以酚醛树脂为黏结剂,在活性炭(ACH)表面担载MnO,制备蜂窝状Mnq/ACH催化剂,考察了制备工艺条件对MnO,/ACH催化剂低温脱硝活性的影响。结果表明,酚醛树脂质量分数越高,所制ACH的机械强度越大,对孔道堵塞越严重;脱硝活性随着酚醛树脂质量分数的增加而逐渐降低。当载锰量(Mn的质量分数)为3%~15%时,随载锰量的增加脱硝活性增加;继续增加载锰量,脱硝活性变化不大。在300-600℃内,脱硝活性随煅烧温度的升高呈先增加后降低的趋势。此外,由于空气氧化使得低价态的锰氧化物转化为高价态的锰氧化物,从而导致脱硝活性大大提高。其中,在酚醛树脂质量分数为25%、载锰量为10%、400℃煅烧并经空气氧化的最佳工艺条件下,该催化剂在200℃下NO转化率达95%左右。
MnOx/ACH catalyst, manganese oxides supported on an activated carbon honeycomb (ACH) using phenolic resin as adhesive, was used for selective catalytic reduction of NO with NH3 at low temperature. The effect of preparation conditions on the activity of NO removal was investigated. The results showed that, with the increasing of mass fraction of phendic resin, the mechanical strength of the ACH increased, while the micropore surface area and micropore volume decreased. With the increasing of mass fraction of phenolic resin in ACH, NO removal activity over MnOx/ACH decreased gradually. NO conversion increased with increasing Mn loading(mass fraction of Mn) from 3% to 15%, while further increase led to less change in NO removal activity. In the temperature range of 300--600 ℃, NO conversion showed a maximum. Additionally, the preoxidation of MnOx/ACH in air significantly enhanced the activity of NO removal, because the low valence state of manganese oxide was transformed into high valence one. Under the optimal preparation conditions of 25% mass fraction of phenolic resin, 10% Mn loading, the calcination temperature of 400 ℃and preoxidized by air, about 95% NO conversion can be obtained over the MnOx/ACH catalyst at 200 ℃.