Encapsulation of metal ions between the biopolymeric layer beads for tunable action on oil particles adsorption from oily wastewater

Abstract

In the present scenario, the challenging task of oil recovery is highly important owing to its increased rate of oil production. Biopolymers are excellent materials for the water treatment process. However, in the adsorption process, the powder form or raw flakes could not be used in column studies as it causes a significant pressure drop. To overcome the above challenge, the biopolymers have been modified into usable bead forms. In this work, the iron incorporated alginate/chitosan (Fe-Alg/CS) and iron incorporated gelatin/chitosan (Fe-Gel/CS) hybrid composite beads were successfully synthesized and were effectively utilized for the removal of oil from oil in water emulsion. The synthesized hybrid composite beads were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy dispersive analysis of X-ray (EDAX), powder X-ray diffraction (XRD), thermogravimetric analysis (TGA) and heat of combustion. Various influencing parameters viz., contact time, dose, pH of the emulsion, temperature and initial oil concentration were optimized for maximum oil removal capacity. The commonly used isotherms namely Freundlich, Langmuir, Tempkin, and D–R isotherms were used to check the suitability of the experimental data. The thermodynamic parameter results indicate that the oil adsorption was endothermic and spontaneous. The mechanism can be explained by different interactions such as surface complexation, electrostatic and hydrophobic interactions, which were adopted for the removal of oily particles at different pH levels. Thus, the experimental results presented herein indicate that the prepared hybrid composite beads can be utilized as the potential adsorbents for the removal of oil from oily wastewater.