Research
Desalination and wastewater treatment using membrane technology:
Water and wastewater treatment with membrane technology has a bright future due to the lower footprint and higher-quality treatment, which leads to the exponential growth of membrane-based treatment technology. However, current membrane technologies are struggling with the problems of inherent material limitations, permeability-selectivity tradeoff and high fouling propensity (biofouling, organic and inorganic fouling) resulting into higher treatment costs. My focus will be to design new membrane surfaces and technologies to control current problems in membrane technologies. We are using state-of-the-art technologies (such as ink-jet printers, CO2 laser) along with nanomaterials, zwitterion, antimicrobial peptides, chemicals to modify membrane surface charge to design and fabricate new generation membranes. Another recent threat to water and wastewater are emerging pollutants, which can be toxic even at a very low concentration. The design of new generation catalytic membranes based on nanotechnology has the potential for in-situ degradation of these emerging pollutants. We are incorporating carbon-based (graphene, carbon nanotube, quantum dots etc.), metal nanoparticles, and enzymes embedded to membranes to be used as photo-catalyst, electrocatalyst, and bio-catalyst. The long-term performance of these new generation membranes (micro-, ultra-, nano- and reverse osmosis membranes) must be evaluated and optimized for best results and will be one of the objectives for my future research. As biofouling in membrane technology is one of the biggest challenges, my approach will be to study biofouling in much more depth, by understanding the microbial ecology in the biofilm. For example, an in-depth understanding of the role of extracellular polymeric substances (EPS) on the biofilm’s physical, chemical, and physiological properties will provide crucial information. Such understanding is critical to effectively design any feasible solution to control and remove biofilm-related problems. These studies will help to design and operate low-cost membrane-based treatment units for drinking water and wastewater in India, which can be effectively integrated with the smart city, smart village and Namami Gange projects.
Environmental nanotechnology:
Nanomaterials have unique properties that can differ considerably from bulk materials. We are interested in utilizing these properties through the engineered application of nanomaterials, in order to address environmental challenges. However, these nanomaterials can affect the environment adversely as well. The sustainable application of nanotechnology should include both of these aspects. We will use nanomaterials such as nano zero-valent metals and carbon-based nanomaterials for effective remediation of the pollutants, environmental sensing and will also investigate the fate, transport, and the adverse effects of these nanomaterials on the ecosystem if released into the environment.
http://www.lawandenvironment.com/2009/12/16/nanotechnology-epa-regulations-on-the-horizon/
Synergy of biological & physicochemical treatment processes:
We are trying to develop protocols that combine physicochemical and biological processes for the effective treatment of highly persistent and emerging contaminants. Each treatment process has advantages and disadvantages, and in combination could complement each other and even be synergistic. For example, the half-life of contaminants varies from days to months in the environment, and microorganisms are not able to use these contaminants as a food source because of their high stability. However, the use of advanced oxidation processes including nanomaterials could lead to faster degradation and smaller degradation by-products. Then, further mineralization could be achieved through biodegradation. We will develop a deeper understanding of the interrelationship of microorganisms with physical and chemical conditions and other biotic components, and this understanding will lead to advanced biological system design for treatment.
Environmental quantum chemical modeling:
The in-depth knowledge of environmental chemical and biological processes could give us critical information regarding the fate and transport of pollutants in the environment, the effectiveness of biological systems, and degradation pathways of the pollutants. In recent times, researchers have shown the great potential of quantum chemical modeling in the chemical and biological systems which can be extended to environmental problems. For example, recently we explained endosulfan isomers’ hydrolysis mechanism using the Density Functional Theory. This provided the critical understanding about how α-endosulfan hydrolyzes different from β-endosulfan at the molecular level. We are using quantum chemical modeling for environmental chemical and biological processes to gain more comprehensive elucidation.
