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Tracers
Published in Werner Käss, Tracing Technique in Geohydrology, 2018
The titrimetrical chloride determination according to Mohr has been used for a long time (1855). For the titration, a few drops of a potassium bichromate solution as an indicator are added to 100 ml of the sample and tritrated with a reference silver nitrate solution until the colour changes from yellow to brown (DEV, D1,2 and DIN 38 405, Part 1). Since it is easy to over-tritrate with this method, another chloride determination method is also often used: the titration with mercury-II-nitrate in nitric acid solution with diphenylcarbazone as an indicator. Although this method is more accurate than that from Mohr, it should be avoided out of environmental considerations due to the mercury.
Simultaneous removal of NOx, SO2, and Hg from flue gas in FGD absorber with oxidant injection (NaClO2)– full-scale investigation
Published in Journal of the Air & Waste Management Association, 2020
Maria Jędrusik, Dariusz Łuszkiewicz, Arkadiusz Świerczok, Mieczysław Adam Gostomczyk, Mariola Kobylańska-Pawlisz
The nitric acid formed in the flue gas reacted with the metallic mercury and oxidized it to the form Hg2+ (mercury (II) nitrate), which explains the relationship between the increase in the amount of oxidant and the HgT removal efficiency from flue gas (Krzyżyńska, Zhao, and Hutson 2010; Lee, Deshwal, and Yoo 2005):
Synthesis, X-ray characterization, and in vitro biological approach of dimeric and polymeric mercury(II) complexes with α-keto stabilized sulfur ylide
Published in Journal of Coordination Chemistry, 2018
Seyyed Javad Sabounchei, Mojdeh Sadat Hashemi, Roya Karamian, Seyed Hamed Moazzami Farida, Parviz Gohari Derakhshandeh, Robert W. Gable, Kristof Van Hecke
DPPH has been broadly used to test the antioxidant potential of different compounds. The antioxidants have the ability to reduce stable radicals changing the characteristic deep purple color (λmax=515–517 nm) of DPPH to the yellow-colored nonradical diphenyl-picrylhydrazine (DPPH-H) [33, 34]. Results of DPPH assay are summarized in Table 3 (see also Table S3 in Supporting Information). According to our results, most of the synthesized compounds display tremendous dose-dependent (0.2–1 mg·mL−1) antiradical activity (46.81–70.53%) (Table 3). The scavenging activity is higher when the IC50 value is low. The effectiveness of the samples as DPPH radical scavengers ranged in the following descending order: (i) ylide (IC50=0.16 ± 0.01 mg·mL−1) < (ii) [HgCl2(Y)]2 (IC50=0.19 ± 0.05 mg·mL−1) < (iii) [HgI2(Y)]2 (IC50=0.52 ± 0.01 mg·mL−1) < (iv) [HgBr2(Y)]2 (IC50=0.53 ± 0.01 mg·mL−1) < (v) [Hg(NO3)2(Y)]n complexes (IC50=0.94 ± 0.01 mg·mL−1). Results showed that (i) and (ii) were compared with ascorbic acid and quercetin as standard antioxidant in radical scavenging. A comparison between the DPPH radical scavenging activity of the synthesized compounds and some of other ylide-based compounds studied in the literature is shown in Table 4. The results exhibited that 1 was nearly twice as active in DPPH radical scavenging abilities as those of C3, being the strongest antioxidant complex studied by our group [35]. In addition to 1, the other studied complexes in this work had higher antioxidant properties than those previously reported [35]. Altogether, the compounds with sulfur ylides and their Hg(II) complexes can significantly improve the radical scavenging activity in comparison to phosphorus ylides and their Pd(II) complexes. Based on the IC50 values, the studied compounds could be divided into three distinct parts (Figure 3). The first part which consisted of quercetin, ascorbic acid, and Y showed low IC50 values (0.13–0.16 mg·mL−1). It could be pointed out that these compounds possess the high antioxidant potential. The second part was made of 1, 2, and 3. This group which has dimeric structure of mercury(II) halides was characterized by a moderate amount of IC50. The IC50 values of this compound varied from 0.19 to 0.53 mg·mL−1. The third part constituted of complex 4 and showed high IC50 values (0.94 mg·mL−1) (Figure 3). This compound has polymeric structure of mercury(II) nitrate.