Spent coffee grounds to biodiesel: Opportunities, challenges, and insights from an experimental studyElissavet Emmanouilidou, Anastasia Kapaka, Stella Koukoumtzi, Marios Loukas, Margarita Mpotani, Virginia Savva and Nikolaos C. KokkinosE3S Web Conf., 638 (2025) 01004DOI: https://doi.org/10.1051/e3sconf/202563801004