Preparation And Release Performance Of Sepiolite-based Antibacterial Materials With Slow-release Of ClO₂ Gas

At present,due to the impact of the COVID-19,public environment sterilization and personal protection have attracted more and more attention.The currently available liquid disinfectants are suitable for sterilization and disinfection in a large range.There are few researches on antibacterial materials for sterilization and disinfection of individual or small areas.In this work,research on antibacterial materials in a small range is carried out.Using sepiolite from Xiangtan as a carrier,a class of solid slow-release materials that can slowly release ClO₂gas depending on environmental humidity were prepared to achieve the purpose of local bacteriostatic.On this basis,the influences of material formulation,modification conditions and ambient temperature and humidity on material release were investigated.It provides guidance for practical application and develops an economical and practical daily gaseous health care product.The experimental raw material in this paper is the purified sepiolite ore,the main agent is sodium chlorite-loaded sepiolite,respectively using HCl,Fe Cl₃and Al Cl₃modified sepiolite as acid activator,supplemented by hygroscopic agent,two kinds of chlorine dioxide sustained release materials were prepared.Fourier transform infrared spectroscopy（FTIR）,specific surface area analysis（BET）,scanning electron microscopy（SEM）,X-ray diffraction（XRD）and pyridine infrared（Py-IR）were used to analyze the characteristics and properties of the materials before and after modification,and the gas release amount of ClO₂was measured by UV-Vis spectrophotometer.The main research contents are as follows:Firstly,the hydrochloric acid-modified sepiolite was used as the material group of the acidifying agent,and the loading concentration and dosage of the main agent sodium chlorite,the dosage of the acidifying agent and the influence of the ambient temperature and humidity on the release of ClO₂were investigated.With the increase of sodium chlorate loading concentration or dosage,the ClO₂release showed a trend of first increase and then decrease,which was mainly related to the hygroscopicity of sodium chlorite.Finally,the formula of the sustained release material of mono-solid chlorine dioxide in this paper is determined as follows:the main agent is sodium chlorite loaded with sepiolite 4 g,hydrochloric acid activated sepiolite 7.5 g,and hygroscopic agent 3 g.The release period of this material formula can reach 17 d,and the total amount of ClO₂gas released is 3134μg.Further,using the metal salt-modified sepiolite as the acidifying agent,the effects of two different metal salts,different modification concentrations,and ambient temperature and humidity on the release of ClO₂were investigated and compared.It was found that with the increase of ion modification concentration,the release of chlorine dioxide showed a trend of first increase and then decrease.The analysis reason was related to the easy deliquescence of acidifier,and the greater the modification concentration,the greater the deliquescence of the material group.It was found that when the modified concentrations of Fe Cl₃-sepiolite and Al Cl₃-sepiolite were 25%and 15%,respectively,the best chlorine dioxide release effects were 13903μg and 12670μg,respectively.In this thesis,the sensitivity of the two types of materials to temperature and humidity were investigated separately,and it was found that the higher temperature and humidity were more favorable to the release of ClO₂.Among them,the ClO₂release cycle shortened with the increase of air humidity in the group of materials with metal salt-modified sepiolite as the acidifying agent.A comparison of the total amount,period and release rate of the two types of materials showed that the group with hydrochloric acid-modified sepiolite as the acidifying agent had a longer release period and lower total chlorine dioxide release;the group with metal salt-modified sepiolite as the acidifying agent had a shorter release period and higher total chlorine dioxide release.Finally,the modification mechanism of two different acidifiers and the generation mechanism of chlorine dioxide were analyzed.In addition,this paper also analyzes and discusses the reaction mechanism model and sterilization mechanism of slow-release chlorine dioxide.