Three different types of Fe(II)-modified natural zeolites were tested as supports in continuous-flow columns for the treatment of Cr(VI) contaminated water. The natural zeolites chosen as support were commercially available Zeosand (80% clinoptilolite), ATZ (79% phillipsite/chabazite), and ZS-55RW (90% Chabazite). All the examined modified zeolites turned out active for hexavalent chromium abatement, lowering its concentration below the European regulation level, even at relatively high flow rates (40 mL/h, linear velocity 15 cm/h). Zeosand, having a broader pH range of stability, was found to be the best one in terms of both Fe(II) uptake (0.54 wt%) and Cr removal (90 mg Cr/Kg zeolite).
The issue of mercury emission and the need to take action in this direction was noticed in 2013 via the Minamata Convention. Therefore, more and more often, work and new law regulations are commencing to reduce this chemical compound from the environment. The paper presents the problem of removing mercury from waste gases due to new BREF/BAT restrictions, in which the problem of the need to look for new, more efficient solutions to remove this pollution was also indicated. Attention is paid to the problem of the occurrence of mercury in the exhaust gases in the elemental form and the need to carry out laboratory tests. A prototype installation for the sorption of elemental mercury in a pure gas stream on solid sorbents is presented. The installation was built as part of the LIDER project, financed by the National Center for Research and Development in a project entitled: “The Application of Waste Materials From the Energy Sector to Capture Mercury Gaseous Forms from Flue Gas”. The installation is used for tests in laboratory conditions in which the carrier gas of elemental mercury is argon. The first tests on the zeolite sorbent were made on the described apparatus. The tested material was synthetic zeolite X obtained as a result of a two-stage reaction of synthesis of fly ash type C with sodium hydroxide. Due to an increase, the chemical affinity of the tested material in relation to mercury, the obtained zeolite material was activated with silver ions (Ag+) by an ion exchange using silver nitrate (AgNO3). The first test was specified for a period of time of about 240 minutes. During this time, the breakthrough of the tested zeolite material was not recorded, and therefore it can be concluded that the tested material may be promising in the development of new solutions for capturing mercury in the energy sector. The results presented in this paper may be of interest to the energy sector due to the solution of several environmental aspects. The first of them is mercury sorption tests for the development of new exhaust gases treatment technologies. On the other hand, the second aspect raises the possibility of presenting a new direction for the management and utilization of combustion by-products such as fly ash.
The insecticidal efficiency of Ag-loaded 4A-zeolite (ZAg) and its formulations with Rosmarinus officinalis essential oil (RO) was evaluated against Sitophilus oryzae (L.) and Rhyzopertha dominica (F.). For comparison, different rates of ZAg (0.25, 0.5, 0.75, and 1 g ⋅ kg–1 wheat) were used solely and in a combination with LC50 concentrations of RO. Mortality was assessed after 7, 14, and 21 days of insect exposure to treated wheat. The progeny production was also evaluated. The use of ZAg accomplished a complete mortality (100%) on S. oryzae and 96.67% on R. dominica as well as 100% mortality of progeny against the two insect species after the longest exposing duration (21 days), at the highest rate (1 g ⋅ kg–1). On the other hand, the complete mortalities of ZAg formulations on S. oryzae were obtained after 14 d of treatment with F1 formulation (0.605 g ⋅ kg–1 RO + 0.25 g ⋅ kg–1 ZAg) and after 7 days with the other tested formulations. In addition, the complete mortality on R. dominica was obtained only by F8 (0.059 g ⋅ kg–1 RO + 1 g ⋅ kg–1 ZAg) formulation after 14 days of treatment. Concerning the efficiency of the examined formulations on the progeny of S. oryzae, F1 (0.605 g ⋅ kg–1 RO + 0.25 g ⋅ kg–1 ZAg) and F2 (0.605 g ⋅ kg–1 RO + 0.5 g ⋅ kg–1 ZAg) formulations recorded 100% mortality. In addition, F3 (0.605 g ⋅ kg–1 RO + 0.75 g ⋅ kg–1 ZAg) and F4 (0.605 g ⋅ kg–1 RO + 1 g ⋅ kg–1 ZAg) formulations suppressed the progeny production. Furthermore, the complete mortality of R. dominica progeny was obtained with F7 (0.059 g ⋅ kg–1 RO + 0.75 g ⋅ kg–1 ZAg) and F8 (0.059 g ⋅ kg–1 RO + 1 g ⋅ kg–1 ZAg) formulations. ZAg, especially its formulations with R. officinalis oil, had potential effects against two stored-product insects. F1 and F8 formulations could be treated efficiently on S. oryzae and R. dominica, respectively.