Dr. Sudipta Ramola is an accomplished environmental scientist and one of the emerging experts in biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More engineering and wastewater remediation. With over nine years of research experience across India, China, and the United States, she has developed a strong international portfolio in biochar-based solutions for contaminant removal, nutrient recovery, and sustainable environmental management.

Her work spans the full spectrum of biochar research—from low-cost biochar production using rural pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More methods to the design of advanced biochar–mineral composites for removing heavy metals, pharmaceuticals, endocrine disruptors, and nutrients from wastewater. She has pioneered the development of engineered biochar materials such as bentonite–biochar, calcite–biochar, and designer biochar for PPCP removal, offering scalable, circular solutions linking water treatment, waste valorization, and soil health improvement. A former Postdoctoral Research Associate at the University of Illinois Urbana-Champaign and previously a postdoctoral researcher at Zhejiang University of Technology, Dr. Ramola has contributed significantly to the global biochar community. She has authored several publications, an edited volume on Engineered Biochar, and serves as a reviewer for several leading environmental science journals.

With her expertise grounded in both fundamental science and practical application, Dr. Sudipta Ramola represents the new generation of researchers advancing innovative, sustainable biochar technologies for environmental remediation and resource recovery. Engaging with her perspectives was a privilege, and it is evident that her contributions are paving the way for transformative solutions in the biochar landscape.

Shanthi Prabha:  Your PhD research began by utilizing locally available waste materials, such as bamboo twigs, sugarcane bagasse, and even discarded tires. What first inspired you to focus on this “waste valorization” approach, and what was the biggest challenge in turning those specific materials into effective biochar?

Dr. Sudipta Ramola: On a lighter note, I was always interested in making something useful from the refuge. In academia, I got introduced to the concept of waste valorization. This time valorization meant more from the scientific perspective rather than just reusing or recycling the refuge. The idea that really fascinated me that time was how interestingly pyrolysis can enhance the properties of biowaste so that it can be used for further environmental and agronomic applications. The biggest challenge that I faced during my initial research time was the unavailability of a proper programmable pyrolysis unit at our research facility. To overcome this problem, I made biochar using a kiln that was easily available that time and is also being commonly used in rural setting especially in developing countries.

SP: During your doctoral work, you used kiln-based pyrolysis, a method common in rural areas. Could you share a key finding from that time that demonstrates the real-world potential of this accessible technology for communities in need of low-cost water treatment?

SR: Of course, as I mentioned earlier, I used an indigenous kiln to prepare biochar from different waste such as bamboo twigs, bagasse and tyre. These biochar were further modified by impregnating ferric hydroxide onto them. Significant changes in elemental composition, atomic ratio, proximate analyses, functional groups and mineral content were observed in biochar from their parent raw materials. These got translated into better removal of heavy metals (Pb, Hg and Cu) and problematic nutrients such as phosphate by biochar or modified biochar, as per the case. These promising results showed that low-cost, not so sophisticated indigenous kilns can also be used to prepare biochar for efficient small scale water treatment.

SP: After your PhD, your research shifted to engineering biochar-mineral composites, such as with bentonite and calcite. What specific environmental problem were you trying to solve that “regular” biochar couldn’t handle as effectively on its own?

SR: Use of minerals to prepare biochar-mineral composite is quite interesting as the minerals are abundant, cost effective, and perform excellent adsorption. Clay minerals are considered as good adsorbent for heavy metals, dyes, and organic compounds owing to their lamellar structure, high surface area, and high ion exchange capacity.  In a study done by us, biochar-mineral composites (using spent cigarette waste, bentonite and calcite) were found to have better removal for lead from waste water. Also in another study, we used rice husk-calcite biochar composite for phosphate removal and the finding indicated that the presence of SiO₂ and calcite in biochar-mineral composite acted synergistically for the removal of phosphate, particularly at low concentrations. The better removal was result of biochar-mineral composites as neither biochar nor mineral alone were able to perform better for removal of Pb and phosphate.

SP: Your more recent work at the University of Illinois focused on “designer biochar” to remove pharmaceuticals and personal care products (PPCPs). For our readers, why are these “emerging contaminants” such a complex problem for conventional wastewater treatment?

SR: Emerging contaminant (EC) is an umbrella term that consists pharmaceutical and personal care products, steroids, hormones, microplastics, pesticides, per- and polyfluoroalkyl substances and other industrial chemicals. These are termed ‘emerging’ because until recent past they were excluded from the list of conventional pollutants and hence were neither monitored nor regulated. This is the reason that most conventional treatment technologies are not designed to efficiently remove ECs. Physical treatment is designed to treat large particles, suspended solids and debris. ECs are present in very low concentration in dissolved state or as very fine particles, making it very tough to get removed by physical treatment. Similarly, the microorganisms are also not able to degrade these novel man-made compounds. The toxicity of EC may cause inhibition of microbial activities. Also sometimes, microbial activity may produce even more toxic byproducts. For example, even low concentrations of active PPCPs and their metabolites may alter the enzymatic, metabolic and cell-signaling mechanism of non-target organisms causing physiological malfunction, adverse metabolism and reproductive hazards.

SP: You’ve mentioned using Response Surface Methodology (RSM) to optimize your biochar. Can you explain in simple terms what this process involves and how it helped you create a more efficient product for removing those PPCPs?

SR: Response surface methodology (RSM) is a mathematical and statistical tool that finds out optimized process or product. It is very convenient in comparison to the other conventional optimization methods as it does not involve doing several experiments. It considers the lower, middle, and higher values of different variables and designs experiments and fit mathematical models accordingly to give best results of optimization. It does also let the user know how the different variables would behave in linear, quadratic and interactive way.

SP: A fascinating part of your work is its link to the circular economy. For instance, you developed a rice husk-calcite biochar to remove phosphate and noted the resulting composite could be reused as a soil conditioner. How important is it to not just remove a pollutant, but to create a new, valuable product in the process?

SR: It is indeed very fundamental of circular economy to add waste as a resource. As a researcher I am always must excited to find ways to use pollutant laden biochar in more meaningful way for next application. Phosphorus laden- rice husk-calcite biochar composite is one such example that can be further used as a soil conditioner and soil carbon sequestration.

SP: One of your postdoctoral studies achieved a very high lead (Pb) adsorption capacity of up to 500 mg/g using a bentonite-biochar composite. What was the “secret ingredient” or key modification that allowed you to achieve such a high level of performance?

SR: The secret ingredient here was use of clay minerals such as bentonite and calcite with spent cigarette waste at pyrolysis temperature of 700 ℃. Optimization of biochar-mineral composite to remove Pb was done by RSM by varying variables such as initial Pb concentration, dose of adsorbent, pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More and contact time. 

SP: You’ve tested your materials on actual rural sewage water, not just “clean” lab-made solutions. What was the most surprising or challenging thing you learned when moving from a controlled lab environment to a complex, “messy” real-world water sample?

The real test of the product is surely when used in real world conditions. I find most challenging the heterogeneity in real waste water that were of course different from what we have in controlled lab conditions.

SP: Looking back at your journey—from low-cost biochar in India to highly engineered composites in China and designer biochar in the US—what would you say is the single most crucial factor to consider when designing a new biochar for a specific environmental problem?

SR: In my opinion, designing of biochar is entirely dependent on the kind of environmental problem we want to solve. The beauty of biochar is that it has a great scope in terms of variability of raw materials, type of pyrolysis and modification agents/methods. So, if I go for designing a biochar I will look deeply into the problem I am going to solve. Thanks to the immense research literature available about biochar, formulation of biochar can be done pragmatically keeping in mind the basics of biochar properties and goal to be achieved.

SP: As a biochar and environmental expert with research experience in India, China, and the US, what is your perspective on the global biochar landscape today? What key factors or misconceptions do you wish you could change, and what innovations or policy shifts do you believe we most need “to bring into the scene” to unlock its full potential for sustainable remediation and a circular economy?

SR: The global biochar scene is surely in a very good space right now. With good fundamental research done on properties of biochar, there are many sectors in which biochar is being used such as remediation, agronomy, and material science and engineering.

I think we need to standardize the biochar products, protocols for characterization and other testing procedures to built better homogeneity and consumers’ trust.  Biochar products should be included in the existing governmental programs and grants and subsidies should be provided by government to biochar facilities.

SP: Finally, to help us track your work, what’s the next big challenge on your research horizon? Are there new, difficult-to-treat contaminants or environmental problems you’re setting your sights on solving with biochar?

SR: I do want to lay my hands on topics like role of biochar in PFAS removal and the mechanism involved. Also, I am curious about exploring the role of biochar in net zero emission technologies.

SP:  After working so closely with materials like sugarcane bagasse, discarded tyres, and bentonite clay, do you ever find yourself looking at everyday waste or a handful of dirt and thinking, “I could probably turn that into a world-class water filter”?

SR: Yes, no doubt about that …..

Those interested in folowing the research of Dr. Sudipta Ramola can find her on LinkedIn and Research Gate.