Synthesis of paraphenylenediamine covalent organic polymer and its application for removal of cationic and anionic organic pollutants from aqueous solutions ad industrial wastes

Abstract

In this study, a paraphenylene diamine-organic polymer adsorbent was synthesized for removal of the cationic and anionic organic pollutants. Adsorbent was characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (FE-SEM), energy diffraction X-ray spectroscopy (EDX-mapping) and BET analysis. Methylene blue and methyl orange were selected as cationic and anionic organic pollutant model. Then the effect of factors such as pH, initial concentration, amount of adsorbent, temperature, contact time and presence of electrolyte on the adsorption efficiency was investigated. The optimum conditions for removal of methylene blue were 0.01 g of adsorbent, pH 7, temperature 25 ° C and contact time of 5 min. For removal of methyl orange the optimum conditions were 0.01 g of adsorbent, pH 4, temperature 25 ° C and contact time of 5 min. According to the obtained data, Freundlich isotherm was consistent with both methylene blue and methylene orange adsorption data. The maximum experimental adsorption capacity was 48.1 mg.g-1 for methylene blue and 38.6 mg.g-1 for methyl orange, respectively. Also, the adsorption data for both dyes were consistent with the second-order kinetic model. Simultaneous removal of two dyes using adsorbent with removal efficiency of more than 99% was successful. The adsorbent was successfully applied for removal of the selected dyes from real industrial wastewaters.

Keywords

• covalent organic polymer
• adsorption
• industrial wastewater
• methylene blue
• methyl orange