Effective Photocatalytic Disinfection of E. coli K-12 Using AgBr−Ag−Bi₂WO₆ Nanojunction System Irradiated by Visible Light: The Role of Diffusing Hydroxyl Radicals

Abstract

Urgent development of effective and low-cost disinfecting technologies is needed to address the problems caused by an outbreak of harmful microorganisms. In this work, we report an effective photocatalytic disinfection of E. coli K-12 by using a AgBr-Ag-Bi(2)WO(6) nanojunction system as a catalyst under visible light (lambda >or= 400 nm) irradiation. The visible-light-driven (VLD) AgBr-Ag-Bi(2)WO(6) nanojunction could completely inactivate 5 x 10(7) cfu mL(-1) E. coli K-12 within 15 min, which was superior to other VLD photocatalysts such as Bi(2)WO(6) superstructure, Ag-Bi(2)WO(6) and AgBr-Ag-TiO(2) composite. Moreover, the photochemical mechanism of bactericidal action for the AgBr-Ag-Bi(2)WO(6) nanojunction was investigated by using different scavengers. It was found that the diffusing hydroxyl radicals generated both by the oxidative pathway and the reductive pathway play an important role in the photocatalytic disinfection. Moreover, direct contact between the AgBr-Ag-Bi(2)WO(6) nanojunction and bacterial cells was not necessary for the photocatalytic disinfection of E. coli K-12. Finally, the photocatalytic destruction of the bacterial cells was directly observed by TEM images and further confirmed by the determination of potassium ion (K(+)) leakage from the killed bacteria. This work provides a potential effective VLD photocatalyst to disinfect the bacterial cells, even to destruct the biofilm that can provide shelter and substratum for microorganisms and resist to disinfection.

Advanced Oxidation Kinetics and Mechanism of Preservative Propylparaben Degradation in Aqueous Suspension of TiO2 and Risk Assessment of Its Degradation Products

“…Therefore, the photocatalytic degradation kinetics of PPB with or without specific scavengers (Table S2) 43 and MeCN was used to rule out the participation of HO • . 44,45 The degradation kinetics is depicted in Figure 4, and the variation of pseudo-first-order rate constants under different conditions is also summarized in 15,47 Overall, oxidative species, in particular HO…”

Z‐Scheme Photocatalytic Systems for Promoting Photocatalytic Performance: Recent Progress and Future Challenges

“…Many works studied different connection modes of Z‐scheme photocatalytic systems 13, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, …”

Enhanced Photo-induced Charge Separation and Simulated Solar Photocatalytic Activity of α-Fe2O3/BiOCl Prepared In-situ

“…As shown in Figure 5, the SPS response of heterojuctions gradually increases as the loading of α-Fe 2 O 3 increasing, and reaches the maximum when the molar ratio of Fe/Bi is 1/3, then drops dramatically at 2/3. According to the SPS principle (25,26), the strong SPS response corresponds to the high separation rate of photoinduced charge, thus, it is clear that the 1/3 sample has the highest charge separation rate among the experimented compositions, while 2/3 has the lowest charge separation rate. Among all the factors that affect the photocatalytic activity, the number of photo-generated charge carriers plays an important role in influencing the photocatalytic activity: the higher the number of carriers, the better the photocatalyst (27).…”