In this study, a solid adsorbent based on Chinese gallotannin and chitosan was generated and applied to adsorb rare and scattered metals, including Ge (Ⅳ), Ga (Ⅲ), and In (Ⅲ), from simulated zinc plant leachates. Fourier-transform infrared spectroscopy (FTIR) and solid state nuclear magnetic resonance (SSNMR) were performed to characterize the grafting way of Chinese gallotannin on the chitosan matrix. It was clearly showed that Chinese gallotannin was immobilized on the chitosan by Schiff-base condensation and phenol-formaldehyde reaction at the molar ratio of glutaraldehyde to tannin of 2:1. And the amount of chitosan amino groups was ten times that of tannin, with an initial pH of 4. The adsorption experiments showed that an appropriate increase in pH was more beneficial to enhance the adsorption capacity of immobilized Chinese gallotannin (ICGT). At a temperature exceeding 30 °C, the immobilized tannin became less sensitive to temperature. Adsorption kinetics studies showed that the adsorption of the three scattered metals by ICGT followed a quasi-second-order kinetic equation , with chemisorption as the mechanism. The adsorption isotherm was well fitted by the Langmuir model, indicating uniform adsorption sites on the surface of ICGT. The adsorption capacities of Ge (Ⅳ), Ga (Ⅲ), and In (Ⅲ) in solution by the adsorption model of monolayer were 61.39 mg/g, 63.82 mg/g, and 59.92 mg/g, respectively. Mechanical property and stability tests showed that ICGT had good resistance to harsh adsorption conditions of scattered metal ions .
Extraction of In(Ⅲ) from the tail liquid of zinc ore which possesses the large amounts of Zn(Ⅱ) and the characteristics of highly acidity, remains a critical challenge. Adsorption method can be considered as an effective and green strategy to recovery In(Ⅲ). However, the adsorption capacity of mostly reported adsorbents is unsatisfactory toward In(Ⅲ) in the acidic environment. In this work, an effective In(Ⅲ) trap is developed by using a mild, simple strategy that introduces zirconium glyphosine coordination networks in situ loaded on carbon nanotube . Benefiting from the characteristics of abundant carboxyl and phosphate groups, excellent hydrophilicity and thermal stability, the resultant zirconium glyphosine carbon nanotube composite (xZrGP-CNT) exhibits remarkable adsorption capacity (193.72 mg g - 1 ) toward In(Ⅲ) under pH 2.5 exceeded most of the reported adsorbents, and its adsorption behavior is consistent with pseudo-second order kinetic and Langmuir isotherm models. In addition, the obtained 2ZrGP-CNT shows prominent kinetics that reaches equilibrium only within 2 h, superior selectivity and excellent regeneration performance for In(Ⅲ) capture, which indicates the highly encouraging potential for the recovery of In(Ⅲ) in practical ore fluids. Our work poses a new way to recovery of In(Ⅲ) under acidic environments with superior adsorption performance and broadens the potential of organocphosphonates for recovering In(Ⅲ).
危险品化学品经营许可证（带存储）