Thiol -functionalized activated carbon fibers as efficient adsorbents for Pb2+

In this study, thiol functionalized activated carbon fibers (ACF-SH) are employed to improve adsorption performances of heavy metals, resulting high density of sulfur-containing and nitrogen-containing groups (6.64 atom % S, 4.49 atom % N confirmed by X-ray Photoelectron Spectroscopy, XPS) and high binding affinity towards Pb 2+ . We find that time, pH, initial ion concentration and adsorbent dosage are important factors affecting the adsorption capacity of modified activated carbon fibers for Pb 2+ . The kinetics and isotherm studies show that the pseudo-second-order model and Langmuir isotherm model can more reasonably explain the adsorption mechanism. Excitingly, the q max obtained through Langmuir isotherm model reaches 700.77 mg g −1 , which significantly surpassed most fiber-based adsorbents. Thermodynamic results significantly exhibit positive ΔH θ and ΔS θ indicating the endothermic property during Pb 2+ adsorption onto ACF-SH with an increase, and a negative ΔG θ reveals its spontaneous at the same time. Moreover, the adsorption mechanism is revealed by diversified analysis. The outcomes from this work indicate that the activated carbon fibers are promising as an adsorbent for effectively repairing Pb 2+ ions in effluent.