微波辐射制备羧甲基纤维素接枝丙烯酰胺树脂及其对Cr(Ⅵ)吸附性能的研究

Preparation of carboxymethyl cellulose grafted acrylamide resin with microwave radiation and its adsorption performance towards Cr(Ⅵ)

以羧甲基纤维素(CMC)为接枝骨架,丙烯酰胺(AM)为单体,过硫酸钾/硫代硫酸钠(KPS/Na_(2)S_(2)O_(3))为引发剂,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,采用微波辐射合成羧甲基纤维素接枝丙烯酰胺(CMC-AM)树脂。探讨了树脂吸附Cr(Ⅵ)效率与AM、KPS/Na_(2)S_(2)O_(3)、MBA以及微波时间的定量关系。通过傅里叶变换红外光谱仪(FT-IR)、非金属元素分析仪和Zeta电位等多种表征手段分析了树脂的官能团种类、元素含量,并确定了树脂的表面电荷特性。通过X射线光电子能谱仪(XPS)分析了树脂吸附Cr(Ⅵ)前后表面元素价态变化。结果表明:当微波功率为350W,CMC∶AM=1∶8,引发剂和交联剂分别为单体质量的3%、0.25%,微波时间为8min时,该树脂对Cr(Ⅵ)的吸附性能最好,吸附率达94.60%,且对Cr(Ⅵ)的吸附符合Langmuir等温吸附模型。最后,对树脂吸附Cr(Ⅵ)的机理进行了分析,Cr(Ⅵ)去除是静电引力和氧化还原的共同作用。

Carboxymethyl cellulose(CMC)grafted with acrylamide(AM)was prepared via microwave irradiation method where CMC,AM,potassium persulfate/sodium thiosulfate(KPS/Na_(2)S_(2)O_(3))and N,N′-methylenebisacrylamide(MBA)were used as grafting skeleton,monomer,initiator and cross-linker,respectively.The effects of AM,KPS/Na_(2)S_(2)O_(3),MBA,and microwave time on adsorption of Cr(Ⅵ)were studied.The functional group type and elemental content of the resin were characterized by means of Fourier transform infrared spectroscopy(FT-IR),non-metallic elemental analyzer and zeta potential,and the surface charge characteristics of the resin were identified.The changes of surface elemental valence of the resin before and after the adsorption of Cr(Ⅵ)were analyzed by X-ray photoelectron spectrometry(XPS).The results showed that adsorption efficiency climbed to 94.60%when microwave power and time were 350W and 8min,respectively,CMC∶AM=1∶8,initiator and cross-linker were 3%and 0.25%,respectively,and the adsorption of Cr(Ⅵ)was in accordance with the Langmuir isothermal adsorption model.Finally,the mechanism of Cr(Ⅵ)adsorption by the resin was analyzed,and the removal of Cr(Ⅵ)was the synergy of electrostatic gravitational force and redox.