Strategic design of advanced sustainable Quaternized poly(zirconyl dimethacrylate-co-vinyl imidazole) microsphere as a potential adsorbent for the mitigation of fluoride from aqueous solution

Abstract

The fabrication of novel functional metallo-polymeric microsphere, i.e., Quaternized poly(zirconyl dimethacrylate-co-vinyl imidazole) (Q-pZrVIm), with spherical geometry via suspension polymerization technique is reported herein. The prepared Q-pZrVIm microsphere exhibited excellent fluoride adsorption efficacy of 109.6 mg g−1 owing to high surface area (SA: 453 m2 g−1) and high anion exchange capacity (3.4 meq g−1) at given experimental condition such as dose: 0.250 g L−1, rpm: 150, contact time: 2 h, temp.:30 ± 2.0 °C, F−: 10 mg L−1 and pH:7.0 ± 0.2. The analytical instrumental techniques were used to characterize Q-pZrVIm. The impact of different variables such as effects of solution pH, initial fluoride concentration, adsorbent dose, coexisting anions, pHpzc, isotherm models and surface chemistry was studied to examine the performance of Q-pZrVIm towards fluoride efficacy. The adsorption followed Langmuir isotherm (R2 = 0.988), and PSO (R2 = 0.997) kinetic model. The spontaneous and endothermic process is revealed by thermodynamic values. The Q-pZrVIm delivers multiple benefits owing to its unique architecture of integrated metal moiety in a functional network i.e., (i). High removal efficiency (~97.9 %) over a wide pH range (2.0 ± 0.2 to 10 ± 0.2), with substantial efficiency at groundwater pH (6–8) (ii). High reusability (iii) Surface charge of 7.79 at 0.1 M NaCl solution represents its practical utility. Thus, due to multiple benefits, Q-pZrVIm microsphere displayed great prospective in water remediation as a potential adsorbent. Column test was performed using real groundwater having fluoride content and adsorption modelling for fixed bed column was studied using MATLAB 15.0 simulation with Pore diffusion model. Breakthrough time was calculated as 926 h for 25 cm bed depth column. The interactions between Q-pZrVIm and fluoride were studied with Density-Functional Theory (DFT) calculations.