When Hari Atkuri visited me with his niece, Krishna, I felt an immediate shift in the air—as if a gentle breeze had entered the room carrying the fragrance of an unseen, far-off garden. Warm, curious, and quietly luminous, their presence brought a rare ease, the kind...
Molecular Separation Man of India
Molecular Separation Man of India
Leaving DRDO in 1997 was a leap of faith for me. I had spent 15 years working with missiles, developing India’s first titanium air bottle and facilitating the industry interface for the indigenous production of astronautical-grade aluminium alloys, as well as AKASH missile airframes. By creating a special stainless steel to make an indigenous coronary (Kalam-Raju) stent, I opted to work on the broader technology ecosystem across organisations.
Dr Kalam was there for me as both my flag and my flagpole. People listened to what I said and helped in the best way they could. Working with Dr. Kalam, I met some of the best minds in scientific laboratories, universities and industries, and developed a great interdisciplinary network across organisations, breathing innovation into societal missions. One such contact was Dr S. Sridhar, whom I met at the CSIR-Indian Institute of Chemical Technology (IICT) during the development of a machine for creating water from atmospheric air in 2018 by Maithri Aquatech, a company founded by my friend M. Ramakrishna.
Hailing from a Tamil lineage in southern India, Sridhar’s father served in the Indian Army and settled in Hyderabad, where Sridhar was born and brought up. He graduated in Chemical Engineering and went on to specialise in molecular separation. Any young scientist faces a fork in life – one road leads to application, while the other leads to specialisation. On one path, you spread out over several areas; in another, you dig deep into one field. Dr Sridhar is unique in that, while he has delved deep into his chosen subject, he has kept the application of his work active by training 500 engineering and science graduates.
Dr Sridhar joined IICT as a Research Assistant in 1995, was promoted to Scientist in 1998, and has been working there ever since. His career exemplifies the progress of membrane technology in molecular separation. Over the years, Sridharhas developed pilot plants based on technologies that were patented as they evolved – electrodialysis, nanofiltration, gas permeation, pervaporation, forward osmosis, membrane distillation and reverse osmosis, with capacities ranging from 500 to 5000 litres per hour for solvent recovery, effluent treatment and gas purification, serving the pharmaceutical, steel, textile, aroma and petrochemical industries. He has developed several indigenous membranes for fuel cellapplications.
Dr Sridhar has to his credit more than 70 water purification plants, ensuring safe drinking water for people living in remote areas, affected by waterborne diseases such as fluorosis, gastroenteritis, jaundice and typhoid, across ten states in India. Every purification method is unique and must be tailored to efficiently and reliably filter out the root cause, while also being affordable. Local people must be able to maintain these plants themselves. This is the challenge where most others failed, but Dr Sridhar proved otherwise. Other significant societal contributions with far-reaching impacts include an import-substitute device for producing ultrapure medical-grade water and an affordable, washable, multi-layered facemask to counter COVID-19, which led to the creation of several start-ups.
Molecular separation technology stands as a cornerstone in the domains of chemistry, biochemistry and materials science. It involves isolating specific molecules from complex mixtures based on their physical and chemical properties, which is critical for applications spanning pharmaceuticals, environmental science, petrochemicals and biotechnology. In India, Prof Sirshendu De at IIT Kharagpur was the pioneer in this field.
The roots of molecular separation can be traced back to Russia with the development of chromatography. The introduction of solid-phase columns and more efficient detection methods allowed for enhanced resolution and sensitivity in analysing complex mixtures. Innovations in polymer science led to membranes with remarkable selectivity, durability and scalability, enabling their application in water purification and medical devices. Computational models and advanced materials transformed distillation setups, making them more energy-efficient and precise.
The maturation of molecular separation technology has ushered in cutting-edge methodologies that leverage computational power and nanotechnology. Today, researchers rely on hybrid approaches that combine multiple separation techniques to achieve unprecedented levels of efficiency.
Nanotechnology plays a pivotal role in refining molecular separation. Nanoporous membranes, for instance, exhibit exceptional selectivity, enabling the separation of molecules based on their size, shape and chemical affinity. These membranes are increasingly utilised in desalination, gas separation and selective molecular capture applications.
With the discovery of natural gas, the Indian petroleum industry faced new challenges. Natural gas is a mixture of different molecules that must be purified from CO2 and H2S to enrich methane. The petrochemical industry heavily relies on C2 and C3–olefins as feedstock to produce a vast array of chemical intermediates and final products. Separation of propylene from propane is essential for a wide range of chemical products, including plastics and solvents. Separation of CO2 from power plant off-gases or its direct air capture for agricultural purposes could reduce the increasingly alarming effects of global warming. Dr. Sridhar’s mission was to improve membrane permeability and selectivity, leading to higher yields and reduced energy consumption, which ultimately earned him the title of ‘Molecular Separation Man of India’, as evidenced by the 75 prestigious awards he has received. His work, his team, and above all, his zeal will not only benefit the Indian petroleum industry but also enhance its global role in the years to come.
The future of molecular separation technology is closely tied to interdisciplinary collaboration and technological convergence. Emerging fields such as quantum computing and synthetic biology are likely to redefine the boundaries of molecular separation. Quantum algorithms can simulate molecular interactions with unparalleled precision, paving the way for designing separation systems tailored to specific chemical profiles. Custom-designed biological molecules, such as engineered enzymes, can act as highly selective agents in molecular separation processes, opening new horizons in medicine and materials science.
The maturation of molecular separation technology reflects humanity’s unwavering quest to manipulate matter at its most fundamental level. From early chromatography to cutting-edge nanotechnologies, this field continues to evolve, addressing global challenges and enabling scientific breakthroughs. As researchers and industries forge ahead, the transformative potential of molecular separation will undoubtedly shape the future of science, technology and sustainability.
It was natural for me to understand the role of Dr. Sridhar’swork in biomedical engineering. I recall meeting a Russian cardiologist in 1999 who used plasmapheresis to separate cholesterol from blood, a process similar to dialysis. A few sessions of plasmapheresis per year can help alleviate the side effects of statins. Russians also remove blood ammonia by this process to help the liver recover. These are all proven methods and established technologies, but their wider application is fraught with commercial forces and the formidable medical-pharmaceutical industry.
As a scientist, Dr Sridhar feels that molecular separation technologies are integral to drug development and diagnostics. Affinity chromatography, for example, is used in the purification of monoclonal antibodies and other biologics. Moreover, microfluidics-based separation systems are gaining traction for their capacity to isolate single cells or molecules in diagnostics and genomics research.
May the tribe of people like Dr. Sridhar increase, and may the culture of working across boundaries – spanning science, engineering, computer science, medicine, pharmaceuticals and more – remain open to the exchange of new ideas. Molecular separation technology stands at the frontier of scientific innovation, offering unparalleled opportunities to revolutionise industries ranging from healthcare and agriculture to energy and manufacturing. This cutting-edge methodology enables the precise isolation, purification, and manipulation of molecules, driving economic growth while addressing critical environmental and societal challenges.
Molecular separation technology represents a transformative force in the global economy, offering solutions that enhance efficiency, sustainability, and profitability across industries.The fear that AI will take away jobs is real. However, new jobs will also be created, and people will be employed in making things more efficient and affordable. That it is happening in India augurs well.
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