From Waste to Resource: Surface-Engineered Spent Coffee Grounds as a Sustainable Adsorbent for Oil-Water Separation

Congcan Shi, Tianqi Wang, Shimul Roy, Shauhrat S. Chopra, Guangxue Chen, Jin Shang, Junfei Tian, Yong Sik Ok

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Oil pollution in water is a serious issue worldwide that urgently requires an efficient and cost-effective method for separating oil-water mixtures. Selective adsorption using solid adsorbents is a promising approach. However, conventional oil-cleaning adsorbents, which are typically derived from non-renewable resources, are expensive, environmentally harmful, incapable of separating oil-water emulsions, or inefficient in recovering the adsorbed oil. Thus, we developed a sustainable method for cleaning oil pollution that addresses environmental challenges and utilizes functionalized organic waste. Superhydrophobic SiO2 nanoparticle-fabricated spent coffee grounds (SSD-SCGs) were developed, which rapidly adsorb various oils in water, including viscous crude oil, in both ambient and harsh chemical environments, with 98.5-99.7% removal efficiency. Our separation method is an energy-efficient, single-unit, flow-through, and gravity-driven system. Furthermore, the unique wettability and hierarchical porosity of the SSD-SCGs enable the effective separation of oil-seawater emulsions. The recovery of adsorbed oils and regeneration of the adsorbent were easily achieved through mechanical compression. After multiple uses, the SSD-SCGs were converted into coffee logs, a fuel source with a high heat value, thereby realizing the goal of converting waste to energy. A life-cycle assessment revealed that the SSD-SCGs had greater positive environmental and economic impacts than conventional SCGs. This study reveals an avenue for converting agricultural waste into advanced functional materials to address multiple challenges related to the United Nations Sustainable Development Goals.

Original languageEnglish
Pages (from-to)1297-1307
Number of pages11
JournalACS ES and T Engineering
Volume3
Issue number9
DOIs
Publication statusPublished - 2023 Sept 8

Bibliographical note

Funding Information:
This work was financially supported by the Science and Technology Innovation Commission of Shenzhen Municipality (Ref: JCYJ20210324134006019, JCYJ20190808181003717) and the Research Grants Council of Hong Kong (Ref: CityU 11317722). This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (no. 2021R1A2C2011734). This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1A6A1A10045235). This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (NRF-2022M3J4A1091450). Supported by OJEong Resilience Institute, Korea University. And we would like to thank Editage ( www.editage.co.kr ) for English language editing.

Publisher Copyright:
© 2023 American Chemical Society.

Keywords

  • alternative fuel source
  • coffee grounds
  • oil adsorption
  • sustainable development goal 5 clean water and sanitation
  • waste-to-energy

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Environmental Chemistry
  • Process Chemistry and Technology
  • Chemical Health and Safety

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