1. Sustainable Energy and Environment Research Group, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, South Africa
2. Clean Coal and Sustainable Energy Research Group, Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, South Africa
3. NRF-DST Sustainable Process Engineering, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, South Africa
4. Environmental Engineering and Management Research Group, Ton Duc Thang University, Ho Chi Minh City, Vietnam
5. Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam
6. Department of Chemical Engineering, University of Johannesburg, Doornfontein Johannesburg, South Africa