Calcium Sulfate Nanoparticles with Unusual Dispersibility in Organic Solvents for Transparent Film Processing

Consolidation of Fragile Oracle Bones Using Nano Calcium Sulfate Hemihydrate as a Protectant

Herein, a nano calcium sulfate hemihydrate suspension in an alcohol solvent was prepared and explored as a novel protectant for fragile oracle bones. The consolidation method involved first introducing the suspension and then adding water into the bones. Through this method, cohesive calcium sulfate dihydrate formed in the bones and can act as a reinforcing material. The protective effect was studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), hardness, porosity, and color difference determination. The results showed that such consolidation increased the strength of the bone samples significantly, and only slightly changed the appearance and porosity of the bone samples, indicating a good prospect for applying nano calcium sulfate hemihydrate in the conservation of indoor fragile bone relics.

One-step fabrication of transparent Barite colloid with dual superhydrophilicity for anti-crude oil fouling and anti-fogging

HYPOTHESIS

Transparent superhydrophilic coatings are very promising in various scenarios. Appropriate fabrication of colloid coatings with superhydrophilicity both in air and under oil would enlarge their application potential in anti-oil fouling and facilitate anti-fogging of transparent surfaces.

EXPERIMENTS

The Barite colloid was obtained from a one-step precipitation method and was transferred onto glasses to prepare transparent coatings with different thicknesses simply by dip-coating. Then, the impact of thickness on wettability and property was studied through the investigation of wettability in various phase, anti-crude oil fouling performance and anti-fogging ability.

FINDINGS

Similar surface morphology and roughness of these coatings were achieved and all the coated surfaces showed ultra-hydrophilicity both in air and under oil. Moreover, the hydrophilicity in air and under oil was found to deteriorate with the decrease of coatings' thickness and dual superhydrophilicity could be achieved on thick coatings. More importantly, excellent anti-crude oil fouling property and durable anti-fogging ability were realized on these transparent coatings with dual superhydrophilicity.

Effect of Cu2+ on the nucleation kinetics and crystallization of rod-shaped CaSO4·2H2O in aqueous solution

In this study, a simple and efficient strategy is developed to synthesize rod-like CaSO₄·2H₂O (DH) crystals with tunable aspect ratio in aqueous solution using Cu²⁺ as modifier. The aspect ratio and length of the DH crystals are effectively reduced to 5.7 : 1 and about 35 μm in the presence of Cu²⁺, respectively. The interfacial tension value (γ) in the aqueous solution is improved significantly with the assistance of Cu²⁺, yet the nucleation rate (J) of the DH crystal is decreased sharply. The interfacial tension value (γ) in the aqueous solution is improved and the nucleation rate (J) of the DH crystal is drastically decreased due to the introduction of Cu²⁺, leading to the induction time of the DH crystallization being extended from 4 min to 25 min. The diversification of morphology for the DH crystals is incited by the changes of nucleation kinetics and Cu²⁺ incorporated into the crystal lattice, affecting the crystal growth habit, and finally controlling the growth of DH crystals in aqueous solution.

The induction time of DH crystals is extended by the introduction of Cu²⁺.

Effects of Impurities on CaSO4 Crystallization in the Ca(H2PO4)2-H2SO4-H3PO4-H2O System

Wet-process phosphoric acid is a fundamental process in the fertilizer industry. The influence of impurities on crystallization kinetics of CaSO₄ was investigated in the Ca(H₂PO₄)₂-H₂SO₄-H₃PO₄-H₂O system using a mixed suspension mixed product removal crystallizer. Effects of Si, Al, Fe, Mg, K, and Na on crystal morphology and structure were examined in the highly acidic system through scanning electron microscopy and high-resolution transmission electron microscopy. Results show that the increase of Mg, K, and Na content facilitates crystal growth. Si, Al, and Fe are beneficial to CaSO₄ crystal growth at a certain concentration range. Impurities also affect the crystal morphology, and the addition of Si, Fe, and Na promotes the formation of needle-like crystals compared with other impurities. X-ray diffraction results show that the preferred crystal growth direction is (020), and the interplanar spacing of the crystals is affected by the element radius of the impurities.