Development of carbon adsorbents with high surface acidity and basicity from polyhydric alcohols with phosphoric acid activation for Ni(Ⅱ) removal

摘要

In this study, polyhydric alcohols, including glycerol, erythritol, xylitol, mannitol, and inositol, were chosen as carbon precursors for preparation of carbon adsorbents via phosphoric acid activation. The thermal behaviors of phosphoric acid-treated polyhydric alcohols revealed the formation and decomposition of organic phosphates at low temperatures, which enhanced the creation of functional groups on activated carbon. In general, the activated carbons showed relative low surface area (the highest one of 509 m(2)/g for AC-xylitol) due to the low activation temperature, and low yields (the highest one of 36.6% for AC-xylitol) due to the volatilization and decomposition of organic phosphates. The activated carbons contained 50-90% larger total amount of surface groups than the reference activated carbon derived from lignocellulose material, which mainly resulted in their 40-75% higher Ni(II) adsorption capacity. These results also indicated that the polyhydric alcohols-based activated carbons can be promising candidates for Ni(II) removal. (C) 2018 Elsevier Ltd. All rights reserved.