Efficient recovery indium(III) from waste LCDs by functionalized MXene

With the surge in demand for the scattered metal indium in high-tech fields and the scarcity of its primary resources, waste LCDs have become a key recycling resource. In this paper, an indium adsorbent Alk-MXene-COOH-NH 2 -COOH with multilayer functional groups was prepared by modifying two-dimensional nanomaterial Alk-MXene with chloroacetic acid and HPEI. The adsorption and separation properties of Alk-MXene-COOH-NH 2 -COOH for In(III) were investigated. The adsorption experiments showed that Alk-MXene-COOH-NH 2 -COOH exhibited excellent adsorption performance for In(III). The maximum adsorption capacity of Alk-MXene-COOH-NH 2 -COOH reached 113 mg/g at 35 ℃, and the adsorption equilibrium was reached within 200 min. The adsorption process conforms to the pseudo-second-order kinetic model and Langmuir adsorption model. The Alk-MXene-COOH-NH 2 -COOH exhibited high selectivity for In(III) in ITO leachate. The adsorption capacity of the adsorbent for In(III) in ITO leachate reached the maximum at pH= 3.2, accompanied by a small amount of Fe(III) and Sn(II) coadsorption. After stepwise elution with 2 mol/L oxalic acid and 1 mol/L hydrochloric acid, the separation coefficients of k In(III)/Fe(III) and k In(III)/Sn(II) were 31.08 and 19.95. This indicated that Alk-MXene-COOH-NH₂-COOH can efficiently and selectively recover In(III) from waste LCDs. • Alk-MXene-COOH-NH 2 -COOH with multilayer functional groups was prepared by modifying MXene. • Alk-MXene-COOH-NH 2 -COOH had excellent adsorption and separation properties for In(III). • Alk-MXene-COOH-NH 2 -COOH can effectively recover indium from waste LCDs.