential, transmission electron microscopy（TEM）and Nz adsorption-desorption stud- ies. Static adsorption experiments were performed to investigate the effects of the pH, adsorption time and initial concentra- tion on the adsorption capacity of composite. The results showed that composite had better selectivity for heavy metals of bigger ionic radius and followed in the order： Pbz＋ ：〉Cu2＋ ~Ni2＋. The adsorption kinetics of three heavy metals obeyed the pseudo-second-order model. Adsorption isotherm of Ni2＋ in accordance with Langmuir and D-R equation very well. Pb2＋ and Cu2＋ closely followed the freundlich model. FTIR spectra indicated that chemical adsorption existed between composite and three heavy metals.