聚N-异丙基丙烯酰胺-丙烯酸共聚微凝胶对水溶液中Ni(Ⅱ)的吸附性能

以聚N-异丙基丙烯酰胺-丙烯酸共聚微凝胶(PNIPA-co-AA)为吸附剂，采用静态批试法研究了Ni(Ⅱ)在共聚微凝胶上的吸附行为。探讨了震荡时间、固液比、pH值、离子强度及温度等因素对吸附结果的影响，测定了共聚微凝胶在不同温度下对Ni(Ⅱ)的吸附等温线。结果表明：固液比、pH值和离子强度均对吸附过程有明显影响；吸附过程在30 min内即可达到平衡；Langmiur方程能够很好的拟合吸附等温线。热力学参数(ΔH、ΔS和ΔG)表明，此吸附过程是一个自发、吸热的过程。吸附能力在经过7次的吸附-解吸附过程后没有明显的下降。离子交换是此吸附过程的主要机理。

Adsorption of Ni(Ⅱ) From Aqueous Solution Onto Poly (N-Isopropyl Acrylamid-Co-Acrylic Acid) Copolymer Hydrogel

In this work, the copolymer microgel of N-isopropyl acrylamid-co-acrylic acid (PNIPA-co-AA) were used as a novel adsorbent for removing Ni(Ⅱ) from aqueous solution. The adsorption of Ni(Ⅱ) onto PNIPA-co-AA was studied as a function of contact time, solid/liquid ratio, pH value, ionic strength and temperature. The adsorption isotherm of Ni(Ⅱ) adsorption onto copolymer microgels at different temperature were measured. The results show that Ni(Ⅱ) adsorption onto PNIPA-co-AA is strongly depend on solid/liquid ratio, pH value and ionic strength. Kinetic data indicate that the adsorption process achieves equilibrium within 30 min. Thermodynamics data indicate that the adsorption fits the Langmiur model and its linearized form well and the Ni(Ⅱ) adsorption onto copolymer microgels is a spontaneous and endothermic nature process. The adsorption capacity is not signification reduced after seven times of adsorption-desorption cycles. Ions exchange is the predominant mechanism of Ni(Ⅱ) adsorption onto PNIPA-co-AA. Present study suggests that the copolymer microgels maybe a promising candidate for concentration of heavy metal ions and radionuclides from industrial wastewater.