Efficient treatment of anthraquinone dye wastewater by adsorption using sunflower torus-like magnesium hydroxide microspheres

Basic magnesium sulfate@TiO2 composite for efficient adsorption and photocatalytic degradation of 4-dodecylmorpholine in brine

More than 70% of the potash fertilizer globally is produced by the froth flotation process, in which 4-dodecylmorpholine (DMP) serves as a reverse flotation agent. As the potash fertilizer production rapidly rises, the increased DMP levels in discharged brine pose a threat to the production of high-value chemicals. In this paper, composite particles of basic magnesium sulfate@TiO2 (BMS@TiO2) were prepared using a simple and mild loading method. These particles were utilized for the adsorption and photocatalytic degradation of DMP in brine. Compared with normal powdered materials, the granular BMS@TiO2 in this study can be easily separated from liquid, and the degradation intermediates will not enter the brine without causing secondary pollution. BMS@TiO2 consists of 5·1·7 phase (5Mg(OH)2·MgSO4·7H2O) whisker clusters embedding 2.3% TiO2. The adsorption equilibrium of DMP on BMS@TiO2 particles was achieved through hydrogen bonding and pore interception with the adsorption capacity of approximately 5 mg g-1 after 6 h. The photodegradation efficiency of DMP adsorbed on BMS@TiO2 reached about 92% within 16 h, which is compared with that of pure TiO2 nanoparticles. Additionally, excellent stability and recyclability of BMS@TiO2 were also observed in five cycle tests of adsorption and photocatalytic degradation of DMP, and the possible photocatalytic degradation pathways and mechanism of DMP are proposed following molecular electrostatic potential analysis. This work provides a sustainable and environmentally friendly approach for eliminating organic micropollutants from water environments.

Synthesis of a New Series of Anthraquinone-Linked Cyclopentanone Derivatives: Investigating the Antioxidant, Antibacterial, Cytotoxic and Tyrosinase Inhibitory Activities of the Mushroom Tyrosinase Enzyme Using Molecular Docking

Purpose

New bioactive anthraquinone derivatives are investigated for antibacterial, tyrosinase inhibitory, antioxidant cytotoxic activity, and molecular docking.

Methods

The compounds were produced using the grindstone method, yielding 69 to 89%. These compounds were analyzed using IR, 1H, and 13C NMR and elemental and mass spectral methods. Additionally, the antibacterial, antioxidant, and tyrosinase inhibitory activities of all the synthesised compounds were evaluated.

Results

Compound 2 showed remarkable tyrosinase inhibition activity, with an (IC50: 13.45 µg/mL), compared to kojic acid (IC50: 19.40 µg/mL). It also exhibited moderate antioxidant and antibacterial activities with respect to the references BHT and ampicillin, respectively. Kinetic analysis revealed that the tyrosinase inhibitory activity of compound 2 was non-competitive and competitive, whereas that of compound 1 was low. All compounds (1-8) were significantly less active than doxorubicin (LC50: 0.74±0.01μg/mL). However, compound 2 affinity for the 2Y9X protein was lower than kojic acid, with a lower docking score (-8.6 kcal/mol compared to (-4.7 kcal/mol), making it more effective.

Conclusion

All synthesized compounds displayed remarkable antibacterial, tyrosinase inhibitory, antioxidant, and cytotoxic activities, with compound 2 showing exceptional potency as a multitarget agent. Anthraquinone substituent groups may offer the potential for the development of treatments. The derivatives were synthesized using the grindstone method, and their antibacterial, antioxidant, tyrosinase inhibitory, and cytotoxic activities were inspected. Molecular docking and molecular dynamics simulations were performed using compound 2 and kojic acid to validate the results and confirm the stability of the compounds.

Preparation and Characterization of Novel 5Mg(OH)2·MgSO4·7H2O Whiskers

Herein, novel monodisperse basic magnesium sulfate whiskers (5Mg(OH)2·MgSO4·7H2O) were prepared under low-temperature and atmospheric-pressure conditions, using the admixture sodium citrate. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, selected area electron diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the structure and morphology of the whisker products. The analysis results showed that the product was composed of high-purity basic magnesium sulfate whiskers. The lengths and diameters of the whiskers were 10-20 μm and 0.1-0.2 μm, respectively, and their aspect ratios were higher than 30. The formation mechanism of 5Mg(OH)2·MgSO4·7H2O involved direct assembly from the precursors without the formation of magnesium hydroxide for redissolution. High-purity MgO whiskers with smooth surfaces were prepared using the as-prepared whisker products via thermal decomposition. Thus, the findings of this study can provide technical support for the cost-effective industrial-scale preparation of basic magnesium-sulfate whiskers and associated whisker products.

Engineering Electronic Structure and Band Alignment of 2D Mg(OH)2 via Anion Doping for Photocatalytic Applications

The wide bandgap of 2D Mg(OH)₂ inhibits its applications in visible-light photocatalytic applications. Besides, its mismatched band alignment to the redox potential of O₂/H₂O, brings about low efficacy of water-splitting performance. Therefore, to release the powder of 2D Mg(OH)₂ in photocatalytic research, we explore anion doping strategies to engineer its electronic structure. Here, anion doping effects on electronic properties of 2D Mg(OH)₂ are investigated by using DFT calculations for seven dopants (F, Cl, S, N, P, SO₄, and PO₄). We found (1) S, N and P doping remarkably reduces its band gap from 4.82 eV to 3.86 eV, 3.79 eV and 2.69 eV, respectively; (2) the band gap reduction is induced by the electron transfer to the dopant atoms; (3) F, Cl, SO₄, and PO₄ doping shifts its valence band to be lower than the oxidation potential of O₂/H₂O to render its band structure appropriate for photocatalytic water splitting. These results suggest that not only electrical conductivity of 2D Mg(OH)₂ can be increased but also their band structure be aligned by using the proposed anion doping strategy. These results enable a new photocatalytic materials design approach while offering exciting possibilities in applications of high-current electrolysis, chemical gas sensing, and photocatalysis.