Activation of nano kaolin clay for bio-glycerol conversion to a valuable fuel additive

Imtisal Zahid, Muhammad Ayoub, Bawadi Bin Abdullah, Muhammad Hamza Nazir, Zulqarnain, Mariam Ameen Kaimkhani, Farooq Sher

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    15 Citations (Scopus)
    124 Downloads (Pure)


    High production of biodiesel results in a surplus of glycerol as a byproduct that leads to a drastic decline in the glycerol price as well as overall biodiesel production. Alternative methods must be introduced for the economical process for biodiesel production via utilization of crude glycerol into valuable chemicals or fuel additives. This study introduces an ecofriendly process of solketal synthesis from glycerol and acetone in the presence of a novel metakaolin clay catalyst, which is a useful additive in biodiesel or gasoline, in order to enhance the octane number and to control the emissions. Moreover, kaolin clay catalysts are low cost, abundantly available, eco-friendly and one of the more promising applications for solketal synthesis. In this study, raw kaolin clay was activated with an easy acid activation technique, modification in physicochemical and textural properties were determined by using X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) and Field Emission Scanning Electron Microscope. Among all acid-treated catalysts, metakaolin K3 have shown best catalytic properties, high surface area and pore size after acid activation with 3.0 mol/dm3 at 98 C for 3 h. Acetalization of glycerol with acetone carried out in the presence of an environmentally friendly and inexpensive novel metakaolin K3 catalyst. The maximum yield of solketal obtained was 84% at a temperature of 50 C, acetone/glycerol molar ratio 6/1 and for 90 min with novel metakaolin clay catalyst. Effect of various parameters (time, temperature, acetone/glycerol molar ratio, catalyst loading) on the solketal yield and glycerol conversion was discussed in detail. This approach offers an effective way to transform glycerol into solketal—a desirable green chemical with future industrial applications.

    Original languageEnglish
    Article number2631
    Number of pages17
    JournalSustainability (Switzerland)
    Issue number5
    Publication statusPublished - 1 Mar 2021

    Bibliographical note

    This article is an open access article distributed under the terms and
    conditions of the Creative Commons Attribution (CC BY) license (


    Funding Information:
    Acknowledgments: Acknowledgements: The authors are gratefully acknowledged to University Teknologi PETRONAS, Centre for Biofuel and Biochemicals Research (CBBR), Centralized Analytical Lab (CAL) and the financial support offered by YUTP grant (015LC0-144) and the Ministry of Higher Education (MOHE), Malaysia, to support financially under the FRGS grant (0153A-L63) for all facilities provided to support postgraduate students.

    Funding Information:
    Funding: The funding was provided by Yayasan Universiti Teknologi Petronas (YUTP) under project number (015LC0-144).


    • Acetalization and renewable fuels
    • Acid treated kaolin
    • Crude glycerol
    • Solketal
    • Sustainable environment

    ASJC Scopus subject areas

    • Geography, Planning and Development
    • Renewable Energy, Sustainability and the Environment
    • Management, Monitoring, Policy and Law


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