Study On Air Purification Of Mixture Of Photocatalyst And Traditional Chinese Medicine

According to the World Health Organization（WHO）about the air quality guide report,indoor air pollutants include gaseous organic and inorganic chemical pollutants and particulate matter,among which formaldehyde,benzene,toluene and various microorganisms are the most common indoor air pollutants.Toxicology studies show that gaseous organic pollutants enter the human body mainly through the respiratory tract and skin,resulting in abnormal functions of the human respiratory system,nervous system,reproductive system and immune system.Therefore,a pure and fresh,neat and wholesome indoor environment is particularly important.There are many kinds of existing air purification products,such as activated carbon and chemical aldehydes（sodium perborate,hypochlorous acid,hydrogen peroxide,etc.）,which have problems such as regular replacement and secondary pollution.As a new environmental protection technology,photocatalyst technology can effectively decompose harmful gases;the traditional Chinese herbal medicine has significant antibacterial and antiviral effects.Therefore,this topic selects Chinese herbal extracts and nano-titanium dioxide to prepare Aiqi air purifier,which utilizes Chinese herbal medicine antibacterial,anti-viral and absorption decomposition of formaldehyde,benzene and other harmful gases and nano-titanium dioxide to completely decompose harmful gases into stable and non-toxic substances such as carbon dioxide and water.The role of the preparation of the Aiqi air purifier,in order to achieve the purpose of effectively removing indoor harmful gases and inhibiting the growth of bacterial viruses.Study on the extraction process of Chinese herbal medicines:（1）Determination of the ratio of herbs.According to the literature research,this paper selects five kinds of medicinal materials of Cassia,Radix,Houttuynia,Artemisia,and Chrysanthemum as raw materials,and uses ethanol as solvent to prepare traditional Chinese medicine extract by reflux method.Taking the dosage of five kinds of medicinal materials as the factors,four factors were designed for each factor.The formaldehyde degradation rate of the five medicinal materials extracts was investigated.Five-factor four-level orthogonal experiment was designed.The results showed that the optimal ratio of medicinal materials screening was Banlangen:Houttuynia:Cassia:Ai Ye:Chrysanthemum=4:4:2:4:3.（2）optimization of the extraction process.Taking the extraction time,the ratio of material to liquid and the concentration of ethanol as the factors,three factors were designed for each factor.The formaldehyde degradation rate of the five medicinal materials extracts was used to investigate the three-factor and three-level orthogonal experiments.The results showed that the optimal extraction was obtained.The extraction time was 6 h,the ratio of material to liquid was 1:6,and the solvent was 80%ethanol.The traditional Chinese medicine extract prepared by the optimal extraction process is filtered,concentrated under reduced pressure into a paste,freeze-dried for 24 h,and the freeze-dried traditional Chinese medicine extract is ground into a powder for use.Study on the elimination performance of formaldehyde by photocatalyst and traditional Chinese medicine composition:simulate indoor formaldehyde environment in air chamber,and add photocatalyst and traditional Chinese medicine composition with different ratios.Photocatalyst and traditional Chinese medicine composition are prepared from Chinese herbal extract powder and nano-TiO₂ in distilled water as solvent.According to the composition and dosage of the prepared photocatalyst and traditional Chinese medicine composition,it is divided into TiO₂ group:25 mg/mL,50 mg/mL,100 mg/mL;Chinese herbal extract group:37.5 mg/mL,75 mg/mL,150 mg/mL;and mixture group（TiO₂:extract=2:3）:62.5 mg/mL,125 mg/mL,250 mg/mL.Formaldehyde samples were collected at 0 h,1 h,2 h,3 h,4 h,5 h,6 h,7 h,8 h,9 h,10 h,11 h,and 12 h after the addition of the composition.The content of formaldehyde was determined by acetylacetone spectrophotometry.The results showed that at 12 h,the degradation rates of formaldehyde in low,medium and high doses of Chinese herbal extracts were 10.47%,21.79%and 27.78%,respectively.Photocatalyst TiO₂ low,medium and high dose groups The degradation rates of formaldehyde were 25.85%,34.73%and 43.20%,respectively.The degradation rates of formaldehyde in low,medium and high doses of TiO₂ and Chinese herbal extracts were 45.40%,49.80%and 62.90%,respectively.The comparison results of the data of each group showed that the photocatalyst and the traditional Chinese medicine composition prepared by mixing the Chinese herbal medicine extract with the photocatalyst material TiO₂ had the best degradation effect on formaldehyde.The degradation rate of formaldehyde in the low,medium and high dose groups was compared.The results showed that the degradation of formaldehyde by the composition was dose dependent.In summary,the high-dose group（250 mg/mL）photocatalyst and traditional Chinese medicine composition of TiO₂ and Chinese herbal extracts mixed in a ratio of 2:3 had the best degradation effect on formaldehyde.Study on the elimination performance of benzene series by photocatalyst and traditional Chinese medicine composition:to investigate the degradation on benzene and toluene by the joint effect of Chinese herbal medicine extract and TiO₂.Activated carbon sampling tube is used for sampling,carbon disulfide as analytical solution and ethyl acetate as internal standard for quantitative analysis,then the analysis is made by chromatography.The injector temperature is at 200℃;the split ratio:33.3:1;Chromatographic column:DB-WAX capillary column（60 m*0.53 mm*1.0μm）;N₂ as the carrier gas;FID Detector with the temperature of 250℃;initial temperature 50℃for 5 minutes;heating at the rate of 3℃/min to 100℃for 4 minutes;sample size:2μL.The result at 12h shows that the degradation rates of benzene and toluene in the high-dose alcohol extract group are 21.02%and 20.21%,respectively;that in the high-dose TiO₂ group are 54.43%and 60.46%,respectively;and that in the high-dose mixture group are63.59%and 74.36%,respectively.The high-dose mixture group has the best degradation effect on benzene and toluene,indicating that the mixture of alcohol extract of Chinese herbal medicine and TiO₂ has a synergistic effect on the degradation of benzene and toluene.Study on antibacterial properties of photocatalyst and traditional Chinese medicine composition:The minimal inhibitory concentrations（MIC）of TiO_2,Chinese herbal medicine alcohol extract and their mixture were studied by agar diffusion method.The study shows that the MIC value of TiO₂ against staphylococcus aureus,candida albicans and escherichia coli is 100 mg/mL.The MIC value of the alcohol extract from Chinese herbal medicines for staphylococcus aureus and candida albicans is 18.75 mg/mL.The MIC value of alcohol extract from Chinese herbal medicine for escherichia coli is 37.50 mg/mL.After the Chinese herbal medicine alcohol extract is mixed with TiO₂,the MIC value for staphylococcus aureus and candida albicans is 31.25 mg/mL,and that for escherichia coli is 62.50 mg/mL.The MIC value depends on the concentration of alcohol extract from Chinese herbal medicine,with comparison between the mixture of alcohol extract from Chinese herbal medicine with TiO₂ and alcohol extract from Chinese herbal medicine alone.The result indicates that the alcohol extract of Chinese herbal medicine plays an important role in sterilization.In this paper,the air purification of photocatalyst and traditional Chinese medicine composition was studied,and a stable and feasible extraction and preparation process was established.Photocatalyst and traditional Chinese medicine composition can effectively degrade harmful gases such as formaldehyde,benzene and toluene,and also have good inhibitory effects on Staphylococcus aureus,Candida albicans and Escherichia coli.