Search

This experimental research comparatively investigates the Escherichia coli (E. coli) bacterial inactivation of the TiO2 photocatalytic thin films fabricated by the sol–gel dip-coating (SG) and low-temperature spray-coating (SP) techniques, with low-intensity (12 μW·cm−2) UVA-light-emitting diodes (UVA-LED) as the light source. The bacteriostatic experiments were undertaken using the nutrient broth (NB) and 0.85% NaCl with the initial E. coli concentrations of 102, 104, 106, and 108 CFU·mL−1. Moreover, the essential physical characteristics of the SG-TiO2 and SP-TiO2 photocatalytic thin films were determined prior to the experimental bacterial inactivation. The findings showed that both photocatalytic thin films possessed the ideal physical characteristics, especially the SP-TiO2 thin film. In addition, the viable cell counts, the cell morphology, and the bioluminescence-based adenosine triphosphate (ATP) indicated that both SG-TiO2 and SP-TiO2 thin films under UVA could effectively inhibit the proliferation of the E. coli cells in both NB and 0.85% NaCl. [ABSTRACT FROM AUTHOR]

Purpose: Fired bricks are an essential construction material in Thailand where the majority of fired brick kilns use rice husk as feedstock. Given the increasing demand of rice husk from other industries, alternative feedstocks are needed for future fired brick production. This life cycle assessment (LCA) study investigates the environmental burden of Thai brick production using different biomass types. Methods: Three biomass fuels for fired brick production were compared: cane leaves, rice straw, and rice husk. Both the attributional and consequential modeling approaches were applied. Separated inventories were compiled using different databases: ecoinvent v. 3 and the Thai National Life Cycle Inventory (TH-LCI). Overall, this study includes a total of nine scenarios, for which characterized results were calculated using the Stepwise method. Differences in biomass scenario, modeling approach, and database used were tested via analysis of variance using four distinct fired brick production plants as replications. Results and discussion: Overall, using cane leaves and rice straw gives lower impacts than using rice husk. The largest burden for cane leaves and rice straw scenarios comes from the burning process, while using electricity and using fertilizers for rice cultivation were the most contributors for rice husk scenario. However, different modeling approaches yield mostly significantly different results and the consequential results were lower than the attributional ones. Regarding database choice in attributional modeling approach, results were lower when using TH-LCI compared with ecoinvent. Conclusions: Using cane leaves and rice straw as fuels in fired brick production are better scenarios than using rice husk. Nevertheless, factors related to season, size, and collection effort should be considered in the large-scale use of these biomasses. For database choice, ecoinvent is currently recommended over TH-LCI despite the higher geographical representativeness of the latter. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO2) and ferric-doped TiO2 (Fe-TiO2) thin films were synthesized on the surface of 304 stainless steel sheets using a simplified sol-gel preparation method. The Fe-TiO2 thin films were prepared with weight-to- volume ratios of Fe3+/TiO2 of 0.3%, 0.5%, and 0.7%, respectively. The crystalline phase structures of the prepared TiO2 and Fe- TiO2 thin films were entirely anatase. The measured optical band gaps of the TiO2, 0.3% Fe-TiO2, 0.5% Fe-TiO2, and 0.7% Fe-TiO2 thin films were 3.27, 3.28, 3.22, and 2.82 eV, respectively. The grain sizes and other physical properties of the prepared thin films were also reported. The kinetics of the photocatalytic processes under a UV-LED light source could be explained by the Langmuir- Hinshelwood kinetic model with the specific rates of 2.00 x 10-3, 4.00 x 10-3, 5.00 x 10-3, and 7.00 x 10-3min-1 mW-1, for TiO2, 0.3% Fe-TiO2, 0.5% Fe-TiO2, and 0.7% Fe-TiO2, respectively. An increase in Fe3+ dopant concentration could enhance the photocatalytic activity of toluene decomposition as a result of lower optical band gaps, smaller grain size, and higher surface area. [ABSTRACT FROM AUTHOR]