This article aims to develop a method for regenerating and reusing carbon and glass fibers extracted from unrecyclable scraps of carbon plastics, printer parts, and laminating coating. A comparison of known methods of fiber regeneration revealed the advantages of thermal treatment: absence of costs of reagents and complex equipment; better preservation of composition; and strength of fibers. Based on the results of thermographic analysis of wastes in nitrogen and air, the destruction temperatures of their organic matrices were determined (200-460°С), and the use of calcination instead of pyrolysis was justified. The appearance and surface quality of the regenerated fibers are characterized by optical and electron microscopy. It has been established that quantitative extraction of pure carbon and glass fibers from waste crushed to 1 cm is efficient by their calcination at 700 °C for 0.5 h and 500 °C for 1 h, respectively. The principle of creating new composites with the obtained fibers based on the similarity of their composition and binding materials (matrices) has been proposed. It was shown that the introduction of 1 wt% of fibers into slag blocks and active carbon pellets considerably increases their compressive strength, but the bending strength does not change due to dispersed reinforcement. Possible improvement of mechanical properties of products requires reagent treatment of the fiber surface or the introduction of binder additives. Calculations show that the developed method of recycling composite waste can produce 2.3 tons/hour of reinforced building materials that are good for the environment and the economy, excluding expenses for landfill waste disposal and reducing the cost of the product by replacing the primary fiber for the secondary one. Doi: 10.28991/ESJ-2022-06-05-04 Full Text: PDF

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An analysis of electrochemical degradation of organic compounds, in particular EDTA is presented. The influence of the nature of the anode and the nature of the oxidizing agent on the degradation of organic compounds is showed. Anode materials are classified based on their oxidizing power in an acidic environment. It is shown that direct oxidation of EDTA effectively occurs on the anodes Ti/PbO2 and Ti/SnO2. In the presence of NaCl EDTA is effectively oxidized on the anodes Ti/RuO2-TiO2 by the formation of hypochlorite. Examples of destruction of EDTA under the influence of ultraviolet radiation are given. Degradation products (nitro acetic acid, amino diacetic acid) form CO2, H2O, NO3-ions at full decomposition. It is noted that the neutralization of wastewater containing copper and EDTA is carried out in two stages: destruction of EDTA and the extraction of copper hydroxide. The extraction of copper ions from the system H2O-Cu2+-EDTA-electrolyte with different ratios of metal-ligand is investigated. The effect of EDTA concentration on the flotation process for extracting copper hydroxide is analyzed. The kinetics of flotation of copper extraction in the presence of two complexing agents - NH3 and EDTA is considered. The presented results allow to assess the degree of extraction of copper from solution copper-EDTA at different coal sorbents and resins. It is shown that the use of anion exchange resin Purolite A500 and anion exchange resin AB-17-8 is effective when the copper concentration is 25 mg/l. It is established that the sorption process is slow: stationary values are set for several hours. The degree of extraction of EDTA reaches 30-40%. When the ratio of copper-EDTA 1:1.0-1.5 it is possible to reach flotation copper extraction up to 80%. Under additional sorption treatment the extraction degree reaches to 99%. It is shown that the use of highly dispersed carbon materials (coal powders) allows extracting ligands from wastewater, increasing the efficiency of copper hydroxides electroflotation.

The possibility of using active carbon produced from coal concentrates and coking batch in waste water purification at OAO Moskoks is investigated. The results of experiments with active carbon produced in this way are analyzed. A method for wastewater purification using such active carbon is proposed, along with the necessary equipment. The results show the feasibility of practically waste free processing of coking batch to produce carbon adsorbents and their use in the purification of the plant's wastewater.

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