New measurements of OClO absorption cross-sections in the 325–435 nm region and their temperature dependence between 213 and 293 K

Phosphorylated Cotton Cellulose as a Matrix for Generating Chlorine Dioxide

Currently, developing disinfectant materials is of utmost importance. A significant advantage of our fabric is its reusability. The disinfectants based on a natural polymer of cellulose have been barely investigated. Our work presents a modified cellulose material, and the data obtained for the first time on the chlorine dioxide generation process when treating the material with a sodium chlorite alcohol solution. A method of applying NaClO₂ onto the fabric by impregnating it with a solution sprayed by an aerosol generator is proposed. This kind of fabric is capable of withstanding multiple usages after pre-washing and rinsing. The lowest alcohols-methanol, ethanol and isopropanol-are proposed as optimal solvents. It was shown that the phosphorylated cotton cellulose fabric impregnated with this solution generates chlorine dioxide during the first 25-35 min. Neither humidity nor expedites improve the process of releasing the chlorine dioxide, but high moisture content in the air causes the complete absorption of ClO₂ by microdrops and its removal from the gas environment. A promising technique for removing the excess ClO₂ by the means of UV treatment is proposed: after 15 min of treating ClO₂ in the gas phase, it disappears entirely. These materials could be used as disinfectants in different industries, such as food and industrial manufacturing.

Study of an Arctic blowing snow-induced bromine explosion event in Ny-Ålesund, Svalbard

Bromine explosion events (BEEs) are important processes that influence the atmospheric oxidation capacity, especially in the polar troposphere during spring. Although sea ice surface is thought to be a significant bromine source, bromine release mechanisms remain unclear. High-resolution ground-based observations of reactive bromine, such as BrO, are important for assessing the potential impacts on tropospheric ozone and evaluating chemical models. However, previous model studies paid little attention to Svalbard, which is surrounded by both open ocean and sea ice. In this paper, we present continuous BrO slant column densities and vertical column densities derived by Multi-Axis Differential Optical Absorption Spectroscopy deployed at Ny-Ålesund (78.92°N, 11.93°E) in March 2017. We focused on one BEE in mid-March, during which the vertical column densities of BrO surged from 4.26 × 10¹³ molecular cm^-2 to the peak at 1.23 × 10¹⁴ molecular cm^-2 on March 17, surface ozone depleted from a background level of 46.25 parts per billion by volume (ppbv) to 13.9 ppbv. This case study indicates that the BEE was strongly associated with blowing snow induced by the cyclone systems that approached Svalbard from March 14 to 18. By considering meteorological conditions, sea ice coverage, and airmass trajectory history, we demonstrate that sea salt aerosols (SSAs) from blowing snow on sea ice, rather than from open ocean, are attributed to the occurrence of this BEE. Model results from a parallelized-tropospheric offline model of chemistry and transport (p-TOMCAT) indicate that this BEE was mainly triggered by a blowing snow event associated with a low-pressure cyclone system. The concentration of blowing-snow-sourced SSAs surged to peak when the airmass pass across the sea-ice-covered area under high wind speed, which is a critical factor in the process of bromine explosion observed in Ny-Ålesund. Due to the coarse resolution, the possible delayed timing of bromine release from SSA and the model-data discrepancies still exist.

UV spectroscopic determination of the chlorine monoxide (ClO) / chlorine peroxide (ClOOCl) thermal equilibrium constant

The thermal equilibrium constant between the chlorine monoxide radical (ClO) and its dimer, chlorine peroxide (ClOOCl), was determined as a function of temperature between 228 and 301K in a discharge flow apparatus using broadband UV absorption spectroscopy. A third-law fit of the equilibrium values determined from the experimental data provides the expression K _eq = 2.16 × 10^-27 e ^{(8527±35 K/T)} cm³ molecule^-1 (1σ uncertainty). A second-law analysis of the data is in good agreement. From the slope of the van't Hoff plot in the third-law analysis, the enthalpy of formation for ClOOCl is calculated, Δ H f ° (298 K) = 130.0 ± 0.6 kJ mol^-1. The equilibrium constant results from this study suggest that the uncertainties in K _eq recommended in the most recent (year 2015) NASA JPL Data Evaluation can be significantly reduced.

DENSITY FUNCTIONAL THEORY STUDIES OF SPECTROSCOPIC CONSTANTS AND ANHARMONIC FORCE FIELD OF O35ClO

The equilibrium structure, spectroscopy constants and anharmonic force field of O35ClO have been calculated at B3PW91 and B3LYP levels of theory with two basis sets 6-311++G(2df,2pd) and 6-311++G(3df,3pd) , respectively. The computed geometries, dipole moment, rotational constants, vibration–rotation interaction constants, vibrational band origins, anharmonic constants, quartic, and sextic centrifugal distortion constants are compared with the available experimental data. The cubic and quartic force constants are predicted. The calculated results show that the B3PW91 results are in excellent agreement with experiment and represent a substantial improvement over the results obtained from B3LYP.