磁性壳聚糖改善污泥脱水性能的研究

采用天然壳聚糖为原料，戊二醛为交联剂，Fe₃O₄为磁核制备磁性壳聚糖，以改善污泥脱水性能.考察了磁性壳聚糖投加量、污泥pH值、调理时间对磁性壳聚糖改善污泥脱水性能的影响，探讨了磁性壳聚糖的作用机理，并通过响应面法研究了磁性壳聚糖和CPAM复配处理污泥对污泥脱水性能的影响.结果表明，保持污泥pH值为6.8时，经20mg/L的磁性壳聚糖调理30min后，污泥比阻（SRF）和含水率（MC）分别由原污泥的13.8×10¹²m/kg和98.7%降低至4.8×10¹²m/kg和75.5%，说明磁性壳聚糖明显改善了污泥脱水性能.响应面实验所拟合的响应值为污泥SRF的二次模型P（Prob>F）<0.05、R²=0.98>0.90，响应值为污泥MC的二次模型P（Prob>F）<0.05、R²=0.95>0.90，表明模型显著，且实验设定变量之间的相关性较好.根据响应值的分布情况，确定污泥脱水的最佳条件为磁性壳聚糖18mg/L、CPAM26mg/L、调理时间27min，相应SRF和MC分别为3.3×10¹²m/kg和59.5%，污泥脱水效果较单独采用磁性壳聚糖或CPAM时得到了明显的提高.

Preparation of magnetic chitosan and improvement of dewatering performance of sludge

Natural chitosan was used as raw material to prepare magnetic chitosan by cross linking with glutaraldehyde and Fe₃O₄for enhancement of the sludge dewatering. The effects of magnetic chitosan dosage, sludge pH and conditioning time on the performance of magnetic chitosan for sludge dewatering were investigated, and the enhancement mechanism was discussed. Subsequently, response surface methodology (RSM) was employed to optimize the process of sludge dewatering by the complex of CPAM and magnetic chitosan. When sludge pH value was 6.8, after conditioned by 20mg/L of magnetic chitosan for 30min, SRF and MC were decreased from 13.8×10¹²m/kg and 98.7% of the original sludge to 4.8×10¹²m/kg and 75.5%, respectively, indicated that the sludge dewatering was significantly enhanced. SRF and MC were settled as the target responses in the experiments designed by RSM, as the determination coefficients (R²) of 0.98and 0.95, the two quadratic models could agree with experimental data well. The optimal conditions for sludge dewatering were magnetic chitosan dosage of 18mg/L, CPAM dosage of 26mg/L, and conditioning time of 27 min, under this optimal condition, SRF and MC appeared as 3.3×10¹²m/kg and 59.5%, respectively, better than the individual using of the magnetic chitosan or CPAM in sludge dewatering.