Hydrothermal Carbonization of Seaweed For Advanced Biochar Production Tirto Prakoso, Rima Nurastuti, Reza Hendriansyah, Jenny Rizkiana, Gede Suantika and Guoqing Guan MATEC Web Conf., 156 (2018) 05012 Published online: 14 March 2018 DOI: 10.1051/matecconf/201815605012