The combined disposal of 1,2,4-trichlorobenzene and nitrogen oxides using the synthesized Ce0.2TiAlαOx micro/nanomaterial

Abstract

Dioxin-like chlorinated aromatics and NO_x are toxic compounds that are typically co-released from thermal industrial processes. Nevertheless, there are few studies reporting their synergetic disposal technology. A designed two-step coprecipitation method was developed to synthesize a novel three-dimensional ball-like Ce–Ti–Al composite oxide (Ce_0.2TiAl_αO_x) micro/nanomaterial to simultaneously dispose 1,2,4-trichlorobenzene (1,2,4-TrCBz, as the model compound) and NO in a fixed-bed flow reactor at 300 °C. The prepared Ce_0.2TiAl_αO_x micro/nanomaterial exhibited superior activities to Ce_0.2TiO_x. This featured the relative increase of 1,2,4-TrCBz degradation and NO conversion efficiencies by 8.0–14.1% and 5.2–33.3%, respectively. NO had a positive effect on the degradation of 1,2,4-TrCBz and induced a significant increase in the activity of the Ce_0.2TiAl_αO_x catalysts. In the presence of NO, 1,2,4-TrCBz was slightly dechlorinated in a stepwise manner to monochlorobenzene and oxidized to small molecules such as formic acid. The oxidative degradation pathway of 1,2,4-TrCBz over Ce_0.2TiAl_αO_x was proposed to proceed via the Mars–van Krevelen mechanism that accounts for the high mobility of the reactive oxygen species, such as O²⁻, O₂⁻, and O⁻, the unique redox properties of CeO₂, the positive effect of NO, and the interactive effect among the different material components.