Green synthesis of TiO2 NPs/pristine pomegranate peel extract nanocomposite and its antimicrobial activity for water disinfection

The development of green chemistry that minimize environmental impact is currently one of the major challenges in green synthesis of nanoparticles. In this study pristine pomegranate peel extract (PPP) was used for green synthesis of titanium dioxide nanoparticles (TiO2 NPs) and formation of a nanocomposite (PPP-TiO2). The synthesized nanocomposite were characterized via Scanning Electron Microscope (SEM), Dynamic Light Scattering (DLS), X-ray Powder Diffraction (XRD), and zeta potential (zeta-potential). The DLS results clearly show that TiO2 NPs has peak intensity of 100% with Z-average value of 620 nm, and PDI = 0.178 which affirm the monodisperisty and homogeneity of the synthesized TiO2 NPs. While the DLS result of PPP-TiO2 shows, a bimodal distribution peaks, confirming the presence of both TiO2 and PPP in the composite. The mean value of the hydrodynamic diameter (Z-average) of PPP-TiO2 was found to be 1230 nm with peak intensity of 87.5%. The values of zeta-potential indorsing the higher stability of PPP-TiO2 NPs (-11.4 mV) relative to TiO2 NPs (-6.96 mV). The biological activity has been evaluated by well diffusion method, Microbial Inhibition Concentration (MIC), Minimum Bactericidal Concentration (MBC) and live/dead cell assay against Gram-positive than Gram-negative strains. The results shows that the antimicrobial activity of PPP-TiO2 was 1.5 times higher than PPP and TiO2 NPs for same pathogenic bacteria. In addition, the results showed the Diameter Inhibition Zone (DIZ) had maximum inhibition against S.aureus than E-coli and P.aeruginosa. Furthermore, Biological Oxygen Demand (BOD5) was used to indicate the microbial communities and organic matter in the real water samples. The results explored a Lower BOD5 values for samples containing PPP-TiO2 compared to TiO2 NPs.