Adsorption and mechanistic study for phosphate removal by rice husk-derived biochar functionalized with Mg/Al-calcined layered double hydroxides via co-pyrolysis

Seon Yong Lee, Jae Woo Choi, Kyung Guen Song, Keunsu Choi, Young Jae Lee, Kyung Won Jung

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Direct or indirect emissions of phosphate from point or non-point sources into aquatic ecosystem may pose serious adverse risks to human life and environmental sustainability. Owing to their environmental and economic benefits, biochar-based adsorption processes have recently emerged as an ideal approach. However, the surface of biochar is normally negatively charged, thus limiting its binding affinity toward anionic contaminants. Herein, in order to address this weakness and further improve adsorption performance, we developed rice husk (RH)-derived biochar functionalized with Mg/Al-calcined layered double hydroxides (RHB/MgAl-CLDHs) via the co-pyrolysis of MgAl-LDH preloaded RH, and we examined its phosphate adsorption properties in aqueous environments. Multiple analyses and phosphate adsorption experiments revealed that the Mg:Al molar ratio (2:1–5:1) and co-pyrolysis temperature (300–700 °C) control the physicochemical properties of synthesized samples and their phosphate adsorption affinities. The molar ratio affects the charge density, whereas the co-pyrolysis temperature determines the surface functionality and porosity. Specifically, RHB/MgAl-CLDHs(2:1/500) (molar ratio = 2:1, co-pyrolysis temperature = 500 °C) exhibited the highest phosphate removal of 97.6% due to the conversion of RH into biochar, decomposition of interlayer water/nitrate, transformation of LDH structures to mixed metal oxides (layered double oxides), and improved porosity, favoring stronger adsorption and intercalation of phosphate. Spectroscopic solid-phase analyses demonstrated that the adsorption mechanism involves the “memory effect” and the formation of both outer- and inner-sphere surface complexes via attractive electrostatic interactions and monodentate/bidentate complexations. In conclusion, considering its high selectivity and excellent recyclability, RHB/MgAl-CLDHs(2:1/500) is a promising material for mitigating eutrophication.

Original languageEnglish
Article number107209
JournalComposites Part B: Engineering
Volume176
DOIs
Publication statusPublished - 2019 Nov 1

Fingerprint

Hydroxides
Phosphates
Pyrolysis
Adsorption
Oxides
Porosity
Aquatic ecosystems
Eutrophication
Intercalation
Coulomb interactions
biochar
Charge density
Complexation
Nitrates
Temperature
Sustainable development
Metals
Impurities
Decomposition
Data storage equipment

Keywords

  • Adsorption
  • Biochar
  • Mg/Al calcined layered double hydroxides
  • One-step functionalization
  • Phosphate

ASJC Scopus subject areas

  • Ceramics and Composites
  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering

Cite this

Adsorption and mechanistic study for phosphate removal by rice husk-derived biochar functionalized with Mg/Al-calcined layered double hydroxides via co-pyrolysis. / Lee, Seon Yong; Choi, Jae Woo; Song, Kyung Guen; Choi, Keunsu; Lee, Young Jae; Jung, Kyung Won.

In: Composites Part B: Engineering, Vol. 176, 107209, 01.11.2019.

Research output: Contribution to journalArticle

@article{0670a643f76b42d2b8272de42fbd9950,
title = "Adsorption and mechanistic study for phosphate removal by rice husk-derived biochar functionalized with Mg/Al-calcined layered double hydroxides via co-pyrolysis",
abstract = "Direct or indirect emissions of phosphate from point or non-point sources into aquatic ecosystem may pose serious adverse risks to human life and environmental sustainability. Owing to their environmental and economic benefits, biochar-based adsorption processes have recently emerged as an ideal approach. However, the surface of biochar is normally negatively charged, thus limiting its binding affinity toward anionic contaminants. Herein, in order to address this weakness and further improve adsorption performance, we developed rice husk (RH)-derived biochar functionalized with Mg/Al-calcined layered double hydroxides (RHB/MgAl-CLDHs) via the co-pyrolysis of MgAl-LDH preloaded RH, and we examined its phosphate adsorption properties in aqueous environments. Multiple analyses and phosphate adsorption experiments revealed that the Mg:Al molar ratio (2:1–5:1) and co-pyrolysis temperature (300–700 °C) control the physicochemical properties of synthesized samples and their phosphate adsorption affinities. The molar ratio affects the charge density, whereas the co-pyrolysis temperature determines the surface functionality and porosity. Specifically, RHB/MgAl-CLDHs(2:1/500) (molar ratio = 2:1, co-pyrolysis temperature = 500 °C) exhibited the highest phosphate removal of 97.6{\%} due to the conversion of RH into biochar, decomposition of interlayer water/nitrate, transformation of LDH structures to mixed metal oxides (layered double oxides), and improved porosity, favoring stronger adsorption and intercalation of phosphate. Spectroscopic solid-phase analyses demonstrated that the adsorption mechanism involves the “memory effect” and the formation of both outer- and inner-sphere surface complexes via attractive electrostatic interactions and monodentate/bidentate complexations. In conclusion, considering its high selectivity and excellent recyclability, RHB/MgAl-CLDHs(2:1/500) is a promising material for mitigating eutrophication.",
keywords = "Adsorption, Biochar, Mg/Al calcined layered double hydroxides, One-step functionalization, Phosphate",
author = "Lee, {Seon Yong} and Choi, {Jae Woo} and Song, {Kyung Guen} and Keunsu Choi and Lee, {Young Jae} and Jung, {Kyung Won}",
year = "2019",
month = "11",
day = "1",
doi = "10.1016/j.compositesb.2019.107209",
language = "English",
volume = "176",
journal = "Composites Part B: Engineering",
issn = "1359-8368",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - Adsorption and mechanistic study for phosphate removal by rice husk-derived biochar functionalized with Mg/Al-calcined layered double hydroxides via co-pyrolysis

AU - Lee, Seon Yong

AU - Choi, Jae Woo

AU - Song, Kyung Guen

AU - Choi, Keunsu

AU - Lee, Young Jae

AU - Jung, Kyung Won

PY - 2019/11/1

Y1 - 2019/11/1

N2 - Direct or indirect emissions of phosphate from point or non-point sources into aquatic ecosystem may pose serious adverse risks to human life and environmental sustainability. Owing to their environmental and economic benefits, biochar-based adsorption processes have recently emerged as an ideal approach. However, the surface of biochar is normally negatively charged, thus limiting its binding affinity toward anionic contaminants. Herein, in order to address this weakness and further improve adsorption performance, we developed rice husk (RH)-derived biochar functionalized with Mg/Al-calcined layered double hydroxides (RHB/MgAl-CLDHs) via the co-pyrolysis of MgAl-LDH preloaded RH, and we examined its phosphate adsorption properties in aqueous environments. Multiple analyses and phosphate adsorption experiments revealed that the Mg:Al molar ratio (2:1–5:1) and co-pyrolysis temperature (300–700 °C) control the physicochemical properties of synthesized samples and their phosphate adsorption affinities. The molar ratio affects the charge density, whereas the co-pyrolysis temperature determines the surface functionality and porosity. Specifically, RHB/MgAl-CLDHs(2:1/500) (molar ratio = 2:1, co-pyrolysis temperature = 500 °C) exhibited the highest phosphate removal of 97.6% due to the conversion of RH into biochar, decomposition of interlayer water/nitrate, transformation of LDH structures to mixed metal oxides (layered double oxides), and improved porosity, favoring stronger adsorption and intercalation of phosphate. Spectroscopic solid-phase analyses demonstrated that the adsorption mechanism involves the “memory effect” and the formation of both outer- and inner-sphere surface complexes via attractive electrostatic interactions and monodentate/bidentate complexations. In conclusion, considering its high selectivity and excellent recyclability, RHB/MgAl-CLDHs(2:1/500) is a promising material for mitigating eutrophication.

AB - Direct or indirect emissions of phosphate from point or non-point sources into aquatic ecosystem may pose serious adverse risks to human life and environmental sustainability. Owing to their environmental and economic benefits, biochar-based adsorption processes have recently emerged as an ideal approach. However, the surface of biochar is normally negatively charged, thus limiting its binding affinity toward anionic contaminants. Herein, in order to address this weakness and further improve adsorption performance, we developed rice husk (RH)-derived biochar functionalized with Mg/Al-calcined layered double hydroxides (RHB/MgAl-CLDHs) via the co-pyrolysis of MgAl-LDH preloaded RH, and we examined its phosphate adsorption properties in aqueous environments. Multiple analyses and phosphate adsorption experiments revealed that the Mg:Al molar ratio (2:1–5:1) and co-pyrolysis temperature (300–700 °C) control the physicochemical properties of synthesized samples and their phosphate adsorption affinities. The molar ratio affects the charge density, whereas the co-pyrolysis temperature determines the surface functionality and porosity. Specifically, RHB/MgAl-CLDHs(2:1/500) (molar ratio = 2:1, co-pyrolysis temperature = 500 °C) exhibited the highest phosphate removal of 97.6% due to the conversion of RH into biochar, decomposition of interlayer water/nitrate, transformation of LDH structures to mixed metal oxides (layered double oxides), and improved porosity, favoring stronger adsorption and intercalation of phosphate. Spectroscopic solid-phase analyses demonstrated that the adsorption mechanism involves the “memory effect” and the formation of both outer- and inner-sphere surface complexes via attractive electrostatic interactions and monodentate/bidentate complexations. In conclusion, considering its high selectivity and excellent recyclability, RHB/MgAl-CLDHs(2:1/500) is a promising material for mitigating eutrophication.

KW - Adsorption

KW - Biochar

KW - Mg/Al calcined layered double hydroxides

KW - One-step functionalization

KW - Phosphate

UR - http://www.scopus.com/inward/record.url?scp=85069669883&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85069669883&partnerID=8YFLogxK

U2 - 10.1016/j.compositesb.2019.107209

DO - 10.1016/j.compositesb.2019.107209

M3 - Article

AN - SCOPUS:85069669883

VL - 176

JO - Composites Part B: Engineering

JF - Composites Part B: Engineering

SN - 1359-8368

M1 - 107209

ER -