Potential of coffee husk biomass waste for the adsorption of Pb(II) ion from aqueous solutions

The uptake of Pb(II) from the aqueous solution by Coffee Husk Biomass Waste (CHBW) as a green low cost solid phase adsorbent was critically studied. The chemical composition and the surface morphology of the CHBW were determined and fully characterized by FESEM-EDX. In batch mode, the effect of various analytical parameters e.g. adsorbent dose, contact time and analyte concentration on lead(II) ions retention by the biomass CHBW was performed. The adsorption equilibrium of Pb(II) ions was achieved after 60 min with very high percentage 98%, and an adsorption capacity of 19.02 mg/g lead towards the adsorbent was determined. Sorption kinetics data was fitted well with pseudo-second-order model with good correlation coefficient (R² = 1) and (q_e,cal) 19.23 mg/g, (eq_e,exp) 19.07 mg/g. The sorption isotherm fitted better with the Freundlich model (R² is close to the unity). The Langmuir gives maximum adsorption capacity (q_max) of Pb(II) was 37.04 mg/g. These results indicated that, the coffee husk is an efficient, sustainable, and low-cost adsorbent for Pb(II) uptake from wastewater.