Halloysite nanotube applications for heavy metals removal from wastewater Cristina Covaliu, Gigel Paraschiv, Oana Stoian, Bogdan Buzatu, Costin Mircea and Camelia Cristea E3S Web Conf., 112 (2019) 04010 Published online: 20 August 2019 DOI: 10.1051/e3sconf/201911204010