Removal of Se(IV) and Se(VI) from drinking water by coagulation

Hu, Chengzhi; Chen, Qingxin; Chen, Guixia; Liu, Huijuan; Qu, Jiuhui

doi:10.1016/j.seppur.2014.12.028

Cited by 65 publications

(35 citation statements)

References 39 publications

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“…For example, the removal of

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was achieved from 68.90% to 93.60% with the SCD values of PDADMAC increasing. The valence of anion pollutants also affected the flocculation process (Bellu et al., ; Hu et al., ). The flocculation efficiencies of high valence anionic pollutants (

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and

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) were lower than that of low valence anionic pollutants (

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, and

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) by PDADMAC with the same SCD value.…”

Section: Resultsmentioning

confidence: 99%

“…Coagulation/flocculation is widely applied in drinking water and wastewater treatment process for its simple and low-cost advantages (Fu & Wang, 2011;Hu, Chen, Chen, Liu, & Qu, 2015). Ionic polymers are often selected as organic flocculants because of their good water solubility, low dosage, and high charge density, such as polydimethyldiallyl ammonium chloride (PDADMAC) and cationic polyacrylamide (CPAM; Bolto, Dixon, Eldridge, & King, 2001;Casellassalha, Acobas, Bontoux, & Moreaud, 1981).…”

Section: Introductionmentioning

confidence: 99%

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A new indicator of ionic polymeric flocculants for the removal of heavy metals anions: Specific charge density

Hou

Zhao

Cao

et al. 2019

Water Environment Research

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Ionic polymeric flocculants, as useful and widely used technology, have been applied for heavy metal pollution control. However, although molecular weight is an important indicator, it is not a comprehensive indicator for evaluating flocculation efficiencies of ionic flocculants. Herein, specific charge density (SCD), defined as charge density of unit molecular weight, is a new indicator to evaluate the performance of ionic polymer flocculants. Polydiallyldimethylammonium chloride (PDADMAC) as coagulant aid is investigated to flocculate different anionic pollutants. The results indicate that PDADMAC with a high SCD value could benefit to the flocculation efficiency of anionic pollutants. According to statistical analysis, the average pollutants residual could decrease to 8.64%–32.27% by that with high SCD value, especially for high valence pollutants with a decrease from 58.97%–60.40% to 27.35%–32.27%. The indicator of SCD values not only could characterize the performance of polymer flocculants but also provide a new sight of the flocculation mechanism of polymeric flocculants. Practitioner points Specific Charge Density (SCD) is defined as charge density of unit molecularweight. SCD as a new indicator to evaluate comprehensively the performance of flocculants. Removal efficiencies by flocculation increase with SCD value of PDADMAC increase. Effect of SCD of PDADMAC on removal of pollutant with high valence is significant. SCD of PDADMAC is less indicative for removal of pollutant with low valence.

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“…For example, the removal of

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<! [C D A T A false[{AsO}_{4}^{3 -} false]] >

and

<! [C D A T A false[Fe {false(CN false)}_{6}^{3 -} false]] >

) were lower than that of low valence anionic pollutants (

<! [C D A T A false[{VO}_{3}^{-} false]] >

<! [C D A T A false[{MoO}_{4}^{2 -} false]] >

, and

<! [C D A T A false[{WO}_{4}^{2 -} false]] >

) by PDADMAC with the same SCD value.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A new indicator of ionic polymeric flocculants for the removal of heavy metals anions: Specific charge density

Hou

Zhao

Cao

et al. 2019

Water Environment Research

View full text Add to dashboard Cite

show abstract

“…Moreover, research has focused on low (acidic) pH values and high selenium concentrations like those encountered in industrial wastewaters rather than potable water [17]. Research on drinking water treatment mostly incorporates the use of relatively low-cost ferric or aluminum salts for the coagulation/precipitation process [19,20]. Hu et al (2015) showed that iron-based coagulant can reduce an initial selenium concentration of 250 µg/L by 98%, when a coagulant dosage of 0.4 mmol Fe 3+ /L) is applied in weakly acidic conditions [19].…”

Section: Introductionmentioning

confidence: 99%

“…Research on drinking water treatment mostly incorporates the use of relatively low-cost ferric or aluminum salts for the coagulation/precipitation process [19,20]. Hu et al (2015) showed that iron-based coagulant can reduce an initial selenium concentration of 250 µg/L by 98%, when a coagulant dosage of 0.4 mmol Fe 3+ /L) is applied in weakly acidic conditions [19]. High coagulant dosages and acidic pH conditions were also reported as the crucial parameters that influence selenium coagulation by Adio et al (2017) when studying the precipitation of selenium by nZVI (nano zero-valent iron) [21].…”

Section: Introductionmentioning

confidence: 99%

Techno-Economic Evaluation of Iron and Aluminum Coagulants on Se(IV) Removal

Kalaitzidou

Bakouros

Mitrakas

2020

Water

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Research on selenium pollution in natural waters is continuous and discouraging. In this study, coagulation/precipitation was applied with the use of Fe(II), Fe(III), and poly-aluminum chloride (PACl) salts for Se(IV) removal at concentration range 10–100 μg Se(IV)/L that is commonly found in drinking waters. Prehydrolyzed Fe(III)-FeCl3 delivered the best uptake capacity (Q10 = 8.9 mg Se(IV)/g Fe(III) at pH 6) at the residual concentration equal to the drinking water regulation limit of 10 μg/L. This was much higher than the efficiencies achieved when applying the other coagulants: i.e., Q10 = 7.3 mg Se(IV)/g Fe3+-FeClSO4, Q10 = 6.4 mg Se(IV)/g prehydrolyzed Fe(III)-Fe2(SO4)3 and 0.7 mg Se(IV)/g Al-PACl at pH 6, and Q10 = 0.45 mg Se(IV)/g Fe(II) at pH 7.2. Comparing the different sources of Fe(III), it is apparent that Se(IV) uptake capacity is inhibited by the presence of SO42− in crystal structure of prehydrolyzed Fe2(SO4)3, while prehydrolyzed FeCl3 favors Se(IV) uptake. Temperature effect data showed that coagulation/precipitation is exothermic. In techno-economic terms, the optimal conditions for Se(IV) removal are coagulation/precipitation at pH values lower than 7 using prehydrolyzed Fe(III)-FeCl3, which provides a combination of minimum sludge production and lower operating cost.

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“…The optimum operating conditions were found to consist of an initial pH of 3.2, a current density of 250 A/m 2 , and an NaCL concentration of 1.5 g/L. About 84% total phenolic removal and 40% COD removal were achieved under optimal conditions Hu et al (2015b). investigated Se(IV) and Se(VI) removal from drinking water by coagulation.…”

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confidence: 99%