Feasibility of using chemical co-precipitation and a high-gravity reactor with blade packings for continuous production of magnetite nanoparticles

• Published in: Journal of the Taiwan Institute of Chemical Engineers Vol. 162; p. 105620
• Main Authors: Lin, Chia-Chang, Wu, Yu-Ching, Wu, Kuan-Yi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2024
• Subjects: Co-precipitation; High-gravity reactor; Magnetic; Magnetite; Nanoparticles; Nanoparticles; Magnetite; Magnetic; High-gravity reactor; Co-precipitation
• ISSN: 1876-1070
• DOI: 10.1016/j.jtice.2024.105620

•Magnetite nanoparticles have a mean crystalline size of 11 nm.•Magnetite nanoparticles exhibit superparamagnetism.•Magnetite nanparticles can adsorb Pb2+ in water. Magnetite nanoparticles (Higee-magnetite) were continuously produced using chemical co-precipitation and a high-gravity reactor with blade packings. A novel process for continuously producing Higee-magnetite involved an Fe2+ concentration of 0.15 mol/L with an Fe2+/Fe3+/OH− molar ratio of 1/2/8, an aqueous Fe2+/Fe3+ flow rate of 0.5 L/min, an aqueous OH− flow rate of 0.5 L/min, and a rotation speed of the high-gravity reactor of 1800 rpm. The mean crystalline size of Higee-magnetite was 11 nm. The average particle sizes of Higee-magnetite as determined using SEM and TEM were 23 nm and 9 nm, respectively. Higee-magnetite was superparamagnetic at 25 °C. The saturation magnetization of Higee-magnetite was 69 emu/g. The BET specific surface area, Langmuir specific surface area, and mean pore size of Higee-magnetite were 152 m2/g, 204 m2/g, and 10 nm, respectively. The rate of continuous production of Higee-magnetite was approximately 12 kg/day. Higee-magnetite had a much higher capacity for adsorbing Pb2+ than magnetite nanoparticles that had been produced in a batch reactor since it had a larger specific surface area. The Pb2+ adsorption isotherm of Higee-magnetite corresponded more closely to the Langmuir isotherm model than to the Freundlich isotherm model. Furthermore, consistent with the Langmuir isotherm model, Higee-magnetite had the maximum Pb2+ adsorption capacity of about 49 mg/g at 25 °C and pH 5. Therefore, Higee-magnetite is a favorable magnetic adsorbent for removing Pb2+ from water. [Display omitted]