Fabrication and characterization of mesoporous guar gum/NiWO4 nanocomposite for efficient adsorption of phloxine B and crystal violet from aqueous solution and evaluation of its antioxidant activity

Abstract

Guar gum/nickel tungstate (GG/NiWO4) nanocomposite is prepared using simple and cost-effective sol-gel technique, while NiWO4 nanoparticles are formed by co-precipitation method. The nanocomposite is characterized by FTIR, XRD, BET, SEM-EDX and TEM techniques. The effectivity of GG/NiWO4 nanocomposite is investigated for the sequestration of phloxine B (PB) and crystal violet (CV) from wastewater. The effect of dose, agitation time, initial solution pH, and initial dyes concentration is appraised. The adsorption isotherm, kinetics and thermodynamic parameters are also studied. Langmuir isotherm and pseudo-second order models are best fitted to the equilibrium data. The thermodynamic parameters confirm that adsorption is spontaneous, exothermic and entropy-driven. An excellent desorption of PB and CV from the loaded adsorbent is acquired by utilizing either ethanol or acetone with a desorption ability in the range of 57.60%–91%. The antioxidant activities of synthesized nanocomposite are also studied.