Effect of conditioning by PAM polymers with different charges on the structural and characteristic evolutions of water treatment residuals.
Effect of conditioning by PAM polymers with different charges on the structural and characteristic evolutions of water treatment residuals.
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DOI：
10.1016/j.watres.2013.08.016
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发表时间：
2013-11
期刊：
影响因子：
12.8
通讯作者：
W. Yan;Yiping Wang;Y. J. Chen
中科院分区：
文献类型：
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作者：
W. Yan;Yiping Wang;Y. J. Chen
使用三种不同电荷的聚丙烯酰胺（PAM）絮凝剂（阳离子PAM WD4960、非离子PAM M351和阴离子PAM WDA110）对水处理残留物（WTR）进行调理，并对原始和调理后的WTR的物理化学、形态和结构特征进行了研究。采用流变学方法分析了 WD4960 典型剂量下原始 WTR 和调理 WTR 之间的内部结构转变。结果表明，当用聚合物调节原始 WTR 时，WD4960 的最佳剂量为 4.82 g/kg 总悬浮固体 (TSS)，而 M351 和 WDA110 的最佳剂量均为 7.24 g/kg TSS。在最佳 WD4960 剂量条件下，WTR 基质上清液中的残留 PAM 含量为 5.59 mg/L，是用三种类型的 PAM 获得的上清液中最少的。此外，上清液中可见的黄腐酸（FA）消失，并且紫外FA的强度降低。随着 PAM 用量的增加，WTR 悬浮液中不规则形状聚集体的平均直径从 35.73 μm 增加到数百微米。在最佳 WD4960 剂量下调节的 WTR 聚集体的尺寸远大于在最佳 M351 或 WDA110 剂量下获得的聚集体的尺寸。随着PAM用量的增加，二维分形维数(D2)值呈现增加的趋势。在最佳WD4960、M351和WDA110用量下，调节后的WTR聚集体的D2值分别为1.87、1.76和1.83。因此，阳离子 PAM (CPAM) WD4960 似乎是 WTR 更理想的调节剂。在最佳 WD4960 剂量下，经调节的 WTR 聚集体的毛细管吸入时间 (CST)、平均粒径和 D2 值之间观察到一致的关系。质量分形维数 (Df) 表明，原始 WTR 和 WD4960 调节后的 WTR 都表现得像弱连接絮凝体/聚集体。使用最佳 WD4960 剂量调节之前和之后的 WTR 聚集体的 Df 值 (logG'-log TSS) 分别为 2.79 和 2.81。尽管在 WD4960 调节过程中发生了从明矾/铁水凝胶到交联凝胶的转变，但只有少量明矾/铁水凝胶被破坏，并且调节后的 WTR 聚集体呈现出凝胶状基质，其中残留的明矾-铁水凝胶嵌入交联的 WD4960 分子中。
Three types of polyacrylamide (PAM) flocculants with different charges (cationic PAM WD4960, nonionic PAM M351, and anionic PAM WDA110) were used for water treatment residuals (WTRs) conditioning, and the physicochemical, morphological and structural characteristics of raw and conditioned WTRs were investigated. Rheological methods were employed to analyze the internal structural transition between the raw and conditioned WTRs under a typical dosage of WD4960. Results showed that when the raw WTRs were conditioned with the polymers, the optimum dosage of WD4960 was 4.82 g/kg total suspended solid (TSS) while that of both M351 and WDA110 was 7.24 g/kg TSS. The residual PAM content in the supernatant of the WTR matrix conditioned at the optimum WD4960 dosage was 5.59 mg/L, which is the least among the supernatants obtained with the three types of PAM. Furthermore, the visible fulvic acid (FA) in the supernatant disappeared and the intensity of the ultraviolet FA decreased. The average diameter of irregularly shaped aggregates in the WTR suspensions increased from 35.73 μm to several hundred micrometers with increasing PAM dosage. The size of WTR aggregates conditioned at the optimum WD4960 dosage was much larger than that of aggregates obtained at the optimum M351 or WDA110 dosages. Two-dimensional fractal dimension (D2) values presented an increasing trend with increasing PAM dosage.D2values of the conditioned WTR aggregates were 1.87, 1.76, and 1.83 at optimum WD4960, M351, and WDA110 dosages, respectively. The cationic PAM (CPAM) WD4960 thus appears to be a more ideal conditioner for WTRs. Consistent relationships were observed among the capillary suction time (CST), average particle size, andD2values of the conditioned WTR aggregates at the optimum WD4960 dosage. Mass fractal dimensions (Df) indicated that both the raw and WD4960-conditioned WTRs behave like weak-link flocs/aggregates.Dfvalues (logG′–log TSS) of the WTR aggregates before and after conditioning with the optimum WD4960 dosage were 2.79 and 2.81, respectively. Although the transition from an alum/ferric hydrogel to a cross-linked gel occurred during the WD4960-conditioning process, only a small amount of the alum/ferric hydrogel was destroyed, and the conditioned WTR aggregates showed a gel-like matrix in which residual alum–ferric hydrogels were embedded in cross-linked WD4960 molecules.