Fabrication of novel chitosan-g-PNVCL/ZIF-8 composite nanofibers for adsorption of Cr(VI), As(V) and phenol in a single and ternary systems.

The chitosan-grafted-poly(N-vinylcaprolactam) (chitosan-g-PNVCL) nanofibers were synthesized via electrospinning method. ZIF-8 metal-organic frameworks nanoparticles were incorporated into the nanofibers for adsorption of Cr(VI), As(V) and phenol from water. The BET, FTIR, XRD and SEM analysis were carrfried out to obtain the characteristics of nanofibers. The optimum parameters of ZIF-8 content, pH, contact time, adsorbent dosage, and initial concentration of adsorbates on the Cr(VI), As(V) and phenol removal were studied. The reusability of synthesized nanofibers for five sorption-desorption cycles was also examined. The maximum experimental adsorption capacity of the chitosan-g-PNVCL/ZIF-8 nanofibers for Cr(VI), As(V) and phenol sorption were 269.2, 258.5 and 152.3 mg g, respectively under ZIF-8 concentration of 3 wt.%, adsorbent dosage of 0.5 g/L, pH of 3, equilibrium times of 30 min, and temperature of 25 °C. The kinetic, and isotherm parameters of adsorption process using chitosan-g-PNVCL/ZIF-8 nanofibers were evaluated. In ternary system, the central composite design was applied to investigate the interaction influence of initial concentrations of selected metal ions and phenol on the performance of nanofibrous adsorbent. The obtained results showed the high capability of nanofibers for the removal of heavy metals and organic pollutants from water.