Electro-generation of hydrogen peroxide using a graphite cathode from exhausted batteries: study of influential parameters on electro-Fenton process.

In this work, the study of hydrogen peroxide (H2O2) electro-generation using graphite from exhausted batteries (Gr-Bat) was conducted. Linear sweep voltammetry and electrolysis experiments were carried out in a single compartment electrochemical cell. Study of the possibility to use this electrode revealed that it presents, as vitreous carbon (VC) electrode, a reduction of oxygen with two successive waves (bi-electronic reduction). The first wave corresponds to the reduction of O2 to H2O2, while the second one corresponds to the reduction of H2O2 to H2O. The cathodic potentials for electro-generation of H2O2 appeared at -600 and -700 mV vs. Ag/AgCl for Gr-Bat and VC electrodes, respectively. Subsequently, electrolysis experiments were conducted by imposing the potentials required for H2O2 formation. The effect of several operating parameters on H2O2 production, such as the nature and concentration of the electrolyte, the pH, the presence of ferrous ions and O2 injection were studied using Gr-Bat and VC electrodes, respectively. For both electrodes, the acidic medium was more favorable for H2O2 electro-generation. The oxygen injection in solution promoted an increase of H2O2 concentration, but its effect was more pronounced in the case of VC electrode. Application for crystal violet degradation by electro-Fenton revealed that Gr-Bat had the best purification performance. A removal rate of 73.18% was obtained with Gr-Bat electrode against 62.27% with VC electrode for an electrolysis time of 120 min. This study has demonstrated the possibility of recycling Gr-Bat by using them as cathode materials in the electro-Fenton process.

Efficacy and tolerability of hyaluronan (ialuset) in the treatment of pressure ulcers: a multicentre, non-randomised, pilot study.

BACKGROUND: Pressure ulcers are complex chronic wounds and a frequent cause of morbidity in elderly subjects in hospitals and nursing homes. Local treatment is based on the use of dressings that protect the wound and provide a favourable environment for healing to occur. ialuset, a treatment based on hyaluronan (hyaluronic acid), is already available on the market and known to be an effective treatment for venous leg ulcers. However, no clinical trials of hyaluronan as a treatment option for pressure ulcers have been reported as yet. METHODS: The purpose of this review was to investigate the efficacy and tolerability of ialuset in the treatment of pressure ulcers. To this end, this article reports data from 21 predominantly elderly patients with National Pressure Ulcer Advisory Panel grade II, III or IV pressure ulcers treated with ialuset cream or gauze pads over a 3-week period in ten hospitals in France. RESULTS: A significant median decrease of 4cm2 in the surface area of treated wounds was observed after 3 weeks of ialuset use (p < 0.05 vs baseline). A >or=50% reduction in pressure ulcer surface area was seen in 65.0% of patients (95% CI 44.8, 84.3). Nine patients (45%) showed a >or=50% increase in epithelial surface compared with the initial lesion. Patient-reported pain appeared to decrease during the 3-week treatment period, although this decrease did not quite reach statistical significance (p = 0.07). Additionally, a significant decrease in the mean percentage of fibrous tissue in the wound was observed (p = 0.02), as was a non-significant increase in granulation tissue (p = 0.1). General efficacy was considered as good or very good for nearly all patients on review of the data (19/20 patients as assessed by clinicians). Overall tolerability was also considered good or very good in 12/15 assessments by patients at day 21. CONCLUSION: These preliminary findings suggest that ialuset is a promising option in the treatment of pressure ulcers; however, further investigation in the form of large, randomised clinical trials is required before firm conclusions can be drawn regarding the efficacy and tolerability of this treatment in this context.