Absorptive removal of Cu²⁺ and Pb²⁺ from aqueous solutions using xanthan gum‐g‐poly[(N,N′‐dimethylacrylamide)-co-(2-acrylamido-2-methylpropanesulfonic acid)]–ZnO nanocomposite gel

ABSTRACT

The present study reports the synthesis of xanthan gum-graft-poly[(N,N-dimethylacrylamide)-co-(2-acrylamido-2-methylpropanesulfonic acid)] in the form of a gel and its zinc oxide nanocomposite. The gel and the nanocomposite were made via microwave irradiation using potassium peroxodisulfate as initiator and diallylphthalate as the crosslinker and characterized using Fourier transform infrared (FTIR), thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FESEM)/energy dispersive X-ray spectroscopy (EDS) techniques. The reaction conditions for maximum grafting were optimized. The optimized products were used to evaluate the adsorption capacity toward Cu²⁺ and Pb²⁺ ions from aqueous solution. The effects of contact time, pH, and initial concentration of the absorbate solution on the adsorption capacity were evaluated. The adsorption kinetic and isotherm models were also studied. The results indicated maximum adsorption of 48.33 and 34.66 mg g⁻¹ of Cu²⁺ and 38.55 and 29.22 mg g⁻¹ of Pb²⁺ for the gel and composite, respectively. The adsorption data indicated that the adsorption of Cu²⁺ and Pb²⁺ on both adsorbents is best explained by Langmuir model with the exception of Cu²⁺ on the composite which is explained best by Freundlich model. The thermodynamics study indicated that the adsorptions of Cu²⁺ and Pb²⁺ are spontaneous and feasible.

KEYWORDS:

• 2-acrylamido-2-methyl-1-propanesulfonic acid
• N
• N-dimethylacrylamide
• xanthan gum
• ZnO
• composite
• Cu²⁺ and Pb²⁺ adsorption

Acknowledgements

One of the authors SAZ thanks the Government of India for providing the scholarship under the Indian Council for Cultural Relations (ICCR) and Usmanu Danfodiyo University Sokoto, Nigeria for the study leave.