کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4481896 1316840 2013 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of conditioning by PAM polymers with different charges on the structural and characteristic evolutions of water treatment residuals
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Effect of conditioning by PAM polymers with different charges on the structural and characteristic evolutions of water treatment residuals
چکیده انگلیسی


• WTRs conditioned by different charged PAMs can show close dewaterability.
• Optimum dosage of CPAM is the least among three kinds of PAMs for conditioning.
• There are the least SS content and CPAM residual in conditioned WTR supernatant.
• The changes in size and compactness of WTR aggregates are consistent with CST.
• CPAM conditioning only destroy a small amount of alum/ferric hydrogels in WTR.

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. D2 values 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, and D2 values 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. Df values (log G′–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.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Water Research - Volume 47, Issue 17, 1 November 2013, Pages 6445–6456
نویسندگان
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