Results in Engineering (Dec 2022)
Fabrication of charcoal-nickel (II)-poly(acrylic acid) nanocomposite hydrogels for photodegradation of rhodamine B under direct sunlight irradiation
Abstract
The fabricated hydrogels charcoal-nickel-poly(acrylic acid) (char-Ni-PAA) synthesized by a free-radical polymerization technique was used for rhodamine B dye degradation under direct sunlight irradiation. Different Ni ions compositions were characterized using ATR-FTIR, TGA, EDAX, and SEM techniques. The shift and intensity change of the peaks in the ATR-FTIR spectrum indicated the binding of Ni ions and charcoal onto PAA chains in the hydrogel. EDAX also showed the incorporation of Ni ions into the composites. TGA results revealed the higher thermal stability of the nanocomposite hydrogel. SEM images revealed porous network nanostructures in the composite hydrogels. Ni ions adhered with charcoal provide an environment with high electron mobility to degrade targeted dye molecules under sunlight irradiation. In addition, different surface functional groups of charcoal enhanced the dye adsorption capacity of the composite hydrogel. Charcoal-nickel-poly(acrylic acid) hydrogel containing 1 g Ni ions showed a maximum of 75.56% rhodamine B degradation under direct sunlight irradiation for 8 h in an open atmosphere at a neutral pH solution. The photocatalytic capability of dispersed Ni ions and enhanced dye adsorption capacity of charcoal improved the photodegradation activity of the fabricated char-Ni-PAA nanocomposite hydrogels. The synthesized hydrogels containing a higher amount of Ni ions also showed promising antibacterial activity towards two microorganisms, B. cereus, and P. aeruginosa, as gram-positive and gram-negative bacteria under visible light illumination. The higher photodegradation activity and antibacterial properties of the synthesized char-Ni-PAA nanocomposite hydrogels demonstrate their efficacy in the treatment of textile wastewater under direct sunlight irradiation.
