Controllable synthesis of uniform small-sized MgCO3 from Mg2+ concentrated seawater brine for the preparation of epoxy resin composite and high purity MgO--颗粒学报PARTICUOLOGY

Yan, S., Guo, H., Zhang, D., Li, Y., & Cao, J. (2025). Controllable synthesis of uniform small-sized MgCO3 from Mg2+ concentrated seawater brine for the preparation of epoxy resin composite and high purity MgO. Particuology, 97, 154-166. https://doi.org/10.1016/j.partic.2024.12.012

Controllable synthesis of uniform small-sized MgCO₃ from Mg²⁺ concentrated seawater brine for the preparation of epoxy resin composite and high purity MgO

Shuo Yan, Hongfei Guo, Dapeng Zhang, Yun Li^*, Jilin Cao

Engineering Research Center of Seawater Utilization Technology of Ministry of Education, School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, 300401, China

10.1016/j.partic.2024.12.012

Volume 97, February 2025, Pages 154-166

Engineering Research Center of Seawater Utilization Technology of Ministry of Education, School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, 300401, China

E-mail: liyun@hebut.edu.cn

Highlights

• Uniform small-sized MgCO₃ is controllably prepare.

• Presence of Mg(OH)₂ colloids inhibits the hydrolysis of urea.

• Uniform small-sized MgCO₃ is synthesized from Mg²⁺ concentrated seawater brine.

• Uniform small-sized MgCO₃ has good flame retardant performance.

• High purity MgO with a purity of 99.54% was prepared by using MgCO₃ as precursor.

Abstract

The large and uneven grain size of anhydrous magnesium carbonate (MgCO₃) seriously restricts its application ranges and performances. In this study, we proposed a controllable and cost-effective strategy to synthesize uniform small-sized MgCO₃ from Mg²⁺ concentrated seawater brine in the absence of crystal modifiers. In this process, solid NaOH was directly added to Mg²⁺ concentrated seawater brine to completely and rapidly convert Mg²⁺ to magnesium hydroxide (Mg(OH)₂) nanoparticles. These nanoparticles are redispersed in water to form the colloidal system, where Mg(OH)₂ nanoparticles hydrothermally reacts with urea to obtain uniform small-sized MgCO₃ particles. The influence of reaction temperature, reaction time, and the molar ratio of magnesium ions to urea on the synthesis of MgCO₃ is systematically investigated. In the highly-dispersed and stable colloidal system, Mg(OH)₂ nanoparticles could exert an effective and sustained retarding effect on the hydrolysis rate of urea by attracting free water, resulting in the controllable release of NH₄⁺, CO₃²⁻, and Mg²⁺. This study presents a simple route to realize the controllable synthesis of uniform small-sized MgCO₃ particles, and demonstrates the feasibility of using MgCO₃ as an ideal filler for enhancing the performance of polymers as well as an ideal precursor for high-purity MgO production.

Graphical abstract

Keywords

Uniform small-sized MgCO₃; Mg(OH)₂ nanoparticles; Mg²⁺ concentrated seawater brine; Flame retardant; High-purity MgO

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