Mechanisms of classical crystal growth theory explain quartz and silicate dissolution behavior

Abstract Due to the high capacity of impurities in its structure, calcite is regarded as one of the most attractive minerals to trap heavy metals (HMs) and radionuclides via substitution during coprecipitation/crystal growth. As a high-reactivity mineral, calcite may release HMs via dissolution. However, the influence of the incorporated HMs and radionuclides in calcite on its dissolution is unclear. Herein, we reported the dissolution behavior of the synthesized calcite incorporated with cadmium (Cd), cobalt (Co), nickel (Ni), zinc (Zn), and uranium (U). Our findings indicated that the HMs and U in calcite could significantly change the dissolution process of calcite. The results demonstrated that the incorporated HMs and U had both inhibiting and enhancing effects on the solubility of calcite, depending on the type of metals and their content. Furthermore, secondary minerals such as smithsonite (ZnCO3), Co-poor aragonite, and U-rich calcite precipitated during dissolution. Thus, the incorporation of metals into calcite can control the behavior of HMs/uranium, calcite, and even carbon dioxide.

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(NH4)3FeF6 Mesocrystal Grown by Electric Field-Assisted in-situ Dissolution and Reaction of Anodic Iron Oxides

Chemical Communications ◽

10.1039/d1cc05980g ◽

2022 ◽

Author(s):

Hui Li ◽

Zixue Su

Keyword(s):

Crystal Growth ◽

Electric Field ◽

Iron Oxides ◽

Growth Process ◽

Electrical Polarization ◽

Crystal Growth Process ◽

Classical Crystal

(NH4)3FeF6 mesocrystalline octahedrons are formed by in-situ dissolution and reaction of anodic iron oxides, followed by a non-classical crystal growth process involving electrical polarization and subsequent alignment of primary (NH4)3FeF6...

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The application of polymer crystal growth theory to the kinetics of formation of the B-amylose polymorph in a 50% wheat-starch gel

Carbohydrate Polymers ◽

10.1016/0144-8617(88)90048-3 ◽

1988 ◽

Vol 9 (4) ◽

pp. 301-317 ◽

Cited By ~ 66

Author(s):

R.D.L. Marsh ◽

J.M.V. Blanshard

Keyword(s):

Crystal Growth ◽

Wheat Starch ◽

Growth Theory ◽

Polymer Crystal ◽

Kinetics Of Formation ◽

Starch Gel ◽

Kinetics Of

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Comparison of Downstream Processing of Nanocrystalline Solid Dispersion and Nanosuspension of Diclofenac Acid to Develop Solid Oral Dosage Form

Pharmaceutics ◽

10.3390/pharmaceutics12111015 ◽

2020 ◽

Vol 12 (11) ◽

pp. 1015

Author(s):

Sanika Jadhav ◽

Amanpreet Kaur ◽

Arvind Kumar Bansal

Keyword(s):

Crystal Growth ◽

Spray Drying ◽

Solid Dispersion ◽

Dosage Form ◽

Crystal Size ◽

Downstream Processing ◽

Process Efficiency ◽

Oral Dosage ◽

Dissolution Behavior ◽

Media Milling

The conventional “top-down”, “bottom-up” and “combination” approaches of generating drug nanocrystals produce a “nanosuspension” (NS). It requires significant downstream processing for drying the liquid by suitable means followed by its granulation to develop an oral solid dosage form (OSD). In this paper, we used a novel, spray drying-based NanoCrySP technology for the generation of drug nanocrystals in the form of nanocrystalline solid dispersion (NCSD). We hypothesized that the NCSD would require minimal downstream processing since the nanocrystals are obtained in powder form during spray drying. We further compared downstream processing of NS and NCSD of diclofenac acid (DCF) prepared by wet media milling and NanoCrySP technology, respectively. The NS and NCSD were characterized for crystallinity, crystal size, assay and dissolution. The NCSD was physically mixed with 0.3% Aerosil® 200, 1.76% croscarmellose sodium (CCS) and 0.4% sodium stearyl fumarate (SSF) and filled into size 0 hard gelatin capsules. The NS was first wet granulated using Pearlitol® SD 200 (G1 granules) and Celphere® 203 (G2 granules) in a fluidized bed processor, and the resulting granules were mixed using the same extra granular excipients as NCSD and filled into capsules. A discriminatory dissolution method was developed to monitor changes in dissolution behavior due to crystal growth during processing. Cost analysis and comparison of process efficiency was performed using an innovation radar tool. The NS and NCSD were successfully fabricated with a crystal size of 363 ± 21.87 and 361.61 ± 11.78, respectively. In comparison to NCSD-based capsules (65.13%), the G1 and G2 granules showed crystal growth and decrease in dissolution to 52.68% and 48.37%, respectively, in 120 min. The overall cost for downstream processing of NCSD was up to 80% lower than that of NS. An innovation radar tool also concluded that the one-step NanoCrySP technology was more efficient and required less downstream processing than the two-step wet media milling approach for conversion of nanocrystals to OSD.

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