An efficient multi-functional ternary reusable nanocomposite based on chitosan@TiO2@Ag NP immobilized on cellulosic fiber as a support substrate for wastewater treatment

Abstract

To effectively remove heavy metals, organic contaminants, and pathogenic bacteria from wastewater, an efficient multi-functional ternary nanocomposite based on chitosan (CS), titanium dioxide (TiO₂ NP), and silver nanoparticles (Ag NP) was prepared. Different tools were used to confirm the successful synthesis of the CS/TiO₂ NP/Ag NP nanocomposite. Then, the CS/TiO₂ NP/Ag NPnanocomposite was immobilized on the cellulosic fiber as a support substrate for its easy removal and reuse. On a lab scale, CS/TiO₂ NP/Ag NP nanocomposite@cellulosic fiber was used to remove Cu (II) ions, methyl orange (MO), and methylene blue (MB), as well as inhibit microbes. The results demonstrate that the greatest removal of Cu (II) ions was 95 % at a concentration of 50 mg/L, pH 5, a temperature of 25 °C, an agitation speed of 200 rpm with 1 g adsorbent dose, and a contact time of 150 min. The pseudo-second-order model explained the batch adsorption kinetics well, while the Langmuir model explained the adsorption isotherm well with an adsorption capacity of 7.71 mg/g. Adsorption thermodynamic parameters revealed that adsorption is a spontaneous, exothermic, increased randomness, and non-specific chemisorption approach. The photodegradation of MO and MB by CS/TiO₂ NP/Ag NP nanocomposite@cellulosic fiber was investigated. The results reveal that at pH 3, the MO dye showed the highest photodegradation percentage (90 %), while the MB dye displayed the highest photodegradation percentage (94 %) at pH 11, after an irradiation time of 120 min under visible light. The rate constants for MO and MB were 0.01218 and 0.01412 min^-1, respectively. The results antimicrobial activities showed that the CS/TiO₂ NP/Ag NP nanocomposite@cellulosic fiber showed excellent antibacterial activity against S. aureus (95 ± 2 %) and E. coli (93 ± 3 %) as well as good antifungal activity against C. albicans (77 ± 2 %).

Keywords: Ag NP; Bacteriological activity; Cellulosic fibers; Chitosan; Dyes; El -rahawy drain; Heavy metals; Nanocomposite; TiO(2) NP; Wastewater.