As explained above, separation technologies are critical in our daily lives. However, they comprise a major chunk of industrial activities, associated costs and energy requirements. Consider any product that you use from the time you wake up till the end of the day - plastics, paper, pharmaceuticals, soaps and detergents, textiles, and many more - separations typically account for 40-70% of the total cost of the complete manufacture process of the item and cumulatively, separations in various industries add up to 15% of the world’s energy requirements. Separation technologies are responsible for several important processes within the product manufacture scheme, such as extracting the final product from the synthesis medium; treating effluent streams before environmental discharge; recovering materials that can be reused for subsequent manufacture cycles; or isolating valuable intermediate products that can be used in a different industry or sold.

In our group, we focus on developing techno-economically optimized separation schemes for industry-relevant processes. Short descriptions of some of our ongoing projects are given below.

Pervaporation is a membrane technology in which certain species in the liquid feed effectively evaporate through the membrane due to the vacuum pressure applied on the permeate side (using a vacuum pump), and the membrane’s selectivity in favour of the permeating components. Consequently, the separation is determined by a combination of the vapor-liquid equilibrium characteristics at the operating conditions and the membrane’s selectivity behaviour. Due to the role of membrane selectivity in allowing selective evaporation, pervaporation is particularly useful for breaking azeotropes, which is traditionally done by extractive distillation, azeotropic distillation, pressure swing distillation, or solvent dehydration using molecular sieves. These conventional techniques suffer from several drawbacks such as complexity, contamination of the final products by a third solvent, and relatively high energy requirement.  Pervaporation is currently used at the industry scale for applications such as ethanol dehydration during the synthesis of biofuels and various chemicals, breaking other azeotropes such as ethanol-ETBE (in the petrochemical industry) and isopropyl alcohol-water (in the food processing and pharmaceutical industries), as well as for the removal of volatile organic compounds from wastewater. In our group, we are exploring pervaporation for various new industrial applications relevant to the pharmaceutical industry and biofuel synthesis. We model systems comprising stand-alone pervaporation, pervaporation-distillation hybrids, and traditional enhanced distillation (extractive distillation, azeotropic distillation, pressure swing distillation) for a given application and propose the techno-economically optimized system design for industrial applications. Our pervaporation modeling is aided by our experimental results, which provide values for modeling parameters.

Phytochemicals are plant-derived compounds, several of which have important properties such as antimicrobial or pesticidal properties, or protection against environmental agents such as ultraviolet (UV) radiation and extreme temperatures – to name a few. Hence, they are widely used in creating pharmaceutical, as well as beauty products, and in the food industry. A few examples relevant to our daily lives are carotenoids extracted from carrots or tomatoes which are primary components in immunity-boosting medication, and the flavonoid galangin is used in sunscreen lotions. Phytochemicals are also essential components in medication of critical disease, for example, the plant alkaloid Paclitaxel is used as an anticancer chemotherapy drug component. Typically, solvent extraction is used to extract phytochemicals from the raw plant material, after which a large fraction of the solvent is evaporated, and further isolation of valuable phytochemicals is conventionally done using chromatography, crystallization, or centrifugation. Membrane separations offer a method to reduce the energy requirement in evaporative techniques as well as reduce the cost and complexity of several of the conventional molecule-isolation techniques named earlier. Furthermore, membrane separations can fractionate different classes of extracted molecules in several cases. In our work, we aim to achieve a techno-economic optimization of phytochemical extraction processes with the help of membrane separations used in conjunction with the other critical steps for phytochemical isolation. As shown in the diagram above, our patented phytochemical extraction and isolation work focuses on curcumin obtained from turmeric. Details of the patent are mentioned on the 'Achievements' Page. 

Adsorption is a fundamental surface phenomenon in which molecules or ions from a fluid (liquid or gas) adhere to the surface of a solid material. This process occurs due to attractive forces between the adsorbate molecules or ions and the adsorbent surface. Our group employs adsorption techniques to address the pressing issue of arsenic contamination in groundwater, a widespread global environmental challenge. As shown in the above picture, we synthesize our own adsorbent beads using novel recipes that ensure the use of non-toxic material and biodegradability after use. Furthermore, our work focuses on sustainability by investigating the regeneration and reuse of the adsorbent. The safe disposal and management of arsenic-containing sludge and waste generated after treatment remains a grave concern in existing arsenic-remediation technologies, and our ongoing research aims to establish a suitable approach for the safe management of isolated arsenic through a patented scheme, as shown in the schematic above. Details of the patent are mentioned on the 'Achievements' Page.

The growing accumulation of plastic waste poses a severe environmental challenge, as conventional recycling methods are often inefficient and energy intensive. We have developed a method for sequential recovery of a single type of plastic material  from plastic waste in a closed system comprising: a) pre-heating a solvent under conditions to obtain a pre-heated solvent; b) adding plastic waste in the pre-heated solvent followed by increasing the temperature to cause evaporation of solvent and the plastic waste gets dissolved and concentrated to obtain a mixture and simultaneous recovery of pure, uncolored solvent; and c) cooling and stirring the mixture of step b) to obtain a powder precipitate, wherein simultaneous solvent evaporation and recovery while concentrating the plastic material occurs, followed by a quick precipitation of plastic in its virgin state. The method of the present disclosure showed about 3% higher yield, about 18% lower energy requirement and about 54 % lower time required than the traditional method. Details of the patent are mentioned on the 'Achievements' page.