Characterization and coagulation of a polyaluminum chloride (PAC) coagulant with high Al13 content

Gao, Baoyu; Chu, Yongbao; Yue, Qinyan; Wang, Bingjian; Wang, Shuguang

doi:10.1016/j.jenvman.2004.12.006

Cited by 131 publications

(62 citation statements)

References 6 publications

(6 reference statements)

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“…A work by Gao et al (2005) confirmed that the higher polymeric Al species is the most effective Al species in water and wastewater treatment.…”

Section: Flotation Conditionsmentioning

confidence: 93%

Coagulation and Flotation Conditions of Humic Acid by Dissolved Air Flotation

Lee

2012

Journal of Environmental Science International

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Coagulation, flocculation, and dissolved air flotation (DAF) experiments were performed with humic acid to evaluate the influence of operational conditions on removal efficiencies. We investigated coagulation, flocculation, and flotation conditions of humic acid removal using a laboratory-scale DAF system. This paper deals with coagulant type (aluminum sulfate and PSO-M) and the most relevant operational conditions (velocity gradients for coagulation and flocculation, retention time and recycle ratio and flotation time). Results showed that optimal conditions for removing humic acid, yielding CHA removal efficiencies of approximately 85 %, are a recycle ratio of 40 %, coagulant dosages of 0.15 -0.20 gAl/gHA as aluminum sulfate and 0.03 -0.12 gAl/gHA as PSO-M, coagulation(400s -1 and 60s), flocculation(60s -1 and 900s or more), and flotation(490 kPa or more and at least 10 min).

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“…A work by Gao et al (2005) confirmed that the higher polymeric Al species is the most effective Al species in water and wastewater treatment.…”

Section: Flotation Conditionsmentioning

confidence: 93%

Coagulation and Flotation Conditions of Humic Acid by Dissolved Air Flotation

Lee

2012

Journal of Environmental Science International

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“…Many studies have confirmed that the content of Al b and Al c in PACl are correlated closely to Al 13 and Al 30 , respectively (Akitt and Farthing, 1981;Chen et al, 2005;He et al, 2003;Yan et al, 2007). It has been generally demonstrated that Al 13 or Al b is regarded as the active species responsible for coagulation or precipitation (Bottero et al, 1988;Gao et al, 2005;Hu et al, 2005;Huang et al, 2006b;Qian et al, 2008;Wang and Hsu, 1994). As we know, high Al b content more than 70% is found stable at total Al concentration (Al T ) below 0.5 mol/L; but the content of Al b would be less than 30% with Al T above 2 mol/L (Huang et al, 2006a;Xu et al, 2003).…”

Section: Introductionmentioning

confidence: 95%

Preparation of high concentration polyaluminum chloride with high content of Alb or Alc

Zhao¹,

Zhang²,

Luan³

et al. 2009

Journal of Environmental Sciences

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A novel membrane distillation concentration method was used to prepare high concentration polyaluminum chloride (PACl) with high content of Al b or Al c . 2.52 mol/L PACl 1 with 88% Al b and 2.38 mol/L PACl 2 with 61% Al c were successfully prepared. Three coagulants, AlCl 3 , PACl 1 and PACl 2 were investigated on their hydrolysis behavior and speciation under different conditions. The effects of pH and dilution ratio on Al species distribution were investigated by ferron assay. Experimental result showed that pH had a significant effect on Al species distribution for the three coagulants. Dilution ratio had little effects on Al b and Al c distribution in whole dilution process except the beginning for PACl 1 and PACl 2 . The results indicated that transformation of Al depends largely on their original composition. AlCl 3 was the most unstable coagulant among these three coagulants during hydrolysis process. PACl 1 and PACl 2 with significant amounts of highly charged and stable polynuclear aluminum hydrolysis products were less affected by the hydrolysis conditions and could maintain high speciation stability under various conditions.

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“…The reagents preparation and procedures for the Ferron colorimetric method are illustrated in the literature [23,29]. Absorbance increase was monitored for 120 min such that three fractions could be operationally defined: Al a , Al b and Al c , corresponding to monomeric species, medium polymer species and larger polymer species and/or solid phase Al(OH) 3 [29,38] proved that the Al b species could be regarded as the Al 13 species that identified by 27 Al nuclear magnetic resonance.…”

Section: Characterization Of Al Speciation During Ec Processmentioning

confidence: 99%

An effective method for improving electrocoagulation process: Optimization of Al 13 polymer formation

Wang

Sun

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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h i g h l i g h t s• Al 13 polymer formation in EC process are investigated.• Al 13 species fraction positively correlated with removal of turbidity and organic.• pH 5-7 and lowering j favored the formation of Al 13 polymer.• Al 13 fraction can reach more than 60% under optimal EC conditions. Keywords: Electrocoagulation Aluminum species Electrochemical parameter a b s t r a c t Al 13 polymer has been believed to be the most active species responsible for coagulation. The character of Al species distribution and the formation of Al 13 polymer in electrocoagulation (EC) process were investigated in order to provide insight into optimizing EC operation and design. The results indicated that predominant Al species shifted from monomer toward medium polymer then to larger polymer or Al(OH) (s) with increasing EC time. The in-situ Al 13 polymer could be generated in EC process, and became the dominant species during 5-15 min. In EC process, Al 13 species fraction positively correlated with the removal of turbidity and organic. The increase of pH and current density could accelerate the hydrolysis-polymerization process of Al 3+ . pH 5-7 and lowering current density favored the formation of Al 13 polymer during EC process, EC process with bipolar electrodes had a higher yield of monomeric and Al 13 species, while EC process with monopolar electrodes facilitated the formation of larger polymer or Al(OH) (s) . The content of Al 13 polymer can reach more than 60% under optimal conditions.

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Characterization and coagulation of a polyaluminum chloride (PAC) coagulant with high Al13 content

Cited by 131 publications

References 6 publications

Coagulation and Flotation Conditions of Humic Acid by Dissolved Air Flotation

Coagulation and Flotation Conditions of Humic Acid by Dissolved Air Flotation

Preparation of high concentration polyaluminum chloride with high content of Alb or Alc

An effective method for improving electrocoagulation process: Optimization of Al 13 polymer formation

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