Preparation of spherical oxalate particles of rare earths in emulsion liquid membrane system

Abstract

Submicron-sized spherical oxalate particles of rare earths were prepared by using an emulsion liquid membrane (ELM, (water-in-oil-in-water

Room‐temperature synthesis and characterization of cross‐like Pr2(C2O4)3·10H2O micro‐particles

“…Furthermore, some efforts were focused on the preparation of single crystals Ln 2 (C 2 O 4 ) 3 ·nH 2 O. Ollendorff and Weigel obtained single crystals of Ln 2 (C 2 O 4 ) 3 ·10H 2 O (Ln = La, Ce, Pr and Nd) by slowly cooling hot, saturated solutions of the oxides in a mixture of sulfuric and oxalic acids [13]. Takayuki Hirai et al prepared spherical Ln 2 (C 2 O 4 ) 3 ·nH 2 O (Ln = Ce, Pr, Nd, Sm, Eu, Gd, Dy, Y and Yb) by using an emulsion liquid membrane (ELM) system, consisting of Span 83 as a surfactant and EHPNA or bis (1,1,3,3-tetramethylbutyl) phosphinic acid as an extractant [14,15].…”

Preparation of Y2O3 nanoparticulate thin films using an emulsion liquid membrane system

“…The internal water phase obtained from the ELM system has been found to be capable of being used to prepare both size-and morphology-controlled fine particles, since the internal water droplet has a restricted reaction area [1,2]. Various kinds of particles have been prepared using ELM systems, such as rare earth oxalate particles [3][4][5], which are applicable as precursor particles for the preparation of oxide particles, such as phosphor particles such as Y 2 O 3 :Eu [6], Gd 2 O 3 :Eu, and Gd 2 O 2 S:Eu [7], and infrared-to-visible upconversion phosphor particles such as Y 2 O 3 :Yb,Er [8], Y 2 O 2 S:Yb,Er [9], Gd 2 O 3 :Yb,Er, and Gd 2 O 2 S:Yb,Er [10]. In these cases for rare earth oxalate particles, the particles formed in the internal water phase were collected by the demulsification of W/O emulsion by adding acetone or ethylene glycol and centrifugation, following the recovery of the W/O emulsion from external water phase.…”

Formation Mechanism of Zinc Oxalate Particles in the Internal Aqueous Droplets of Emulsion Liquid Membrane

“…[18][19][20][21] Morphology and size of the particles could be controlled through changing carrier concentration or water-oil ratio for controlling mass transfer rate. [7,22] However, few studies have been preformed to study the evolution process of particles and interaction between particle growth and interface property at a micro level. Moreover, a limited number of reports are insufficient to explain formation mechanism of particles in the ELM.…”

“…[1][2][3][4][5][6] This typical process inspires researchers to employ ELM as reaction media for particle synthesis, i.e., employ the internal water droplets as micro reactors. Such facile and mild method has already been utilized to prepare various materials such as oxalate, [7][8][9] oxide, [10][11][12] cadmium sulfide, [13] phosphate, [14,15] calcium carbonate, [16,17] sulfate [14] and composites. [18][19][20][21] Morphology and size of the particles could be controlled through changing carrier concentration or water-oil ratio for controlling mass transfer rate.…”