Ciprofloxacin Removal Using Pillared Clays

Abstract

In this work, Ti-pillared bentonites were evaluated to remove ciprofloxacin (CIP) from the aqueous solution. Pillared sodium bentonite (BSP) and pillared calcium bentonite (BCP) were prepared by means of the sol–gel method using titanium tetraisopropoxide with calcination for 3 h at 500 ◦C. They were characterized using the BET method for N2 adsorption, and subjected to X-ray diffraction and Fourier transform infrared spectroscopy. The results show that the surface area of the pillared bentonites increased after the process, more than the natural ones. Pillared sodium bentonite has a more porous structure, larger surface areas, and higher adsorption capacity than pillared calcium bentonite. The kinetic adsorption of ciprofloxacin (CIP) onto pillared bentonites is well described by the pseudo second-order kinetic model. The BSP isotherm well fitted the Freundlich model, while the BCP isotherm fits the BET model better, suggesting multilayer adsorption. DR model shows mostly physical adsorption for CIP on the two adsorbents. The pH influence study indicated that CIP is adsorbed at pH between 6 and 8, which facilitates the use of BCP and BSP in wastewater treatment, whose pH generally oscillates between these ranges.