Recovery of H2SO4 from spent acid waste using bentonite adsorbent Marwan Asof, Susila Arita Rachman, Winny Andalia Nurmawi and Cindy Ramayanti MATEC Web Conf., 101 (2017) 02007 Published online: 09 March 2017 DOI: 10.1051/matecconf/201710102007