In the quest to make industrial processes more sustainable, a novel approach has emerged that could significantly impact how we assess and treat effluent streams, particularly in the energy sector. Roelof Frederick Maritz, a researcher from the Department of Chemical Engineering at Stellenbosch University in South Africa, has developed a methodology that incorporates the Gibbs free energy of mixing to model the environmental impact of industrial brine treatment processes. This work, published in the South African Journal of Chemical Engineering, offers a more nuanced way to evaluate the environmental footprint of various industrial processes, particularly in the recycling of lithium-ion batteries.
The challenge Maritz addresses is a familiar one in the energy sector: how to accurately compare the environmental impact of different effluent streams produced by chemical and metallurgical processes. Traditional life cycle assessment studies often rely on generalized datasets, which overlook the unique thermodynamic properties of each effluent stream. “This approach disregards the thermodynamic properties of the effluent streams and only considers the volume of effluent being treated,” Maritz explains. His solution involves calculating the Gibbs free energy of mixing, which can then be analyzed as either a regular or a specific energy value. This method highlights the importance of both improving effluent quality and reducing effluent quantity to minimize environmental impact.
To demonstrate the practical application of this methodology, Maritz conducted a case study comparing the environmental impact of effluent streams produced by different hydrometallurgical lithium-ion battery recycling plants. The study revealed that the process using citric acid as a leaching reagent had a lower specific effluent impact compared to a more traditional sulphuric acid-based process. However, the citric acid-based process generated a larger volume of effluent, ultimately requiring more energy for complete theoretical separation of contaminants.
The implications of this research are significant for the energy sector, particularly as the demand for lithium-ion batteries continues to grow. “By incorporating the Gibbs free energy of mixing into our assessments, we can make more informed decisions about the environmental impact of different recycling processes,” Maritz notes. This approach could lead to more efficient and sustainable practices in the treatment of industrial effluents, ultimately reducing the environmental footprint of energy-related industries.
As the energy sector strives to balance economic growth with environmental sustainability, methodologies like Maritz’s offer a promising path forward. By providing a more accurate and comprehensive assessment of effluent treatment processes, this research could shape future developments in the field, driving innovation and promoting more sustainable practices. The work, published in the South African Journal of Chemical Engineering, underscores the importance of integrating thermodynamic principles into environmental impact assessments, paving the way for a more sustainable future.