Biosorptive Removal of Congo Red Dye Using Eco-friendly Biomass from Polyalthia longifolia
M. Sarwar
Department of Chemistry, Minhaj University, Lahore, Pakistan and Department of Chemistry, Lahore Garrison University, Jinnah Campus, Lahore, Pakistan
Umar Farooq *
Institute of Chemistry, University of the Punjab, Lahore, Pakistan
Khalid Mehmood
Department of Chemistry, Minhaj University, Lahore, Pakistan
M. Ajmal
Department of Chemistry, Minhaj University, Lahore, Pakistan
M. Farooq
Department of Chemistry, Minhaj University, Lahore, Pakistan
M. Athar
Institute of Chemistry, University of the Punjab, Lahore, Pakistan
M. Salman
Institute of Chemistry, University of the Punjab, Lahore, Pakistan
*Author to whom correspondence should be addressed.
Abstract
Being toxic, Congo red is one of the most important dyes to be treated before being disposed of into waters. In the present study, dried powdered branches and leaves from an ornamental plant (Polyalthia longifolia) have been investigated for the biosorptive removal of Congo red dye from its aqueous solution. Infrared spectrum of the leaves and branches indicated the presence of -OH, -NH2 and -C=O groups as the main binding sites. Influence of time of contact, pH of dye solution and initial concentration of dye was studied in batch adsorption experiments. Using nonlinear modeling, it was found that dye-leaves and dye-branches systems obeyed pseudo-second-order kinetic model with equilibrium reaching in 60 minutes at 2 g/L of biomass and 20 mg/L of dye concentration. Langmuir model was followed by both systems with maximum capacity as leaves (10.32 mg/g) and branches (8.57 mg/g). The biosorption capacities have been compared with a number of reported studies.
Keywords: Polyalthia longifolia, Congo red, nonlinear kinetics, langmuir, adsorption