Acidity control of the gliding arc treatments of aqueous solutions: application to pollutant abatement and biodecontamination

A tight control of acidity is needed for performing oxidation–reduction reactions of organic compounds dissolved in liquid media, since the relevant reactions often involve the occurrence of protons; the matching kinetics are therefore acidity dependent. This feature holds for plasma treatments of aqueous wastes which are intended to abate the concentration in organic pollutants. Exposure of aqueous solutions to a gliding arc plasma in humid air induces acid and oxidising reactions in the condensed phase. Acid effect results from the occurrence of NO species formed in the plasma and leads to the formation in water of nitrous and nitric acids, which are responsible for a steep pH fall. Using selected buffers allows accurate controlling of the acidity, which is necessary for most of the plasma-chemical or plasma-biochemical reactions

Plasma-activated water: a new and effective alternative for duodenoscope reprocessing

Gheorghe G Bălan,1 Irina Roşca,2 Elena-Laura Ursu,2 Florica Doroftei,2 Andra-Cristina Bostănaru,3 Eugen Hnatiuc,4 Valentin Năstasă,3 Vasile Şandru,5 Gabriela Ştefănescu,1 Anca Trifan,1 Mihai Mareş3 1Grigore T. Popa University of Medicine and Pharmacy, Iaşi, Romania; 2“Petru Poni” Institute of Macromolecular Chemistry, Iaşi, Romania; 3Ion Ionescu de la Brad University of Agricultural Sciences and Veterinary Medicine of Iasi, Iaşi, Romania; 4“Gheorghe Asachi” Technical University, Iaşi, Romania; 5Department of Gastroenterology Research, Clinical Emergency Hospital of Bucharest, Bucharest, Romania Introduction: Duodenoscopes have been widely used for both diagnostic and therapeutic endoscopic retrograde cholangiopancreatography procedures. Numerous outbreaks of duodenoscope-associated infections involving multidrug-resistant bacteria have recently been reported. Plasma activated water (PAW) has been widely considered an effective agent for surface decontamination and is increasingly used for disinfection of medical equipment. The aim of this study was to evaluate whether the duodenoscopes currently on market are suited for the repeated use of PAW and to test the efficacy of PAW for their disinfection. Materials and methods: In order to evaluate the disinfection efficacy and the required time of contact, the duodenoscope samples were contaminated by immersing them in fasted-state simulated intestinal fluid containing Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, prior to PAW exposure. In order to test the duodenoscope polymer compatibility with PAW, a challenge test was conducted by immersing the samples in PAW for 30 minutes daily for 45 consecutive days. Results: Significant reductions in bacterial populations were achieved after 30 minutes of PAW treatment, indicating a high-level disinfection. Atomic force microscopy and scanning electron microscopy were used to demonstrate that repeated PAW treatment of duodenoscope coating polymer samples did not result in significant differences in morphological surface between the treated and untreated samples. Energy-dispersive X-ray spectroscopy analysis also showed no significant differences between the elemental composition of the duodenoscope coating polymer samples before and after repeated PAW treatment. Conclusion: Considering these preliminary results, PAW could be considered as a new alternative for duodenoscope reprocessing. Keywords: PAW, antibacterial activity, duodenoscope, disinfectio