Effective Adsorption of Crystal Violet Dye from an Aqueous Solution Using Lignin-Rich Isolate from Elephant Grass

Abstract

A lignin-based adsorbent ELGA, obtained from alkaline hydrolysis of elephant grass, was utilized for the removal of aqueous crystal violet dye (CVD). Batch mode experiments were carried out to study the effects of various process parameters on adsorption. ELGA was characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The isotherm data fit into the Freundlich and Tempkin models for linear and nonlinear models, respectively; while kinetic data fit best to pseudo-first order (PFO) and Elovich models for linear and nonlinear kinetic models, intraparticle diffusion studies indicate that many mechanisms influenced the adsorption process. Gibb’s free energy and enthalpy changes of − 1198.57 and + 66.911 KJ mol−1, respectively, indicated spontaneous and endothermic process. An uptake efficiency (> 90%) recorded at an equilibrium time of 30 min shows that ELGA was a fast and effective adsorbent for the removal of aqueous CVD.