Synthesis of Mussel-Inspired Polydopamine Mediated with Ionic Liquid Hybrid Nanomaterial as an Efficient and Sustainable Adsorbent for the Selective Removal of Anionic Dyes and Nutrients from Aqueous Solutions

  • Rawan Mohammad Abu Alwan

Student thesis: Master's Thesis

Abstract

In this work, Polydopamine-Ionic Liquid (PDA-IL) adsorbent was synthesized by a facile oxidative polymerization method and used as an efficient adsorbent for the removal of anionic dye (Alizarin Red S, ARS) and anionic nutrient (phosphate) from aqueous solutions. Characterizations of the synthesized PDA-IL particles were performed using multiple techniques such as SEM, EDX, TEM, FTIR, Raman, TGA, Zeta potential, and XRD. Moreover, the effects of initial pH of the solution, initial concentration, contact time, adsorbent dose and temperature on the removal of ARS using PDA-IL were investigated. Results showed that the maximum adsorption capacity at 25 °C could reach up to 234.19 mg/g for ARS removal and 93.08 mg/g for phosphate. Additionally, analysis of adsorption kinetics showed that the adsorption behavior followed the pseudo-second-order kinetic model, which indicates that adsorption is governed by chemisorption. The equilibrium adsorption data for ARS removal was in agreement with the Freundlich isotherm indicating multilayer adsorption on heterogeneous surfaces. Thermodynamic analysis confirmed that the adsorption of ARS using PDA-IL was exothermic and spontaneous. Furthermore, regeneration studies confirmed that PDA-IL could be used for at least 4 adsorption-desorption cycles without any deterioration in its morphology or performance. A selectivity test was also conducted to investigate the adsorption behavior of PDA-IL in dye mixtures. Lastly, a thorough understanding of the possible adsorption mechanism was proposed based on the FTIR and EELS mapping results.
Date of AwardApr 2022
Original languageAmerican English

Keywords

  • Polydopamine
  • Ionic liquids
  • Dyes
  • Phosphates
  • Wastewater treatment.

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