Kateřina Mamulová Kutláková

Dangerous gases arising from combustion processes must be removed from the air simply and cheaply, e.g., by adsorption. This work is focused on competitive adsorption experiments and force field-based molecular modeling of the interactions at the molecular level. Emission gas, containing CO, NO, SO₂, and CO₂, was adsorbed on activated carbon, clay mineral, silicon dioxide, cellulose, or polypropylene at two different temperatures. At 20 °C, activated carbon had the highest NO and SO₂ adsorption capacity (120.83 and 3549.61 μg/g, respectively). At 110 °C, the highest NO and SO₂ adsorption capacity (6.20 and 1182.46 μg/g, respectively) was observed for clay. CO was adsorbed very weakly, CO₂ not at all. SO₂ was adsorbed better than NO, which correlated with modeling results showing positive influence of carboxyl and hydroxyl functional groups on the adsorption. In addition to the wide range of adsorbents, the main novelty of this study is the modeling strategy enabling the simulation of surfaces with pores of controllable sizes and shapes, and the agreement of the results achieved by this strategy with the results obtained by more computationally demanding methods. Moreover, the agreement with experimental data shows the modeling strategy to be a valuable tool for further adsorption studies.

The importance of studies on photoactive zinc oxide nanoparticles (ZnO NPs) increases with increasing environmental pollution. Since the ZnO NPs (and NPs in general) also pose an environmental risk, and since an understanding of the risk is still not sufficient, it is important to prevent their spread into the environment. Anchoring on phyllosilicate particles of micrometric size is considered to be a useful way to address this problem, however, so far mainly on the basis of leaching tests in pure water. In the present study, the phytotoxicity of kaolinite/ZnO NP (10, 30, and 50 wt.%) nanocomposites in concentrations 10, 100, and 1000 mg/dm³ tested on white mustard (Sinapis alba) seedlings was found to be higher (relative lengths of roots are ~ 1.4 times lower) compared with seedlings treated with pristine ZnO NPs. The amount of Zn accumulated from the nanocomposites in white mustard tissues was ~ 2 times higher than can be expected based on the ZnO content in the nanocomposites compared with the ZnO content (100 wt.%) in pristine ZnO NPs. For the false fox-sedge (Carex otrubae) plants, the amount of Zn accumulated in roots and leaves was ~ 2.25 times higher and ~ 2.85 times higher, respectively, compared with that of the pristine ZnO NPs (with respect to the ZnO content). Increased phytotoxicity of the nanocomposites and higher uptake of Zn by plants from the nanocomposites in comparison with pristine ZnO NPs suggest that the immobilization of ZnO NPs on the kaolinite does not reduce the environmental risk.