U(Ⅵ)吸附偕胺肟化聚丙烯腈薄膜的制备条件优化

Optimization of conditions for preparation of amidoximated polyacrylonitrile membrane for U(Ⅵ) adsorption

目的制备一种便于回收、重复使用的偕胺肟化聚丙烯腈(PAO)薄膜吸附剂,并优化制备条件。方法以聚丙烯腈(PAN)粉末为原料,用非溶剂致相分离法制备了PAO薄膜,研究不同制备条件下PAO薄膜对U(Ⅵ)的吸附性能,考察制备铸膜液时PAN浓度、偕胺肟化温度和时间以及吸附前碱处理对PAO薄膜对U(Ⅵ)吸附性能的影响。结果碱处理会显著提高PAO薄膜对U(Ⅵ)的吸附性能,碱处理温度和时间均会影响最终的U(Ⅵ)吸附效果,最佳碱处理条件为用0.1 mol/L NaOH在60℃处理80 min;合成铸膜液时PAN含量、偕胺肟化温度和时间都会影响PAO薄膜的吸附性能,最佳合成条件为:PAN浓度10wt%,65℃偕胺肟化反应18 h,在此条件下合成的PAO薄膜经最佳碱处理条件处理后的吸附容量可达255 mg/g。结论PAO薄膜制备方法简单,吸附容量高,便于从水体中收集复用,是一种理想的用于吸附废水中U(Ⅵ)的吸附剂材料。

Objective To optimize conditions for the preparation of amidoximated polyacrylonitrile (PAO) membrane for U(Ⅵ)adsorption that can be easily recycled and reused. Methods Using polyacrylonitrile powder as a raw material, the PAO membrane was prepared using the nonsolvent-induced phase separation method under different conditions. The effects of the polyacrylonitrile concentration and temperature and duration of amidoximation in the preparation of casting solution as well as alkali treatment before adsorption on the U(Ⅵ)adsorption performance of PAO membrane were investigated.Results Alkali treatment significantly improved the U(Ⅵ)adsorption performance of PAO membrane, and the temperature and duration of alkali treatment affected the U(Ⅵ)adsorption capacity. The optimal alkali treatment conditions were 0.1 mol/L NaOH, 80 min, and 60℃. The polyacrylonitrile concentration and temperature and duration of amidoximation in the preparation of casting solution influenced the adsorption performance of PAO membrane. The optimal preparation conditions were 10wt% polyacrylonitrile and amidoximation at 65℃ for 18 h. Under the optimal preparation and alkali treatment conditions, the U(Ⅵ)adsorption capacity of PAO membrane reached 255 mg/g. Conclusion The PAO membrane has the advantages of simple preparation, high adsorption capacity, and easy recycling and reuse, which can be used as an ideal material for adsorbing U(Ⅵ)in wastewater.