With the development of the chemical industry, benzene, toluene, ethylbenzene, and xylene (BTEX) have gradually become the major indoor air pollutants. Various gas treatment techniques are widely used to prevent the physical and mental health hazards of BTEX in semi-enclosed spaces. Chlorine dioxide (ClO₂) is an alternative to chlorine as a secondary disinfectant with a strong oxidation ability, a wide range of action, and no carcinogenic effects. In addition, ClO₂ has a unique permeability which allows it to eliminate volatile contaminants from the source. However, little attention has been paid to the removal of BTEX by ClO₂, due to the difficulty of removing BTEX in semi-enclosed areas and the lack of testing methods for the reaction intermediates. Therefore, this study explored the performance of ClO₂ advanced oxidation technology on both liquid and gaseous benzene, toluene, o-xylene, and m-xylene. The results showed that ClO₂ was efficient in the removal of BTEX. The byproducts were detected by gas chromatography-mass spectrometry (GC-MS) and the reaction mechanism was speculated using the ab initio molecular orbital calculations method. The results demonstrated that ClO₂ could remove the BTEX from the water and the air without causing secondary pollution.

2,2′,4,4′,6,6′-hexanitrostilbene (HNS) is a heat-resistant, low-sensitivity energetic material with widespread applications in pliable linear-shaped charges, high-temperature-resistant oil well perforating charges, and rocket propellants. However, the presence of highly toxic and mutagenic nitroaromatic compounds in HNS wastewater necessitates efficient and accurate detection methods. Unfortunately, the existing analytical methods for HNS detection are outdated and incompatible with modern equipment. This limits their application due to issues with detection range, accuracy, and cost. To address this gap, an improved method was developed using an Ultimate 3000 UHPLC system with methanol and water as the mobile phase and UV-Vis detection at 271 and 226 nm wavelengths. The results indicate that the optimal detection conditions are achieved with a methanol-to-water ratio of 70:30 and a flow rate of 0.5 mL/min, providing high accuracy and efficiency. Compared to traditional methods, this approach reduced the detection time by nearly 70%, with the shortest analysis time ranging from 6 to 6.5 min, significantly lowering the cost of HNS detection. The method demonstrated excellent linearity (R² > 0.9999) and high sensitivity within the concentration range of 0.50–150.00 mg/L, with precise and reliable results. This work provides both theoretical insights and experimental validation for the detection and analysis of HNS in wastewater.