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

Abstract

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

Self-Symmetrical 3D Hierarchical α-Calcium Sulfate Hemihydrate Twin-Flowers Composed of Microplates as a Renewable Material for Water Separation from Water-in-Oil Emulsion

“…The target product was prepared by a simple one-pot synthesis using H 2 O as the solvent, Na 2 SO 4 and CaCl 2 as precursors, and trisodium citrate (TSC) as the shape mediator. The X-ray diffraction (XRD) pattern of the product synthesized in this study (Figure a) displays a series of characteristic diffraction peaks at 14.72, 25.67, 29.69, 31.90, 42.71, 49.24, and 49.36°, respectively, which could be indexed to the (200), (020), (400), (204), (006), (−424), and (424) facets of the calcium sulfate hemihydrate (CaSO 4 ·0.5H 2 O, HH) phase (PDF#41-0244) . The specific surface area was determined to be 4.36 m 2 g –1 by Brunauer–Emmett–Teller (BET) analysis.…”

“…The X-ray diffraction (XRD) pattern of the product synthesized in this study (Figure 1a) displays a series of characteristic diffraction peaks at 14.72, 25.67, 29.69, 31.90, 42.71, 49.24, and 49.36°, respectively, which could be indexed to the (200), (020), (400), ( 204), (006), (−424), and (424) facets of the calcium sulfate hemihydrate (CaSO 4 •0.5H 2 O, HH) phase (PDF#41-0244). 37 The specific surface area was determined to be 4.36 m 2 g −1 by Brunauer−Emmett−Teller (BET) analysis. The HH phase is further confirmed by the corresponding thermogravimetry (TG) pattern (Figure 1b), which shows a weight loss of 6.22 wt % when the product is heated to 250 °C, agreeing with the crystal water content of the HH.…”

Role of Additives in Crystal Nucleation from Solutions: A Review

“…15,236 In the case of inorganic crystals and ionic crystals, additives affect the direction and rate of growth by changing the interspecific interactions or forming the ion− organic molecular complex. 74,237,238 In addition to the above research methods, we suggest that the synergistic strategy of additives in regulating crystal morphology, size, structure, and other properties is worthy of more exploration in the future.…”

“…found 74 that the solubility of saturated gypsum gradually increased with the increase of impurity Cu 2+ concentration during the nucleation of CaSO 4 •2H 2 O (DH). Quan et al reported that piperazine significantly aggrandized the solubility of triethylenediamine (TEDA) in the methyltert butylether (MTBE) system, as shown in Figure 4a.…”

“…Sun et al 74 found that the value of γ in the aqueous solution of DH crystals increased significantly with Cu 2+ , and J decreased significantly (Table 1a). This was consistent with the conclusion of citric acid as an additive in the DH crystallization.…”