Preparation of Rumex abyssinicus based biosorbent for the removal of methyl orange from aqueous solution

Mikiyas Abewaa; Eba Adino; Ashagrie Mengistu

doi:10.1016/j.heliyon.2023.e22447

Preparation of Rumex abyssinicus based biosorbent for the removal of methyl orange from aqueous solution

Heliyon. 2023 Nov 20;9(12):e22447. doi: 10.1016/j.heliyon.2023.e22447. eCollection 2023 Dec.

Authors

Mikiyas Abewaa¹, Eba Adino², Ashagrie Mengistu³

Affiliations

¹ Department of Chemical Engineering, College of Engineering and Technology, Wachemo University, P. O. Box 667, Hossana, Ethiopia.
² Department of Chemical Engineering, School of Mechanical, Chemical and Materials Engineering, Adama Science and Technology University, P.O. Box 1888, Adama, Ethiopia.
³ The Federal Democratic Republic of Ethiopia, Manufacturing Industry Development Institute, P. O. BOX 1180, Addis Ababa, Ethiopia.

Abstract

Methyl orange is abundantly present in wastewater generated from textile industries causing serious human health and environmental problems. Therefore, this study was aimed at preparing a low cost and effective biosorbent from the stem of Rumex abyssinicus plant for the removal of methyl orange from aqueous solution. Characterization of the prepared adsorbent material was carried out using a pH point of zero charge, Scanning Electron microscope (SEM), Fourier Transform Infrared (FTIR) spectroscopy and X-Ray Diffraction (XRD). The design and optimization of methyl orange batch adsorption was carried out using the Box Behnken approach to Response Surface methodology aiming to reduce the experimental runs and time with adequate results. The characterization of the adsorbent revealed 7.9 (pHpzc), porous and heterogonous surface (SEM), presence of multiple functional groups (FTIR) and amorphous structure (XRD). The maximum removal efficiency of 98.5 % was found at pH, contact time, Methyl orange concentration and adsorbent dosage of 6, 60 min, 20 mg/L and 0.2 g/100 mL respectively. The isotherm studies were carried out using Langmuir, Freundlich, Toth and Koble Corrigan models in which Freundlich isotherm with a maximum R² of 0.95 was found to fit data best showing heterogeneous and multilayer surface interaction. On the other hand, a kinetics study revealed that pseudo-second-order fitted the data best. Moreover, the thermodynamics analysis showed the nature of the adsorption to be endothermic, spontaneous and feasible. Generally, this work proved that the low-cost, environmentally friendly and easily prepared Rumex abyssinicus-based material could be an alternative adsorbent for dye detoxification at an industrial scale.

Keywords: Biosorbent; Environmental pollution; Methyl orange; Rumex abyssinicus; Wastewater treatment.