Lignin-based adsorbent for effective removal of toxic heavy metals from wastewater

Water pollution due to heavy metals is one of the great concerns in the present scenario. Lignin as emergent material has the potential to adsorb the heavy metals from wastewater as even in low concentrations heavy metals are very harmful to living organisms. Researchers are also working on functional (nano) material where lignin is used as an additive for the synthesis of nanomaterials or composite materials. The lignin can be considered as recyclable biosorbents with high adsorption for heavy metals. But the adsorption capacity of lignin material is not superior to that of commercial adsorbent and ion exchange resin materials. To overcome this problem, multifunctional composite materials are used to improve the removal capacity of lignin. The surface properties of lignin can be modified by chemical and physical methods to obtain new materials. This review summarizes the recent advancement in lignin and lignin-based biosorbents in the remediation of heavy metals from wastewater.