ABSTRACT

This study focused on the oxidative degradation of congo red dye using tiger nut as bio adsorbent. The potential use of Tiger nut (Cyperus esculentus), a sustainable and biodegradable adsorbent to adsorb Congo red dye from aqueous solutions was investigate.  In this study, we explore the viability of using both modified and unmodified tiger nut residue to effectively remove congo red dye. The Tiger nut was purchased, processed and characterized to evaluate its suitability as an adsorbent. Batch adsorption studies were carried out by varying parameters such as adsorbent dosage, contact time, pH and initial dye concentration. The adsorption mechanism was predicted by some kinetic models such as pseudo-first-order, pseudo-second-order, intra particle diffusion model and Elovich model.

The results of batch adsorption study showed that for both modified and unmodified tiger nut increasing the adsorbent dosage and contact time resulted in increased percentage dye removal while increasing the pH and initial dye concentration resulted to decrease in percentage dye removal. The optimum adsorbent dosage was 3g, optimum contact time was 55 minutes, optimum pH was 4.0 and optimum initial dye concentration for the adsorption process was 25mg/l. The sorption kinetics for the adsorption processes were found to be best represented by the pseudo-second-order kinetic equation, as its R² values were greater than 0.98. and the qe experimental and qe calculated are virtually equal. The Elovich model also showed a significant fitting to the kinetics of the adsorption process as its R² values were also high. This suggests that chemisorption with heterogeneous sorption mechanism is likely responsible for congo red dye uptake. Hence Tiger Nut Residue has proven to be effective and sustainable bio adsorbent for the removal of Congo Red dye from wastewater.