Coagulation behavior of polyferric chloride for removing NOM from surface water with low concentration of organic matter and its effect on chlorine decay model

Xu, Zhan; Gao, Baoyu; Wang, Yan; Cao, Baichuan

doi:10.1016/j.seppur.2010.07.012

Cited by 42 publications

(26 citation statements)

References 50 publications

(67 reference statements)

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“…Previous studies showed that broken flocs formed with natural organic matter (NOM) are difficult to return to their size before breakage (Xu and Gao 2012;Zhan et al 2010). Yukselen et al investigated the breakage and regrowth process of kaolin flocs using three different coagulants.…”

Section: Introductionmentioning

confidence: 99%

Breakage and regrowth of flocs formed by sweep coagulation using additional coagulant of poly aluminium chloride and non-ionic polyacrylamide

Nan

Yao

Chen

et al. 2016

Environ Sci Pollut Res

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The breakage and regrowth of flocs formed by sweep flocculation were investigated on different flocculation mechanisms using additional dosage coagulant of poly aluminium chloride (PACl) and non-ionic polyacrylamide (PAM) to explore the reversibility after floc breakage. The optimal dosage of PACl was 0.15 mM (as alum), and zeta potential exceeding 1 mV meant that sweep flocculation was dominant in the pre-flocculated process. Re-coagulation efficiency increased with additional coagulants dosing, and sedimentation rates of flocs re-formed by small additional dosage of non-ionic PAM are faster than that of flocs re-formed by additional PACl. For additional inorganic coagulant (PACl) during regrowth processes, few negatively charged particles that existed in water sample restricted the effect of charge neutralization. An amorphous aluminum hydroxide precipitation could re-activate the weaker points on the broken floc surface, but regrown flocs have loose structure indicating worse settleability. For additional non-ionic PAM dosing, lower dosage showed large values of fractal dimension and average size, probably due to that unfolded curly molecular chain and exposed amide groups of non-ionic PAM which provide superb conditions for amide group interacting with particles. The use of non-ionic PAM in flocculation has advantage of being more effective than the cationic PACl, probably because it may avoid the re-stabilization of broken flocs by polymer adsorption driven by electrostatic attraction. Hence, appropriate dosing of PAM after breakage could improve the flocs characteristics with large size and compact structure.

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Section: Introductionmentioning

confidence: 99%

Breakage and regrowth of flocs formed by sweep coagulation using additional coagulant of poly aluminium chloride and non-ionic polyacrylamide

Nan

Yao

Chen

et al. 2016

Environ Sci Pollut Res

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“…Based on earlier studies on inorganic polymeric coagulants [21][22][23], this issue could be resolved by developing polytitanium salts that might minimise the release of H + through prehydrolysed titanium coagulants. Also, similar to other inorganic polymer coagulants, polytitanium salts may perform better than titanium salts in terms of organic matter removal and pH dependence.…”

Section: Introductionmentioning

confidence: 99%

Coagulation performance and floc characteristics of polytitanium tetrachloride (PTC) compared with titanium tetrachloride (TiCl4) and iron salts in humic acid–kaolin synthetic water treatment

Chekli

Galloux

Zhao

et al. 2015

Separation and Purification Technology

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a b s t r a c tPolymeric metal coagulants are increasingly used to improve the coagulation/flocculation process efficiency, yet the research on the development of titanium and particularly polytitanium salts remains very limited. In this study, the performance of recently developed polytitanium tetrachloride (PTC) coagulant was compared with both titanium tetrachloride (TiCl 4 ) and a commonly used coagulant, ferric chloride (FeCl 3 ) in terms of water quality parameters and floc properties. Compared with FeCl 3 coagulant, titanium-based coagulants had broader region of good flocculation in terms of pH and coagulant dose. Further, they achieved higher removal of UV 254 and turbidity but lower dissolved organic carbon (DOC) removal. Charge neutralisation, physical entrapment of colloids within coagulant precipitates and adsorption were found to be the main coagulation mechanisms for TiCl 4 while sweep coagulation and adsorption were found to play a more important role for both FeCl 3 and PTC. The aggregated flocs formed by PTC flocculation had the largest floc size of around 836 lm with the highest floc growth rate. A little distinction of the floc strength factor was found among the coagulants tested (i.e. 44.8%, 44.2% and 38.9% for FeCl 3 , TiCl 4 and PTC respectively) while TiCl 4 coagulant yielded the flocs with the highest floc recovery factor. This study indicates that Ti-based coagulants are effective and promising coagulants for water purification. Besides, the resulted flocculated sludge can be recycled and produce functional TiO 2 photocatalyst which is a significant advantage over conventional coagulants.

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“…Natural sludge has also more hydrophobic (repelling water) content than synthetic sludge, so that it is more easily coagulated, producing bigger floc sizes than synthetic sludge [13]. Hydrophobic components can also support the formation of ferric hydroxide flocs [36,37]. Moreover, the hydrophobic fraction has a higher molecular weight and lower repulsion against the flocculant, so that the natural sludge has a bigger floc size and a more uniform floc size distribution than the synthetic wastewater sludge [38].…”

Section: Natural Water Floc Size Distributionmentioning

confidence: 99%

Impact of Sludge Floc Size and Water Composition on Dewaterability

et al. 2014

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In order to observe the impact of different water compositions on sludge dewaterability, assessments of floc sizes using a particle size analyzer and of sludge dewaterability based on the capillary suction time (CST) test were carried out. Synthetic raw water had small floc sizes, and synthetic domestic wastewater had both larger median floc sizes and a better correlation between sludge dewaterability and median floc sizes. The floc size distribution results showed that synthetic raw water is associated with a narrow particle size distribution. In comparison, synthetic domestic wastewater produced a wider distribution. However, the CST values were similar for both waters. Compared to synthetic wastewater, natural wastewater had the largest distribution with generally larger particle sizes.

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Coagulation behavior of polyferric chloride for removing NOM from surface water with low concentration of organic matter and its effect on chlorine decay model

Cited by 42 publications

References 50 publications

Breakage and regrowth of flocs formed by sweep coagulation using additional coagulant of poly aluminium chloride and non-ionic polyacrylamide

Breakage and regrowth of flocs formed by sweep coagulation using additional coagulant of poly aluminium chloride and non-ionic polyacrylamide

Coagulation performance and floc characteristics of polytitanium tetrachloride (PTC) compared with titanium tetrachloride (TiCl4) and iron salts in humic acid–kaolin synthetic water treatment

Impact of Sludge Floc Size and Water Composition on Dewaterability

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