Synthesis and evaluation of activated carbon/nanoclay/thiolated graphene oxide nanocomposite for lead(II) removal from aqueous solution

Novel porous nanocomposite (AC/NC/TGO) was successfully synthesized through the composition of activated carbon, nanoclay and graphene oxide as a Pb(II) adsorbent for the treatment of contaminated aqueous environment. The physicochemical properties and morphology of AC/NC/TGO were examined by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and nitrogen adsorption-desorption techniques. Results showed Pb(II) adsorption on the AC/NC/TGO was rapid in the first 20 min and reached equilibrium in 40 min. Kinetic studies showed significant fit to the pseudo second order kinetic model (R-2 >= 0.9965) giving an equilibrium rate constant (K2) of 0.0017 g mg(-1) min(-1) for Pb(II) loaded. The experimental adsorption data were better fitted with the Langmuir isotherm model than with the Freundlich isotherm model. Prepared nanocomposite exhibited high values of Brunauer-Emmett-Teller (BET) surface area of 1,296 m(2) g(-1) and total pore volume of 1.01 cm(3) g(-1). Maximum adsorption capacity (Q(max) = 208 mg g(-1)) and a relatively high adsorption rate was achieved at pH 5.0 using an adsorbent dose of 0.5 g L-1 and an initial lead concentration of 50 mg L-1. High adsorption capacity, reusability, fast kinetics and simple synthesis method indicate that prepared nanocomposite can be suggested as a high-performance adsorbent for Pb(II) removal from polluted water.