Adsorption of Procion Blue MX-R dye from aqueous solutions by lignin chemically modified with aluminium and manganese

A macromolecule, CML, was obtained by purifying and carboxy-methylating the lignin generated from acid hydrolysis of sugarcane bagasse during bioethanol production from biomass. The CMLs complexed with Al3+ (CML-Al) and Mn2+ (CML-Mn) were utilised for the removal of a textile dye, Procion Blue MX-R (PB), from aqueous solutions. CML-Al and CML-Mn were characterised using Fourier transform infrared spectroscopy (FTIR), scanning differential calorimetry (SDC), scanning electron microscopy (SEM) and pH(PZC). The established optimum pH and contact time were 2.0 and 5 h, respectively. The kinetic and equilibrium data fit into the general order kinetic model and Liu isotherm model, respectively. The CML-Al and CML-Mn have respective values of maximum adsorption capacities of 73.52 and 55.16 mg g(-1) at 298 K. Four cycles of adsorption/desorption experiments were performed attaining regenerations of up to 98.33% (CML-Al) and 98.08% (CML-Mn) from dye-loaded adsorbents, using 50% acetone +50% of 0.05 mol L-1 NaOH. The CML-Al removed ca. 93.97% while CML-Mn removed ca. 75.91% of simulated dye house effluents. (C) 2014 Elsevier B.V. All rights reserved.