Trapping heavy metals

Rapid industrialization has contributed to the contamination of water and wastewater streams by toxic heavy metals. Mining and metalworking, electroplating and the textile industry are the main sources of heavy metal ion contamination. Heavy metals can be highly toxic as ions or in compound forms. Chemical precipitation, coagulation, and flocculation are the most generally applied methods for removing heavy metals, especially for the simple and low-cost removal of Cu, Zn, Fe, and Co. Biomass waste is renewable and available abundantly at no or low cost. Biomass is a good low-cost adsorbent for removing heavy metal ions. Fixed-bed adsorbers, where the liquid is passed through the bed of adsorbents, are widely used in industry. Experiments have shown that the smaller particles of biomass waste are better adsorbent than larger particles.