Experimental Research On The Catalytic Degradation Of Formaldehyde By Nickel Foam Loading With TiO₂

Formaldehyde has become the main source of indoor pollution,and the removal of formaldehyde has gained the top priority of removing indoor pollutants.With the development of photocatalytic technology,an effective formaldehyde removal method has been found.Photocatalytic technology is a kind of environment-friendly technology with good catalytic performance and no secondary pollution in catalytic process.In recent years,it has made great breakthroughs in the treatment of waste gas?water?,became the main method of dealing with formaldehyde.In this paper,nickel foam loading with Sr/TiO₂ photocatalyst were prepared,its character were analyzed,the Sr/TiO₂ photocatalytic degradation toward formaldehyde gas were studied,the optimal process conditions were determined.In this paper selects foam nickel as the carrier of catalyst.By the pulling method,nickel foam was loaded with Sr/TiO₂ prepared by sol-gel method,and then were characterized by XRD,SEM,XPS and TGA.The XRD and TGA characterization shows that the Sr doping modification minishes the size of TiO₂ particle size,anatase type TiO₂ generates at 450?,and gradually transforms into rutile type TiO₂ with the increase of temperature after above570?.The SEM characterization indicates that it is more conducive to the adhesion of the catalyst after pretreatment of foam nickel carrier.The catalyst prepared at 500?had uniform particle size and well dispersion.The XPS analysis show that the Sr element is doped into the catalyst uniformly,the new lattice is formed in the catalyst,improving the efficiency of the catalytic.The photocatalytic activity of Sr/TiO₂ photocatalytic degradation of formaldehyde under gas phase was studied by photocatalysis experiment with Sr/TiO₂ catalyst.The optimal conditions were determined as followed:doping ratio Sr:Ti=0.1?molar ratio?,the calcination temperature was 500?,and the number of tensile membrane was 7 times.The effects of photocatalytic conditions on the removal of formaldehyde were studied systematically.It is determined that the catalyst usage was 2.1 g/L,the temperature was 25?,the relative humidity was 50%and the reaction time was 2h,and the optimal effect was observed;The catalyst was repeatedly used more than 10 times and could be activated by high temperature activation.The experiment simulated the environment of household and spray scene,and tested the removal efficiency of formaldehyde in the range of low concentration and high concentration.The removal rate of formaldehyde can be over 90%in the range of 1.0 mg/m³-1.6 mg/m³.The removal rate of formaldehyde within 59mg/m³-236mg/m³is up to about 70%,and the effect of removal is better.After the catalytic degradation of the actual gas in the newly decorated laboratory,formaldehyde removal rate is about 92%;The reaction kinetics analysis found that the catalytic oxidation rate of the catalyst reaction was dominate in low concentration and high concentration.