Chromium Removal from Modjo Tannery Wastewater Using Moringa stenopetala Seed Powder as an Adsorbent

Degefu, Dagmawi Mulugeta; Dawit, Mekibib

Chromium Removal from Modjo Tannery Wastewater Using Moringa stenopetala Seed Powder as an Adsorbent

2013

Degefu, Dagmawi Mulugeta | Dawit, Mekibib

Finding an environmentally safe and cost-effective method which is efficient enough to meet the regulatory standards of potable and industrial wastewater presents unique challenges. In this work, Moringa stenopetala seed powder which had particle size of 300 μm was characterized; ash content 4.7 %, bulk density 0.531/cm3, particle density 0.88 g/cm3, color yellowish, and pH 4.5. Fourier transform infrared spectroscopy analysis showed the multifunctionality of the M. stenopetala seed powder. M. stenopetala seed powder was assessed for percentage chromium removal and milligrams per gram chromium uptake as a function of contact time, pH, and dose of the adsorbent and initial concentration. The maximum percent removal was 99.74 %. Sorption kinetics of chromium adsorption by M. stenopetala seed powder was predicted reliably using a pseudo-second order model. An intra-particle diffusion model revealed that the biosorption of metals proceeds through various processes. Equilibrium uptakes were evaluated using Langmuir, Freundlich, Temkin, and the Dubinin-Radushkevich adsorption isotherm models. Even though the correlation coefficient was not as high as the Langmuir and Freundlich models for Temkin adsorption isotherm model, the metal uptake which was predicted by the model is comparable with the experimental value. Generally, the seed powder of M. stenopetala was found to be effective in the removal of chromium from tannery wastewater. © 2013 Springer Science+Business Media Dordrecht.

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