Mg/Fe-LDHO/PES复合膜吸附材料的制备与除氟性能

以层状氢氧化镁铁的焙烧产物(Mg/Fe-LDHO)和聚醚砜(PES)为原料,采用共混法制备了Mg/Fe-LDHO/PES复合膜吸附材料,并研究了其对水中氟离子的吸附性能,考察了初始pH值、初始F-浓度、吸附温度、吸附时间以及共存阴离子等因素对吸附效果的影响。结果表明:在25℃条件下,该复合膜饱和吸附容量为12.34mg/g,能在pH=4~10范围内保持稳定的吸附性能,吸附速率较高,前5min内即可达到平衡吸附容量的75%;低温有利于提高复合膜的吸附性能,吸附过程符合准二级动力学模型。通过傅里叶变换红外光谱仪(FT-IR)和扫描电子显微镜(SEM)对复合膜的形貌及结构进行了表征,采用电位滴定法测得复合膜的零电位点pH值(pHpzc)为9.4。

Preparation and Defluoridation Performance of Mg/Fe-LDHO/PES Membranous Adsorbent

A hybrid membranous adsorbent for defluoridation of water was prepared by blending method using roasted product of Mg-Fe layered double hydroxides and polyethersulfone as raw materials. Defluoridation performance of the hybrid membranous adsorbent was systematically evaluated with various operation parameters including initial pH, initial fluoride concentration, temperature, contact time and co-existing anions. The hybrid membranous adsorbent performed well over a broad pH range and an instant defluoridation capacity (DC) accounting for 75% of equilibrium absorption capacity was obtained within the initial 5 minutes.A maxi-mum DC of 12.34 mg/g for the hybrid membranous adsorbent was obtained by isotherm study, and it suggested a relative low operation temperature would be favor for the fluoride adsorption. The pseudo-second-order kinetic equation described the kinetic date fairly well. The surface morphology and cross-section structure of the hybrid membrane were characterized by FT-IR and SEM. pH_pzc of the hybrid membranous adsorbent determined by pH drift method was 9.4.