Efficient and fast recovery of indium with phosphate-functionalized polyaniline porous carbon self-supported electrode by electrosorption-deposition strategy

[Display omitted] •A phytic acid-doped polyaniline/porous carbon electrode is designed and developed.•PA-PANI/PC exhibits the ultrahigh extraction capacity of 284.67 mg/g at pH 2.5.•Rapid kinetics is achieved in that majority recovery be completed within 20 min.•In(Ⅲ) is collected in the form of precipitate, allowing easy recovery.•The regenerated PA-PANI/PC can retain around 80% after seven reuse cycles. Extraction of indium, that an important strategic resource, is limited by the low extraction capacity in the acidic environment, and sluggish adsorption kinetics. Electrodes and adsorption technologies can be combined to improve extraction capacity and kinetics, having high exploitation in metal recovery. A novel phytic acid-doped polyaniline/porous carbon (PA-PANI/PC) carbon cloth self-supported electrode is developed for extracting In(Ⅲ) from aqueous solutions by electrosorption-deposition strategy in this work. A series of characterization analysis show that PA-PANI/PC exhibits electrics double-layer capacitance and pseudocapacitance as well as abundant specific binding sites for In(Ⅲ) and improved hydrophilicity, which all conducive to the extraction of In(Ⅲ). As expected, PA-PANI/PC-2 exhibits the maximum extraction capacity of 284.67 mg/g within 60 min at pH 2.5, which represents the highest reported capacity for the extraction of In(Ⅲ), to date. Benefiting from complexation with phosphate groups, In(Ⅲ) can be directly recovered in the form of precipitation, avoiding backwashing with concentrated acid. Furthermore, the adsorbent maintains great affinity and selectivity for In(Ⅲ) even in multi-component simulated system. The low-cost adsorbent PA-PANI/PC based on simple and low-energy electrosorption-deposition process shows potential in terms of effectively recovering In(Ⅲ) from practical ore fluid.