Wet separation between palladium(II) and molybdenum(IV) ions by using laser-induced particle formation: Enhancement of recovery efficiency of palladium by laser condition

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2015-02, Vol.299, p.189-193
• Main Authors: Saeki, Morihisa, Taguchi, Tomitsugu, Nakashima, Nobuaki, Ohba, Hironori
• Format: Article
• Language: English
• Subjects: Laser-induced particle formation; Molybdate(VI) ion; Palladium(II) ion; Particle growth mechanism; Recovery efficiency; Wet separation
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2014.11.022

[Display omitted] •We performed wet separation of Pd and Mo by using laser-induced particle formation.•We selectively reduced Pd ion by laser and successfully recovered as particles.•Laser condition had an influence on recovery efficiency of Pd.•Recovery efficiency and particle size of Pd increased in using pulsed laser.•Laser contributes not only in reduction of Pd ions but also Pd particle growth. Metal separation by using laser-induced particle formation was applied to the recovery of Pd from a mixed solution with Mo. In this separation, the Pd ions in the mixed solution containing 1vol% ethanol were selectively reduced by irradiation of pulsed laser (10Hz repetition rate) and high-repetition-pulse (HRP) laser (30kHz repetition rate) with the wavelength of 355nm while keeping irradiation power constant. The laser-induced reduction resulted in the generation of the Pd neutrals, which is followed by the aggregation of Pd neutrals in the absence of a stabilizing agent. The generated Pd particles were recovered and separated from the Mo ions by filtration. ICP-AES analysis of the filtrate elucidated that the Pd metals were successfully separated from Mo with a high recovery efficiency (84%). The recovery efficiency of Pd was different in the irradiation between the pulsed and HRP lasers; the efficiency obtained using the pulsed laser was 12% higher than that from the HRP laser. XRD analyses demonstrated that the Pd particles subjected to pulsed laser irradiation were 30 times larger than those subjected to the HRP laser. Based on TEM observations, the sizes of the Pd primary particles were approximately 200nm (pulsed laser) and