制备了不同的Cr基双金属氧化物,并在同时去除多VOCs混合物(丙酮,苯,甲苯,和邻二甲苯)通过臭氧化。其中,Co-Cr催化剂在催化臭氧化芳烃中脱颖而出,通过提高温度和臭氧浓度来促进其对丙酮转化的活性,由于较低的结晶,更大的表面积,优异的氧化还原和VOCs/CO2解吸能力。当温度为100°C并且过量臭氧比率λ(臭氧的实际摩尔数与所需臭氧的理论摩尔数的比率)等于3时,在Co-Cr催化剂上实现了超过95%的所有多VOC转化率。在四种挥发性有机化合物的去除过程中发现了竞争关系,在芳香挥发性有机化合物的存在下,丙酮转化受到显著抑制,可以想象是由于吸附竞争和副产物积累。还研究了NO/SO2/H2O的影响和各自的可逆性。NO/SO2/H2O对芳香VOCs的抑制作用远小于丙酮。Further,NO的阻滞作用是可逆的,归因于物理吸附竞争,但SO2/H2O的抑制作用是不可逆的,由于挥发性有机化合物去除活性部位的堵塞。随着擦洗的结合,催化臭氧化可以同时有效地去除多VOCs和NO/SO2。还进行了原位DRIFTS测量,以研究多VOCs混合物的吸附和催化臭氧化过程,以及在SO2/H2O的存在下,发现主要中间体,表面羧酸盐和羧酸。
Different Cr-based bimetallic oxides were prepared, and their catalytic performance was evaluated on the simultaneous removal of multi-VOCs mixtures (acetone, benzene, toluene, and o-xylene) by ozonation. Among them, Co-Cr catalyst stood out in catalytic ozonation of aromatic VOCs, and its activity on acetone conversion was promoted by raising the temperature and ozone concentrations, owing to lower crystallization, larger surface area, excellent redox and VOCs/CO2 desorption ability. Above 95% conversion of all multi-VOCs was achieved over the Co-Cr catalyst when the temperature was 100 °C and an excess ozone ratio λ (the ratio of actual moles of ozone to theoretical moles of ozone needed) was equal to 3. A competitive relationship was noticed during the removal process of four multiple VOCs, with significant inhibition of acetone conversion in the presence of aromatic VOCs, conceivably due to adsorption competition and byproducts accumulation. Effects of NO/SO2/H2O and respective reversibility were also investigated. The inhibition effects of NO/SO2/H2O on aromatic VOCs were far less than those on acetone. Further, the retarding effect of NO was reversible, attributing to physical adsorption competition, but the inhibition effect of SO2/H2O was irreversible, due to the blockage of active sites for VOCs removal. With the combination of scrubbing, multi-VOCs and NO/SO2 could be removed by catalytic ozonation simultaneously and efficiently. In-situ DRIFTS measurement was also conducted to investigate the adsorption and catalytic ozonation process of multi-VOCs mixtures, as well as under the presence of SO2/H2O, discovering the major intermediates, surface carboxylates and carboxylic acids.