Valorizing saline biomass from horticultural waste via pyrolysis

Large emissions of greenhouse gases (GHGs) are severely affecting the planet. Thus, considerable effort has been undertaken to deploy technologies for CO₂ capture and long-term storage. Biochar is a carbon-rich material that can have a two-fold contribution toward mitigating climate change: (a) it enhances soil fertility, thus reducing the requirement for fertilizers and (b) it can persist in soil for thousands of years, serving as a carbon sink material. Herein, we evaluate the operating conditions required to produce biochar using saline biomass obtained from horticultural waste in a university campus on the coast of the Red Sea in Saudi Arabia. The biomass has >10 wt% of Ca, Na, and Mg, which allows for the production of microporous biochar with a surface area of ∼150 m²/g without any additional chemical or physical activation treatment. The bio-oil obtained as an associated product has ∼25 %–50 % of terpenoids and 9 %–42 % of phenols, and its composition varies based on the pyrolysis conditions. These high-value compounds can enhance the economic feasibility of a process that can contribute to environmental remediation.