ferrihydrite and titanium-dioxide

Accurate detection and analysis of arsenic pollutants are an important means to enhance the ability to manage arsenic pollution. Infrared (IR) spectroscopy technology has the advantages of fast analysis speed, high resolution, and high sensitivity and can be monitored by real-time in situ analysis. This paper reviews the application of IR spectroscopy in the qualitative and quantitative analysis of inorganic and organic arsenic acid adsorbed by major minerals such as ferrihydrite (FH), hematite, goethite, and titanium dioxide. The IR spectroscopy technique cannot only identify different arsenic contaminants but also obtain the content and adsorption rate of arsenic contaminants in the solid phase. The reaction equilibrium constants and the degree of reaction conversion can be determined by constructing adsorption isotherms or combining them with modeling techniques. Theoretical calculations of IR spectra of mineral adsorbed arsenic pollutant systems based on density functional theory (DFT) and analysis and comparison of the measured and theoretically calculated characteristic peaks of IR spectra can reveal the microscopic mechanism and surface chemical morphology of the arsenic adsorption process. This paper systematically summarizes the qualitative and quantitative studies and theoretical calculations of IR spectroscopy in inorganic and organic arsenic pollutant adsorption systems, which provides new insights for accurate detection and analysis of arsenic pollutants and arsenic pollution control. PRACTITIONER POINTS: This paper reviews the application of infrared spectroscopy in the qualitative and quantitative analyses of inorganic and organic arsenic acid adsorbed by major minerals such as ferrihydrite, hematite, goethite, and titanium dioxide, which can help identify and evaluate the type and concentration of arsenic pollutants in water bodies. In this paper, theoretical calculations of infrared spectra of mineral adsorbed arsenic pollutant systems based on density functional theory reveal the adsorption mechanism of arsenic pollutants in water at the solid-liquid interface and help to develop targeted arsenic pollution control technologies. This paper provides a new and reliable analytical detection technique for the study of arsenic contaminants in water bodies.

Topics: Adsorption; Arsenic; Arsenicals; Ferric Compounds; Minerals; Organic Chemicals; Spectrophotometry, Infrared; Spectroscopy, Fourier Transform Infrared; Water; Water Pollutants, Chemical

Over the last 3 years, there has been a proliferation of legislation aimed at restricting the rights of transgender Americans, including their access to gender-affirming health care. While the health implications of not having access to gender-affirming care are well documented, there may be additional indirect harms associated with proposing this type of legislation, such as those associated with being exposed to negative messages about transgender people or having to contend with friends and family who support the legislation.. Results showed that news consumption was associated with increased rumination and physical health symptoms and that perceived support for the legislation was associated with greater rumination, depressive symptoms, physical health symptoms, and fear of disclosing one's identity. Themes from the open-ended questions further underscored that the current legislation has impacted transgender youth and young adults' access to general health care; increased experiences of discrimination and other maltreatment; and resulted in some respondents engaging in unhealthy coping responses.. Policy makers should consider these adverse consequences when responding to current, and crafting future, legislation directed at transgender Americans.. Supplementary material is available in the online version of this article at 10.1007/s11814-023-1461-8.. Hyperglycemia at admission was associated with poor outcomes in COVID-19 patients, even in those without known pre-existing diabetes. Glycemic testing should be recommended for all COVID-19 patients.. Intermittent relacorilant + nab-paclitaxel improved PFS, DOR, and OS compared with nab-paclitaxel monotherapy. On the basis of protocol-prespecified Hochberg step-up multiplicity adjustment, the primary end point did not reach statistical significance (

Topics: Acute Kidney Injury; Adult; Aged; Albumins; Alloys; Amides; Amino Acids; Animals; Antineoplastic Combined Chemotherapy Protocols; Antioxidants; Bioaccumulation; Blood Glucose; Brain; Brassica napus; Breast Neoplasms; Carcinoma, Ovarian Epithelial; Catalysis; Child; China; Chlorides; Chlorine; Chromium; Chronic Disease; Cohort Studies; Copper; Corrosion; COVID-19; Creatinine; Dermatitis; Diabetes Mellitus; Diazepam; Disease-Free Survival; DNA Repair; DNA-(Apurinic or Apyrimidinic Site) Lyase; Dyspnea; Electron Spin Resonance Spectroscopy; Environmental Monitoring; Escherichia coli; Escherichia coli Infections; Esophageal Neoplasms; Esophagogastric Junction; Estradiol; Exercise Test; Exercise Tolerance; Female; Ferric Compounds; Fishes; Food Chain; gamma-Aminobutyric Acid; Genomics; Halogenation; HEK293 Cells; Hemolysis; Heterocyclic Compounds; Hospitalization; Humans; Hydrogen Peroxide; Hyperglycemia; Introns; Iron; Kidney; Kinetics; Laboratories; Limit of Detection; Lipopolysaccharides; Liver Neoplasms; Magnesium; Male; Mammals; Materials Testing; Mercury; Metal-Organic Frameworks; Methylmercury Compounds; Mice; Microscopy, Electron, Scanning; Mifepristone; Minerals; Molecular Weight; Mutation; Nanoparticles; Neuroprotection; NF-kappa B; Nitrates; Nitrogen; NLR Family, Pyrin Domain-Containing 3 Protein; Orthopedics; Ovarian Neoplasms; Ovariectomy; Oxidation-Reduction; Oxidative Stress; Oxygen; Oxygen Consumption; Paclitaxel; Phenols; Progesterone; Prospective Studies; Proteins; Protons; Pulmonary Disease, Chronic Obstructive; Ramucirumab; Rats; Receptor, ErbB-2; Respiratory Function Tests; Retrospective Studies; Saliva; SARS-CoV-2; Seeds; Sesbania; Shock, Septic; Silicon Dioxide; Sleep; Soil; Specimen Handling; Spectroscopy, Mossbauer; Spin Labels; Staphylococcus aureus; Stomach Neoplasms; Streptococcus mutans; Thiamine; Toll-Like Receptor 2; Toll-Like Receptor 4; Trastuzumab; Tumor Microenvironment; Tumor Necrosis Factor-alpha; Ubiquitin-Protein Ligases; Water; Water Pollutants, Chemical; Water Purification; Xeroderma Pigmentosum; Zebrafish

The redistribution process of arsenate (As(V)) and the variation in As(V) content in different locations must be clarified to ensure low mobility of As(V) during microbial ferrihydrite reduction. In this study, we investigated As(V) immobilization and redistribution processes when ferrihydrite was incubated with Geobacter sulfurreducens in the presence of titanium dioxide (TiO

Topics: Ferric Compounds; Geobacter; Minerals; Nanoparticles; Oxidation-Reduction; Titanium

A coal ash spill that occurred from an ash impoundment pond into the Dan River, North Carolina, provided a unique opportunity to study the significance and role of naturally occurring and incidental nanomaterials associated with contaminant distribution from a large-scale, acute aquatic contamination event. Besides traditional measurements of bulk watercolumn and sediment metal concentrations, the nanoparticle (NP) analyses are based on cross-flow ultrafiltration (CFUF) and advanced transmission electron microscopy (TEM) techniques. A drain pipe fed by coal ash impoundment seepage showed a high level of arsenic, with concentrations many times over the EPA limit. The majority of the arsenic was found sorbed to large aggregates dominated by incidental iron oxyhydroxide (ferrihydrite) NPs, while the remainder of the arsenic was truly dissolved. These ferrihydrites were probably formed in situ where Fe(II) was leached through subsurface flowpaths into an aerobic environment, and further act as a significant contributor to the elevated As concentrations in downstream sediments after the spill. In addition, we discovered and describe a photocatalytic nano-TiO2 phase (anatase) present in the coal ash impacted river water that was also carrying/transporting transition metals (Cu, Fe), which may also have environmental consequences.

Topics: Arsenic; Chemical Hazard Release; Coal Ash; Ferric Compounds; Metal Nanoparticles; Metals; Microscopy, Electron, Transmission; Nanotechnology; North Carolina; Rivers; Titanium; Ultrafiltration; Water Pollutants, Chemical

Arsenic concentration in the pore water of paddy fields (Csoln) irrigated with arsenic-rich groundwater is a key parameter in arsenic uptake by rice. Pore water extracts from cores and in situ deployment of DET and DGT probes were used to measure the arsenic concentration in the pore water. Ferrihydrite (Fe) and titanium dioxide (Ti) were used as DGT binding agents. Six sampling events during different growing stages of the rice, inducing different biogeochemical conditions, were performed in one rice field. A time series of DGT experiments allow the determination of an in situ arsenic diffusion coefficient in the diffusive gel (3.34×10(-6) cm(2) s(-1)) needed to calculate the so-called CDGT(Fe) and CDGT(Ti) concentrations. Over 3 days of a given sampling event and for cores sampled at intervals smaller than 50 cm, great variability in arsenic Csoln concentrations between vertical profiles was observed, with maxima of concentrations varying from 690 to 2800 μg L(-1). Comparisons between arsenic measured Csol and CDET and calculated CDGT(Fe) and CDGT(Ti) concentrations show either, in a few cases, roughly similar vertical profiles, or in other cases, significantly different profiles. An established iron oxyhydroxide precipitation in the DET gel may explain why measured arsenic CDET concentrations occasionally exceeded Csoln. The large spread in results suggests limitations to the use of DET and type of DGT probes used here for similarly representing the spatio-temporal variations of arsenic content in soil pore water in specific environmental such as paddy soils.

Topics: Arsenic; Bangladesh; Environmental Monitoring; Ferric Compounds; Groundwater; Soil; Soil Pollutants; Titanium; Water Pollutants, Chemical

Using the isotope specificity of 57Fe Mössbauer spectroscopy, we report spectroscopic observations of Fe(II) reacted with oxide surfaces under conditions typical of natural environments (i.e., wet, anoxic, circumneutral pH, and about 1% Fe(II)). Mössbauer spectra of Fe(II) adsorbed to rutile (TiO2) and aluminum oxide (Al2O3) show only Fe(II) species, whereas spectra of Fe(II) reacted with goethite (alpha-FeOOH), hematite (alpha-Fe2O3), and ferrihydrite (Fe5HO8) demonstrate electron transfer between the adsorbed Fe(II) and the underlying iron(III) oxide. Electron-transfer induces growth of an Fe(III) layer on the oxide surface that is similar to the bulk oxide. The resulting oxide is capable of reducing nitrobenzene (as expected based on previous studies), but interestingly, the oxide is only reactive when aqueous Fe(II) is present. This finding suggests a novel pathway for the biogeochemical cycling of Fe and also raises important questions regarding the mechanism of contaminant reduction by Fe(II) in the presence of oxide surfaces.

Topics: Adsorption; Aluminum Oxide; Ferric Compounds; Ferritins; Ferrous Compounds; Iron Compounds; Iron Isotopes; Minerals; Oxidation-Reduction; Oxides; Spectroscopy, Mossbauer; Surface Properties; Titanium; Water