Innovative Amidoxime Nanofiber Membranes for Highly Effective Adsorption of Ga(III) from Waste Bayer Solution

The effective treatment of Ga-containingwastewater fromthe Bayerprocess is a promising strategy for the sustainable development ofthe gallium resource. Among the adsorption materials, nanofibers playindispensable roles in the recovery of gallium with their adsorptioncapacity. However, developing facile, easy scale-up, and low-costgrafting methods for polyacrylonitrile nanofiber membranes (PAN NFs)is still challenging in view of the traditional grafting methods withlower grafting rates and strict requirement of fiber flexibility.In this study, a newly and highly efficient amidoxime nanofiber membranepreparation method with electrostatic spinning technology was exploredto apply in the Ga(III) adsorption from Ga-containing wastewater.The results of Ga(III) adsorption studies by amidoxime polyacrylonitrilenanofiber membranes (AOPAN NFs) showed that Ga(III) was remarkablyconsistent with the Langmuir isotherm, with a maximum adsorption capacityof 39.80 mg/g of Ga(III) at 30 & DEG;C, a gallium concentration of200 mg/L, a solid to liquid ratio of 1.0 mg/mL, and a solution pHof 12, which is generally higher than those of other materials. Thekinetic adsorption experiment demonstrated that the adsorption processwas controlled by a chemical reaction and followed the pseudo-second-orderkinetic model. Furthermore, the adsorption mechanism of AOPAN NFswas proposed, and the oxime group played an essential role in theadsorption process. This strategy combines the advantages of AOPANNFs to open up a new way to develop the next generation of galliumadsorption materials.

Automated summary

In this study, a new and highly efficient method of preparing amidoxime nanofiber membranes (AOPAN NFs) was developed using electrostatic spinning technology for Ga(III) adsorption from Ga-containing wastewater. The results showed that AOPAN NFs exhibited remarkable adsorption capacity for Ga(III) and followed the Langmuir isotherm. The adsorption process was controlled by a chemical reaction and the oxime group played an essential role in the adsorption mechanism.