Mercury is a highly toxic metal which naturally occurs in the Earth’s crust and has adverse effects on both humans and the environment. The use of fossil fuels for electricity generation and specific industries sources of mercury emissions. These emissions depend on the mercury content in fuels of different types, the process gas temperature and composition, the implementation of air pollutant control devices (APCDs), etc. The APCDs partially capture and/or oxidize mercury in flue gas as a side benefit. In some cases, the emissions are reduced by mercury-dedicated or mixed methods. Mercury transformation in process gases is generally based on a chain of homogeneous and/or heterogeneous reactions. The theory of gaseous mercury/solid phase reactions and its mechanisms is widely studied in the literature. In this review, we focused on the theoretical and practical studies of these mechanisms, including mercury oxidization and capture from specified laboratory simulated or process gases and industries. We summarized research on various reactions – mostly of a chemical type – between different forms of mercury derived from process gases, and solids, including particles of different kinds (fly ash, adsorbents or catalysts). We additionally reviewed the literature on the interactions between mercury and sulfur compounds in the simulated and process gases.

The Suborder Clupeoidei Bleeker, 1859 comprises mostly marine fishes, which form large schools feeding on plankton. The fossil record of the suborder in the Late Paleogene reveals that clupeoids were abundant in the Western, Central, as well as Eastern Paratethys. Clupeoid descriptions from the Polish Outer Carpathians (SE Poland, Central Paratethys) remain incomplete due to usage of ‘collective species’, taxonomical inaccuracies, and lack of clear links between extinct and extant representatives. In this paper we present a new clupeoid, † Beksinskiella gen. nov., from the Oligocene of the Outer Carpathians, Poland. The new genus encompasses the nominal species † Maicopiella longimana (Heckel, 1850). † Beksinskiella gen. nov. has a unique combination of characters (skull roof with frontoparietal striae; smooth opercle; 6–7 branchiostegal rays; 42–48 vertebrae; dorsal and anal fins with 21–23 rays; the last two rays of the anal fin being elongated, and the presence of a complete series of abdominal scutes with the postpelvic ones poorly developed), supporting recognition of a new genus of the Suborder Clupeoidei. Similarities and differences between fossil and extant genera of Cluepoidei are discussed to shed light on their relationship.