A versatile study of single and binary removals of Pb(II) and Cd(II) ions from aqueous solutions using pine cone as biosorbent
Bashkim Thaçi, Salih Gashi, N.M. Daci, Fetah I. Podvorica, F. Sopaj
Abstract
A naturally occurring biosorbent (pine cone) was utilized to remove single and binary Pb(II) and Cd(II) ions from aqueous solutions. The biosorbent has been examined using ATR-IR, SEM, XRD, and pHpzc. The impacts of process factors such as contact time, pH value, biosorbent dosage, initial concentration, and medium temperature on the biosorption of Pb(II) and Cd(II) ions were researched. Langmuir and Freundlich's isotherms were implemented to describe the equilibrium process. At the most favorable condition for each metal, the Langmuir isotherm yielded a maximum loading capacity (qmax) of 43.47 mg/g for Pb(II) and 32.89 mg/g for Cd(II). The highest biosorption was reached with a single system and then reduced in the presence of coexisting ions in the mixtures under optimal conditions. Desorption studies show that 0.5 M HNO3 is the most effective way to remove heavy metals from a biosorbent loaded with metal ions. Thermodynamic parameters (ΔHo, ΔSo, and ΔGo) calculated from temperature data indicate that the biosorption mechanism is exothermic for Pb(II) and endothermic for Cd(II), spontaneous and favorable.