Preparation Of Porous TiHAP Composite And It's Purification Effect On Aldehydes Organic Pollutants

Aldehyde gases was handed out from interior decoration and furniture which was a threat to the environment and people's health.Adsorption and photocatalytic was combined to remove aldehyde gas contaminants,it was taken more attention at home and abroad for environmentally friendly and without secondary pollution.In this paper,two kinds of materials:porous titanium apatite?MP-TiHAP?and silver chloride-supported porous titanium apatite?AgCl/MP-TiHAP?,with good adsorption and catalytic properties were prepared.The efficiency of adsorption,degradation and its influence factors of acetaldehyde by MP-TiHAP and AgCl/MP-TiHAP were studied.MP-TiHAP and AgCl/MP-TiHAP were applied to wall coatings to study the purifying effect on acetaldehyde gas,in order to give full play to their comprehensive advantages and provide experimental instructions to practical applications for the materials.The main research contents and conclusions of the paper are as follows:?1?MP-TiHAP was prepared by co-precipitation method using porous CaCO₃ as a template.The characteristics of MP-TiHAP were studied by using X-ray diffractometer,scanning electron microscope,specific surface area tester,ultraviolet-visible diffuse spectrophotometer,and ultraviolet steady-state fluorescence spectroscopy.The effect of the template synthesis temperature,co-precipitation reaction temperature,and the molar ratio of calcium and titanium ions in the solution on the structure and properties of the product was analyzed.The optimized synthesis conditions were obtained.At the same time,the difference of adsorption and photocatalytic degradation to acetaldehyde between MP-TiHAP and non-porous TiHAP was studied.The path and mechanism of degradation of acetaldehyde by MP-TiHAP were analyzed.MP-TiHAP exhibits a cellular porous structure with a large specific surface area and has good adsorption and degradation properties for acetaldehyde.The adsorption energy for acetaldehyde was reached to 72.4%at 24 h,the degradation rate was reached to 85.8%at 120 min.The degradation process was meet the first grade kinetic characteristics,and the reaction rate constant is 0.017 min^-1.The degradation of acetaldehyde by MP-TiHAP was mainly resulted by the interaction of hydroxyl,vacancy and superoxide radicals.Acetaldehyde was oxidized to non-toxic CO₂ and H₂O in course of the catalytic degradation to acetaldehyde.?2?AgCl/MP-TiHAP was prepared by loading AgCl onto MP-TiHAP with in-situ precipitation method using AgNO₃ as Ag source.The analysis and test results show that the load of AgCl reduces collapse of porosity on the surface of MP-TiHAP,but the absorption of visible light by AgCl/MP-TiHAP and the utilization of light energy were improved.As the loading of AgCl,the separation rate of electron and hole pairs was accelerated and the recombination rate was slowed down,which leads to the enhance of the catalytic degradation to rhodamine B?RhB?and acetaldehyde.It is speculated that the degradation mechanism is that the heterojunction structure between AgCl and TiO₂ accelerates the electron transfer and the catalytic degradation was relied on the generated superoxide radical.In addition,MP-TiHAP also retains the original catalytic degradation of acetaldehyde.?3?A wall paint was made by adding MP-TiHAP and AgCl/MP-TiHAP to the waterborne epoxy resin emulsion provided by Chenyang Industry&Trade Group,and performing adsorption and degradation of acetaldehyde was proced in a self-made sealed glass reaction box.In the experiment,the adsorption and degradation performance of the coating on acetaldehyde was studied by analyzing the residual amount of acetaldehyde gas.The results show that when the MP-TiHAP content is10wt%,the coating made by MP-TiHAP has a higher degradation rate of acetaldehyde gas and good stability.The degradation of acetaldehyde gas was improved by adding MP-TiHAP in coating and it was improved in the short term.Experiments show that MP-TiHAP and AgCl/MP-TiHAP can give the paint a better purification effect,which provides a new method and experimental basis for the purification of indoor aldehyde gas pollutants.