The effective removal of mercury ions (Hg2+) from water using cadmium sulfide nanoparticles doped in polycaprolactam nanofibers: kinetic and equilibrium studies

In the present research, a novel nanocomposite polymer based on cadmium sulfide nanoparticles doped in polycaprolactam (nylon 6) nanofibers (CdS/N6) was fabricated by the electrospinning technique and used for the removal of highly toxic mercury ions (Hg2+) from aqueous media. Chemical properties and the structural morphology of the adsorbent were investigated using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy analyses. The removal ability of the adsorbent toward Hg2+ ions in aqueous solution and the effect of significant parameters (pH, adsorbent dosage, and contact time) on the adsorption performance were also studied, and the optimal experimental conditions were established. The isotherm studies of the adsorption experimental data validated on the Langmuir and Freundlich models, and the maximum adsorption capacity of CdS/N6 for Hg2+ ions obtained from Langmuir isotherm was 162 mg g−1. The kinetic studies showed that pseudo-second-order model was well fitted to experimental contact time. High adsorption capacity, reusability, easy separation, and inexpensive synthesis make the fabricated nanoadsorbent (CdS/N6) suitable for the enhanced removal of Hg2+ ions in environmental wastewaters.