For the adsorption and recovery of rare earth elements from aqueous nitric acid, solid-phase extraction resins were prepared by impregnating and immobilizing of bis(2-ethylhexyl)phosphoric acid extractant into the macroporous silica-based polymeric (SiO 2-P) particles. It was found that bis(2-ethylhexyl)phosphoric acid/SiO 2-P had higher adsorption distribution coefficient for heavy rare earth elements than for light rare earth elements. The adsorption capacity of Gd(III) was observed to be 0.315 mmol g À1 by bis(2-ethylhexyl)phosphoric acid/SiO 2-P in 0.1 M HNO 3 at 298 K, which increased slightly when increasing temperature from 298 to 323 K. The adsorption isotherms of Gd(III) matched well with the Langmuir and Freundlich models. The obtained thermodynamic parameters (ÁH o and ÁG o) showed that the adsorption of Gd(III) by bis(2-ethylhexyl)phosphoric acid/SiO 2-P was a spontaneous and exothermic process. This study also evaluated the chemical stability of bis(2-ethylhexyl)phosphoric acid/SiO 2-P treated with nitric acid at different temperatures and demonstrated that bis(2-ethylhexyl)phosphoric acid/SiO 2-P had considerable stability against nitric acid and heat.
A new porous organic polymer (POP) with high thermal stability and large surface area has been synthesized and applied in the preparation of Pd/POP catalyst. Pd/POP was characterized by XRD, TGA, SEM and TEM. The catalyst consists of highly dispersed palladium nanoparticles of 0.9–4 nm size on POP with a large surface area of 650 m2/g. It presents high catalytic activity for Suzuki‐Miyaura and Sonogashira reactions. The catalyst was reusable for three to five times without significant loss of activity.
Aiming at the separation of Pd(II) along with MA(III) from high-level liquid waste, a porous silica based adsorbent isoBu-BTP/SiO 2 -P was prepared. The adsorption properties of isoBu-BTP/SiO 2 -P toward Pd(II) were investigated. It was found that with the increase of HNO 3 concentration, Pd(II) adsorption ability increased initially as HNO 3 concentration increased until 1 M, then remained unchanged as HNO 3 concentration further increased. The adsorption kinetics and isotherm of Pd(II) onto isoBu-BTP/ SiO 2 -P fit well with the pseudo-second-order rate law and Langmuir adsorption model, respectively. The adsorption thermodynamic parameters revealed that the adsorption process was spontaneous and endothermic. A hot test utilizing isoBu-BTP/SiO 2 -P packed column was conducted and the simultaneous separation of Pd(II) and MA(III) was achieved from solution by using 0.01 M HNO 3 -0.1 M TU and 0.01 M HNO 3 -0.01 M DTPA as eluents, respectively. The Pd(II) with isoBu-BTP/SiO 2 -P complex was illustrated to be 1:1 type by HRMS, while 1:3 Eu(III) to isoBu-BTP complex was found by single-crystal X-ray diffraction.
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