Tannery wastes water treatment using <i>Moringa Stenopetala</i> seed extract

Abstract

High amount of heavy metal ions like Cr in the environment has been harmful for animal and human health. Bioadsorption of Cr from tannery wastes would be an alternative method to the chemical treatment in tannery industries. Hence, in this study the efficiency of Moringa  stenopetala seed extract to adsorption Cr from tannery waste water was investigated. The influence of solution pH, adsorbent concentration, initial concentration of Cr, contact time and temperature on the efficiency of Moringa stenopetala seed extract for the adsorption of Cr from tannery effluent was studied. Results obtained revealed that in strongly acidic condition Moringa stenopetala seed extract was less efficient to remove Cr. However, the result of the present study showed that Moringa stenopetala seed extract at a concentration of 1g/100 ml and pH of 9.5 decreased the concentration of Cr in tannery waste by 99.86%. In addition, the adsorption data was correlated using the Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherm models. Among models studied Dubinin-Radushkevich isotherm was the best fit with correlation coefficient of 0.958. Moreover, thermodynamics parameters, such as Gibbs free energy (ÄGo), enthalpy (ÄHo), and entropy (ÄSo) were calculated. Results indicated that the bioadsorption of Cr by Moringa stenopetala seed extract was  spontaneous, feasible and endothermic. The results of this study proved that Moringa stenopetala seed extract can be used to remove Cr from tannery effluent.

KEYWORDS: Moringa stenopetala, Cr, tannery, pH, temperature, concentration