Application of Noug (Guizotia abyssinica cass.) stalk activated carbon for the removal of lead (II) ions from aqueous solutions

Abstract

Due to the rise of industries worldwide, huge amounts of pollutants including heavy metals are released into the surroundings. Disposal of effluents containing heavy metals in higher concentrations without proper treatment is common in industries; lead is one of them. This study aims to determine and optimize the efficiency of Noug (Guizotia abyssinica Cass.) stalk porous carbon (NSAC) for the elimination of lead (II) from aqueous solutions. For studying the adsorption characteristics of Noug stalk activated carbon (NSAC) an adsorbate of lead (II) ions was used. The interaction and effect of the following parameters on Pb(II) adsorption were investigated using Design Expert version 7.0 software (central composite design) to determine the optimum adsorption condition: pH, initial concentration of Pb(II) ion, adsorbent dose, and contact time. The optimized condition for the elimination of lead (II) using Noug stalk porous carbon (98.77 %) was achieved at pH [4.87], initial concentration of Pb(II) [84.66 mg/L], adsorbent dose [18.43 g/L], and contact time [2.04 h]. The pseudo-second-order kinetics and the Langmuir isotherm model which had a maximum adsorption capacity of 89.25 mg/g, provided the best-fit models for Pb(II) adsorption, with R2 values of 0.99 and 0.98, respectively. Efficient elimination of Pb(II) from wastewater can be performed through the use of NSAC. Future research should delve more into column adsorption under continuous wastewater flow.