M. Farzadkia, M. Gholami, M. Kermani, and K. Yaghmaeian, “Biosorption of Hexavalent Chromium from Aqueous Solutions by Chemically Modified Brown Algae of Sargassum sp. and Dried Activated Sludge”, ajc, vol. 24, no. 11, pp. 5257–5263, Jun. 2012.