Simultaneous degradation of glucocorticoids and sterilization using bubbling corona discharge plasma based systems: A promising terminal water treatment facility for hospital wastewater.

Glucocorticoids (GCs) have drawn great concern due to their widespread contamination in the environment and application in treating patients with COVID-19. Due to the lack of data about GC removal using advanced treatment processes, a novel Paralleling and bubbling corona discharge reactor (PBCD) combined with iron-loaded activated-carbon fibre (Fe-ACF) was addressed in this study to degrade GCs represented by Hydrocortisone (HC) and Betamethasone (BT). The results showed that the PBCD-based system can degrade GCs effectively and can achieve effective sterilization. The removal rates of GCs were ranked as PBCD/Fe-ACF > PBCD/ACF > PBCD. The concentration of E. coli was reduced from 109 to 102 CFU/mL after 60 min of PBCD-based system treatment. The abundance of bacteria in actual Hospital wastewater (HWW) was significantly reduced. Plasma changed the physical and chemical properties of ACF and Fe-ACF by etching axial grooves and enhancing stretching vibrations of surface functional groups, thus promoting adsorption and catalytic degradation. For GC degradation, the functional reactive species were identified as •OH, 1O2, and •O2 radicals. Possible degradation pathways for HC and BT were proposed, which mainly included defluorination, keto acid decarboxylation, demethylation, intramolecular cyclization, cleavage and ester hydrolysis, indicating a reduction in GC toxicity. Since GCs are widely used in patients with COVID-19 and their wastewater needs to be sterilized simultaneously, the intensive and electrically driven PBCD-based system is promising in GC pollution control and sterilization in terminal water treatment facilities.

Effect of Dielectric Barrier Discharge Cold Plasma on Pea Seed Growth.

Traditional seed pretreatment methods cause secondary pollution for the application of various chemicals. This study investigated the effect of dielectric barrier discharge (DBD) cold plasma on seedling growth. Effects of plasma-activated tap water (PATW) and plasma-activated seeds (PAS) were compared for germination rates, seedling height, dry weight, and chlorophyll content. Results show that compared with controls these growth parameters were all increased by more than 50%. The yields and contributions of hydrogen peroxide, nitrate, nitrite, and ammonium were quantified. Hydrogen peroxide and nitrate have an important role in seedling growth. By etching, the seed epidermis free radicals can reduce the apparent contact angle and increase the water absorption of the seeds. In addition to the low cost of PATW and PAS compared with commercial fertilizers, DBD does not involve any chemical addition. Thus, both PATW and PAS can be an alternative for improvement of agricultural production.