Efficient synthesis of size-controlled open-framework nanoparticles fabricated with a micro-mixer: route to the improvement of Cs adsorption performance

• Published in: Green chemistry : an international journal and green chemistry resource : GC Vol. 17; no. 8; pp. 4228 - 4233
• Main Authors: Takahashi, Akira, Minami, Nobutsugu, Tanaka, Hisashi, Sue, Kiwamu, Minami, Kimitaka, Parajuli, Durga, Lee, Kyoung-Moo, Ohkoshi, Shin-ichi, Kurihara, Masato, Kawamoto, Tohru
• Format: Journal Article
• Language: English
• Published: 01.08.2015
• Subjects: Adsorption; Copper; Crystallites; Flow rate; Mathematical analysis; Nanoparticles; Potassium; Synthesis
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/c5gc00757g

We demonstrated an efficient method for size-controlled nanoparticles of the open framework coordination polymer potassium copper hexacyanoferrate (KCuHCF) using only aqueous solutions of the raw materials and a Y-type micro-mixer. Despite the high viscosity of the synthesized NP slurry, the micro-mixer provides continuous synthesis without clogging for a few hours with a high flow rate of 100 mL min −1 , i.e. a linear velocity of 94 m s −1 . The crystallite size, evaluated by the Scherrer equation using X-ray diffraction measurements, can be controlled by changing the flow rate. With the highest flow rate of 100 mL min −1 , the smallest NPs with a size of ∼11 nm were obtained, less than half of the NP size obtained using the batch method. By downsizing the nanoparticles (NPs) using the micro-mixer synthesis, the Cs adsorption performance of potassium copper hexacyanoferrate (KCuHCF) was drastically improved. The KCuHCF with the smallest primary particles showed the fastest Cs adsorption: 1.4 times in the saturated capacity, 3.9 times in the distribution coefficient, and 7.7 times in the rate constant for the pseudo-second order adsorption theory, compared with the batch-synthesized sample. An efficient preparation of size-controlled nanoparticles of an open framework coordination polymer.