Removal of ibuprofen from water using recycled clay waste

Abstract

This work presents studies on the regeneration of spent bleaching earth (SBE) from edible oil refinery and the use of recycled material (RSBE) in the treatment of water containing ibuprofen. This waste is bentonite (clay) that is activated by sulfuric acid at hot and used to bleach edible oils. The regeneration method used in this study was thermal treatment of clay waste (SBE) in a furnace at 400 °C for 1 h, followed by cold washing with 1 M hydrochloric acid solution. Recycled material (RSBE) is characterized by a variety of techniques (X-ray diffraction, FTIR and fundamental methods). The characterization results showed that the bentonite structure was not affected by the heat treatment and that the treatment only resulted in the disappearance of organic compounds from the spent bleaching earth. Subsequently, regenerated spent clay (RSBE) was tested for the removal of ibuprofen from aqueous solutions by adsorption to estimate the efficiency of the regeneration method used in this study. The effects of physicochemical parameters on the ibuprofen adsorption by regenerated spent bleaching earth and virgin bleaching earth (VBE) were focused. The obtained results indicated that ibuprofen was rapidly adsorbed onto both materials. The amount of ibuprofen adsorbed on the both adsorbents increased with the increase of the initial solute concentration. The pH value of the solution plays a very important role in the ibuprofen adsorption by the recycled waste (RSBE). The elimination of ibuprofen is maximized in an acidic environment. Kinetic modeling showed that the second-order kinetic pseudo-model could well describe the adsorption process. The adsorption isotherms followed the Langmuir and Freundlich model. Calculation of q_max and 1/n with these two isotherms indicated that the recycled material had found its adsorption capacity and could be used as an inexpensive sorbent for the removal of ibuprofen.