Competitive Adsorption of Indole and Ortho-Phenylenediamine onto Commercial Ativated Carbon

Abstract

Ortho-phenylenediamine and Indole are two of such organic compounds that are highly malignant and have been reported as a threat to human health. Both of these organic compounds are prominent environment pollutants. Indole is a nitrogenous heterocyclic compound has the bicyclic structure and the formula C8H7N. It occurs naturally in human feces and has an intense fecal odor. It is commonly used in industries such as agrochemicals, pesticides, cosmetics. Ortho-phenylenediamine (OPD) is an endocrine disrupting chemicals, and are widely distributed in environment. OPD is an aromatic amine, used as a component of polymers, pesticides, drugs, and dyeing intermediate compounds. Various types of methods for their eradication from polluted water bodies have been reported in literature. In the present study, simultaneous adsorption of OPD (O) and Indole (I) onto low cost adsorbent such as commercial grade activated carbon (ACC) at various temperatures (303 K and 318 K) from O-I binary aqueous solution was performed. Further, the equilibrium adsorption data from the experiments were analyzed using various multicomponent competitive isotherm models isotherm models such as non-modified and extended Langmuir isotherm, extended Freundlich model, Sheindorf–Rebuhn–Sheintuch (SRS) model, and non-modified and modified competitive Redlich-Peterson isotherm model. In binary solution of O and I, it was observed that increasing the initial concentration of one of the adsorbate affects equilibrium adsorption uptake of another adsorbate from binary mixture. The extended Freundlich isotherm model and SRS models best represented the experimental data from binary adsorption of OPD and Indole at all the temperatures (303 K and 318 K) studied.