合成沸石对重金属离子Ni2+、Pb2+、Cu2+的吸附性能

摘要

The experiments were conducted to examine the adsorption of mixed heavy meta1s Ni2+,Pb2+ and Cu2+ ions through synthesizing zeo1ite. The adsorbent dosage, initia1 pH and reaction time were investigated to study the competitive adsorption effect of these three ions. The adsorption isotherm and kinetics equation was a1so discussed. The resu1ts showed that the adsorbent dosage,initia1 pH and the reaction time had significant effect on the remova1 of Ni2+,Pb2+ and Cu2+ ions. With the increasing of adsorbent dosage,the adsorption remova1 rate of Ni2+ ions,Pb2+ and Cu2+ ions was improved,and the saturated adsorption capacity showed a decreasing tendency. The competitive adsorption sequence of these three heavy meta1 ions was Pb>Cu>Ni. The adsorption remova1 rate was 1ower than 20% whi1e the initia1 pH of a strong1y acidic environment,which was not suitab1e for the adsorption of Ni2+,Pb2+ and Cu2+ ions. The adsorption effect of Pb2+ ions was best at initia1 pH8. With the increasing of reaction time,the adsorption remova1 rate of Ni2+,Pb2+ and Cu2+ ions was improved continuous1y. The adsorption remova1 order of these three heavy meta1 ions was unchanged at different reaction time. The adsorption process of Ni2+ and Cu2+ ions accorded with Freund1ich adsorption isotherm, whi1e the adsorption process of Pb2+ ions accorded with Langmuir adsorption isotherm. In addition, the reaction of adsorption on zeo1ite to Ni2+,Pb2+ and Cu2+ ions matched to the pseudo-second c1ass reaction kinetics mode1.%利用合成沸石吸附混合重金属Ni2+Pb2+Cu2+，考察吸附剂量初始pH反应时间对其竞争吸附效果的影响，探讨沸石吸附等温线和吸附动力学。结果表明，吸附剂量初始pH反应时间对沸石吸附Ni2+Pb2+Cu2+的吸附效果影响较大。随着沸石投加量增大，其对Ni2+Pb2+Cu2+的吸附去除率逐渐上升，而单位质量吸附剂对3种重金属饱和吸附量呈下降趋势。沸石对3种重金属离子的竞争吸附去除顺序为Pb>Cu>Ni。初始pH为强酸性环境不利于Ni2+Pb2+Cu2+吸附，其吸附去除率均低于20%；不同初始pH，沸石对Pb2+吸附效果最好。随着反应时间延长，沸石对Ni2+Pb2+Cu2+吸附去除率逐步提高；不同反应时间下，沸石对3种重金属的吸附去除顺序不变。沸石吸附Ni2+与Cu2+的过程符合Freund1ich吸附等温式，对Pb2+的吸附过程符合Langmuir吸附等温式。准二级吸附动力学方程能够描述沸石对Ni2+Pb2+Cu2+的吸附行为。