PubMed · 14215580
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R EKINS, A SGHERZI. 1964-12-05. INTRINSIC FACTOR ASSAY.. https://doi.org/10.1016/s0140-6736(64)91082-7
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The contamination of water resources by uranyl (UO22+) ions poses significant environmental and health risks, requiring the development of efficient and sustainable remediation strategies. Adsorption-based techniques have emerged as promising approaches in the field of UO22+ removal, but the design of cost-effective, high-capacity, and environmentally friendly adsorbents remains challenging. In this study, a three-dimensional porous nano-hydroxyapatite@gelatin (nHAP@Ge) composite was synthesized through glutaraldehyde cross-linking, combining the structural stability of Ge with the high uranium affinity of nHAP. The optimized nHAP@Ge, with a nHAP:Ge mass ratio of 1:0.5, exhibited exceptional UO22+ removal efficiency (97 %), along with high adsorption capacity (364.03 mg/g). Systematic characterizations using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) methods revealed that the porous structure and surface functional groups (-OH, Ca2+, and PO43-) of the material synergistically contributed to binding UO22+ species. Furthermore, the incorporation of nHAP into the Ge framework resulted in enhanced thermal stability while significantly improving the UO22+ adsorption performance. This work presents a scalable, eco-friendly, and recyclable strategy for the effective treatment of uranium-contaminated water, with potential applications in nuclear wastewater treatment and environmental remediation.
The effect of polyelectrolyte chain length on the formation of multilayered assemblies of alternating globular proteins and linear polyanions prepared by the layer-by-layer electrostatic adsorption technique was investigated. The systems studied were albumin/sodium poly(styrenesulfonate), immunoglobulin G/sodium poly(styrenesulfonate), albumin/sodium dextran sulfate, and albumin/heparin. The formation of assemblies was followed using FTIR multiple internal reflection spectroscopy. While the amount of polyelectrolyte adsorbed on the first (primary) protein layer did not depend on its molecular weight, the effect of polyelectrolyte chain length was clearly observed in the following steps of alternating adsorption. Some short-chain polyanion molecules were removed from the surface when a next protein layer was adsorbed from solution. The short polyanion chains were not able to make a sufficient number of ion pairs for stable interaction with additional protein molecules and left the surface as soluble protein/polyanion complexes. The most pronounced effect could be seen with sodium poly(styrenesulfonate) of Mw up to ca. 2 x 10(4), but a detectable effect could be traced even up to Mw ca. 8 x 10(4). Such a pronounced effect, however, was not observed with dextran sulfate. The effect of molecular weight of heparin was clearly observed but all heparins tested, regardless of their molecular weight, effectively assembled with albumin to form multilayer.
Thioglycolic acid was immobilized onto silica gel surface using 3-aminopropyltrimethoxysilane as precursor silylating agent to yield silica. The amount of thioglycolic acid immobilized was 1.03 mmol per gram of silica. This new surface displayed a chelating moiety containing nitrogen, sulfur, and oxygen basic centers which are potentially capable of extracting cations from ethanolic solution, such as MCl3 ( M=Fe, Cr, and Mo). This process of extraction was carried out by the batch method when similar chemisorption isotherms were observed for all cations. The data were adjusted to a modified Langmuir equation. The sequence of the maximum retention capacity was Cr(III) > Mo(III) > Fe(III). The same adsorption was determined by calorimetric titration and the enthalpic values of -35.75 +/- 0.02, 32.90 +/- 0.15, and -84.08 +/- 0.12 kJmol(-1) for chromium, molybdenum, and iron, respectively, were obtained. From the calculated Gibbs free energy -23.4 +/- 0.2, -27.2 +/- 0.2, and -32.7 +/- 0.3 kJmol(-1), the variations in entropy obtained were 42 +/- 1, 201 +/- 1, 172 +/- 1 JK(-1)mol(-1) for the same sequence. All thermodynamic values are in agreement with the spontaneity of the proposed cation-basic center interactions for these chelating processes.