Recovery of Precious Metals: A Promising Process Using Supercritical Carbon Dioxide and CO2-Soluble Complexing Polymers for Palladium Extraction from Supported Catalysts.

Precious metals such as palladium (Pd) have many applications, ranging from automotive catalysts to fine chemistry. Platinum group metals are, thus, in massive demand for industrial applications, even though they are relatively rare and belong to the list of critical materials for many countries. The result is an explosion of their price. The recovery of Pd from spent catalysts and, more generally, the development of a circular economy process around Pd, becomes essential for both economic and environmental reasons. To this aim, we propose a sustainable process based on the use of supercritical CO2 (i.e., a green solvent) operated in mild conditions of pressure and temperature (p = 25 MPa, T = 313 K). Note that the range of CO2 pressures commonly used for extraction is going from 15 to 100 MPa, while temperatures typically vary from 308 to 423 K. A pressure of 25 MPa and a temperature of 313 K can, therefore, be viewed as mild conditions. CO2-soluble copolymers bearing complexing groups, such as pyridine, triphenylphosphine, or acetylacetate, were added to the supercritical fluid to extract the Pd from the catalyst. Two supported catalysts were tested: a pristine aluminosilicate-supported catalyst (Cat D) and a spent alumina supported-catalyst (Cat A). An extraction conversion of up to more than 70% was achieved in the presence of the pyridine-containing copolymer. The recovery of the Pd from the polymer was possible after extraction, and the technological and economical assessment of the process was considered.

S2k guideline for diving accidents.

For the purposes of this guideline, a diving accident is defined as an event that is either potentially life-threatening or hazardous to health as a result of a reduction in ambient pressure while diving or in other hyperbaric atmospheres with and without diving equipment. This national consensus-based guideline (development grade S2k) presents the current state of knowledge and recommendations on the diagnosis and treatment of diving accident victims. The treatment of a breath-hold diver as well as children and adolescents does not differ in principle. In this regard only unusual tiredness and itching without visible skin changes are mild symptoms. The key action statements: on-site 100% oxygen first aid treatment, immobilization/no unnecessary movement, fluid administration and telephone consultation with a diving medicine specialist are recommended. Hyperbaric oxygen therapy (HBOT) remains unchanged as the established treatment in severe cases, as there are no therapeutic alternatives. The basic treatment scheme recommended for diving accidents is hyperbaric oxygenation at 280 kPa.

Synthesis and Phase Behavior of a Platform of CO2-Soluble Functional Gradient Copolymers Bearing Metal-Complexing Units.

The synthesis and characterization of a platform of novel functional fluorinated gradient copolymers soluble in liquid and supercritical CO2 is reported. These functional copolymers are bearing different types of complexing units (pyridine, triphenylphosphine, acetylacetate, thioacetate, and thiol) which are well-known ligands for various metals. They have been prepared by reversible addition-fragmentation chain-transfer (RAFT) polymerization in order to obtain well-defined gradient copolymers. The copolymers have been characterized by proton nuclear magnetic resonance (1H-NMR) spectroscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, thermal gravimetric analysis (TGA), dynamical scanning calorimetry (DSC) and cloud point measurements in dense CO2. All the investigated metal-complexing copolymers are soluble in dense CO2 under mild conditions (pressure lower than 30 MPa up to 65 °C), confirming their potential applications in processes such as metal-catalyzed reactions in dense CO2, metal impregnation, (e.g., preparation of supported catalysts) or metal extraction from various substrates (solid or liquid effluents). Particularly, it opens the door to greener and less energy-demanding processes for the recovery of metals from spent catalysts compared to more conventional pyro- and hydro-metallurgical methods.

Treatment of children with hyperbaric oxygenation (HBOT): a Europe-wide survey.

BACKGROUND: Hyperbaric oxygenation therapy (HBOT) is used as emergency treatment for decompression sickness, gas embolism, carbon monoxide intoxication, and necrotizing fasciitis. There is low evidence and little clinical knowledge about the treatment of children with HBOT. METHODS: We sent an internet-based questionnaire to HBO centers in Europe to gain information about their experience with children and HBOT. RESULTS: Out of all HBO-centers who participated in the questionnaire 90% treat children analogue to adults about indication and HBOT protocol. Most treated children had life-threatening indications or the risk of organ loss. The reported rate of side effects was: 6.8% anxiety, 2.4% barotrauma, 0.9% seizure, 0.2% retinopathy and no case of pulmonary barotrauma or oxygen toxicity. CONCLUSIONS: HBO therapy for children is present in European HBO centers. The rate of severe side effects is as low to the rates in adults; apart from this, oxygen-related seizures and anxiety are more frequent. A special focus seems necessary on the psychological management of the children, because anxiety is common depending on the age of the children. Especially for smaller children, an adequate psychological support seems essential. Prospective observational or controlled studies in children seem necessary to create relevant clinical evidence for HBOT and to observe the rate of side-effects.

S2k guideline diagnosis and treatment of carbon monoxide poisoning.

Carbon monoxide (CO) can occur in numerous situations and ambient conditions, such as fire smoke, indoor fireplaces, silos containing large quantities of wood pellets, engine exhaust fumes, and when using hookahs. Symptoms of CO poisoning are nonspecific and can range from dizziness, headache, and angina pectoris to unconsciousness and death. This guideline presents the current state of knowledge and national recommendations on the diagnosis and treatment of patients with CO poisoning. The diagnosis of CO poisoning is based on clinical symptoms and proven or probable exposure to CO. Negative carboxyhemoglobin (COHb) levels should not rule out CO poisoning if the history and symptoms are consistent with this phenomenon. Reduced oxygen-carrying capacity, impairment of the cellular respiratory chain, and immunomodulatory processes may result in myocardial and central nervous tissue damage even after a reduction in COHb. If CO poisoning is suspected, 100% oxygen breathing should be immediately initiated in the prehospital setting. Clinical symptoms do not correlate with COHb elimination from the blood; therefore, COHb monitoring alone is unsuitable for treatment management. Especially in the absence of improvement despite treatment, a reevaluation for other possible differential diagnoses ought to be performed. Evidence regarding the benefit of hyperbaric oxygen therapy (HBOT) is scant and the subject of controversy due to the heterogeneity of studies. If required, HBOT should be initiated within 6 h. All patients with CO poisoning should be informed about the risk of delayed neurological sequelae (DNS).

Supercritical CO2 Extraction of Palladium Oxide from an Aluminosilicate-Supported Catalyst Enhanced by a Combination of Complexing Polymers and Piperidine.

Precious metals, in particular Pd, have a wide range of applications in industry. Due to their scarcity, precious metals have to be recycled, preferably with green and energy-saving recycling processes. In this article, palladium extraction from an aluminosilicate-supported catalyst, containing about 2 wt% (weight%) of Pd (100% PdO), with supercritical CO2 (scCO2) assisted by complexing polymers is described. Two polymers, p(FDA)SH homopolymer and p(FDA-co-DPPS) copolymer (FDA: 1,1,2,2-tetrahydroperfluorodecyl acrylate; DPPS: 4-(diphenylphosphino)styrene), were tested with regards to their ability to extract palladium. Both polymers showed relatively low extraction conversions of approximately 18% and 30%, respectively. However, the addition of piperidine as activator for p(FDA-co-DPPS) allowed for an increase in the extraction conversion of up to 60%.

Decentralized safety concept for closed-loop controlled intensive care.

This paper presents a decentralized safety concept for networked intensive care setups, for which a decentralized network of sensors and actuators is realized by embedded microcontroller nodes. It is evaluated for up to eleven medical devices in a setup for automated acute respiratory distress syndrome (ARDS) therapy. In this contribution we highlight a blood pump supervision as exemplary safety measure, which allows a reliable bubble detection in an extracorporeal blood circulation. The approach is validated with data of animal experiments including 35 bubbles with a size between 0.05 and 0.3 ml. All 18 bubbles with a size down to 0.15 ml are successfully detected. By using hidden Markov models (HMMs) as statistical method the number of necessary sensors can be reduced by two pressure sensors.

Physiological closed-loop control of mechanical ventilation and extracorporeal membrane oxygenation.

A new concept is presented for cooperative automation of mechanical ventilation and extracorporeal membrane oxygenation (ECMO) therapy for treatment of acute respiratory distress syndrome (ARDS). While mechanical ventilation is continuously optimized to promote lung protection, extracorporeal gas transfer rates are simultaneously adjusted to control oxygen supply and carbon dioxide removal using a robust patient-in-the-loop control system. In addition, the cooperative therapy management uses higher-level algorithms to adjust both therapeutic approaches. The controller synthesis is derived based on the introduced objectives, the experimental setup and the uncertain models. Finally, the autonomous ARDS therapy system capabilities are demonstrated and discussed based on in vivo data from animal experiments.

Blood lead levels in scuba divers: a pilot study.

INTRODUCTION: Lead is a toxic element which is known to accumulate in the body. Nevertheless, it is very widely used as a diving weight. METHODS: Blood samples were taken from 20 recreational scuba divers to assess blood lead concentrations. RESULTS: The last dive before blood sampling was an average of 4.8 weeks previously (range 1-18 weeks). All the samples were within the normal background range, the highest lead concentration being 44.8 µg∙L⁻¹ with an average concentration of 26.5 µg∙L⁻¹ (range 11.7-44.8 µg∙L⁻¹). CONCLUSIONS: The results show no elevated blood lead concentrations in this group of divers compared to background levels. However, owing to the small number of divers studied and the variable, often long interval between the last dive and blood sampling, the results cannot be generalized.

Cerebral air embolism after pleural streptokinase instillation.

Iatrogenic pulmonary barotrauma and cerebral arterial gas embolism (CAGE) may complicate a variety of medical procedures, such as certain types of surgery, drug administration through thoracic drainage, pneumoperitoneum, cystoscopy, bronchoscopy, etc. Hyperbaric oxygen treatment following the guidelines for CAGE in diving is the treatment of choice. Pleural streptokinase instillation is a common treatment for parapneumonic pleural effusion and may lead to CAGE. We present such a complication in a 79-year-old woman with a left-sided empyema. Neurological recovery was reasonable, but a left hemiparesis persisted. Prompt treatment of CAGE is necessary to avoid permanent injury and severe disability.

Expected and observed mortality in critically ill patients receiving initial antibiotic therapy.

OBJECTIVE: To evaluate the predictors of mortality in critically ill patients receiving initial antibiotic therapy (IAT; < 48 h after admission). METHODS: Six hundred thirty-one consecutive patients admitted to an intermediate care (IMC) unit were included. IAT was initiated in 227 patients. Laboratory markers, interventions, medications, systemic inflammatory response syndrome (SIRS) and sepsis criteria, length of stay, and hospital mortality as well as expected mortality, based on the SAPSII-expanded score, were assessed retrospectively. Failure of IAT was defined as a rise in C-reactive protein (CRP) or leukocyte count on day 3 compared with the values on admission. RESULTS: Patients with IAT were significantly older (67 ± 14 vs. 64 ± 14 years; p = 0.006) and had a higher prevalence of chronic renal failure (33 vs. 23 %; p = 0.015), chronic obstructive pulmonary disease (COPD; 27 vs. 16 %; p = 0.002), malignoma (17 vs. 9 %; p = 0.007), acute renal failure (11 vs. 4 %; p = 0.001), respiratory failure (22 vs. 7 %; p < 0.001), and a shock index < 1.0 (21 vs. 8 %; p < 0.001). Although patients with IAT did not have significantly different expected mortality compared with patients without IAT (19.2 vs. 14.5 %; p = 0.144), they did have a significantly higher observed mortality (16.7 vs. 3.7 %; p < 0.0001). Based on the number of SIRS criteria (0, 1, 2, or 3-4) or sepsis criteria (no sepsis, sepsis, or severe sepsis) fulfilled, expected mortality (16.4, 18.2, 20.6, or 21.0 %, respectively; p = 0.955/17.5, 18.3, or 23.4 %, respectively; p = 0.689) did not differ in IAT patients. In contrast, observed mortality differed significantly (4.8, 10.6, 20.6, or 29.4 %, respectively; p = 0.029/8.3, 19.7, or 29.3 %, respectively; p = 0.013). Patients who responded to IAT did not differ regarding comorbidities, SIRS or sepsis criteria, but they had a lower observed mortality (11.9 vs. 26.3 %; p = 0.008) than patients who failed to respond to IAT. Central venous lines were more frequently present in patients with failure to IAT when compared with those with response (51 vs. 22 %; p = 0.009). In the subgroup of patients with acute myocardial infarction (AMI), those with IAT (n = 41) were treated less frequently according to the current cardiac guidelines than those without (n = 124) CONCLUSIONS: Patients with IAT have a high morbidity burden and higher observed than expected mortality. The SAPSII-expanded score does not seem to precisely estimate the risk of in-hospital mortality in these patients. Failure of response to IAT was associated with an even higher mortality. Whether central venous lines and nonadherence to cardiac care guidelines influence the mortality of patients with IAT should be investigated in further studies.