Treatment of Oil Spill by Adsorption onto Activated Rice Husk and E-Waste

Abstract

A tremendous rise in off-shore oil production, transportation of petrochemicals, and regular oil spillage contribute to environmental problems in the marine environment. Adsorption is one of the effective methods that are used to remediate oil spill. One of the potential adsorbents is rice husk. In this project, rice husk is used as an adsorbent and is activated with stearic acid. Also, the activated non-metallic fraction of e-waste acts as a suitable additive that could increase the adsorption. The adsorbents’ preparation processes were optimized as the time of pyrolysis, Pyrolysis temperature, and concentration of stearic acid (SA) is optimized for maximum oil adsorption. Also, their morphology and composition are studied using FTIR, SEM, EDS, and BET Analysis and using the data of oil adsorbed, various isotherms such as Freundlich, Langmuir, and Redlich Peterson isotherms are plotted, which could be used to find the model that suits this adsorption data. It was found that when activated e-waste was mixed with Activated Rice Husk in the ratio 1:10, it adsorbs 50% of the oil present in a 50 ml oil-water mixture. The equilibrium adsorption data of oil on the adsorbent mixture were analyzed by Langmuir, Freundlich, and Redlich - Peterson isotherm models. The isotherm that fits the experimental data the best is the Freundlich isotherm model. The monolayer adsorption capacity (q_max) was 428 mg/g. Pseudo-first-order, pseudo-second-order, and intra particle diffusion models were used to evaluate the kinetic data. The model that fits the experimental data the best is Pseudo-first-order kinetic model. Thus, the adsorbent mixture has the potential to remove oil in marine environment as both of the adsorbents used are discarded mainly as waste, there is an addition of value as these "waste" products could be utilized to combat one of the most convoluted problems of this modern era.