阳离子型木质素基絮凝剂的半干法合成及在造纸废水处理中的应用

Hemi-dry Synthesis of Cationic Lignin-based Flocculants and Its Application in Papermaking Wastewater Treatment

中文关键词:  木质素  接枝共聚  PMETAC  絮凝剂  造纸废水

Key Words:lignin  copolymerization  PMETAC  flocculant  papermaking wastewater

中文摘要:

      在以预水解木质素（PHL）为原料、甲基丙烯酰氧乙基三甲基氯化铵（METAC）为单体、K2S2O8为引发剂条件下，通过自由基聚合反应，半干法合成了阳离子型木质素接枝聚合物（PHLM）。采用元素分析仪、电荷滴定仪、傅里叶红外光谱仪（FT-IR）、核磁共振氢谱分析仪（1H-NMR）对制备的PHLM的结构与性能进行表征。以PHLM的溶解度、接枝率和电荷密度作为考核指标，对反应条件进行了优化；并探索了PHLM在造纸废水处理中作为阳离子型絮凝剂的应用效果。结果表明，制备PHLM的最佳条件为：反应浓度60%、METAC/PHL单体摩尔比2∶1、引发剂用量3.0%、pH值4.0、温度80℃，此条件下制备的PHLM溶解度为9.65 g/L，电荷密度为3.88 mmol/g，接枝率为214.93%。当PHLM用量为25 mg/L、pH值为5.0时，PHLM对造纸废水的处理效果最优，浊度和COD_Cr去除率分别达93.3%和65.6%。

Abstract:

      The cationic lignin graft polymer （PHLM） was prepared by hemi dry synthesis through free radical polymerization using PHL （pre-hydrolyzed lignin） as raw material and METAC （［2-（methacryloyloxy） ethyl］ trimethylammonium chloride） as monomer， K2S2O8 as initiator. The structures and properties of PHLM were characterized by elemental analyzer， charge density analyzer， Fourier transform infrared spectroscopy （FT-IR） and nuclear magnetic resonance spectroscopy （1H-NMR） techniques. The reaction conditions were optimized based on the evaluation of the indexs of the solubility， graft ratio and charge density of PHLM. The optimal conditions were found that 60% reaction concentration， 2.0 molar ratio of METAC/PHL， 3.0% initiator dosage， pH value 4.0， 80℃， which generated the PHLM with 9.65 g/L solubility， 3.88 meq/g charge density and 214.93% graft ratio. The PHLM was used as flocculant in papermaking wastewater， the flocculation efficiency was the best when the dosage of PHLM was 25 mg/L and the pH value of wastewater was 5.0. The removal efficiency of COD_Cr and turbidity was up to 65.6% and 93.3%，respectively．