The continuous expansion of the market demand and scale of commercial amidoxime chelating resins has caused large amounts of resin to be discarded around the world. In this study, the waste amidoxime chelating resin was reutilized as an adsorbent for the removal and recovery of Pb(II), Cu(II), Cd(II) and Zn(II) ions from aqueous solutions. The physical morphology and chemical composition of the waste amidoxime chelating resin (WAC-resin) from the factory was characterized by the elemental analyzer, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The influence of the initial metal ions concentration, contact time, temperature and the solution pH on the adsorption performance of the metal ions was explored by batch experiments. It was shown that the optimal pH was 4. Kinetic studies revealed that adsorption process corresponded with the pseudo-second-order kinetic model and the adsorption isotherm was consistent with the Langmuir model. At room temperature, the adsorption capacities of WAC-resin for Pb²⁺, Cu²⁺, Zn²⁺ and Cd²⁺ reached 114.6, 93.4, 24.4 and 20.7 mg/g, respectively.

The phase evolution mechanism and purification of titanium oxycarbide (TiC_xO_y) synthesized via the carbothermal reduction of ilmenite are investigated. The reaction process and products of the performed carbothermal reduction are analyzed by means of X-ray diffraction (XRD), scanning electron microscopy-energy disperse spectroscopy (SEM-EDS), X-ray photoelectric spectroscopy (XPS) and enthalpy, entropy and heat capacity (HSC) thermodynamic software. According to the shapes of Ti 2p3/2 and Ti 2p1/2 peaks in XPS spectra, together with the XRD analyses, the reduction products of TiO, TiC_xO_y or TiC can be judged. The phase evolution mechanism involves FeTi₂O₅, Ti₂O₃, Fe, TiO, TiC_xO_y and TiC under enhancing the content of carbon. The phase evolution law can be written as FeTiO₃ → FeTi₂O₅ → Ti₂O₃ + Fe → TiO + Fe → TiC_xO_y + Fe. Due to the incomplete reduction state of TiC_xO_y, the ΔG^θ of TiC_xO_y is detected between TiC and TiO. TiC_xO_y could be attained under reduction conditions of Ti:C, 1:3–1:4 in argon atmosphere at 1550 °C after 2 h. Grinding, flotation and magnetic separation processes displayed that C, TiC_xO_y and Fe are not dissociated until the particle size of −38 μm. TiC_xO_y and Fe can be separated by an iron-bath in a high temperature. 95.56% TiC_xO_y can be obtained, and resistance of TiC_xO_y is less than 0.05 Ω.

Utilising waste amine-oxime (WAO) resin through microwave semi-carbonization, a carbon adsorbent (CA) was obtained to remove Pb(II). After microwave treatment, the pore size of the skeleton structure, three-dimensional porous network, and lamellar pore structure of WAO was improved. The distribution coefficient (Kd) of Pb(II) onto CA is 620 mL/g, and the maximum adsorption capacity of Pb(II) is 82.67 mg/g after 20 min of WAO microwave treatment. The adsorption kinetics and adsorption isotherms conform to the quasi-second-order kinetic equation and Langmuir adsorption isotherm model, respectively. The surface of MT-WAO is negatively charged and the adsorption mechanism is mainly electrostatic interaction. Pb(II) elution in hydrochloric acid solution is more than 98%, and its recovery is high at 318 K and for 1 h.