Adsorption And Conversion Of Formaldehyde For Catalyst-loaded Activated Carbon

Formaldehyde, as one of the mainest indoor organic pollutants, possesses strongtoxicity and does great harm to human’s health. So far, there are various methods totreat formaldehyde pollutant, but the catalytic oxidation method of formaldehyde isthe optimal way. Catalyst-loaded activated carbon has many advantages, such asextensive raw material sources, good selectivity, low pollution, easy recycling and soforth, therefore it has become a hot research area nowadays.Activated carbon, A and D were used as carrier and catalyst sources respectivelyin this thesis to make M/AC, C/AC and (M, C)/AC, and then, the relationship betweenimpregnation concentration, ultrasonic time, activation temperature, air velocity, thecoating amount of active component and purification performance of formaldehydewere investigated in detail. SEM, EDS, and Nitrogen adsorption isotherm were usedto examine surface morphology, elemental composition and the distribution of activecomponent; XRD was used to analyse the thermal decomposition of A and D loadedin the actived carbon.Effects of impregnation concentration of A and ultrasonic time on the coatingamount of active component and its distribution were researched firstly in the thesis.The experimental results showed that with the increasing of mass concentration, thequantity of A loaded in activated carbon increased, the formaldehyde adsorption ofM/AC increased firstly and then decreased, and reached the maximum at2wt%.Within the appropriate mass concentration range, it’s in favour of dispersing andloading of active components when the ultrasonic time was extended, meanwhile,increasing the formaldehyde purification performanC of M/AC, and the best time is3h. Activation temperature influenced the property of the active components, Adecomposed into MOxand B at400℃, then B decomposed at650℃, and MOxreactedwith AC at800℃, resulting the consumption of MOx, hence the best activationtemperature was650℃. The formaldehyde adsorption values of M/AC(massconcentration2wt%, ultrasonic time3h, activation temperature650℃) and activated carbon were111.05mg/gAC and93.48mg/gAC respectively in150mL/min airvelocity, the adsorption performance improved19%；in250mL/min, the values were220.72mg/gAC and144.01mg/gAC respectively, the adsorption performanceimproved53%.Secondly, based on the Mars-Van Krevelen oxidation reduction mechanism ofmetal oxide and the active oxygen transformation mechanism of MOx, A and D wereused as catalyst sources to make (M, C)/AC. The influence of total mass concentration,mM:mC,activation temperature, air velocity and the coating amount of activecomponent on the formaldehyde purification performance of (M, C)/AC werediscussed in this thesis. The experimental results showed that the adsorption value of(M, C)/AC(mass concentration4wt%, mM:mC2:2, ultrasonic time3h, activationtemperature650℃) achieved117.23mg/gAC in150mL/min, improved20%thanAC；in250mL/min, the adsorption value was253.00mg/gAC, improved76%thanAC.