Synthesis of Lignin Nanoparticles from Agro Industrial Waste and Its Application

Abstract

The chief constituents of biomass are hemicellulose (20 35%), cellulose (30 50%) and lignin (15-30%). Lignin ranks second amplest component after cellulose. It is one of the most extensive natural resources available to human communities. There are wide range of lignin sources available such as jute, hemp, cotton, and wood pulp, sugar cane bagasse, coconut coir fiber etc. Coir fiber contains comparatively large amount of lignin. In this research work, attention has been given to extract lignin from coconut coir fiber, an agro-industrial waste. Lignin has three-dimensional polymeric network structure with three monolignols namely sinapyl, coniferyl and p-coumaryl alcohol. The structure of the lignin depends on the nature of the source and the method of extraction. The present study aims at extraction of lignin using mild alkali at low temperature and low pressure in order to isolate lignin with native structure, without much modifications in its structure and to deduce the optimized condition for extraction using the statistical tool -Response Surface Methodology. Several methods for the synthesis of lignin nanoparticles have been reported in the literature. The present study focus on the synthesis of lignin nanoparticles with size less than 100nm by green method using natural, non-toxic, non-corrosive, biodegradable acid methane sulphonic acid in aqueous medium followed by ultrasonication for short period. The lignin nanoparticles exhibit enhanced properties with wide range of applications. The present investigation involves the study of application of lignin as an 2 adsorbent for the removal of 4-amino phenol, an environmental detrimental pollutant from waste water streams generated from industries. The first chapter provides information about the History of lignin, its structure, chemistry and its reactivity. In this chapter a detailed information regarding the sources of lignin, extraction methods and types of lignin based on the extraction methods is detailed out. This chapter also provide information about