Effect of pH, ionic strength, temperature and humic substances on the sorption of Ni(II) to Na―attapulgite

By Q. Fan, D. Shao, Yi Lu, Wang-suo Wu, Xiangke Wang. 2009

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Sorption of Ni(II) on Na-attapulgite as a function of pH and ionic strength is investigated under ambient conditions. The results indicate that sorption of Ni(II) is strongly dependent on ionic strength at pH 8. Results of the desorption tests of Ni(II) from bare and HA bound attapulgite hybrids indicate that the sorption is reversible at pH 6.0. Outer-sphere complexation or ion exchange may be the main sorption mechanism of Ni(II) to attapulgite at pH 8 is mainly dominated by inner-sphere complexation. The presence of FA and HA decreases Ni(II) sorption to FA/HA-attapulgite hybrids at pH > 7 obviously, and the influence at pH < 7 is weakly. Sorption of Ni(II) to Na-attapulgite increases with increasing temperature. The thermodynamic data (� H 0 , � S 0 , � G 0 ) are calculated from the temperature-dependent sorption isotherms, and the results suggest that sorption process of Ni(II) on attapulgite is spontaneous and endothermic.

Subfields: Biomaterials, Inorganic Chemistry, Water Science and Technology

View Paper: https://www.semanticscholar.org/paper/d9e9cccc5b434493c0dcca1aceed22874fa7d081