Preparation Of Impregnated Active Carbon Fiber, Coated Impregnated Resin And Their Adsorption And Separation Of In(Ⅲ) And Fe(Ⅲ)

Due to its special chemical and physical properties, indium as one of rare andscattered mental is widely used in liquid crystal materials, high-performance alloys, thenuclear industry and other fields. It is mainly obtained as a by-product from otherminings and secondary resources. In either way, a variety of metals containing ironaccompany indium in the leaching solution in hydrometallurgical process of indium.However, Fe(Ⅲ) is similar with In(Ⅲ) in the leaching solution. It is hard to achieve theeffective and green separation of In(Ⅲ) and Fe(Ⅲ) with the traditional methods.Activated carbon fiber (ACF) is mechanically robust, highly hydrophobic and hasexceptionally high surface area, and a selective adsorbent can be prepared where ACFcan be used as a special carrier for the immobilization of an extractant. Solventimpregnated resin (SIR) technique combines the advantageous features of bothliquid-liquid and ion exchange techniques. It is possible to prepare a novel adsorbent bydesigning and selecting special carrier and extractant. Hence, novel adsorbents whichare used to separate In(Ⅲ) and Fe(Ⅲ) effectively are expected to be preparedconsidering the properties of ACF and SIR.ACF was modified by using either oxidized or solvent impregnated treatments.Three adsorbents prepared above were named after oxidized ACF (OACF),2-ethylhexylphosphoric acid mono (2-ethylhexyl) ester (P507) solvent impregnated ACF (SIACF)and P507solvent impregnated oxidized ACF (SIOACF), respectively. The coatedimpregnated resin (CSIR) was prepared with P507as the extractant, HZ818macroreticular resin as the carrier, polyacrylic acid as the coating film andN,N’-methylenebis(2-propenamide) as crosslinked agent. These adsorbents werecharacterized by scanning electron microscopy, thermogravimetric analysis and infraredspectroscopy. The adsorption properties of In(Ⅲ) and Fe(Ⅲ) were investigated withthese adsorbents.In the static adsorption experiment, OACF, SIACF and CSIR showed superioradsorption for In(Ⅲ) and Fe(Ⅲ). The sorption isotherms of all adsorbents were found tofit with Langmuir isotherms. The pseudo second-order kinetics model were used to fitdata of the adsorption process of In (Ⅲ) and Fe (Ⅲ) with adsorbents. It was shown thatthe optimum adsorption pH of In(Ⅲ) and Fe(Ⅲ) were1.1and2.0for SIACF,0.8and 0.1for CSIR, respectively. The adsorption capacities increased with the increase oftemperature. SIACF and CSIR have potential of separation In (Ⅲ), Fe (Ⅲ) bycontrolling the adsorption conditions.The separation of In (Ⅲ) and Fe (Ⅲ) was investigated using a column packed. Theresults to adsorb In(Ⅲ) and Fe(Ⅲ) have been obtained with SIACF and CSIR. Firstly,both of In(Ⅲ) and Fe(Ⅲ) were adsorbed in the column from aqueous solutions, butmore In(Ⅲ) was adsorbed than Fe(Ⅲ). Then, the successful and selective separation ofIn (Ⅲ) and Fe (Ⅲ) was achieved by selecting the different elution solutions with30g·L-1oxalic acid and2mol·L-1hydrochloric acid as aubstep elution. The adsorptionstability and rate was improved when CSIR was used.Waste LCD was used as the practical application system. Results of XRD and XRFshowed that indium in LCD were in the form of In2O3.Content of In2O3in the sampleswas0.052%. After crushing, the concentration of indium is20.3mg·L-1by leachingwith sulfuric acid. Indium could be recovered in the leaching liquid through selectiveadsorption follow by substep elution with CSIR...