Preparation of aminated porous polyacrylonitrile nanofibers as adsorbent for methyl orange removal

In this study, porous electrospinning polyacrylonitrile nanofiber (PPAN) surface functionalization with amine groups is studied for methyl orange (MO) dye removal from aqueous solution. A series of adsorption experiments were carried out to investigate the influence of initial solution pH value, contact time, initial solution concentration, and adsorption temperature on the adsorption performance. The experimental results showed that the removal of MO on these PPAN-PEI and PPAN-TEPA nanofibrous mats was a pH-dependent process with the maximum adsorption capacity at the initial solution pH of 3, and that the PPAN-PEI and PPAN-TEPA nanofibrous mats could be regenerated successfully after 4 recycling processes. The adsorption equilibrium data were all fitted well to the Langmuir isotherm equation, with maximum adsorption capacity of 1414.52 mg g(-1) and 1221.09 mg g(-1) for PPAN-PEI and PPAN-TEPA, respectively. The kinetic study indicated that the adsorption of MO could be well fitted by the pseudo-second-order equation and Weber-Morris model. Thermodynamic parameters such as free energy, enthalpy, and entropy of adsorption of the MO were also evaluated, and the results showed that the adsorption was a spontaneous exothermic adsorption process.

Automated summary

This study investigated the functionalization of porous electrospinning polyacrylonitrile nanofiber (PPAN) surfaces with amine groups for the removal of methyl orange (MO) dye from aqueous solution. Experimental results showed that the maximum adsorption capacity of the PPAN-PEI and PPAN-TEPA nanofibrous mats was achieved at an initial solution pH of 3, and the mats could be successfully regenerated after 4 recycling processes. The Langmuir isotherm equation was well-fitted to the adsorption equilibrium data, and the adsorption of MO followed the pseudo-second-order equation and Weber-Morris model. Thermodynamic analysis indicated that the adsorption of MO was a spontaneous exothermic process.