Fabrication of polyaniline based calcium ferrite nanocomposite and its application in sequestration of Victoria blue dye from wastewater

Abstract

Fabrication of a novel nanocomposite named calcium ferrite/polyaniline (CaFe2O4-PANI) was reported and its potential for adsorption of toxic cationic dye named Victoria blue (VB) was studied in this work. The CaFe2O4-PANI has showcased improved adsorptive potential for VB dye with approximately 95.35 (±1.48)% of removal efficiency at solution pH 8.0, CaFe2O4-PANI dose of 0.5 g/L, contact time of 20 min and initial VB dye concentration of 50 mg/L. The adsorption process follows pseudo-second-order kinetic model and Freundlich isotherm model with a maximum uptake capacity of 266.67 mg/g. The adsorbent was also tested against surface and ground water sample loaded with VB dye and in presence of several ions. It was found that surface water has caused less interference (∼2 (±0.85)% reduction in VB dye removal efficiency) followed by ground water (∼4 (±0.91)% reduction) and wastewater (∼8 (±1.24)% reduction) and also the removal efficiencies are affected the most by bicarbonate ions (∼12 (±1.39)%–14 (±1.62)% reduction in VB dye removal efficiency). The experimental process was optimized utilizing a five level, three factor based response surface methodology (RSM) approach and the experimental parameters were optimized to CaFe2O4-PANI dosage = 0.5 g/L, contact time = 65 min and initial VB dye conc. = 60 mg/L, using the developed quadratic model to achieve a maximum VB removal efficiency of 98.63 (±2.13)%. Regeneration study suggests that the fabricated adsorbent can be reused up to five cycles with ∼10 (±1.13)% decrease in the VB dye removal efficiency.