Formation of reactive chlorine species in saline solution treated by non-equilibrium atmospheric pressure He/O-2 plasma jet

0505573 - ÚFP 2020 RIV GB eng J - Článek v odborném periodiku
Jirásek, Vít - Lukeš, Petr
Formation of reactive chlorine species in saline solution treated by non-equilibrium atmospheric pressure He/O-2 plasma jet.
Plasma Sources Science & Technology. Roč. 28, č. 3 (2019), č. článku 035015. ISSN 0963-0252. E-ISSN 1361-6595
Grant CEP: GA ČR(CZ) GA19-25026S
Institucionální podpora: RVO:61389021
Klíčová slova: hydrogen-peroxide photolysis * acidic aqueous-solutions * hypochlorous acid * radiation-chemistry * oxychlorine ions * rate constants * kinetics * mechanism * dioxide * water * atmospheric pressure plasma jet * oxygen atoms * plasma-liquid interactions * hypochlorite * reactive chlorine species
Obor OECD: Fluids and plasma physics (including surface physics)
Impakt faktor: 3.193, rok: 2019
Způsob publikování: Omezený přístup
https://iopscience.iop.org/article/10.1088/1361-6595/ab0930

The aqueous-phase chemistry of reactive chlorine species initiated in saline solution by the gas phase discharge plasma above the liquid surface was investigated. A micro-atmospheric pressure 13.56 MHz plasma jet operating with a 0.6% O-2 in He was used to promote reactions of plasma-generated oxygen atoms with chloride anions at the gas-liquid interface. Physiological NaCl solution and phosphate buffered saline (PBS) were used. Three chlorine oxoacids or their conjugate bases were detected in the plasma treated saline: hypochlorites HOCl/OCl-, chlorites ClO2-, and chlorates ClO3-, being formed in the concentration ratio 4.5:1:1, respectively. In addition, chlorine dioxide ClO2 was formed in minor amounts. The final pH value of the plasma treated saline was typically 10.2. The total hypochlorite production, [HOCl] [OCl-], was directly proportional to the initial NaCl concentration, supporting the idea of a direct reaction of Cl- with O atoms. Subsequent post-discharge chemical processes in the bulk plasma treated saline solution were found to lead to the disproportionation of hypochlorite into different oxidation states of chlorine with formation of ClO3- as the final product. The reactivity of O atoms in NaCl solution was studied using taurine and phenol as chemical probes. Experiments with 50 mM taurine revealed a very high initial formation rate of OCl- in PBS (up to 4 mu M s(-1)). Chlorinated products of phenol (2- and 4-chlorophenol) in addition to the hydroxylated products (hydroquinone and catechol) demonstrated chlorination of phenol by hypochlorite. The rate of Cl- oxidation by O atoms was estimated to be 2-3 orders slower than the reaction of O atoms with phenol.
Trvalý link: http://hdl.handle.net/11104/0297050