Design of lignin-based flocculants and dispersants for various aqueous systems

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Dispersants and flocculants are water-soluble chemicals with industrial applications worldwide. Dispersants have a wide range of industrial uses, mainly to reduce viscosity of suspension and solution systems. Flocculants are widely used in wastewater treatments to remove suspended particles and dissolved organic/inorganic chemicals. However, commercially available dispersants and flocculants are mainly oil-based, expensive, ineffective, environmentally unfriendly and non-biodegradable. For these reasons, the incentives for developing greener and more efficient lignin-based dispersants/flocculants are high in the chemical industry.******Lignin has a three-dimensional structure with several aliphatic and aromatic group attachments, making it amenable for producing dispersants and flocculants. Because of its chemical structure, lignin can be tailored to have a wide range of charge densities and molecular weights, making it possible to design dispersants and flocculants with a range of different properties for potential applications in the textile, mining, and oil-sand industries and wastewater treatment systems. ******The majority of kraft lignin is currently combusted as a low-grade energy source. Lignin valorization has been considered a feasible option to make the pulping industry more profitable by using already accessible lignin resources. Dr. Fatehi's research program is unique in Canada and offers an environmentally friendly and industrially attractive approach for producing value-added water-soluble products such as dispersants and flocculants from lignin. ******The objectives of this research program are to: 1) investigate new pathways to produce lignin-based dispersants and flocculants, 2) investigate physical/rheological aspects of lignin polymerization, and 3) identify the correlations between the properties of lignin-based dispersants and flocculants and their performance in various simulated models and industrially-produced solution and suspension systems. The potential impact of this program will be the development of processes for designing lignin-based dispersants and flocculants for various colloidal systems. Considering the urgency for expanding the use of kraft lignin (and thus increasing the revenues of kraft pulp mills) and the demand for using more environmentally friendly dispersants and flocculants in the mining and oil-sand industries, it is expected that newly designed processes will be of great interest to kraft pulp mills who will use the developed technologies. The results of the proposed research will have the potential to support the kraft pulping, mining and oil-sand industries, which will increase Canada's competitiveness in the global commodities market and bring stable jobs and greater prosperity to rural communities.