Accelerated Decolorization of Congo Red by Powdered Termite Mound

• Published in: Clean : soil, air, water air, water, 2017-12, Vol.45 (12), p.n/a
• Main Authors: Ayanda, Olushola S., Odo, Ekundare A., Malomo, Dosu, Sodeinde, Kehinde O., Lawal, Olaide S., Ebenezer, Oluwapese T., Nelana, Simphiwe M., Naidoo, Eliazer B.
• Format: Article
• Language: English
• Subjects: Adsorption; azo dyes; Binoculars; Biologists; Capacity; Chemical oxygen demand; Chemisorption; Decoloring; Decolorization; equilibrium; Fluorescence; Kinetics; Mineral composition; pH effects; Regression analysis; Removal; Textile industry wastewaters; thermodynamics; Wastewater; Wastewater discharges; Wastewater treatment; X-ray diffraction; X-ray fluorescence
• ISSN: 1863-0650; 1863-0669
• DOI: 10.1002/clen.201700537

The decolorization of congo red (CR) in aqueous solution is investigated in a batch mode using termite mound as an adsorbent. Elemental analysis and identification of the mineral composition/phases in the termite mound sample is carried out by means of X‐ray fluorescence and X‐ray diffraction. The optimal percentage removal and equilibrium adsorption capacity of CR by the termite mound achieved is found to be 95.68% and 2.30 mg g−1, respectively, when 0.5 g of termite mound is added to 30 mL of 40 mg L−1 CR for 60 min−1 at 400  rpm. The decolorization of CR increases with an increase in the termite mound dosage, contact time, stirring speed, pH, and temperature; however, the adsorption capacity decreases with an increase in the initial CR concentration. The adsorption process shows that CR obeys the Freundlich adsorption model with a 0.9355 coefficient of regression, denoting multilayer formation onto the termite mound. The adsorption kinetics follow the pseudo‐second‐order model with a coefficient of regression value of 0.9966, showing that chemisorption is the main rate limiting step. ΔG is negative, an indication that the adsorption of CR onto termite mound is spontaneous. Approximately 86.6% chemical oxygen demand reduction is achieved with real textile wastewater. This study shows how termite mound can be harnessed for the treatment of textile wastewater before discharged into the environment. Termite mounds built by termites are relatively cheap and abundant. Hence, termite mound is mined, ground, and applied for the decolorization of congo red. Parameters affecting the sorption rate are investigated, and experimental evidence suggests that termite mound will serve as a low‐cost adsorbent for treatment of textile wastewater before discharged into the environment.