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Relation Between Natural Radionuclide Activities and Chemical Constituents in Ground Water in the Newark Basin, New Jersey
Published in Barbara Graves, Radon, Radium, and Other Radioactivity in Ground Water, 2020
Iron and manganese hydroxides are soluble where ground water pH values decrease below 7.0 and Eh values decrease below approximately +200 mV [25]. In such waters, iron and manganese hydroxide coatings are less abundant on mineral grains or along microfractures, because they are unstable in such environments and would tend to dissolve. Therefore, radium-226 released by alpha-recoil will have a smaller likelihood of being adsorbed onto iron and manganese hydroxides in such waters, and will have a greater likelihood of migrating into larger pore spaces and major fractures. Concentrations of iron, manganese, and radium-226 increase together in the ground water with decreasing dissolved oxygen concentrations, decreasing Eh, and decreasing pH. These relations are observed throughout the study area.
New Emerging and Experimental Materials for Wound Closure
Published in Chih-Chang Chu, J. Anthony von Fraunhofer, Howard P. Greisler, Wound Closure Biomaterials and Devices, 2018
In addition to reported use by Chu et al. of Ag-coated nylon sutures for wound infection control, Farrah and Erdos recently reported the use of silver salts-impregnated polyester suture (Ethibond®) to render it antimicrobial.13 Ethibond sutures were modified by two different methods: adsorption of silver metals onto the suture surface pretreated either with manganese hydroxide [Mn(N03)2 + NH4OH] or sodium pyrophosphate [Na4P2O7] to facilitate the precipitation of silver metal. Both precipitation methods resulted in polyester sutures having good antimicrobial properties toward P. aeruginosa, E. coli, and S. aureus. However, the manganese hydroxide pretreatment appeared to exhibit a better antimicrobial property toward P. aeruginosa than sodium pyrophosphate pretreatment, as evident in the larger zone of bacterial inhibition. For example, 2.4 ± 0.7 and 0.6 ± 0.5 mm zones of inhibition were found with manganese hydroxide and sodium pyrophosphate pretreatments, respectively. This tendency, however, was not found in E. coli and S. aureus in which both treatments showed a statistically insignificant difference in zone of inhibition, as shown in Table 12.3. Presoaking of the antimicrobial Ethibond suture in saline solution for 4 d before inhibition zone evaluation, however, reduced the antimicrobial capability of the treated suture, as indicated by the significant reduction in the size of the inhibition zone with both pretreatments.
Synthesis of Zinc, Copper, Cadmium, and Iron Sulfides and Their Sorption Properties
Published in D.S. Sofronov, K.N. Belikov, M. Rucki, S.N. Lavrynenko, Z. Siemiątkowski, E. Yu. Bryleva, O.M. Odnovolova, Synthetic Sorbent Materials Based on Metal Sulphides and Oxides, 2020
D.S. Sofronov, K.N. Belikov, M. Rucki, S.N. Lavrynenko, Z. Siemiątkowski, E. Yu. Bryleva, O.M. Odnovolova
In order to confirm Mn3O4 formation as a result of manganese application during ZnS synthesis, additional experiments were performed to observe manganese sulfate reaction with thiourea and sodium sulfide. In the IR spectra of the obtained particles shown in Figure 1.47, intensive absorption bands are seen at 488 and 614 cm−1. X-ray structure analysis provided information that the main phase of the synthesized powders was Mn3O4. It was formed as a result of manganese hydroxide and sulfide oxidation with the air oxygen during drying process. Thus, we were unable to obtain the manganese sulfide in the precipitation process from the aqueous solution.
Minreview: Recent advances in the development of gaseous and dissolved oxygen sensors
Published in Instrumentation Science & Technology, 2019
Q. Wang, Jia-Ming Zhang, Shuai Li
The indirect Winkler method uses residual iodine and the replacement of iodine methods. This procedure must be in neutral or weak acid solution. High acidity oxidizes iodide, which promotes the decomposition of sodium thiosulfate. In highly alkaline solution, disproportionate reactions occur with iodine. The surplus iodine method uses excess iodine as reducing substances. The first reaction involves reducing substances and excess iodine, while the remaining iodine with a sodium thiosulfate back-titration, and amount of sodium thiosulfate is used to determine the concentration. The determination of water-soluble oxygen is replaced by the Winkler method. The basic procedure uses manganese chloride and sodium hydroxide to induce manganese hydroxide precipitation, water-soluble oxygen precipitation into a brown precipitate, followed by reaction with sulfuric acid to produce manganese sulfate. Lastly, the potassium iodide is oxidized to iodine, and the resulting iodine is titrated with sodium thiosulfate.
Microwave-assisted synthesis of gold nanoparticles supported on Mn3O4 catalyst for low temperature CO oxidation
Published in Environmental Technology, 2021
Moataz Morad, Mohammad A. Karim, Hatem M. Altass, Abd El Rahman S. Khder
Manganese hydroxide gel was prepared by direct precipitation method by mixing 0.3 M solution of Mn(NO3)2 4H2O (Sigma-Aldrich 97%) with 10 M NaOH solution dropwise at constant stirring until pH 12. Then, the first part of the obtained gel (represented as Mn3O4 HT) was heated at 150°C 24 h in 75 mL Teflon-lined autoclave, then filtered, washed and dried 100°C. While the second part of the obtained gel (represented as Mn3O4) was directly filtered, washed and dried at 100°C without hydrothermal treatment.