Kinetics, equilibrium and thermodynamics studies of Pb2+ adsorption onto new activated carbon prepared from Persian mesquite grain

In the present study, adsorption of Pb2+ from aqueous solutions onto prepared activated carbon using Persian mesquite grain was studied. Several techniques and methodologies such as, proximate analysis, N-2 adsorption-desorption isotherms, scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature programmed desorption (TPD), Thermo gravimetric analysis TGA/DTA, elemental analysis(CHNS), Boehm titration, and point of zero charge (pH(pzc)) have been used to determine physicochemical properties of raw material and activated carbon. Through the XRD, SEM, TGA/DTA, elemental and FT-IR analysis, it could be observed that significant changes in porosity occurred after the activation process. The N-2 adsorption results demonstrated that the activated carbon is composed mainly of microspores (63.8%), presenting high BET surface area of 1243 (m(2).g(-1)) and exhibit Type I isotherm. According to Boehm titration, surface of activated carbon includes a majority of acidic groups which is in agreement with the obtained pH(pzc) value of 3.73. The maximum adsorption capacity for Pb2+ is much higher than the other granular and powdered activated carbons. High efficiency in Pb2+ removal indicates that activated Persian mesquite grain could be successfully used as an excellent adsorbent in water purification. (C) 2016 Elsevier B.V. All rights reserved.