The hydrothermal synthesis of hydrotalcite by using different partially soluble and insoluble in water mangesium and aluminium components

In this work, the influence of different partially soluble and insoluble in water Mg and Al components on the formation of hydrotalcite by using only hydrothermal synthesis was examined. Hydrothermal synthesis duration was 4, 24 and 72 h at 200°C and Mg/Al ratio was equal to 3:1. The starting materials were: 4MgCO3•Mg(OH)2•5H2O, Mg5(CO3)4•(OH)2•4H2O, Al(OH)3 and γ-Al2O3. It was determined that Mg and Al containing compounds have most important influence on the formation of hydrotalcite by hydrothermal conditions. 4MgCO3⋅Mg(OH)2⋅5H2O as raw material is not recommendable for the synthesis of hydrotalcite, because even after 24 h of isothermal curing at 200°C temperature hydrotalcite is not formed and magnesium aluminum hydroxide hydrate is dominant in the synthesis products. Besides, initial magnesium containing component is decomposed into magnesium carbonate and hydroxide. It was examined that hydrotalcite is formed already after 4 h of hydrothermal synthesis at 200°C temperature when Mg/Al molar ratio is equal to 3:1 in the Mg5(CO3)4•(OH)2•4H2O - γ-Al2O3/ Al(OH)3 - H2O system. However, together with this compound a fair amount of an intermediate compounds (boehmite and magnesium carbonate) are formed. The duration of isothermal curing determines the formation of a hexagonal plates which are characteristic to hydrotalcite

Sustainable PHBV/CuS Composite Obtained from Waste Valorization for Wastewater Purification by Visible Light-Activated Photocatalytic Activity

The persistency of antimicrobial compounds in the water cycle accelerates the issue of antimicrobial resistance. Therefore, effective wastewater remediation approaches, which can be implemented on a large scale, are urgently required. This study aims at preparing a sustainable organic/inorganic composite material that can photo-catalyze the degradation of organic pollutants in wastewater by using visible light. Specifically, films and porous composites are composed of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) as supporting material, and copper sulfide (CuS) as active photocatalyst. It is noteworthy that the proposed composite can be fully produced from waste valorization, since PHBV is a polymer, which can be obtained by fermentation of vegetable wastes, and CuS is synthesized from industrial sulfur wastes. The produced composites show remarkable capabilities in the photodegradation of tetracycline and methylene blue, selected as model organic pollutants. Moreover, the PHBV/CuS composites can be reused multiple times with minimal loss in photocatalytic efficiency. The suggested approach is not only sustainable and cost-effective, but also solves issues occurring in the application of the photodegradation techniques currently reported, such as the consumption of fossil-based chemicals and photocatalyst removal from the purified water using with expensive procedures

The influence of Zn containing components on the synthesis of Z-phase

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The formation of different Mg-Al LDHs (Mg/Al=2:1) under hydrothermal conditions and their application for Zn2+ ions removal

The formation of different Mg-Al LDHs (Mg/Al = 2:1) under hydrothermal conditions (200°C; 4-24 h) was investigated in the 4MgCO3⋅Mg(OH)2⋅5H2O - γ-Al2O3/Al(OH)3 - H2O and Mg5(CO3)4(OH)2•4H2O - γ-Al2O3 - H2O systems. It was determined that chemical nature of the initial Mg containing components changes the formation mechanism of the synthesis products during isothermal curing. Magnesium aluminum hydroxide hydrate is crystallized by using 4MgCO3⋅Mg(OH)2⋅5H2O as starting material while hydroxide hydrate in the Mg5(CO3)4(OH)2•4H2O presence. The sequence of the compounds formation is presented. It should be noted that different modifications of Al containing components have only a slight influence on the meixnerite-type LDH hydrothermal synthesis. It was determined that after 45 min of sorption all Zn2+ ions are incorporated into the crystal structure of hydrotalcite. It should be underlined that crystallinity of the latter compound do not change during ion exchange experiments. Thus, the latter compound can be used as adsorbent for Zn2+ ion removal. Synthesized samples were characterized by powder X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), simultaneous thermal analysis (STA) and scanning electron microscopy (SEM)