A study is performed of the effect the means of activation of bentonite-like clays (acidic, alkaline, combined) have on the adsorption characteristics of Fe3+ ions under static conditions. The mechanism of the acidic and alkaline activation of montmorillonite is identified and found to depend on the concentration of the activating agent. Solutions of sulfuric acid and lithium hydroxide are used as activating agents. It is shown that during combined treatment of enriched clay which includes activation with sulfuric acid and lithium hydroxide, its sorption capacity grows by 2.0–9.4 times, in relation to Fe3+ ions.
CO2-assisted gasification of carbon-based waste materials is one of the processes that both utilises waste carbon chemicals and produces CO, which is a highly sought after raw material. In this work, we aimed at finding and clarifying the synergistic effects of simultaneous potassium and Fe, Co, or Ni-driven catalysis. To reveal the behaviour of such systems, a series with different potassium loadings and a fixed second metal loading of 5 wt.% was prepared. The following methods were applied for this purpose: SEM, TEM, EDX, XRD, electron diffraction, and catalytic tests. The most active sample was found to be 3 wt.% K and 5 wt.% Co- or Fe-loaded hydrolysis lignin. The attained CO2 conversion was up to 92%, while the pure lignin sample demonstrated only 62% conversion under the same conditions.
A study is performed of the adsorption of glyphosate on carbon-containing materials obtained from pyrolysis products of sugar cane waste and commercial coconut activated carbon. The adsorption capacity of the materials with respect to glyphosate was determined using a variety of experimental models. The obtained data indicate the adsorption of glyphosate on the samples occurs due to chemical interaction with the adsorbent surfaces.
Interchain exchange, proceeded by the transesterification mechanism, allows one to obtain polyethylene terephthalate-based polyester products, bypassing the stage of molecular weight reduction and polycondensation used in classical methods of chemical recycling. A kinetic model is presented, which describes the change in the concentrations of bound and terminal units of ethylene glycol from PET and glycol from another polyester, as well as free molecules of ethylene glycol and another glycol, during transesterification reactions for the first time. Experimental data on the dependence of the degree of randomness and conversion on timeduring the interaction of polyethylene terephthalate and oligodiethylene terephthalate with terminal hydroxyl groups with a number-average molecular weight of 860 g/mol in different ratios were obtained. Molecular weight characteristics of the products of PET and oligoesters with hydroxyl end group interchain exchange, with number-average molecular weights from 610 to 860 g/mol, were also investigated. The simulation results were also compared with published data on the dependence of the degree of randomness and conversion on time during ether exchange in PET/PEN blends. The developed kinetic model was found to be in agreement with the experimental data.