State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, PR China; Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.
State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, PR China.
Chemosphere. 2023 Nov;340:139851. doi: 10.1016/j.chemosphere.2023.139851. Epub 2023 Aug 17.
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/CO 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/SO/HO and respective reversibility were also investigated. The inhibition effects of NO/SO/HO 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 SO/HO was irreversible, due to the blockage of active sites for VOCs removal. With the combination of scrubbing, multi-VOCs and NO/SO 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 SO/HO, discovering the major intermediates, surface carboxylates and carboxylic acids.
不同的 Cr 基双金属氧化物被制备出来，并在臭氧氧化法同时去除多种 VOCs（丙酮、苯、甲苯和二甲苯）的反应中评估了它们的催化性能。其中，Co-Cr 催化剂在芳香族 VOCs 的催化臭氧氧化中表现突出，随着温度和臭氧浓度的升高，其对丙酮转化率的活性得到了提高，这是由于较低的结晶度、更大的表面积、优异的氧化还原和 VOCs/CO 脱附能力所致。当温度为 100°C 且臭氧过剩比 λ（实际臭氧摩尔数与理论臭氧摩尔数之比）等于 3 时，Co-Cr 催化剂可实现所有多 VOCs 超过 95%的转化率。在去除四种多种 VOCs 的过程中，注意到存在竞争关系，芳香族 VOCs 的存在显著抑制了丙酮的转化率，这可能是由于吸附竞争和副产物积累所致。还研究了 NO/SO/HO 的影响及其各自的可逆性。NO/SO/HO 对芳香族 VOCs 的抑制作用远小于对丙酮的抑制作用。此外，NO 的抑制作用是可逆的，归因于物理吸附竞争，但 SO/HO 的抑制作用是不可逆的，这是由于活性位点对 VOCs 去除的阻塞所致。通过洗涤、催化臭氧氧化可同时高效去除多 VOCs 和 NO/SO。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氧化过程，以及在 SO/HO 的存在下，发现了主要的中间产物、表面羧酸盐和羧酸。
