Sulfate removal by Mg–Al layered double hydroxide precipitates: Mechanism, settleability, techno-economic analysis and recycling as demulsifier

Xiaoce Tian; Zhen Zhou; Wei Wu; Yi Xin; Lu Man Jiang; Xiaodan Zhao; Ying An; Zhiwei Wang

doi:10.1016/j.jclepro.2019.118503

Sulfate removal by Mg–Al layered double hydroxide precipitates: Mechanism, settleability, techno-economic analysis and recycling as demulsifier

Xiaoce Tian
, Zhen Zhou^*
, Wei Wu
, Yi Xin
, Lu Man Jiang
, Xiaodan Zhao
, Ying An
, Zhiwei Wang

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

19 Scopus citations

Abstract

This study investigated sulfate (SO₄ ²⁻) removal by Mg–Al hydrotalcite-type (HT) compound (Mg₆Al₂SO₄(OH)₁₆•mH₂O), and analyzed applicable condition of the method from techno-economic perspective. Under optimized condition of pH 8.80, molar ratio of Mg²⁺ and SO₄ ²⁻ (Mg/S ratio) of 6.63 and molar ratio of Al³⁺ and SO₄ ²⁻ (Al/S ratio) of 2.53, HT compound achieved a greatly lower concentration of SO₄ ²⁻ (3.76 mmol/L) than conventional gypsum precipitation. The composition and morphological analysis of precipitates showed that HT compound was transformed to Mg(OH)₂ at pH > 9.0, and Mg(OH)₂, Al(OH)₃ and MgAl₂(OH)₈ at Al/S ratio > 2.5. HT compound had better settleability than Mg(OH)₂ and ettringite, and was easier to be flocculated by anionic polyacrylamide to obtain a lower SV₃₀ of 16.4%. Turbiscan showed that HT compound had the highest instability and aggregation property among the three systems. Techno-economic analysis showed that HT compound coupled ettringite route was more economic than Mg(OH)₂ coupled ettringite route at Mg/S ratio > 6.08, but was not applicable when concentrations of Mg²⁺ and SO₄ ²⁻ were very low. The precipitated HT compound was recovered as demulsifier and showed more efficient COD removal than conventional demulsifier for chemical cleaning wastewater treatment.

Original language	English
Article number	118503
Journal	Journal of Cleaner Production
Volume	242
DOIs	https://doi.org/10.1016/j.jclepro.2019.118503
State	Published - 1 Jan 2020
Externally published	Yes

Keywords

Mg–Al layered double hydroxide
Sulfate removal
Turbiscan
Wastewater

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/j.jclepro.2019.118503

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@article{84c7ba2f077b4da3a02a8cf2485b23d1,

title = "Sulfate removal by Mg–Al layered double hydroxide precipitates: Mechanism, settleability, techno-economic analysis and recycling as demulsifier",

abstract = "This study investigated sulfate (SO4 2−) removal by Mg–Al hydrotalcite-type (HT) compound (Mg6Al2SO4(OH)16•mH2O), and analyzed applicable condition of the method from techno-economic perspective. Under optimized condition of pH 8.80, molar ratio of Mg2+ and SO4 2− (Mg/S ratio) of 6.63 and molar ratio of Al3+ and SO4 2− (Al/S ratio) of 2.53, HT compound achieved a greatly lower concentration of SO4 2− (3.76 mmol/L) than conventional gypsum precipitation. The composition and morphological analysis of precipitates showed that HT compound was transformed to Mg(OH)2 at pH > 9.0, and Mg(OH)2, Al(OH)3 and MgAl2(OH)8 at Al/S ratio > 2.5. HT compound had better settleability than Mg(OH)2 and ettringite, and was easier to be flocculated by anionic polyacrylamide to obtain a lower SV30 of 16.4\%. Turbiscan showed that HT compound had the highest instability and aggregation property among the three systems. Techno-economic analysis showed that HT compound coupled ettringite route was more economic than Mg(OH)2 coupled ettringite route at Mg/S ratio > 6.08, but was not applicable when concentrations of Mg2+ and SO4 2− were very low. The precipitated HT compound was recovered as demulsifier and showed more efficient COD removal than conventional demulsifier for chemical cleaning wastewater treatment.",

keywords = "Mg–Al layered double hydroxide, Sulfate removal, Turbiscan, Wastewater",

author = "Xiaoce Tian and Zhen Zhou and Wei Wu and Yi Xin and Jiang, \{Lu Man\} and Xiaodan Zhao and Ying An and Zhiwei Wang",

note = "Publisher Copyright: {\textcopyright} 2019 Elsevier Ltd",

year = "2020",

month = jan,

day = "1",

doi = "10.1016/j.jclepro.2019.118503",

language = "英语",

volume = "242",

journal = "Journal of Cleaner Production",

issn = "0959-6526",

publisher = "Elsevier Ltd",

}

TY - JOUR

T1 - Sulfate removal by Mg–Al layered double hydroxide precipitates

T2 - Mechanism, settleability, techno-economic analysis and recycling as demulsifier

AU - Tian, Xiaoce

AU - Zhou, Zhen

AU - Wu, Wei

AU - Xin, Yi

AU - Jiang, Lu Man

AU - Zhao, Xiaodan

AU - An, Ying

AU - Wang, Zhiwei

PY - 2020/1/1

Y1 - 2020/1/1

N2 - This study investigated sulfate (SO4 2−) removal by Mg–Al hydrotalcite-type (HT) compound (Mg6Al2SO4(OH)16•mH2O), and analyzed applicable condition of the method from techno-economic perspective. Under optimized condition of pH 8.80, molar ratio of Mg2+ and SO4 2− (Mg/S ratio) of 6.63 and molar ratio of Al3+ and SO4 2− (Al/S ratio) of 2.53, HT compound achieved a greatly lower concentration of SO4 2− (3.76 mmol/L) than conventional gypsum precipitation. The composition and morphological analysis of precipitates showed that HT compound was transformed to Mg(OH)2 at pH > 9.0, and Mg(OH)2, Al(OH)3 and MgAl2(OH)8 at Al/S ratio > 2.5. HT compound had better settleability than Mg(OH)2 and ettringite, and was easier to be flocculated by anionic polyacrylamide to obtain a lower SV30 of 16.4%. Turbiscan showed that HT compound had the highest instability and aggregation property among the three systems. Techno-economic analysis showed that HT compound coupled ettringite route was more economic than Mg(OH)2 coupled ettringite route at Mg/S ratio > 6.08, but was not applicable when concentrations of Mg2+ and SO4 2− were very low. The precipitated HT compound was recovered as demulsifier and showed more efficient COD removal than conventional demulsifier for chemical cleaning wastewater treatment.

AB - This study investigated sulfate (SO4 2−) removal by Mg–Al hydrotalcite-type (HT) compound (Mg6Al2SO4(OH)16•mH2O), and analyzed applicable condition of the method from techno-economic perspective. Under optimized condition of pH 8.80, molar ratio of Mg2+ and SO4 2− (Mg/S ratio) of 6.63 and molar ratio of Al3+ and SO4 2− (Al/S ratio) of 2.53, HT compound achieved a greatly lower concentration of SO4 2− (3.76 mmol/L) than conventional gypsum precipitation. The composition and morphological analysis of precipitates showed that HT compound was transformed to Mg(OH)2 at pH > 9.0, and Mg(OH)2, Al(OH)3 and MgAl2(OH)8 at Al/S ratio > 2.5. HT compound had better settleability than Mg(OH)2 and ettringite, and was easier to be flocculated by anionic polyacrylamide to obtain a lower SV30 of 16.4%. Turbiscan showed that HT compound had the highest instability and aggregation property among the three systems. Techno-economic analysis showed that HT compound coupled ettringite route was more economic than Mg(OH)2 coupled ettringite route at Mg/S ratio > 6.08, but was not applicable when concentrations of Mg2+ and SO4 2− were very low. The precipitated HT compound was recovered as demulsifier and showed more efficient COD removal than conventional demulsifier for chemical cleaning wastewater treatment.

KW - Mg–Al layered double hydroxide

KW - Sulfate removal

KW - Turbiscan

KW - Wastewater

UR - https://www.scopus.com/pages/publications/85072530149

U2 - 10.1016/j.jclepro.2019.118503

DO - 10.1016/j.jclepro.2019.118503

M3 - 文章

AN - SCOPUS:85072530149

SN - 0959-6526

VL - 242

JO - Journal of Cleaner Production

JF - Journal of Cleaner Production

M1 - 118503

ER -

Sulfate removal by Mg–Al layered double hydroxide precipitates: Mechanism, settleability, techno-economic analysis and recycling as demulsifier

Abstract

Keywords

UN SDGs

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