两性生物基絮凝材料优化制备及其絮凝造纸废水性能评价

Synthesis and performance evaluation of an amphoteric bio-based flocculant for papermaking wastewater treatment

关键词:  壳聚糖季铵盐  羧甲基纤维素  两性生物基絮凝材料  絮凝  造纸废水

Key Words:Chitosan quaternary ammonium salt  carboxymethyl cellulose  amphiphilic bio-based flocculating material  flocculation  papermaking wastewater

摘要:传统聚丙烯酰胺类絮凝剂处理废水条件单一、生物降解性差且易引发环境二次污染。为了改善这一问题,文中以壳聚糖季铵盐和羧甲基纤维素为基础原料,通过戊二醛交联,优化制备了一种两性生物基絮凝材料(HTCC-g-CMC)。采用傅里叶变换红外光谱、热重分析、X-射线衍射光谱等方法对HTCC-g-CMC结构进行表征,并将其应用于高岭土悬浊液和实际造纸废水的絮凝处理以评价其絮凝性能。结果表明：HTCC与CMC通过缩醛反应成功合成了具有阴阳离子两性的HTCC-g-CMC产品；当pH为4、6、10时,HTCC-g-CMC对高岭土悬浊液最高浊度去除率分别为89.7%、99.4%、98.9%；将HTCC-g-CMC和商业PAM分别用于造纸废水的絮凝处理,废水的浊度和CODCr去除率分别为90.3%、89.3%和67.2%、58.6%,表明HTCC-g-CMC絮凝在浊度和CODCr去除率方面与商业PAM的效果基本相当,可考虑将其用于造纸废水的絮凝沉淀工段。

Abstract:The traditional polyacrylamide flocculants have some problems such as limited treatment condition, poor biodegradability and possibility to cause secondary pollution. In order to solve those problems, an amphoteric bio-based flocculating material (HTCC-g-CMC) was optimized by cross-linking glutaraldehyde with chitosan quaternary ammonium salt and carboxymethyl cellulose. The structure of HTCC-g-CMC was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and X-ray diffraction spectroscopy. To evaluate the flocculation effect of this product, it was applied to the flocculation treatments of kaolin suspension and actual papermaking wastewater. The results showed that the HTCC-g-CMC products with anionic and cationic groups were successfully synthesized by HTCC and CMC through aldolization. The highest turbidity removal rates of HTCC-g-CMC on kaolin suspension were observed at pH 4, 6, and 10 were 89.7 %, 99.4 %, and 98.9 %, respectively. HTCC-g-CMC and commercial PAM were used for flocculation treatments of papermaking wastewater to make a comparison. The turbidity and CODCr removal rates of wastewater were 90.3%, 89.3%, and 67.2%, 58.6%, respectively. It indicates that the HTCC-g-CMC flocculant is basically equivalent to the commercial PAM in terms of turbidity and CODCr removal rate, and can be applied in the flocculation and precipitation section of papermaking wastewater treatment.