Simulation of the Influence Mechanism of Hydrothermal Modification on Magnesium Hydroxide

Abstract

To overcome the drawbacks of strong polarity and easy agglomeration of ordinary magnesium hydroxide (MH), hydrothermal modification is customary applied to achieve its excellent dispersion as well as controllable morphology and particle size. In this paper, the influence mechanism of hydrothermal modification is elaborated from microstructure of MH. Structures and surface energy of crystal planes, affinity of water molecules for crystal planes, and crystal growth process are calculated by Materials Studio software. Furthermore, molecular dynamics simulations about solid-liquid interface model of MH and 1 mol L −1 NaOH solution at different temperatures are performed based on the theory of modified attachment energy model. The results indicate that (0 0 1) plane with the smallest surface energy has the strongest thermodynamic stability, equipping modified crystals with lamellar morphology and excellent dispersion. (0 0 1) plane cannot be dissolved easily because of the smallest affinity of water molecules. The magnesium atoms and hydroxyl groups on (1 0 1) plane dissolved are absorbed on (0 0 1) plane, resulting in the large value of I 001 /I 101 in the X-ray diffraction pattern. The relative growth rate of (1 0 1) plane R 101 decreases with the increasing temperature, explaining why crystals become thicker with raising temperature.

Highly Concentrated Electrolyte Superlubricants Enhanced by Interfacial Water Competition Around Chemically Active MgO Additives

“…For LiTFSI 10 , the weak interaction between the formed Li + hydrated soft clusters effectively reduces the sliding resistance at the shear interface, but the load-bearing capacity is still low. However, the addition of chemically active MgO promotes the formation of low-shear sliding interfaces that may lie between interfacial water and free water due to the generation of Mg­(OH) 2 layer, so that solid–liquid asymmetric contact may be between it (i.e., MgO@Mg­(OH) 2 micrometer-hard clusters) and the original nanometer-sized Li + hydrated clusters (Figure b), which reduces the shear resistance and improves the load-bearing capacity, and enables the lubricant to reach a stable macroscopic superlubricity. LiTFSI 10 and MgO 0.10 /LiTFSI 10 are elastohydrodynamic lubricants with film thicknesses of 146 and 276 nm (the corresponding λ are 4.1 and 9.8), respectively, between the corresponding friction pairs.…”

Seed germination and phytotoxicity evaluation of Vigna radiata and Allium cepa via triple-doped green hematite nanoparticles and their photocatalytic effect

“…This result is in agreement with the crystalline structure of α-Fe2O3 NPs and the iron organized in the Face face-centered cubic (FCC) (Wang et al 2023). The following equation (Shi et al 2023) relates the interplanar spacing between the atoms' (hkl) planes, dhkl, rhkl, on the pattern between the spot (hkl) and the spot (104):…”