Dissertation (MSc Chemistry)The purpose of this study was to scrutinize the synergetic effects of the applied calcination temperature and holding time on the synthesis, characterization and photocatalytic antimicrobial applications of the developed polysaccharides based TiO2/Fe3O4 nanocomposite materials. Polysaccharide/TiO2/Fe3O4 nanocomposite materials were synthesized through modified sol-gel process using Titanium (IV) butoxide as precursor and Iron (II, III) oxide nanopowder as a support. The developed composite materials at 80 °C were calcined at 473 K, 673 K and 873 K. Their spectral, structural and thermal stability features were characterized. FTIR confirmed the formation of the nanocomposite material witnessed by the change in bond frequencies in the nanocomposite materials in reference to their control samples i.e. Chitosan and Guar gum. TGA indicated high thermal stability of the nanocomposite materials. XRD demonstrated that TiO2 and Fe3O4 nano powder dispersed homogeneously within the sol mixture of Chitosan and Guar gum matrices; hence coating took place. Nevertheless XRD proved the presence of both rutile and anatase phase of TiO2. Moreover, the antimicrobial activities were evaluated by using E coli (-) bacteria against Chitosan/TiO2/Fe3O4 and S aureus (+) bacteria against Guar-gum/TiO2/Fe3O4 NCMs. Both the two NCMs exhibited superior photocatalytic antimicrobial activity under UV irradiation for 2 hour. Chitosan/TiO2/Fe3O4 NCMs at B1 (353 K), B2 (473 K), B3 (673 K) and B4 (873 K) in the ratio of (200 mg/3 mL/50 mg) exhibited superior antimicrobial PCA activity of about B1 (75 %), B2 (78 %), B3 (80 %) and B4 (85 %) against Gram negative bacteria (E.coli) respectively. Also Guar-gum/TiO2 /Fe3O4 NCMs at A1 (353 K), A2 (473 K), A3(673 K) and A4 (873 K) in the ratio of (200 mg/3 mL/50 mg) exhibited the superior antimicrobial photocatalytic activity of about A1 (80 %), A2 (85 %), A3 (87 %) and A4 (90 %) in the ratio of (200 mg/3 mL/50 mg) against Gram positive bacteria (S.aureus) respectively. Moreover the sol-gel prepared TiO2 nano powder at 353 K and annealed at 673 K indicated highest antimicrobial activity of about 90 % and Chitosan/TiO2/Fe3O4 in the ratio of (200 mg/3 mL/50 mg) annealed at 400 °C exhibited approximately 45 % antimicrobial PCA against (S.aureus). Furthermore, the Guar-gum/TiO2/Fe3O4 nanocomposite materials (200 mg/1.5 mL/50 mg) annealed at 200 °C indicated less PCAA against (S.aureus). As the applied calcination temperature and holding time increased the photocatalytic antimicrobial activity increased respectively