New insights into the role of chemical components on metal ions sorption by grape stalks waste

In this work, metal sorption onto grape stalks waste structural compounds and extractives has been studied for determining their role in Cr(VI), Cu(II) and Ni(II) metal sorption. For this purpose, a sequential extraction of extractives and other compounds from the lignocellulosic material has been carried out. The resulting solid samples obtained in the different extraction processes were used as sorbents of Cr(VI), Cu(II) and Ni(II). Sorption results were discussed taking into account the elemental composition and polarity of the solid extracts. Results indicated that tannins and polyphenols are involved in chromium reduction and sorption. Lignin and celluloses are involved in chromium, Cu(II) and Ni(II) sorption. FTIR analysis confirmed the involvement of lignin moieties in the studied metal ions sorption by grape stalks waste. This study presents a new approach on metal sorption field as the knowledge of the role of the sorbent chemical compounds is essential to determine the key sorbent compounds in the sorption processThis research was funded by the Spanish Ministry of Science and Innovation as part of the projects CTM2010-15185 and CTM2012-37215-C02-01. Chang Liu was financially supported by a fellowship from the Chinese Scholarship Council [2011] 3005. David Pujol was financially support by the Spanish Ministry of Education, Culture and Sport (MHE2011-00258