Kinetics, Isotherms and Thermodynamic Studies on Removal of Divalent Copper using Mallet Flower Leaf Powder as Bio-Adsorbent

Abstract

The effectiveness and efficacy of Mallet Flower Leaf Powder (MFLP) as a bio-sorbent for the removal of heavy metal copper ions from the aqueous solutions have been studied. Experiments were conducted varying the pH, agitation time, temperature, biosorbent size and dosage as parameters. Speed of the mixing is kept at 200 rpm. The analysis of copper was done by using Atomic Absorption Spectrophotometer (AAS). The adsorption of copper was found to be dependent on pH and a maximum removal of 98.78 % was obtained at an optimum pH of 6.0. The optimum biosorbent dosage was 1 g for an agitation time of 40 min. The biosorption data obtained were validated for the best isotherm. The data collected were verified with the available adsorption isotherms. Experimental data obtained was well represented by Langmuir (RL = 0.161, qm = 5.96 mg/g, R2 = 0.9142), Freundlich (n = 0.64, Kf = 0.79L/g, R2 = 0.9995) and Tempkin (R2 = 0.9083, bT = 267.63) isotherms, indicating favorable biosorption. The experimental data obtained were tested for the best fit and the Freundlich Model has yielded the best correlation with the highest regression coefficient, R2 = 0.9844. Kinetic data has also been presented using thermodynamic analysis and the pseudo second order model was found to be the best fit with a correlation coefficient of 0.999. For the removal of copper from the solution, bioadsorbent showed a maximum adsorption capacity of 5.96 mg/g.
 HIGHLIGHTS
 
 Removal of divalent copper from the aqueous solution using Mallet Flower Leaf powder
 Atomic Absorption Spectroscopy, Scanning Electron Microscopy and Fourier transform infrared analysis were used to characterize the Mallet Flower Leaf Powder
 Kinetic data has been presented using thermodynamic analysis and the pseudo second order model was found to be the best fit with a correlation coefficient of 0.999
 The maximum adsorption capacity of MFLP for copper was found to be 5.96 mg/gm
 
 GRAPHICAL ABSTRACT