RESUMO
The food hygiene problems caused by bacterial biofilms in food processing equipment are directly related to human life safety and health. Therefore, it is of great strategic significance to study new food sterilization technology. An acidic electrolyzed water (AEW) disinfectant is an electrochemical sterilization technology which has the characteristics of wide adaptability, high efficiency, and environmental friendliness. However, since the sterilization efficiency of AEW for biofilms is not ideal, it is necessary to increase the available chlorine content (ACC) in AEW. A feasible method to increase the ACC is by increasing the chlorine evolution reaction (CER) selectivity of the electrode for AEW preparation. In this paper, the RuO2@TiO2 electrode was prepared by thermal decomposition combined with high-vacuum magnetron sputtering. Compared with the oxygen evolution reaction (OER) activity of an ordinary RuO2 electrode, the OER activity of the RuO2@TiO2 electrode is significantly reduced. However, the CER activity of the RuO2@TiO2 electrode is close to the OER activity of RuO2. The CER mechanism of the RuO2@TiO2 electrode is the second electron transfer, and the OER mechanism is the formation and transformation of OHads. The potential difference between the CER and OER of the RuO2@TiO2 electrode is 174 mV, which is 65 mV higher than that of the RuO2 electrode, so the selectivity of the CER of the RuO2@TiO2 electrode is remarkably improved. During the preparation of AEW, the ACC obtained with the RuO2@TiO2 electrode is 1.7 times that obtained with the RuO2 electrode. In the sterilization experiments on Escherichia coli and Bacillus subtilis biofilms, the logarithmic killing values of AEW prepared the by RuO2@TiO2 electrode are higher than those of AEW prepared by the RuO2 electrode.
RESUMO
RuCo-ANFs with different proportions can be successfully prepared by magnetron sputtering, and their lattice constants can be adjusted accurately. In the RuCo-ANF, there is an obvious electronic interaction between Ru and Co, thus adjusting the ΔGH* on its surface. There is a volcanic relationship between the HER activity and the lattice constant of RuCo-ANF.
RESUMO
Food-borne diseases are widespread all over the world, and food safety has attracted much attention. This study is the first to use plasma to activate acidic electrolyzed water (AEW) to obtain a new disinfectant for food processing. The germicidal efficacy of plasma-activated acidic electrolyzed water (PA-AEW) on B. subtilis suspension and biofilm was investigated. Furthermore, the synergistic effect of different bactericidal factors was inferred by investigating the physicochemical parameters of PA-AEW and the influencing factors of bactericidal effect. The results demonstrate that PA-AEW is a highly effective and rapid disinfectant. The killing logarithm (KL) value of PA-AEW on B. subtilis suspension could reach 2.33 log10CFU/mL with a sterilization time of 10 s, which is significantly higher than that of AEW (KL = 0.58 log10CFU/mL) and plasma-activated water (PAW) (KL = 0.98 log10CFU/mL) (significant difference, p < 0.01). Moreover, the KL value of the B. subtilis biofilm of PA-AEW was 2.41 log10CFU/mL, better than that of PAW and AEW (significant difference, p < 0.01), indicating that PA-AEW has important application prospects in food processing. The synergistic effect should come from the interaction between reactive chlorine species (RCS) and reactive oxygen and nitrogen species (RONS) in PA-AEW.