Adsorption efficacy of Cedrela odorata seed waste for dyes: Non linear fractal kinetics and non linear equilibrium studies

Alteration of the structural and functional integrity of the aquatic ecosystems due to contamination from toxic industrial dyes warrants cost effective remedial strategies. Cedrela odorata Seed Chaff (COSC) was locally sourced, indigenous and ubiquitous. In support of this proposition, the efficacy of the COSC was assessed for the adsorption of some toxic industrial dyes, namely Methylene Blue (MB), Congo Red (CR), Methyl Violet (MV) and Methyl Orange (MO) from aqueous solutions. The microstructures of Cedrela odorata Seed Chaff (COSC) were carried out using pH of Point of Zero Charge (PZC), Specific Surface Area (SSA), Bulk Density (BD), Fourier Transform Infra Red Spectroscopy (FTIR), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM) which indicated that various organic moieties were present in COSC, which the toxic industrial dyes studied were adsorbed onto. Non linear equilibrium and non linear fractal models were used to fit experimental data. The experimental data best fit the Fritz-Schlunder four-parameter isotherm and the fractal-like pseudo-second order (three-parameter) kinetic equation. The Langmuir monolayer adsorption capacities, q_maxL of COSC for the uptake of MB, CR, MV and MO were 88.32-111.88 mg/g, 79.46-128.84 mg/g, 75.11-121.23 mg/g and 57.35-68.23 mg/g respectively as temperature increased from 298 to 318 K. The results support the use of Cedrela odorata Seed Chaff (COSC) as a cost effective material for removal of toxic industrial dye from an aquatic system. Large scale studies are required in the future to prove the efficacy of Cedrela odorata Seed Chaff (COSC) for toxic industrial dyes from varied environmental conditions.