Application of polyurethane foam/zinc oxide nanocomposite for antibacterial activity, detection, and removal of basic dyes from wastewater

Abstract

In this paper, a new multifunctional nanocomposite was synthesized to combine both the advantages of sorption properties and antibacterial efficiency. The thiourea polyurethane/zinc oxide nanocomposite was prepared by coupling thiourea polyurethane foam and zinc oxide nanoparticles. The thiourea polyurethane/zinc oxide was characterized using several tools. The change in the surface chemistry of the thiourea polyurethane/zinc oxide nanocomposite (surface area was increased from 2.8 to 10.6 m2/g), due to the attached functional groups, increased its sorption properties. Also, the thiourea polyurethane/zinc oxide showed a crystalline phase, embedded inside the amorphous structure, with good thermal stability to 230 °C. The pore volume and radius of thiourea polyurethane/zinc oxide were 0.017 cm3/g and 3.4 nm with mesopores/micropores ratio of 11:1. It combines collecting pollutants on its surface, the ability to degrade these pollutants, and a good antibacterial effect. Thiourea polyurethane/zinc oxide was applied for the removing toluidine blue and brilliant green basic dyes from the wastewater. Several parameters such as pH, dye concentration, temperature, and time were studied. The removal percentages of brilliant green and toluidine blue dyes from the wastewater were 92.4–98.2% at pH 3–12. Also, the removing rate of the dyes was very fast (3–5 min) at 25 °C. The estimated capacities of new nanocomposite for toluidine blue and brilliant green were 92 and 227 mg/g. The removal process was spontaneous (ΔG was − 7.3 and − 8.6). As a result, the applicability of thiourea polyurethane/zinc oxide as an effective renewable antibacterial sorbent for removing cationic dyes was maintained.