Indium（Ⅲ） Adsorption With Impregnated Resins Containing Phosphonic Acids Based On Fe₃O₄@SiO₂ And HZ830 Carriers

Scare metal indium with excellent physical and chemical properties, is widely used in electronics, solar photovoltaic cells, aerospace and other fields. Solar photovoltaic cells containing indium are promising especially in recent years, and indium demand will increase markedly. Indium at present is mainly extracted from the leach liquor of smelting slag containing Zn, Fe, Pb, Cu, etc by solvent extraction. A large number of organic solvent used in the extraction process can cause environmental pollution, and extractants are easy to emulsify. Hence, solvent impregnated resin method was put forward to be used in indium extraction.The shortcomings of traditional solvent impregnated resin method contain the loss of the weak combination between extractant and the traditional macroporous resin support, and extraction solvent loss. In this work, ATMP/Fe₃O₄@SiO2 impregnated resin was fristly preparated by taking ATMP（amino trimethylene phosphonic acid） as the extractant, and Fe₃O₄@SiO2 as the carrier. Secondly, Cyanex272/HZ830,Cyanex301/HZ830 and Cyanex302/HZ830 impregnated resins based on HZ830（a kind of styrene-divinyl nonpolar macroporous resin） as carrier were preparated by using bis（2,4,4-trimethylpentyl）phosphinic acid（Cyanex272）, bis（2,4,4 trimethylpentyl）dithiophosphinic acid（Cyanex301） and bis（2,4,4 ‐ trimethylpentyl）monothiophosphinic acid（Cyanex302） as the extractant, respectively. And the adsorption properties of In（III） with the two kinds of impregnated resins were studied from sulfuric acid medium.ATMP/Fe₃O₄@SiO2 impregnating resin was characterized by IR spectra,thermogravimetric, X-ray photoelectron spectroscopy, X-ray diffraction and other methods. In In（Ⅲ） adsorption with ATMP/Fe₃O₄@SiO2, it was shown that the optimal adsorption pH range was 1.8².6. The kinetic followed the pseudo-second-order equation, and it took about 4 hours to reach balance. The sorption isotherm was found to fit with Langmuir isotherm. The maximum adsorption capacity was 47.5 mg/g.Thermodynamic data showed that the adsorption process was spontaneous, endothermic and entropy increase reaction.Cyanex272/HZ830, Cyanex301/HZ830, Cyanex302/HZ830 impregnating resins were characterized by IR spectra and thermogravimetric analysis. In（ Ⅲ） adsorption results with three kinds of impregnating resins showed that the optimum pH ranges were 1.5, 0.6².2, and 1.5, respectively. The kinetics all followed the pseudo-second-order rate equations. The sorption isotherms were all found to fit with Langmuir isotherms and the maximum adsorption capacities were 16.1 mg/g, 18.1 mg/g,and 27.8 mg/g respectively. The thermodynamic data showed that the adsorption processes of the three kinds of impregnated resins were displayed as spontaneous,endothermic and entropy increase reactions. Fe（ Ⅲ） adsorption performance was also investigated with the three kinds of impregnating resins, and the results showed that the best Fe（Ⅲ）adsorption pH were 1.5, 1.5².2, 1.5, respectively. Adsorption kinetics and thermodynamics of Fe（Ⅲ） with Cyanex301/HZ830, Cyanex302/HZ830 were similar to that of In（Ⅲ）, which followed the pseudo-second-order rate equations and Langmuir isotherms, and the maximum adsorption capacities were 15.5 mg/g and 13.2 mg/g,respectively. Cyanex301/HZ830 showed good separation trend of In（Ⅲ） and Fe（Ⅲ）.