Assessment of the adsorption kinetics, equilibrium, and thermodynamic for Pb(II) removal using a low-cost hybrid biowaste adsorbent, eggshell/coffee ground/sericite.

A hybrid adsorbent (CES), coffee grounds, eggshell powder and sericite as a binder, was prepared to remove Pb(II) from aqueous solution. The Fourier-transform infrared spectroscopy analysis showed that the CES contained a large amount of OH groups and had a favorable structure for adsorbing heavy metals. The value of pH of CES was estimated at 7.08. In the neutral pH region, the surface of CES is negatively charged and favorable for adsorption of Pb(II). The maximum Langmuir adsorption amount was 155.67 mg/g, and the adsorption process of Pb(II) using CES fitted pseudo-second-order kinetic model and Langmuir isotherm model. Moreover, the analysis of adsorption energy, free energy, enthalpy, and entropy found that the adsorption of Pb(II) onto CES was physical and a spontaneous exothermic reaction. CES is a hybrid adsorbent using general municipal waste and has great advantages in terms of environmental conservation and sustainable environmental circulation. This allows it to compete with other adsorbents. PRACTITIONER POINTS: A hybrid adsorbent, coffee grounds, eggshell, and sericite (CES), was used to remove Pb(II) Adsorption of Pb(II) using CES in an aqueous solution was physical rather than chemical CES contained a large amount of OH groups and had a favorable structure for adsorbing heavy metals The reactivity and strength of the adsorption of Pb(II) onto CES was very good CES has great advantages in terms of environmental conservation and sustainable environmental circulation.