Study of colloidal properties of natural and Al-pillared smectite and removal of copper ions from an aqueous solution

Author(s)

Sartor, Lucas Resmini ^[1] ; de Azevedo, Antonio Carlos ^[1] ; Pugliese Andrade, Gabriel Ramatis ^[1]

Affiliation

^[1] Univ Sao Paulo ESALQ USP, Dept Ciencia Solo, Escola Super Agr Luiz de Queiroz, BR-13418900 Sao Paulo - Brazil

• Document type: Journal article
• Source: ENVIRONMENTAL TECHNOLOGY; v. 36, n. 6, p. 786-795, MAR 19 2015.
• Web of Science Citations: 2

Abstract

In this study, an Al-pillared smectite was synthesized and changes in its colloidal properties were investigated. The pillaring solution was prepared by mixing 0.4 mol L-1 NaOH and 0.2 mol L-1 AlCl3.6H(2)O solutions. Intercalated clays were heated to obtain the pillared clay, and X-ray diffractometry (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR) spectroscopy and N-2 sorption/desorption isotherms analysis were done to characterize the changes in clay properties. Moreover, adsorption experiments were carried out in order to evaluate the capacity of the pillared clays to remove Cu2+ from an aqueous solution and to characterize the interaction between adsorbent and adsorbate. The results indicate that the natural clay has a basal spacing of 1.26 nm, whereas the pillared clays reached 1.78 nm (500 degrees C) and 1.80 nm (350 degrees C) after calcination. XRF analysis revealed an increase in the Al3+ in the pillared clay as compared to the natural clay. The surface area and pore volume (micro and mesoporous) were higher for the pillared clays. Experimental data from the adsorption experiment were fit to Langmuir and Freundlich and Temkin adsorption models, and the former one was the best fit (highest r(2) value) for all the clays and lower standard deviation (Delta g%) for the natural clay. On the other hand, the Temkin model exhibited Delta g% value lower for the pillared clays. Thermodynamics parameters demonstrate that the Cu2+ adsorption process is spontaneous for all the clays, but with higher values for the pillared materials. In addition, application of the Dubinin-Radushkevich model revealed that the bond between the metal and the clay are weak, characterizing a physisorption. (AU)

• FAPESP's process: 12/19270-5 - Synthesis and study of colloidal and surface properties of aluminum pillared smectite
• Grantee: Lucas Resmini Sartor
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 08/08257-2 - Pillaring phyllosilicates and comparison with 2:1 HI isolated from soil
• Grantee: Antonio Carlos de Azevedo
• Support Opportunities: Regular Research Grants