壳聚糖衍生物用于市政废水阻垢

Scale Inhibition Performance of Chitosan Derivatives for Municipal Wastewater

摘要:

以壳聚糖(CTS)、丙烯酸(AA)为单体，以过硫酸铵(APS)为引发剂，在体积分数为2%的冰醋酸水溶液中共聚，制备了N-羧乙基化壳聚糖(CEC)。采用红外光谱、核磁共振光谱等对壳聚糖衍生物CEC进行了表征。以阻垢性能为评判标准，通过单因素实验筛选出CEC的最佳合成条件为：m(AA):m(CTS)=5.30:3.00，反应温度为75 ℃，反应时间为4 h，引发剂APS质量分数为3%。考察了CEC用于二级市政废水中的阻垢性能，结果表明：在经过二级处理的市政废水中，CEC阻CaCO3垢性能优异，当CEC的加药量为30 mg/L时，对CaCO3的阻垢率可达92.93%，明显优于市售阻垢剂羟基乙叉二膦酸(HEDP)。通过SEM、XRD对CEC阻CaCO3机理进行了初步探究，结果表明，CEC对CaCO3的作用机理主要是晶格畸变作用。

Abstract:

A new chitosan copolymer (CEC) was successfully synthesized by chitosan (CTS) and acrylic acid (AA) as monomer and ammonium persulfate (APS) as initiator, which copolymerization under 2% (volume fraction) glacial acetic acid solutions. The chitosan derivative was characterized by FTIR, 1H NMR. According to scale inhibition performance, the optimal synthesis conditions of CEC were selected by single factor tests, which were as follows: the mass ratio of AA: CTS was 5.30: 3.00, the reaction temperature was 75 ℃, the reaction time was 4 h and the APS mass fraction was 3%. The scale inhibition performance in secondary municipal wastewater treatment of CEC was studied and the results presented that CEC exhibited excellent inhibition performance to CaCO3 and the scale inhibition rate could reach 92.93% in the presence of 30 mg/L of CEC, which was significantly better than comercial scale inhibitor 1-hydroxy ethylidene-1,1-diphosphonic acid (HEDP). The resistance mechanism to CaCO3 was investigated by SEM and XRD, and it could be noted that the mechanism of CEC on CaCO3 was mainly lattice distortion.