Effect of Bicarbonate, Calcium, and pH on the Reactivity of As(V) and U(VI) Mixtures

Abstract

Supporting InformationThe Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.est.9b06063. Additional information regarding final pH of the batch aqueous chemistry experiments, solid analyses methods and results, and speciation calculations is available in Supporting Information.

An Optical Fiber Sensor for Uranium Detection in Water

“…Calcium, which is known to form strong complexes with phosphonates [ 25 ], and magnesium, did not interfere even at Ca 2+ or Mg 2+ to uranyl weight ratio 1000 to 1 [ 17 ]. However, another possible interference could be given by the combination of calcium and carbonate with uranyl leading to stable soluble compounds, such as CaUO 2 (CO 3 ) 3 2− and Ca 2 UO 2 (CO 3 ) 3 [ 26 ]; this could cause some interference in environmental waters in which all these species co-exist.…”

“…Similarly, it is expected that both acidity and the presence of metal ions affect the strength of the interaction of uranyl with the sensing surface, and so the resonance wavelength. In particular, the formation of uranyl hydroxo complexes in water solution even at slightly acidic pH values is well documented [ 25 , 26 , 27 ], and they could have a chemical structure unsuitable for interacting with MUPA. Comparing the calibration curves in Figure 9 with that in NaNO 3 0.1 M in the absence of any competing metal ion ( Figure 6 ), it is seen that no interaction of uranyl with weak sites takes place, indicating that Ca 2+ and Mg 2+ effectively compete with uranyl for access to these sites.…”

“…These previous results are shortly reported here for convenience: cations such as Cu 2+ , Zn 2+ , Co 2+ , Ni 2+ , and Pb 2+ are demonstrated to not interfere up to a 20:1 metal ion/uranyl weight ratio, as well as common anions (nitrates, carbonates, chloride, sulfate, phosphates) up to 1000:1 anion: uranyl weight ratio. Due to the well-known ability to complex uranyl [ 25 ], hydrogen carbonate was mainly investigated in [ 17 ] and found to interfere only at higher than 200 mg L − 1 concentration, with a 15% reduction in the analytical signal of 50 μg L − 1 uranyl. The influence of possible organic ligands on the uranyl response was investigated too [ 17 ]; humic substances did not cause any interference even at concentrations up to 10 mg L − 1 (uranyl: 50 μg L − 1 ), while strong ligands as EDTA interfere at 1 mg L − 1 .…”

Uptake and Toxicity of Respirable Carbon-Rich Uranium-Bearing Particles: Insights into the Role of Particulates in Uranium Toxicity

“…The cell viability of A549 was assessed using the CellTiter-Blue Cell Viability Assay (Promega Corporation, evaluates the metabolic activity of cells). Dose–response was tested following treatments with C-rich U-bearing particle suspensions or the molar equivalent of soluble U solutions at environmentally relevant concentrations of U (from 0.01 to 445 μM). , The effects of the U particulate form on cell viability were emphasized by comparing C-rich U-bearing particles to organosilica particles containing comparable organic content without U and pure silica particles as an additional control. As a secondary measure of cytotoxicity, cell death was assessed by propidium iodide staining that tests membrane permeability.…”

“…The objective of this study is to determine the cellular uptake and toxicity of respirable synthesized C-rich U-bearing particles as a model organic particulate over a range of environmentally relevant U concentrations (0–445 μM). − Carbon-rich U-bearing particles are used in this study as a solid particulate phase of U distinct from soluble U salts that have been used for other toxicity studies. ,, We investigated the effects of different size distributions of C-rich U-bearing particles on cell viability, genotoxicity, intracellular U concentration, and the translocation of particles into the human lung epithelial cell model (A549). The cytotoxicity of particulate U was emphasized by using organosilica particles containing comparable organic content but without U and silica particles as an additional control.…”