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Purpose. The research aims to develop a technology for tailings solution purification using membrane nanofiltration to reduce waste volume and enterprise costs by reusing the purified water.       Methods. The research uses polyamide nanofiltration membranes on a semi-industrial plant. The nanofiltration process is conducted at a pressure of 3.5 MPa with 30% permeate yield. The chemical composition of the solutions is analyzed using atomic-absorption and chemical methods.       Findings. Removal of 69% arsenic, 68.5% zinc and 95.7% iron has been achieved under optimal conditions. The purified solution with a residual sulphuric acid concentration of ~3.5 g/l can be used again for leaching lead dust. The concentrated metal solution allows for additional zinc extraction. The use of technology reduces waste volumes by more than 30% and reduces the enterprise’s recycling costs.       Originality. The research proposes a new environmentally friendly nanofiltration technology for tailings solution purification that can effectively remove heavy metals and extract valuable components. This approach uniquely integrates membrane nanofiltration at an optimized pressure of 3.5 MPa, achieving high removal rates of heavy metal ions such as As3+, AsO43⁻, Zn2+, Fe2+, and Fe3+, while reducing waste by 30% and enabling the reuse of sulfuric acid and water in the leaching process, leading to significant cost and resource savings.       Practical implications. Implementation of the proposed technology at lead dust processing enterprises reduces the costs of wastewater treatment, reduces the waste volume and allows for the reuse of water and acids in the production process. [ABSTRACT FROM AUTHOR]

Arsenic, an element found in the Earth’s mantle, can be highly toxic, especially in its As(III) form. It enters our food chain through human activities like melting metals, using arsenic-based pesticides, and natural processes like volcanoes and rock breakdown. Consuming too much arsenic is extremely dangerous, impacting many countries worldwide. To tackle this issue, various methods like filtering, adding chemicals, and using electricity have been developed to clean arsenic-contaminated water. Among these, adsorption is a standout approach due to its simplicity and effectiveness. Biopolymers from living sources offer a natural solution, easily tweaked for arsenic removal. These biopolymers contain functionalities that can strongly latch onto toxic materials, acting like magnets. By customizing them with compounds like titanium dioxide (TiO2), magnetite (Fe3O4), and others, they become even better at capturing arsenic, shaped into tiny particles or beads. This adaptation makes biopolymers a promising choice for cleaning arsenic from water. This review focuses on ways to clean water, specifically exploring how materials like chitosan, alginate, and modified cellulose can be used to remove arsenic by adsorption. It investigates how these materials work under different conditions, highlighting important details. By sharing these insights, this article contributes to the ongoing efforts to ensure cleaner water resources. [ABSTRACT FROM AUTHOR]

Background: Abelmoschus esculentus L., okra, has been known as a healthy plant and classically employed in food and folk medicine for several human and animal diseases. Aim: The in vitro antioxidant and antibacterial capacities, in addition to the phytochemical compounds of the okra fruit extracts gathered at three maturity stages, were the objectives of this study. Methods: This study examined the modifications in total phenolic content (TPC), total flavonoid content (TFC), and antioxidant and antibacterial capacities of three okra fruit hydroalcoholic extracts during three comestible maturity stages. The different maturity stages of okra pods were demonstrated as early-stage, mid-stage, and late-stage maturation. Results: The mid-stage of okra fruit maturity had the highest TPC (43.27 ± 2.029 mg GAE g-1), TFC (29.96 ± 0.19 mg RE g-1), and antioxidant capacity (75.64% ± 0.79%). Moreover, at mid-stage maturity, okra fruit extracts exhibited a major antibacterial effect against Vibrio anguillarum. The phenolic content was significantly increased at the mid-stage maturity, while the flavonoid level and the antioxidant activity were greatly decreased at the end of fruit maturity. Conclusion: The results confirmed that A. esculentus L. fruits at mid-stage maturity are an excellent source of biomolecules with high antiradical and bactericidal activities, which could be used as functional foods and as an option for chemical compounds for fish farming to prevent and treat numerous marine animal diseases. [ABSTRACT FROM AUTHOR]

The accumulation of free radical production impacts on the development of degenerative diseases which are the highest cause of morbidity and mortality in the world. Biofortification of purple okra in the form of encapsulated extract has the potential as a nutraceutical through the role of antioxidants. This study aimed to analyze the potential of encapsulated purple okra extract as a nutraceutical by determining physical-chemical characteristics, microbial and heavy metals contamination, antioxidant capacity, total flavonoids, and quercetin. This was a laboratory experimental study on purple okra which was extracted using the maceration method. The results of physical-chemical characteristics showed that purple okra extract has the form of dry powder, greenish-brown color, odor characteristic of okra extract (caramel-like), and sour taste with yield of 4%, pH of 4.8, undetectable solvent residue, water content of 13.5%, total ash content of 10.4%, and disintegration time of 1.25 minutes. The results of microbial contamination showed a total plate count of 3.1 102 CFU g⁻¹, yeast and mold count, E. coli, S. aureus negative CFU g⁻¹, and Salmonella spp negative CFU 10g⁻¹. The results of heavy metal contamination showed that As, Pb, Cd, and Hg were not detected every mg Kg⁻¹. The results of antioxidant capacity, total flavonoids, and suspected quercetin derivatives showed a value of 84.88%, 81.32 mg QE g⁻¹, and 4.91 mg g⁻¹. These bioactive components act as free radical scavengers in helping to prevent chain reactions. Encapsulated purple okra extract has shown its potential as a nutraceutical that helps prevent degenerative diseases. [ABSTRACT FROM AUTHOR]

In wave propagation phenomena, time-advancing numerical methods must accurately represent the amplitude and phase of the propagating waves. The acoustic waves are non-dispersive and nondissipative. However, the standard schemes both retain dissipation and dispersion errors. Thus, this paper aims to analyse the dissipation, dispersion, accuracy, and stability of the Runge--Kutta method and derive a new scheme and algorithm that preserves the symmetry property. The symmetrised method is introduced in the time-of-finite-difference method for solving problems in aeroacoustics. More efficient programming for solving acoustic problems in time and space, i.e. the IMR method for solving acoustic problems, an advection equation, compares the square-wave and step-wave Lax methods with symmetrised IMR (one-and two-step active). The results of conventional methods are usually unstable for hyperbolic problems. The forward time central space square equation is an unstable method with minimal usefulness, which can only study waves for short fractions of one oscillation period. Therefore, nonlinear instability and shock formation are controlled by numerical viscosities such as those discussed with the Lax method equation. The one- and two-step active symmetrised IMR methods are more efficient than the wave method. [ABSTRACT FROM AUTHOR]

The formation of heat stable salts (HSS) during the natural gas sweetening process by amine solvent causes many problems such as corrosion, foaming, capacity reduction, and amine loss. A modeling study was carried out for the removal of HSS ions from amine solution using nanofiltration (NF) membrane process that ensures the reuse of amine solution for gas sweetening. This model studies the physics of the nanofiltration process by adjusting and investigating pore radius, the effects of membrane charge, and other membrane characteristics. In this paper, the performance of the ternary ions was investigated during the removal process from methyl di-ethanol amine solution by the nanofiltration membrane process. Correlation between feed concentration and permeate concentration, using experimental results with mathematical correlation as Ci,p = f (Ci,f) was used in modeling. The results showed that the calculated data from the model provided a good agreement with experimental results (R2 = 0.90–0.75). Also, the effect of operating conditions (including feed pressure and feed flow rate on ions rejection and recovery ratio across the flat-sheet membrane) was studied. The results showed that the recovery and rejection ratios of the NF membrane depend on the driving pressure across the membrane. While the driving pressure is affected by the feed flow conditions and feed pressure. [ABSTRACT FROM AUTHOR]