Key Engineering Materials Vol. 925

Abstract: The ecological situation in the world requires the solution of environmental problems associated with the processes of wastewater treatment, hydrogen sulfide pollution of various industrial facilities in order to remove such harmful impurities. The unpleasant odor that appears in industrial and adjacent waste processing areas is a constant concern for the protection of the environment. To solve these problems, it is advisable to use selective sorbents - complex. The introduction of metal ions into complex fibers due to the formation of a coordinated bond between the groups of the metal and the polymer ligand gives high molecular weight complex compounds. The operational and selective properties of the materials based on high-molecular-weight complex compounds can be determined by the type of metal ion introduced into macromolecules, the nature of the polymer chain, and thermodynamic stability. By changing the action of the above factors, complexites can be synthesized for use as highly selective catalysts for various chemical processes. The paper presents data on the catalytic activity of fibers with Cu²⁺, Co²⁺, Ni²⁺ ions with complexing fibers containing carboxyl, amidoxime, hydroxamic groups, using the example of the decomposition of hydrogen peroxide and oxidation of H₂S, Na₂S. An inhibitory effect on the oxidation of fiber functional groups in the pH range 5.5 - 12.5 was revealed. The operational and selective properties of materials based on complexites can be determined by the type of metal ion introduced into the macromolecules, by the nature of the polymer chain. By changing the action of the above factors, complexites can be synthesized to be used as highly selective catalysts for various chemical processes. It was found that the catalytic activity of the complex depends on pH, the stereochemistry of the coordination centers in the fiber matrix and significantly exceeds the activity of model low-molecular-weight complex compounds.

Abstract: The work is devoted to solving the current problem of increasing the level of environmental safety of treatment industrial wastewater of leather production from chromium ions (III) through the use of natural and modified bentonite. The investigation about the efficiency of purification of model solutions, which containe 1 g/dm³ of chromium ions and 0.75 g/dm³ of phosphate ions was carried out by the method of ideal displacement. In our research, we proposed a method of sequential adsorption, according to which phosphate ions are absorbed in the first stage and chromium ions are sequentially adsorbed in the second stage. Structural features of natural carbonate-rich and modified with chromium and phosphate ions bentonite clay have been studied. researched and analyzed.

Abstract: Even though dates are produced in large scales in Saudi Arabia, it is not the only product palm trees can offer. Transformative products of palm trees that can be beneficial for the community are intense. For instance, using fronds waste as a biomass to generate power at remote areas or central cities where palm trees population is intense might be a transformative product of palm trees. Using natural waste as a supplement source of electricity at the communities living near palm farms will have a profound effect on the environment and economy. This paper discusses the feasibility of using palm trees' fronds as a biomass in Saudi Arabia. It complies with the kingdom's strategic power plan where alternative power sources are encouraged in the vision 2030. This paper briefly illustrates the opportunity of using biomass, statistics of palm trees in Saudi and the use of biomass as a feedstock to generate electricity in Medina region as a case study.

Abstract: The process of adsorption treatment of effluents from ammonium ions is considered as an integrated two-stage process consisting of the stage of adsorption of contaminants by natural sorbents in the apparatus with a stirrer and the liquid separation stage and solid phases. Mathematical models of ammonium ions adsorption from effluents by natural dispersed sorbents are proposed, based on the assumption that the process is described by Langmuir and Friendlich isotherms. The values of ion exchange equilibrium constants for different types of natural sorbents have been established by identifying experimental data for theoretical dependences. The obtained constants can be used to calculate the average concentration of ammonium ions in the solution and in the grain of the sorbent in the process of integrated adsorption process. Based on the analysis of the research results, the optimum method of the spent sorbent separation was selected - separation of the suspension of purified ammonium-containing effluents - spent sorbent under the action of gravity. Indicators of optimization of complex process of sewage treatment from ammonium ions are offered.

Abstract: Natural zeolites are materials which, due to the peculiarities of their crystal structure and high adsorption and ion exchange properties, have wide prospects for use in technologies of adsorption purification of aquatic environments. The paper presents the results of laboratory research in dynamic and static conditions of sorption properties of natural zeolite, which is currently used for purification of natural water from suspended solids in industrial water treatment plants. The sorption capacity of different fractions of this zeolite to ammonium nitrogen, fluorides and petroleum products has been established.

Abstract: Clay from the Khmelnytskyi region was enriched in montmorillonite by separation of a fraction with a particle size  0.5 ∙ 10^-6 m. The X-ray diffraction and thermal analyses suggest that the enriched clay composition is close to mono-mineral, that is, represented by ferric-type montmorillonite in the form of Ca and Mg. The mineral interlayer spacings are partially filled with natural organic matter. An exchange capacity of montmorillonite is 0.78 mmol/g as shown by the photocolorimetry studies of the adsorption of the cationic methylene blue (MB) dye. It is recommended that studied clay be used as an effective natural adsorbent for wastewater treatment and for the arrangement of geochemical barriers to prevent harmful substances from entering the environment.

Abstract: The sorption method of purification of flushing water from non-ferrous metal ions in galvanizing-bath rooms of mechanical facilities was investigated, which is one of the most realistic ways to solve the problem of environmental protection from such pollution. The effect of preliminary thermal and chemical modification of the crystal structure in order to improve the sorption capacity of clinoptilolite was established. The kinetics of the copper ion exchange process on clinoptilolite in static conditions was determined.

Abstract: Today, most surface waters of Ukraine are eutrophied due to the entry into water bodies of a significant amount of nutrients – compounds of carbon, nitrogen and phosphorus. Nitrogen and phosphorus enter water bodies with wastewater, sewage from agricultural lands and livestock farms, as well as with precipitation, due to the decomposition of water biomass, aquatic vegetation and zoocenoses. In the presence of free carbon dioxide (the concentration of which depends on bicarbonate alkalinity and water pH) and at certain rates of biochemical oxygen utilization (BOD) 7.2 g of nitrogen and 1 g of phosphorus produce 115 g of algae, which decomposition then consumes 115 g of oxygen [1].

Abstract: The paper presents studies of the process of purification of model wastewater, which contained high concentrations of animal proteins, fats and hydrocarbons. The model wastewater solution was treated by biosorption treatment in a bioreactor; with pre-ozonation (O₃) and biosorption purification in the bioreactor and in the variant with pre-treatment with ozonation and hydrogen peroxide – by the method of AOPs (O₃/H₂O₂) or the process «Peroxon». The efficiency of cleaning by chemical oxygen consumption when using the AOPs method reached (97-98) %, disinfection – up to 100 %.

Abstract: Researches of chemical-technological parameters of electrochemical production of aluminum-based coagulants for electrocoagulation wastewater treatment of milk processing enterprises have been carried out. The impact of pH and the timing of the electrocoagulation process was studied in two cases of the implementation of the technological process: with the addition of an alkaline additive before and after the electrocoagulation treatment. The mechanism of the coagulation action of aluminum compounds formed as a result of electrocoagulation has been studied. It has been established that the addition of an alkaline additive after electrocoagulation is more effective. At the same time, the degree of wastewater treatment remains quite high. This will ensure energy savings and will positively affect the environmental and economic assessment of the technology.