Mass Transfer Coefficient of Ozone in a Bubble Column Ratnawati Ratnawati, Dyah Arum Kusumaningtyas, Purbo Suseno and Aji Prasetyaningrum MATEC Web Conf., 156 (2018) 02015 Published online: 14 March 2018 DOI: 10.1051/matecconf/201815602015