Effect of humic acid on sorption of trace metal ions by sodium aluminosilicate

• Published in: Desalination Vol. 268; no. 1; pp. 189 - 194
• Main Authors: Singh, B.K., Bhadauria, Jyoti, Tomar, Radha, Tomar, B.S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2011; Elsevier
• Subjects: Adsorption; Aluminosilicates; Aluminum silicates; Applied sciences; calcium; Chemical engineering; clay; desalination; Entropy; Exact sciences and technology; Humic acid; Humic acids; ionic strength; ions; Lead; Mercury; Metal ions; Pollution; Sodium; Sodium aluminosilicate; Sorption; sorption isotherms; surface area; temperature; trace elements; X-ray diffraction; zeta potential; Zinc; Sorption; Lead; Mercury; Zinc; Humic acid; Sodium aluminosilicate; Organic matter; Density measurement; Adsorption isotherm; Metal ion; Entropy; X ray diffraction; Trace element; Ionic strength; pH; Electrokinetic potential; Thermodynamic properties; Surface area
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2010.10.022

Sorption of trace metal ions (Pb 2+, Zn 2+ and Hg 2+) on synthesized sodium aluminosilicate (Na–AS), an important clay mineral, was carried out in the presence and absence of humic acid (Aldrich) at different pH (3 to 10). The material was synthesized by solution route method and it was characterized by using different techniques such as X-ray diffraction, FT-IR, zeta potential measurement, BET surface area analysis and site density measurement. A series of experiments were made to find out the effect of ionic strength, calcium ions, sorbent dose, metal ions concentration and temperature on the sorption of divalent metal ions by Na–AS. The sorption was found to be dependent on pH as well as humic acid. At lower pH (< pH 6) sorption was observed to be enhanced in the presence of humic acid. Ionic strength played an important role in the sorption of metal ions. Sorption was observed to be decreased with increase in metal ion concentration (10 −5 M to 10 −2 M) and data was fitted well in Freundlich isotherm. Thermodynamic study showed endothermic, entropy favorable and spontaneous sorption behavior of metal ions by sodium aluminosilicate. [Display omitted] ►Solution route synthesis of the sodium aluminosilicate (Na–AS). ►Characterization by XRD, FT-IR, BET surface area analysis, zeta potential and site density measurement. ►Humic acid enhanced sorption at lower pH. ►Freundlich isotherm was applied well for all the metal ions. ►Speciation data showed the presence of cationic species only up to pH ~ 7.