H2O and H2S adsorption by assistance of a heterogeneous carbon-boron-nitrogen nanocage: Computational study

A model of heterogeneous carbon-boron-nitrogen (C-B-N) nanocage was investigated in this work for adsorbing H2O and H2S substances. To achieve this goal, quantum chemical calculations were performed to obtain optimized configurations of substances towards the surface of nanocage. The calculations yielded three possible configurations for relaxing each of substances towards the surface. Formation of acid-base interactions between vacant orbitals of boron atom and full orbitals of each of oxygen and sulfur atoms yielded the strongest complexes of substance-nanocage in comparison with orientation of substances through their hydrogen atoms towards the surface of nanocage. As a consequence, formations of interacting H2O@C-B-N and H2S@C-B-N complexes were achievable, in which mechanism of action showed different strengths for the obtained complexes. Variations of molecular orbital features and corresponding energy gap and Fermi energy for the models before/after adsorption could help for detection of adsorbed substance through a sensor function. And finally, such C-B-N nanocage showed benefit of providing activated surface for efficient adsorption of each of H2O and H2S substance with possibility of differential adsorption regarding the strength of complex formations.

Testing Sorption Properties of Halloysite by Means of the Laser Interferometry Method

The objective of the present study has been to test the laser interferometry method in terms of its usability for investigating sorption properties of minerals. This method was used to test the absorption capacity of halloysite with reference to glucose, which is often found in industrial wastewater and whose excess can disturb the environmental eco-balance. The sorption capacity of halloysite was thus determined indirectly, basing on the comparison of concentration profiles as well as time characteristics of glucose quantities released from the control solution and from the solution incubated with a halloysite adsorbent. An analysis of glucose diffusion was conducted in a two-chamber membrane system. On the basis of the obtained concentration profiles, the evolution of the concentration field was determined; so were the removal efficiency (%) and the amount of glucose adsorbed at equilibrium (qe, mg/g). The obtained results confirm good sorption properties of halloysite with respect to the investigated substance as well as usability of the method for this kind of investigations. The presented tests suggest that the measurement set-up can be optimised in such as way that visual rendering and testing the kinetics of the adsorbed substance direct release from the studied material become possible.

Probabilistic and Statistical Model of Air-Drying Process in Devices for the Maintenance of Shells Under Overload Pressu

Application possibility of probabilistic and statistical calculation method of adsorptive air-drying process by silica-gel in devices for the maintenance of shells under overload static pressure is shown. It is established that distribution density function change of adsorbate and adsorbed substance concentration can be described by Fokker-Plank-Kolmogorov kinetic equation. In such a case the air-drying process by silica-gel can be presented as two-modal function of distribution density.

Adsorption and Oxidation of Thiosulfate on a Platinum Electrode in Acid Solution

The adsorption of thiosulfate on a platinum electrode was measured at the open circuit potential. A monolayer of the adsorption products covers the electrode at lower thiosulfate concentrations. The charge used up during the reduction of the monolayer roughly corresponds to 0.5 electron per surface site (e.p.s.), the charge used up during the oxidation of the monolayer after reduction corresponds approximately to 4 e.p.s. Multiple adsorbed layers, which are presumably constituted mainly by adsorbed sulfur, build up at higher thiosulfate concentrations. The amount of the adsorbed substance increases with increasing thiosulfate concentration and time of adsorption. Desorption from the surface coated by multiple layers can take place in supporting electrolyte solution. The build-up of multiple adsorbed sulfur layers also takes place during adsorption from solutions of colloidal sulfur.

Effects of adsorbed substances on bioactivity of attached bacteria on granular activated carbon

Experimental study was carried out to clarify the effects of adsorbed substances on bioactivity of attached bacteria on GAC using ammonia oxidizing bacteria and m-aminobenzoic acid as an inhibitory adsorbed substance against ammonia oxidizing bacteria. Effects of adsorbed substances on GAC was determined by the activity of attached ammonia oxidizing bacteria in comparison with boiling stone with no capacity of adsorption. 50 % inhibition of ammonia oxidation were noted in m-aminobenzoic acid concentration of 60 mg.l−1 and 330 mg.l−1 on the GAC and the boiling stone columns, respectively. Inhibition of ammonia oxidation on GAC was clearly stronger than that on boiling stone, in spite of the same m-aminobenzoic acid concentrations in bulk solution between the GAC and the boiling stone columns. Bioactivity of attached bacteria was affected by adsorbed substances on GAC, when GAC was kept in equilibrium condition.