Advanced Oxidation Processes (AOPs) – Utilization of Hydroxyl Radical and Singlet Oxygen

Considering the nature of organic contaminants in water, methods of their oxidative decomposition seem to be most appropriate for their removal from contaminated water. There are a lot of methods of chemical oxidation, however, Advanced Oxidation Processes (AOPs) seem to be the most suitable technologies for organic contaminants removal. AOPs belong to a group of processes that efficiently oxidize organic compounds towards harmless inorganic products such as water or carbon dioxide. The processes have shown great potential in treatment of pollutants of low or high concentrations and have found applications for various types of contamination. The hydroxyl radical (•OH) is oxidizing agent used at AOPs to drive contaminant decomposition. It is a powerful, non-selective chemical oxidant, which reacts very rapidly with most organic compounds. Another strong oxidizing agent, singlet oxygen, can be generated by photosensitization of phthalocyanines. Phthalocyanines are molecules based on pyrrol structures connected mainly with methionine groups (–CH=) having a metallic central atom. Illumination upon specific wavelengths initiates formation of singlet oxygen that attack organic contaminants

Ecologically Non-Invasive Decontamination of Natura 2000 Locality from Old Deposits of Hexavalent Chromium and Bivalent Nickel by Modular Electrocoagulation Combined with Ca(OH)2 Addition

A modular electrocoagulation unit, supported by Ca(OH)2 addition to treated water, was operated in the vicinity of a Natura 2000 site for the removal of Cr6+ or Ni2+ from contaminated groundwater. The process was performed at a constant flow rate of 350 L/h. Day 0 concentrations of Cr6+ and Ni2+ started at 91.6 mg/L for Ni2+ and 43 mg/L for Cr and during testing, were decreased by 15%–25%. Residual concentrations of Crtot. and Ni2+ below the required limits of 0.5 mg/L for Crtot. and 0.8 mg/L for Ni2+ can be achieved with the electrocoagulation unit and total removal efficiencies often exceeded 98%. The overall economic assessment showed its feasible application for removal of Cr6+ and Ni2+ on sites with requirements of high environmental protection standards. The polluted area was about 150 × 150 m (22,500 m2), and it contained approximately 78,750 m3 of water contaminated with Cr6+ and Ni2+ (over 41 and 91 mg/L, respectively). The modular arrangement might allow a scaling up. The process’ output could be thus increased according to the number of EC modules in operation

Fasting Plasma Glucose and Its Relationship to Anthropometric Phenotype in Women Diagnosed with Gestational Diabetes According to IADPSG Criteria

Background: Gestational diabetes mellitus (GDM) is characterized by new-onset hyperglycemia in pregnancy. According to the International Association of Diabetes and Pregnancy Study Groups (IADPSG) recommendations, GDM may be diagnosed based on repeatedly increased fasting glucose levels in the first trimester, or later, the detection of increased fasting glucose and/or increased glucose levels during a 75 g oral glucose tolerance test (OGTT). The study aimed to assess whether differences may be found between women diagnosed with GDM by fasting glucose or glucose challenge tests in early or late pregnancy. Methods: The retrospective observational study enrolled 418 women diagnosed with GDM in accordance with the IADPSG criteria: early pregnancy fasting plasma glucose (FPG) ≥ 5.1 mmol/L; late pregnancy FPG ≥ 5.1 mmol/L (0 min) and/or postprandial plasma glucose (PPG) ≥ 10.0 mmol/L (60 min), PPG ≥ 8.5 mmol/L (120 min) 75 g OGTT. The analyses included anthropometric parameters at the beginning and during pregnancy, laboratory values of glycated hemoglobin, fructosamine, birth weight measures and the presence of neonatal complications. Results: There were significant differences in body weight (78.3 ± 19.1; 74.0 ± 16.7; 67.2 ± 15.7 kg) and body mass index (BMI) (27.9 ± 6.6; 26.4 ± 5.8; 24.4 ± 5.2 kg/m2) in early pregnancy. Differences were also found in gestational weight gain (9.3 ± 6.8 vs. 12.4 ± 6.9 vs. 11.1 ± 4.7 kg) and the need for insulin therapy (14.7%; 7.1%; 4.0%). The study revealed no difference in the presence of neonatal complications but differences in birth weight (3372.2 ± 552.2 vs. 3415.6 ± 529.0 vs. 3199.0 ± 560.5 g). Conclusions: Gestational diabetes, characterized by FPG ≥ 5.1 mmol/L in early pregnancy, is associated with higher body weight and BMI at the beginning of pregnancy as well as with a higher risk for insulin therapy and increased birth weight

Nickel Silicide Catalyst from Photovoltaic Waste for the Methanation Reaction

A technology designed for recycling photovoltaic (PV) cells at the end of their life was successfully used for the preparation of a nickel silicide catalyst. PV cells were mixed with magnesium scrap to produce magnesium silicide (Mg2Si), with almost total conversion under optimized conditions (400 °C, 5 Pa, 25 min), in a constructed semi-open tubular reactor. Subsequently, magnesium silicide was hydrolyzed by 25% phosphoric acid to produce a mixture of silicon hydrides, which were utilized as chemical vapor deposition (CVD) precursors for the preparation of a nickel silicide catalyst. The activity and stability of the prepared catalyst was repeatedly tested for methanation reactions. It was verified that the nickel silicide catalyst showed an approximately 20% higher activity for the methanation reactions compared to the commonly used nickel catalyst

Fenton Reaction–Unique but Still Mysterious

This study is devoted to the Fenton reaction, which, despite hundreds of reports in a number of scientific journals, provides opportunities for further investigation of its use as a method of advanced oxidation of organic macro- and micropollutants in its diverse variations and hybrid systems. It transpires that, for example, the choice of the concentrations and ratios of basic chemical substances, i.e., hydrogen peroxide and catalysts based on the Fe2+ ion or other transition metals in homogeneous and heterogeneous arrangements for reactions with various pollutants, is for now the result of the experimental determination of rather randomly selected quantities, requiring further optimizations. The research to date also shows the indispensability of the Fenton reaction related to environmental issues, as it represents the pillar of all advanced oxidation processes, regarding the idea of oxidative hydroxide radicals. This study tries to summarize not only the current knowledge of the Fenton process and identify its advantages, but also the problems that need to be solved. Based on these findings, we identified the necessary steps affecting its further development that need to be resolved and should be the focus of further research related to the Fenton process

Nickel Silicide Catalyst from Photovoltaic Waste for the Methanation Reaction

A technology designed for recycling photovoltaic (PV) cells at the end of their life was successfully used for the preparation of a nickel silicide catalyst. PV cells were mixed with magnesium scrap to produce magnesium silicide (Mg2Si), with almost total conversion under optimized conditions (400 °C, 5 Pa, 25 min), in a constructed semi-open tubular reactor. Subsequently, magnesium silicide was hydrolyzed by 25% phosphoric acid to produce a mixture of silicon hydrides, which were utilized as chemical vapor deposition (CVD) precursors for the preparation of a nickel silicide catalyst. The activity and stability of the prepared catalyst was repeatedly tested for methanation reactions. It was verified that the nickel silicide catalyst showed an approximately 20% higher activity for the methanation reactions compared to the commonly used nickel catalyst

Effective Assessment of Diabetes Control Using Personal Glucometers (CONTOURLINK, Bayer, Germany; CALLA, Wellion, Austria; LINUS, Agamatrix, USA)

Aim of this trial was to assess (1) the accuracy and precision of electrochemistry-based glucometers CONTOURLINK, CALLA, and LINUS and (2) the diabetes control using Ambulatory Glycaemic Profiles (AGP) as markers of therapeutic effectiveness. Glucometers and COBAS INTEGRA 400 Plus analyzer were used by one laboratory professional to estimate P-glucose (PG) in 112 out-patients. There were 112 sets of 12 PG estimations analyzed. In each set, means of 3 capillary PG estimations on 3 respective glucometers and on INTEGRA analyzer were calculated. The statistical program SPSS, v. 15, was applied. The mean INTEGRA PG values ranged from 2.7 to 25.3 mmol/L. There were strong correlations between mean PG on INTEGRA versus CONTOURLINK, versus CALLA, and versus LINUS; PG deviations from INTEGRA were mostly within the range ±15%. Wilcoxon Signed Rank Test revealed differences between CONTOURLINK-INTEGRA and LINUS-INTEGRA; CALLA-INTEGRA showed no difference. SD INTEGRA = 0.061 mmol/L, SD CONTOURLINK/SD CALLA/SD LINUS were 0.256/0.290/0.286 mmol/L. All patients were trained to perform defined 10-point PG profiles to adapt food, exercise, and insulin doses. The PG differences between all tested glucometers and reference values were in borderline of ISO 15197 but worthy of consideration. AGP are helpful markers of diabetes control

Adiponectin, A-FABP and FGF-19 Levels in Women with Early Diagnosed Gestational Diabetes

Background: Adiponectin, adipocyte fatty acid-binding protein (A-FABP), and fibroblast growth factor-19 (FGF-19) belong to proteins involved in glucose metabolism regulation. The aims of the study were to compare the plasma levels of these proteins in women with early diagnosed gestational diabetes mellitus (GDM) to those in healthy controls and to investigate their changes during pregnancy after early intervention. Methods: The study was undertaken as a case-control study. Early GDM diagnosis was based on repeated fasting plasma glucose ≥5.1 and <7.0 mmol/L during the first trimester of pregnancy and exclusion of overt diabetes. Age-matched controls comprised healthy pregnant and non-pregnant women. In addition to adipokines, clinical parameters and measures of glucose control were assessed. Results: Women with GDM (n = 23) had significantly lower adiponectin and higher A-FABP levels compared to healthy pregnant (n = 29) or non-pregnant (n = 25) controls, while no significant differences in FGF-19 between the groups were found. The therapeutic intervention shifted adiponectin and A-FABP levels in GDM women towards concentrations of healthy pregnant controls. Adipokines were associated with visceral adiposity and glucose control. Conclusion: Women with GDM showed altered adipokine production even in the first trimester of pregnancy. Early therapeutic intervention not only improved glucose control but also normalized impaired adipokine production