壳聚糖基镍铝水滑石的制备及吸附性能

Abstract

本文采用微波辅助合成壳聚糖基Ni-Al水滑石(LDHs)，研究了焙烧水滑石(C-LDHs)以及未焙烧水滑石(LDHs)对水溶液中氟离子的吸附行为，以壳聚糖基Ni-Al水滑石为吸附剂，研究了吸附剂用量、pH值、干扰离子、焙烧温度等对水中氟离子吸附的影响。同时用X射线衍射(XRD)和红外分析(FTIR)对LDHs以及吸附氟离子后的LDHs的结构和性质进行了表征，并且对样品进行了热重差热(TG-DTA)和透射电镜(TEM)分析。结果表明：Ni-Al水滑石的焙烧温度过高会导致水滑石的层状结构被破坏，原样的吸附性能优于焙烧产物的吸附性能。低浓度氟离子有利于水滑石的吸附，吸附剂用量为0.2 g/L，吸附率达到85.78%，pH值在6~7之间吸附氟离子效果最佳，强酸和强碱环境都不利于吸附氟离子。 In this study, microwave assisted method was used for preparing chitosan based NiAl-hydrotalcite, and NiAl-hydrotalcites with and without calcination were used in the adsorption of fluoride from aqueous solution. Various conditions such as adsorbent dosage, solution pH value, co-existing interfering ions and calcination temperature etc., were investigated. The adsorption mechanism was studied by contrasting analysis of X-ray diffract pattern and FTIR of as-prepared sample before and after adsorption, and the sample was characterized by TG-DTA and TEM. The results indicated that the structure of chitosan based NiAl-hydrotalcite would be destroyed when the calcination temperature is higher. Adsorption properties of the sample without calcination were better than those of the calcined sample. The lower fluorine ion concentration was beneficial to adsorption of hydrotalcite, when the adsorbent dosage was 0.2 g/L, the removal rate was 85.78%. It had the best removal efficiency when the pH of solution was in the range of 6 to 7, and strong acid and strong base were not conducive to the adsorption of fluoride ion.