Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Numerical simulation of the current, potential and concentration distributions along the cathode of a rotating cylinder Hull cell

Numerical simulations of the non-uniform current, potential and concentration distributions along the cathode of a rotating cylinder Hull (RCH) cell (RotaHull® cell) are performed using finite element methods. Copper electrodeposition from an acid sulfate electrolyte is used as a test system. Primary, secondary and tertiary current distributions are examined. The importance of controllable and uniformly accessible hydrodynamics along the length of the RCH cathode is demonstrated. Charge transfer kinetics are described by a Tafel approximation while mass transport is considered using a Nernstian diffusion layer expression. The effects of applied current density and electrode rotation speeds on the distribution of potential and current along the RCH cathode are investigated. An expression of the primary current distribution and a dimensionless mass transport correlation facilitate comparisons with the simulations

Effect of electrochemical regeneration on the surface of a graphite adsorbent loaded with an organic contaminant

A regeneration efficiency of greater than 100% was obtained for electrochemical regeneration of a graphite interaction compound loaded with a phenol adsorbate. Time-of-flight secondary ion mass spectrometry was employed to study the effect of electrochemical regeneration on the graphite adsorbent. Using this technique, the elemental composition of the graphite surface was determined as a function of depth. The surface composition of the adsorbent was compared in three states: a fresh graphite before adsorption, after loading with a phenol adsorbate and after electrochemical regeneration. The fresh graphite exhibited a hydrogen and oxygen-rich surface layer approximately 150 nm thick. After loading with the adsorbate, the adsorbent had a thicker surface layer, approximately 370 nm, and significant enhancement in the hydrogen and oxygen abundance extending beyond 600 nm from the surface. After electrochemical regeneration, the graphite adsorbent showed an oxygen-rich layer, slightly thicker than the fresh case at approximately 220 nm, and a very much lower hydrogen enrichment at the surface. These results demonstrate that whilst the electrochemical regeneration effectively removes the phenol model pollutant, it also oxidises the exposed carbon surface. This oxidation may lead to new adsorption sites, but also has a significant impact on the estimation of adsorbent life

Hydrodynamic voltammetry in microreactors: multiphase flow

A new hydrodynamic microelectrochemical reactor design is presented for the voltammetric sensing of chemical species contained within two immiscible liquid streams flowing within rectangular ducts, in direct contact. This article describes the design, fabrication and experimental characterisation of the device. A microfabricated rectangular duct (of typical dimensions: height 75μm, width 500μm and length 3 cm) was constructed using FOTURAN glass and standard photolithographic procedures. Microelectrode sensors were positioned on one internal duct wall with a geometry to permit separate voltammetric monitoring of the two solvent phases. Reagent solutions containing N,N,N′,N′-tetramethyl-1,4-phenylene diamine in 1,2-dichloroethane and hexaamineruthenium(III)chloride in water were pumped through the device under laminar flow conditions. Linear sweep voltammetric measurements were performed separately on the two electrolyte streams and the variation of the transport limited current as a function of volume flow rate through the cell monitored. Under conditions where stable flow was obtained the current flow rate relationship was observed to follow analogous voltammetric behaviour to that observed in macroscopic flow cell devices. Keywords: Hydrodynamic voltammetry, Immiscible liquid/liquid flow, Microreactor

Thermochemical CO2 splitting using double perovskite-type Ba2Ca0.66Nb1.34-xFexO6-δ

A carbon-neutral fuel is desired when it comes to solving the issues associated with climate change. A smart approach would be to develop new materials to produce such fuels, which could be integrated with renewables to improve the efficiency (e.g., solid oxide fuel cells (SOFCs) in smart grid and concentrated solar fuel technologies). In this study, we report the utilization of nonstoichiometric perovskite oxides, BaCaNbFeO (BCNF) (0 ≤ x ≤ 1), to split CO into carbon, carbon monoxide, and oxygen at elevated temperatures. Powder X-ray diffraction shows the chemical stability of double perovskite-type BCNF after being exposed to 2000 ppm CO in Ar at 700 °C. Furthermore, all x ≤ 0.66 BCNF members exhibit high chemical stability even under pure CO at 700 °C. Scanning electron microscopy coupled with energy dispersive X-ray, Raman spectroscopy, temperature programmed oxidation (TPO) and mass spectroscopy (MS), and DFT analyses confirm the formation of solid carbon upon CO exposure, which increases with increasing Fe in BCNF. Mössbauer spectroscopy of the as-prepared BCNF shows the presence of Fe, Fe and Fe. Upon Ar exposure, the higher valent Fe component is reduced to Fe and subsequent oxidation of Fe seems to promote the CO reduction. Overall, these promising results of BCNFs, displaying redox activity at significantly lower temperatures compared to state-of-the-art ceria for CO reduction, show great potential for their use in renewable-driven fuel technologies.Peer Reviewe