Purification, characterization and application of dual coagulants containing chitosan and different Al species in coagulation and ultrafiltration process

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• 作者：Wenyu Wang¹ ; ^{sduwenyuwang@foxmail.com} ; Shuang Zhao¹ ; Qinyan Yue¹ ; ^{qyyue58@aliyun.com} ; Baoyu Gao¹ ; Wen Song¹ ; Lijuan Feng²
• 关键词：Al species ; Chitosan ; Dual-coagulants ; Coagulation&ndash ; ultrafiltration ; Floc characteristics ; Membrane resistance
• 刊名：Journal of Environmental Sciences
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：51
• 期：Complete
• 页码：214-221
• 全文大小：1017 K
• 卷排序：51

文摘

The objective of this study was to investigate the effect of different Al species and chitosan (CS) dosages on coagulation performance, floc characteristics (floc sizes, strength and regrowth ability and fractal dimension) and membrane resistance in a coagulation–ultrafiltration hybrid process. Results showed that different Al species combined with humic acid in diverse ways. Ala had better removal efficiency, as determined by UV254 and dissolved organic carbon, which could be further improved by the addition of CS. In addition, the optimal dosage of different Al species was determined to be 4.0 mg/L with the CS concentration of 1.0 mg/L, by orthogonal coagulation experiments. Combining Ala/Alb/Alc with CS resulted in larger flocs, higher recovery, and higher fractal dimension values corresponding to denser flocs; in particular, the floc size at the steady state stage was four times larger than that obtained with Al species coagulants alone. The results of ultrafiltration experiments indicated that the external fouling percentage was significantly higher than that of internal fouling, at around 85% and 15%, respectively. In addition, the total membrane resistance was significantly decreased due to CS addition.