Sourabh Chakraborty

Porous carbon from renewable resources like biomass is a key material utilized in many applications ranging from environmental remediation to energy storage. There are limited reports in the literature on the effects of biomass pretreatment, production process parameters, and downstream processing on the final product properties. This is the first study aimed at closing the latter research gap. Six different types of underutilized biomass were examined: eastern red cedar wood, pecan shells, hazelnut shells, algal biomass, miscanthus, and sludge produced at municipal wastewater treatment facilities. Although pretreatment of biomass with KOH or ZnCl₂ enhanced formation of micro- and mesopores, carbon yield was lower (15.3–32.5%) than that obtained via non-catalytic pyrolysis (28.3–48%). An optimization study performed using response surface methodology and cedar wood has shown the significant effects (p < 0.05) of temperature and catalyst/biomass ratio on total BET pore volume and surface area. Additionally, catalyst/biomass ratio had a significant effect on the crystal structure and pore size distribution in the carbon produced by pyrolysis. Hence, optimization of process temperature, hold time, and activation ratio is capable of yielding porous carbon from cedar wood pyrolysis with desirable properties.

Microalgae-based renewable energy, industrial chemicals, and food have received great attention during the last decade. This review article highlights the versatility of algal biomass as a feedstock for producing various commodities and high-value products, including aromatic hydrocarbons and lipids within biorefinery systems. Lipid content and the composition of algal biomass cultivated in various media, specifically in wastewater streams generated at agricultural and industrial production facilities, are reviewed. Technical and chemical aspects of algal biomass conversion via thermochemical techniques including pyrolysis, hydrothermal liquefaction, and hydrothermal carbonization are discussed. The properties of the final products are reviewed based on the conversion process employed. Studies published within the last 5 years are reviewed. The importance of further research on inexpensive and more effective catalysts and the development of downstream processes to upgrade crude products obtained from thermal conversion processes is emphasized. This review concludes with an in-depth discussion of the opportunities and challenges involved in algal biomass-based bioproduct manufacturing and commercialization.