Antibacterial Inactivation of Escherichia coli after TiO2-Fe3O4-Bentonite Photocatalytic Treatment

Abstract

TiO 2-Fe 3 O 4-Bentonite photocatalytic material has been developed to inactivate of Escherichia coli. The syntheses of the TiO 2-Fe 3 O 4 based photocatalyst have been carried out by sol-gel method. The bentonite used for porous support was obtained from Pacitan, Indonesia. The photocatalyst material will capture energy of UV radiation followed by the electron excitation and oxidationreduction reactions. Because of the processes, the various types of pollutants and microorganisms can be decomposed and reduced. The electron excitation will induce the formation of hydroxyl radical and O 2. These radicals are responsible to decompose the cell wall of bacteria and further damage the bacteria's cytoplasmic membrane. Decomposing of cytoplasmic membrane causes lipid peroxidation in the membrane, and then losing their viability. It is followed by the death of bacterial cell. This study conducted a series of Escherichia coli inactivation by using photocatalyst material of TiO2-Fe 3 O 4-Bentonite which was irradiated with UV light. The photocatalytic inactivation of Escherichia coli was conducted in a reactor under ultraviolet (325 nm) exposing. The photocatalytic degradation was observed for 5 hours to determine the optimum initial bacteria concentration, intensity of UV light and also photocatalyst concentration. The inactivation kinetic was approached by Chick-Watson and Hom kinetic models. The colonies calculations were conducted by Total Plate Count. The optimum condition was achieved for 300 minutes process to reach 7 bacterial log reduction units for an average bacterial inoculum size of 3.8 × 10 4 CFU/ml. All disinfection experiments showed a non-linear bacterial inactivation kinetic profile, which is started with shoulder lag followed by a log reduction and the tailing curve. The inactivation kinetics of Escherichia coli using TiO 2-Fe 3 O 4-Bentonite photocatalytic material system satisfactorily obeyed the Hom kinetic model.

Application of Photocatalyst Material Bentonite Ti Based as Antimicrobial Paint

“…However, various problems tend to arise that need further treatment during the degradation process. This study is, therefore, a continuation of our initial report [32] and also the preliminary study on coatings formulated using TiO 2 -Fe 3 O 4bentonite to fight against microbial. This paper aims to emphasize on the application of TiO 2 -Fe 3 O 4 -bentonite in the water purification process by adding material into the paint and coating it on ceramic containers as a reactor to help neutralize E. coli and S. Aureus.…”

“…A. Photocatalyst Characterization XRD characterization of photocatalysts has also been described in substantial details [31], [32]. The main peak on 2θ = 30.3° and 35,7 o refer to the crystal of the magnetite phase, and these were supported by 2θ = 30.…”

“…TiO 2 -Fe 3 O 4 -bentonite has been prepared according to the method described in our previous work [31], [32]. PANalytical PW 3373/00 X'Pert X-ray was used to observe the crystalline phase of the photocatalyst material (CuKα, 1.54 Å, radiation at 30 mA and 40 kV applied).…”

Synthesis and application of g-C3N4/Fe3O4/Ag nanocomposite for the efficient photocatalytic inactivation of Escherichia coli and Bacillus subtilis bacteria in aqueous solutions

“…Given on-going growing population and climate change phenomena, provision of high quality and clean water from reused aqueous sources remains a great challenge (Widi et al 2018 ). This highlights the importance of water purification with regard to chemical and microbial contamination (Rojviroon and Sirivithayapakorn, 2018 ; Feilizadeh et al 2015 ).…”

“…Recently, the development of new technologies for the treatment of pathogens in aquatic environments has dramatically increased (Widi et al 2018 ). Until now, various methods such as chlorination, UV and ozone have been used to disinfect and remove pathogens (Ouyang et al 2016 ).…”