Adsorption of Biebrich scarlet dye onto nano NiO and modified nano NiO: Isotherms, thermodynamic and kinetic studies

Abstract

Present research includes the modification of the commercial nano nickel oxide NiO-C using Tetraethoxysilane (TEOS) compound. The modified nickel oxide NiO-M NPs and the commercial NiO-C NPs are both used as adsorbents to remove Biebrich Scarlet (BS) dye from water using adsorption technique. These samples were characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD, scanning electron microscopy (SEM) and Brunauer-Emmett-and-Teller (BET) to determine specific surface area and mean pore diameter. Langmuir and Freundlich adsorption isotherms were utilized and the obtained data showed that the Langmuir isotherm well described the equilibrium experimental data. Thermodynamic functions such as ΔG°, ΔH° and ΔS° were estimated and it can be indicated from this functions that the adsoption of BS dye onto NiO-M and NiO-C surfaces are spontaneous and endothermic process. The pseudo-first order (PFO) and pseudo-second order (PSO) kinetic models were used to estimate the adsorption rate, it is found that the rate mechanism explained well by the pseudo-second order model (PSO).