Ultra-cheap and ultra-stable adsorption materials based on nylon and removal performance of copper ion

Abstract

A novel adsorbent material, nylon@Fe3O4, was prepared by co-precipitation of nylon and FeSO4/FeCl3/NaOH solution. The structure of the composite was characterized using FTIR and TG methods. The results of FTIR and TG indicated that nylon@Fe3O4 was successfully synthesized. The adsorption effect of nylon@Fe3O4 on Cu(II) was explored under different experimental conditions. The optimum adsorption conditions of nylon@Fe3O4 on Cu(II) were reached when the amount of composite was 12.50 mg, the concentration of Cu(II) was 15.36 mg/L, the reaction temperature was 50 °C, and the pH value was 9. Under the above conditions, the optimum adsorption efficiency was 94.67 % and the optimum adsorption capacity was 11.57 mg/g. The kinetic modeling indicated that the adsorption of nylon@Fe3O4 belonged to chemisorption, and the initial adsorption rate (h = 69.92 mg/g/min) was larger, which indicated that the nylon@Fe3O4 adsorption rate was faster. The adsorption isotherm experiments showed that the nylon@Fe3O4 adsorption process occurred in the monomolecular layer adsorption, and the separation coefficients 0 < RL = 0.322/0.300/0.287 < 1, which indicated that the adsorption process of nylon@Fe3O4 for Cu(II) was favorable adsorption. The adsorption thermodynamics showed that ΔG0 < 0, ΔS0 = 118 J/mol/K > 0, and ΔH0 = 31.14 kJ/mol > 0, indicating that the adsorption process of nylon@Fe3O4 on Cu(II) was spontaneous and favorable adsorption. Through 8 cycle experiments, the adsorption efficiency decreased from 94.67 % to 61.55 %, so nylon@Fe3O4 had good regenerative performance. In conclusion, nylon@Fe3O4 has potential applications in the adsorption of heavy metal ions.