A Comprehensive Review on Lignin Based Electrospun Nanomaterials as Suitable Adsorbents for Remediation of Detrimental Water and Air Pollutants

Lignin is an amorphous natural polymer with multifunctional phenolic network accounting for approximately 15–30% of lignocellulosic biomass. Different functional groups like carboxyl, hydroxyl, phenolic and methoxy in lignin molecule may act as suitable interaction sites for the removal of pollutants. Lignin, as an abundant and renewable bioresource, can be used to create nanofibrous membranes via electrospinning technique. Such nanofibrous membranes with elevated specific surface area, uniform fiber diameter, and high porosity may serve as highly efficient adsorbents for the entrapment of detrimental pollutants like dyes, heavy metals, particulates, etc. Hence, numerous research has been carried out to develop lignin based electrospun membranes in recent years. For example, a low-cost electrospun nano-fibrous membrane (ENM) comprising of alkali lignin/polyvinyl alcohol (PVA) was developed for effective removal of Safranine T dye. Similarly, palm fronds and banana bunch waste biomass derived lignin was successfully employed as an electrospun material for the removal of methylene blue dye. An alkali lignin/PVA ENM was developed for the adsorption of fluoxetine contaminant from its solution. This review paper provides the up-to-date information on the development and usage of eco-friendly, sustainable and cost-effective electrospun lignin nano-adsorbents for the removal of various environmental contaminants.