Mesoporous-rich calcium and potassium-activated carbons prepared from degreased spent coffee grounds for efficient removal of MnO42− in aqueous media

Suranjana Bose; Rebecca D. Kirk; Harry Maslen; Martha A. Pardo Islas; Benedict Smith; Thomas I.J. Dugmore; Avtar S. Matharu

doi:10.1039/d2ra02214a

Mesoporous-rich calcium and potassium-activated carbons prepared from degreased spent coffee grounds for efficient removal of MnO₄²⁻ in aqueous media

Suranjana Bose^*, Rebecca D. Kirk, Harry Maslen, Martha A. Pardo Islas, Benedict Smith, Thomas I.J. Dugmore, Avtar S. Matharu

^*Corresponding author for this work

Chemistry

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

Abstract

Commercial ACs typically possess high surface areas and high microporosity. However, ACs with appreciable mesoporosity are growing in consideration and demand because they are beneficial for the adsorption of large species, such as heavy metal ions. Thus, in this study, degreased coffee grounds (DCG) were used as precursors for the production of ACs by means of chemical activation at 600 °C for the efficient removal of manganese in the form of MnO₄²⁻. One of the most common activating agents, ZnCl₂, is replaced by benign and sustainable CaCl₂ and K₂CO₃. Three ratios 1 : 1, 1 : 0.5 and 1 : 0.1 of precursor-to-activating agent (g g⁻¹) were investigated. Porosimetry indicates 1 : 1 CaCl₂ DCGAC is highly mesoporous (mesopore volume 0.469 cm³ g⁻¹). CaCl₂ DCGAC and K₂CO₃ DCGAC shows high adsorption capacities of 0.494 g g⁻¹ and 0.423 g g⁻¹, respectively for the uptake of MnO₄²⁻ in aqueous media. The adsorption process follows pseudo-second order kinetics inline with the Freundlich isotherm (R² > 0.9). Thermodynamic data revealed negative values of ΔG (approx −0.1751 kJ mol⁻¹) demonstrating that the adsorption process on 1 : 1 CaCl₂DCGAC was spontaneous.

Original language	English
Pages (from-to)	19417-19423
Number of pages	7
Journal	RSC Advances
Volume	12
Issue number	30
DOIs	https://doi.org/10.1039/d2ra02214a
Publication status	Published - 4 Jul 2022

Bibliographical note

Funding Information:
A. S. M. would like to thank the British Council and the Newton Fund to support S. B. as a research technician. This work was supported by an Institutional Links grant, ID 527663548, under the UK-Colombia partnership. The grant is funded by the UK Department for Business, Energy and Industrial Strategy and Minciencias (formerly Colciencias) and delivered by the British Council. For further information, please visit https://www.newtonfund.ac.uk .

Publisher Copyright:
© 2022 The Royal Society of Chemistry.

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Cite this

@article{e7419536716249c0b0b4ad4e5c870f2d,

title = "Mesoporous-rich calcium and potassium-activated carbons prepared from degreased spent coffee grounds for efficient removal of MnO42− in aqueous media",

abstract = "Commercial ACs typically possess high surface areas and high microporosity. However, ACs with appreciable mesoporosity are growing in consideration and demand because they are beneficial for the adsorption of large species, such as heavy metal ions. Thus, in this study, degreased coffee grounds (DCG) were used as precursors for the production of ACs by means of chemical activation at 600 °C for the efficient removal of manganese in the form of MnO42−. One of the most common activating agents, ZnCl2, is replaced by benign and sustainable CaCl2 and K2CO3. Three ratios 1 : 1, 1 : 0.5 and 1 : 0.1 of precursor-to-activating agent (g g−1) were investigated. Porosimetry indicates 1 : 1 CaCl2 DCGAC is highly mesoporous (mesopore volume 0.469 cm3 g−1). CaCl2 DCGAC and K2CO3 DCGAC shows high adsorption capacities of 0.494 g g−1 and 0.423 g g−1, respectively for the uptake of MnO42− in aqueous media. The adsorption process follows pseudo-second order kinetics inline with the Freundlich isotherm (R2 > 0.9). Thermodynamic data revealed negative values of ΔG (approx −0.1751 kJ mol−1) demonstrating that the adsorption process on 1 : 1 CaCl2DCGAC was spontaneous.",

author = "Suranjana Bose and Kirk, {Rebecca D.} and Harry Maslen and {Pardo Islas}, {Martha A.} and Benedict Smith and Dugmore, {Thomas I.J.} and Matharu, {Avtar S.}",

note = "Funding Information: A. S. M. would like to thank the British Council and the Newton Fund to support S. B. as a research technician. This work was supported by an Institutional Links grant, ID 527663548, under the UK-Colombia partnership. The grant is funded by the UK Department for Business, Energy and Industrial Strategy and Minciencias (formerly Colciencias) and delivered by the British Council. For further information, please visit https://www.newtonfund.ac.uk . Publisher Copyright: {\textcopyright} 2022 The Royal Society of Chemistry.",

year = "2022",

month = jul,

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doi = "10.1039/d2ra02214a",

language = "English",

volume = "12",

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AU - Bose, Suranjana

AU - Kirk, Rebecca D.

AU - Maslen, Harry

AU - Pardo Islas, Martha A.

AU - Smith, Benedict

AU - Dugmore, Thomas I.J.

AU - Matharu, Avtar S.

N1 - Funding Information: A. S. M. would like to thank the British Council and the Newton Fund to support S. B. as a research technician. This work was supported by an Institutional Links grant, ID 527663548, under the UK-Colombia partnership. The grant is funded by the UK Department for Business, Energy and Industrial Strategy and Minciencias (formerly Colciencias) and delivered by the British Council. For further information, please visit https://www.newtonfund.ac.uk . Publisher Copyright: © 2022 The Royal Society of Chemistry.

PY - 2022/7/4

Y1 - 2022/7/4

N2 - Commercial ACs typically possess high surface areas and high microporosity. However, ACs with appreciable mesoporosity are growing in consideration and demand because they are beneficial for the adsorption of large species, such as heavy metal ions. Thus, in this study, degreased coffee grounds (DCG) were used as precursors for the production of ACs by means of chemical activation at 600 °C for the efficient removal of manganese in the form of MnO42−. One of the most common activating agents, ZnCl2, is replaced by benign and sustainable CaCl2 and K2CO3. Three ratios 1 : 1, 1 : 0.5 and 1 : 0.1 of precursor-to-activating agent (g g−1) were investigated. Porosimetry indicates 1 : 1 CaCl2 DCGAC is highly mesoporous (mesopore volume 0.469 cm3 g−1). CaCl2 DCGAC and K2CO3 DCGAC shows high adsorption capacities of 0.494 g g−1 and 0.423 g g−1, respectively for the uptake of MnO42− in aqueous media. The adsorption process follows pseudo-second order kinetics inline with the Freundlich isotherm (R2 > 0.9). Thermodynamic data revealed negative values of ΔG (approx −0.1751 kJ mol−1) demonstrating that the adsorption process on 1 : 1 CaCl2DCGAC was spontaneous.

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