Efficiency of Natural Bio-adsorbent of Corn Silk for Removal of Lead Ions from Agricultural Effluents

Abstract

Introduction and purpose: Nowadays, the entrance of heavy metals as inorganic pollutants into agricultural waters is one of the major concerns in all over the world. In the past few years, the adsorption of heavy metals by various categories of bio-adsorbents has been investigated via different process, including surface and chemical adsorption. In this research, corn silk has been used as an efficient bio-adsorbent for adsorption of lead ions from agricultural effluents. Materials and methods: Firstly, corn silk prepared from the fields around Kermanshah, afterward washed with distilled water and heated in an oven for 24 hours until it dried and rubbed. The prepared sample used for the adsorption of lead metal experiments. Findings: In higher concentration of the adsorbent, the absorption capacity of ions decreases drastically. Also, the optimal pH value for the absorption process obtained around 5. The kinetic data exhibited that the metal adsorption process followed pseudo-second-order kinetics. Furthermore, thermodynamic data revealed that the process of metal absorption is spontaneous and the absorption happened physically. Conclusion: The results clearly showed that the corn silk as a biosorbent can be effective for the removal of lead ions from aquatic solutions compared to previous reports. We can conclude that, the efficiency of biosorbent refers to the functional groups with high absorption power such as hydroxyl. In addition, the rate of adsorption of pollutants by the corn silk is significant, so that after 30 minutes the surface adsorption process reaches equilibrium stage.

Keywords

• biosorbent
• agricultural effluent
• heavy metals
• corn silk
• adsorption