The Preparation Of Modified Bentonite And Its Characteristic Of Adsorption Of Indoor Formaldehyde

In recent years, due to the development of economy and the improvement of personal living environment, people demand better and better dwelling condition. But indoor synthetic building materials emit a large number of volatile organic compounds (VOCs) and deteriorate indoor air quality badly. Formaldehyde is a commonly detected VOCs pollutant in the door,irritant and susceptivity, which do the serious harm to many apparatus .It has been listed the material causing cancer and abnormality by World Health Organization. Bentonite is a kind of clay mineral that is abundant in our country. Bentonite is an inorganic microporous material, having the ability of selective adsorption ability due to its unique samdwich structure.In this dissertation, a series of modified bentonites(sodium bentonite, acidation bentonite and organobentonite ) were prepared by calcium bentonite. And the mineralogical and physicochemical properties of these bentonite were tested and characterized. After a series of modify, the structural characteristics, the specific surface area, organic carbon content and interlayer space, and other aspects of the bentonite have undergone changes.The adsorptions to formaldehyde of these bentonites were investigated. Results show that acidification bentonite was the best, sodium bentonite was the better one and calcium bentonite next to it.The adsorption of Bentonite is mainly physical adsorption on the surface of bentonite. The results suggested that sorb effects of calcium bentonite and sodium bentonite were relevant tohydration film. Acidification bentonite may also sorb formaldehyde by because the surface acidity, the proton and its interlayer water. The adsorption of organic bentonite may occur by partition process, too. The adsorption process of CTMAB-organobentonite is liberation of heat, and other types of bentonites may were endothermic process.A series of Ti02-bentonite were prepared by calcium bentonite, sodium bentonite and acidation bentonite. Their photocatalytic degradation behavior of formaldehyde is studied. The result shows that adsorption of Ti02-bentonite formaldehyde was two phases: adsorption and photocatalytic purification. The phases were mutually integrated and promote each other. Ti02 calcium bentonite was better than Ti02 sodium bentonite, the Ti02 acidation bentonite was relatively poor.Finally the pilot-scale study was tried with acidation bentonite. Acidation bentonite can effectively adsorbed formaldehyde in a short time and the concentration of formaldehyde was reduced to the state below standards. Acidation bentonite has efficacious adsorption before saturation.In a word, bentonite is an excellent sorbent for formaldehyde and it has extensive prospect on the treatment of indoor pollutant.