1. Introduction
2. Materials and Methods
2.1. Materials
2.2. Particle Synthesis
- Reactor System 1: this configuration comprised a liquid–liquid segmented flow reactor, where the organic phase (heptane) wets the reactor wall and segments the aqueous stream. A segmented flow pattern was achieved (size of slugs/droplets ~4 mm) by mixing the streams containing the iron precursor with the base solution and the organic stream in a polyether ether ketone (PEEK) cross junction (1 mm ID, Upchurch Scientific, Oak Harbor, WA, USA). The flow rate of the organic stream was set to 1 mL/min, while equal flow rates of 0.5 mL/min were used for the iron precursor and the base solutions. In this system, the gas–liquid contactor was not used, as the solutions were preventively bubbled with (inert gas). A schematic of the setup is shown in Figure 1b.
- Reactor System 2: this configuration comprised the tube-in-tube gas–liquid contactor upstream of the reaction coil. In the tube-in-tube contactor, an organic stream (heptane) was saturated with . The heptane stream was used to segment the aqueous one before entering the reactor. The two water solutions (base and iron precursor) were mixed and segmented in a PEEK cross junction (1 mm ID, Upchurch Scientific, Oak Harbor, WA, USA). The flow rate of the organic stream was set to 1 mL/min, while equal flow rates of 0.5 mL/min were used for the iron precursor and the base solutions. A schematic of the setup is shown in Figure 1c.
- Reactor System 3: this configuration consisted of a single-phase reactor where the two reactant streams containing the iron precursor and the base were mixed in a PEEK T-junction (1 mm ID, Upchurch Scientific, Oak Harbor, WA, USA) before entering the reaction stage. The overall flow rate was set to 2 mL/min, and each aqueous stream was pumped at 1 mL/min. In this case, the gas–liquid contactor was not used, as the solutions were preventively bubbled with (inert gas). A schematic of the setup is shown in Figure 1d.
- Reactor System 4: this configuration consisted of a single-phase reactor. Here the base solution passed through the tube-in-tube contactor at a flow rate of 0.5 mL/min, where it was saturated with , and then mixed with the solution of iron precursor (1.5 mL/min). The two solutions were mixed in a PEEK T-junction (1 mm ID, Upchurch Scientific, Oak Harbor, WA, USA) before entering the reaction stage. A schematic of the setup is shown in Figure 1e.
2.3. Reactor Scale Up
2.4. Particle Characterization
3. Results and Discussion
3.1. Two-Phase Flow Reactor Systems
3.2. Single-Phase Flow Reactor Systems
3.3. Magnetic and Heating Properties of the Nanoparticles
3.4. Scaled-up Reactor System
4. Conclusions
Supplementary Materials
Author Contributions
Funding
Conflicts of Interest
References
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Reactor System | Particle Size (nm) | Saturation Magnetization () | SAR () | ILP () |
---|---|---|---|---|
2 (two-phase flow with -saturated heptane) | 501 * 765 ** | 2.7 * 2.65 ** | ||
3 (single-phase flow with solutions preventively bubble with ) | 79 | 220 * 395 ** | 1.25 * 1.3 ** | |
4 (single-phase flow with CO-saturated base solution) | 80 | 215 * 382 ** | 1.2 * 1.3 ** |
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