Study on Dynamic Disinfection Model of Gas Chlorine Dioxide Space and Monitoring Technology of Disinfection Condition

In recent years, the prevalence of severe infectious diseases such as Ebola haemorrhagic fever, Middle East respiratory syndrome, and severe acute respiratory syndrome has received worldwide attention. The outbreak and spread of these potent infectious diseases pose a serious threat to human life and cause public health security risks. Space disinfection is an important measure to cut off the transmission of infectious diseases, prevent cross-infection and ensure the safety of personnel. Therefore, it is necessary to develop an efficient disinfection technique that can thoroughly disinfect the air and surface of the space. Compared with liquid disinfectants, gas disinfectants have the advantages of large processing area, strong penetrating ability and convenient operation, and are more suitable for space disinfection. Among them, gaseous chlorine dioxide has strong oxidizing properties, no carcinogenicity and teratogenicity, and has the advantages of rapid, high efficiency, safety and environmental protection. It is considered to be a new type of disinfecting gas with broad prospects. However, at present, the research on chlorine dioxide disinfection technology at home and abroad mainly focuses on the evaluation of application effects, but there are few studies on disinfection process, disinfection dynamics and disinfection mechanism. The influence of key factors on the disinfection effect of gaseous chlorine dioxide is still Unclear, this technology lacks the theoretical basis for predicting disinfection effect and designing effective disinfection conditions in practical applications. Therefore, it is necessary to establish a spatial disinfection kinetic model of gaseous chlorine dioxide, and based on this, in-depth study of the disinfection process of gaseous chlorine dioxide and the influence of key factors on the disinfection effect and mechanism of action. In addition, because key factors such as environmental humidity have a significant impact on disinfection efficiency, disinfection condition monitoring is also a key technology for gas chlorine dioxide disinfection. It is of great significance to solve the problem of monitoring disinfection conditions in gas chlorine dioxide disinfection environment. Based on the gas chlorine dioxide spatial disinfection experimental platform, this study established a gas chlorine dioxide spatial disinfection kinetic model and a response surface methodology for gas chlorine dioxide spatial disinfection multi-factor prediction model, and explored gas concentration, environmental humidity, disinfection The influence of time and other key factors on the disinfection process and the mechanism of action provide a theoretical basis for evaluating the disinfection effect and guiding the disinfection practice. In addition, based on tunable diode laser absorption spectroscopy (TDLAS) technology, the research on gas chlorine dioxide disinfection condition monitoring technology was carried out, and the disinfection environment temperature and humidity monitoring system based on TDLAS technology was established, which can realize the online and accurate disinfection environment temperature and humidity. Reliable monitoring provides technical support for the application and promotion of gas chlorine dioxide space disinfection technology and equipment. The research on the experimental platform and method of gas chlorine dioxide space disinfection was carried out. According to the requirements of the experimental research on the space disinfection of gaseous chlorine dioxide, a gas chlorine dioxide space disinfection experimental platform was established. The platform has good air tightness, which can realize the actual simulation of the space environment, online monitoring of disinfection conditions and disinfection gas. It continues to happen. A laboratory method for gas disinfection of chlorine dioxide was established, and representative indicator microorganisms were identified. The preparation method of biological indicator, the experimental procedure of space disinfection and the method of bacterial elution counting were clarified. The experimental platform and method research provides a standard space environment, ideal disinfection conditions, safe operation mode and standardized experimental methods for the gas chlorine dioxide space disinfection experiment. It is an important hardware foundation and technical guarantee for this research. Based on the gas chlorine dioxide space disinfection experimental platform, the kinetic model of gas chlorine dioxide spatial disinfection was studied. Firstly, the disinfection experiments of gaseous chlorine dioxide on Bacillus subtilis var. sp. (hereinafter referred to as Bacillus subtilis) and Staphylococcus aureus were carried out under different gas concentrations, and based on the first-order linear model and hom, Weibull, iq, etc. A nonlinear model was established to establish a disinfection kinetics model at different gas concentrations. The results show that the Weibull model has the advantages of simple formula, clear parameter meaning and high fitness compared with other models. The inactivation rate of gas chlorine dioxide on microorganisms increases with the increase of gas concentration; gas chlorine dioxide on spores and The inactivation of bacterial propagules is a non-linear process. The survival curve of spores is the shape of the shoulders. The inactivation rate is slower and faster, while the bacterial propagules are tail-shaped. The inactivation rate is fast and slow. Compared with the body, the spores have stronger resistance to gaseous chlorine dioxide, and the predicted sterilization time is longer than the sterilization assurance level. Then, the disinfection experiments of gaseous chlorine dioxide on black spores and Staphylococcus aureus were carried out under different relative humidity. Using the Weibull model as the benchmark model, the Weibull-h model with humidity coefficient was proposed, and the model was first fitted with the first-order linear model to fit the disinfection experiment results. The results show that the Weibull-h model has a higher degree of fit to the experimental data than the first-order linear model; the disinfection efficiency of gaseous chlorine dioxide to microorganisms also increases with the increase of relative humidity; the relative humidity vs. microbial inactivation rate The effect is non-linear, and the disinfection efficiency of gaseous chlorine dioxide is significantly improved in 70%-90% of high-humidity environment; compared with bacterial propagules, the promotion of spore inactivation in high-humidity environment is more obvious. On the basis of single factor experimental research, in order to study the interaction between multiple factors and predict the disinfection effect of gas chlorine dioxide under multi-factor interaction, the multi-factor prediction of gas chlorine dioxide spatial disinfection based on response surface methodology was carried out. Model research. Based on the box-behnken center combination experiment design, a multivariate quadratic regression prediction model with gas concentration, relative humidity and disinfection time as experimental factors was established. The results show that the prediction model has high fitness and prediction accuracy, and the coefficient r2 is 0.99. Increasing gas concentration, environmental humidity and disinfection time can effectively increase the inactivation rate of microorganisms, gas concentration and environmental humidity, and environmental humidity. There is a synergistic effect between the interactions with the disinfection time. The prediction model provides response surfaces and corresponding contour lines under different disinfection conditions, which can effectively predict the sterilization conditions that meet the sterilization assurance level under the combined action of multiple factors, and provide guidance and reference for the practical application of gas chlorine dioxide disinfection. In order to evaluate the disinfection effect of gas chlorine dioxide on typical biosafety equipment and the penetration ability of hepa filter, and further verify the practical application effect of disinfection kinetic model and multi-factor prediction model, the application of gas chlorine dioxide space disinfection was carried out. Research and model validation. A disinfection evaluation experiment was carried out on the biosafety cabinet and the high efficiency air filtration unit using a gas chlorine dioxide generation technology based on a binary solid preparation and a portable disinfection device. The results show that the gas chlorine dioxide can completely disinfect the biosafety cabinet and the high efficiency air filtration unit. The pressure diffusion or active circulation method can effectively pass the gas chlorine dioxide through the hepa filter and complete the downstream area of the filter. Thoroughly sterilized, and active circulation has faster penetration speed and higher sterilization efficiency than pressure diffusion. The prediction results of the two types of models are consistent with the actual disinfection results. The multi-factor prediction model has higher accuracy and wider application range than the disinfection kinetic model. Research on monitoring technology of gas chlorine dioxide disinfection conditions based on TDLAS technology was carried out. A disinfection environment temperature and humidity monitoring system was established. The monitoring system uses a tunable laser with a center wavelength of 1370 nm as a light source, develops an online monitoring chamber as a gas absorption tank, and uses a photodetector to collect an optical signal containing water and gas content information. The optical signal is sent to the receiving and processing system for post-processing, and the inversion calculation of the relative humidity of the disinfection environment is performed based on the first harmonic signal of the water-gas absorption line, and the temperature of the disinfection environment is monitored based on the digital temperature sensor of the side wall of the gas chamber. The monitoring system was calibrated and tested for performance. The results show that the temperature and humidity monitoring system based on TDLAS technology has good precision and can be applied to the gas chlorine dioxide disinfection environment under different conditions. It has better stability and corrosion resistance than the traditional electronic temperature and humidity sensor. Provides a new method for online, reliable and accurate monitoring of temperature and humidity in a gas chlorine dioxide disinfection environment or other corrosive environment. In summary, this study carried out the space disinfection experiment of gas chlorine dioxide under different conditions, based on the experimental data, established a variety of disinfection kinetic models and multi-factor prediction models, and completed the gas chlorine dioxide on typical bio-safety equipment. Based on the results of this experiment, the accuracy and practicability of the above two types of models were verified. In addition, a temperature and humidity monitoring system for disinfection environment based on TDLAS technology was established. Through the above research, the non-linear disinfection process of gas chlorine dioxide on spores and bacterial propagules and the disinfection kinetics behavior are revealed. The influence of various key factors and their interactions on the disinfection effect and the mechanism of action are clarified. Predictive disinfection conditions for bacteria assurance levels and online, reliable and accurate disinfection conditions monitoring techniques. This study clarifies the spatial disinfection kinetics of gaseous chlorine dioxide and provides theoretical basis and technical support for the application and promotion of gaseous chlorine dioxide space disinfection technology.