Factors affecting the efficiency of rye husk as a potential biosorbent for the removal of metallic pollutants from aqueous solutions

Biosorbents have maintained their high rank for the removal of toxic substances from water. In this study, the rye husk was used to remove the toxic lead (Pb) and zinc (Zn) ions from water using batch mode of adsorption. The rye husk was characterized by scanning electron microscopy and Fourier transform infra-red spectroscopy. The concentration of metals was determined using atomic absorption spectroscopy. The maximum uptake of Pb2+ from the water was found to be 97.2% at 3 g of adsorbent dose, 96.64% at 240 min of contact time, and 95.44% for 100 ppm initial metal ion concentration. On the other hand, the Zn2+ uptake was comparatively low at optimized conditions, that is, 3 g adsorbent dose, 150 min contact time, and 125 ppm of initial metal ion concentration. The data was well fitted in both Langmuir and Freundlich adsorption isotherms. It is concluded that the efficiency of rye husk for Pb and Zn removal is dependent on adsorbent dose, contact time, and metal ion concentration. The rye husk is probably one of the efficient adsorbents for the removal of metallic pollutants.