Institution: | 1.Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gon?alves 9500, P.O. Box 15003, Porto Alegre, RS, 91501-970, Brazil ;2.Department of Process Engineering, University of Ngaoundere, Ngaoundere, Cameroon ;3.Department of Process Engineering, Saint Jerome Catholic University Institute, Av. Akwa Koumassi, Douala, Cameroon ;4.Department of Metallurgy, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gon?alves, Porto Alegre, RS, 9500, Brazil ;5.Institute of Exact Sciences, Federal University of South and Southeast of Pará (UNIFESSPA), Marabá, PA, Brazil ; |