Study On Mold-inhibiting Property And Mold-inhibiting Mechanism Of Sphagnum/Diatomite Humidity-controlling Materials

Indoor air environment includes indoor hot and wet environment and indoor air quality.Inappropriate indoor humidity and mold pollution are do great harm to human health,building enclosure structure.The relative humidity of the room can be controlled by air conditioning equipment and humidity-controlling materials,but the air conditioning energy consumption is high,which will increase the environmental load.Humidity-controlling materials have good hygroscopicity,but in humid and hot climate,which will be often in a high wet content state because of its frequent adsorption of moisture in the air,and at the same time,it may increase the risk of indoor air quality.Therefore,it is of great significance to develop functional materials with both humidity-controlling and mold inhibition.In this study,the mold-inhibiting properties,influencing factors of sphagnum/diatomite humidity-controlling materials were studied by petri mean.In addition,the mold-inhibiting mechanism of the materials were also studied through the test of conductivity,soluble protein and nucleic acid in mycelium leakage,and the technology of SEM,EDS and TEM.The results show that:(1)The materials have good mold-inhibiting,the degree of mold growth of them is 0 grade in solid medium,the germination time of P.citrinum and Asp.niger's spores on the surface of them is on day 18 and 15,respectively and the mycelial growth also be inhibited in Czar's medium.(2)The main mold inhibiting component of the material is modified admixture,followed by diatomite,while sphagnum can't inhibit mold;Mold growth degree of modified admixture is 0 grade,when in the Czar's medium test,the germination time of P.citrinum and Asp.niger on it is on day 17 and 23,respectively.The higher the content of humidity-controlling material,the stronger the inhibition effect on P.citrinum and Asp.niger;When the content of the materials is greater than 1.5 g/100 ml,the mold-inhibiting property of them is enhanced observably.The larger the pH value,the stronger the inhibition of humidity-controlling material on the germination of mold spores and mycelial growth.The suitable range of pH to inhibit P.citrinum and Asp.niger is not lower than 9 and 10 respectively.At higher humidity,the materials still have good mold-inhibiting.(3)Through the result of mycelium leakage test and analysis of SEM,EDS and TEM,something can be seen that when treated with the materials and the antibacterial components,the number of mold spores is obviously reduced,the structure of mold cell is severely deformed,the cytoplasmic wall separation is serious,the destruction of the cell membrane leads to extravasation of intracellular and most organelles are destroyed by oxidation,which indicates that the materials have good mold-inhibiting properties.(4)The OH-and active O2-produced after the MgO contact with water molecules and oxygen in the modified admixture can destroy the cell structure of mold by inducing lipoperoxide and strong oxidation,respectively.As well,when the C2S dissolve in water,it will also produce a large number of OH-,which can enhance the mold inhibited properties of the material.Those are the mold-inhibiting mechanism of the materials.