Production of Sodium Lignosulfonate (SLS) Surfactant from Oil Palm Empty Fruit Bunches (OPEFB) Using MicrowaveLailatul Qadariyah, Dhanar Ramadhan and Ampeldenta GustiE3S Web Conf., 481 (2024) 06006DOI: https://doi.org/10.1051/e3sconf/202448106006