Potential Application of Orange Peel as an Eco-friendly Adsorbent for Textile Dyeing Effluents Available to Purchase

Orange peel (OP) has been considered as an ideal, alternative low-cost, natural waste adsorbent for the removal of textile effluents. The effectiveness of OP in adsorbing C.I. Direct Red 79 (DR 79) and C.I. Direct Yellow 27 (DY 27) from their dye baths has been studied in accordance with pH, solid/liquid ratio, agitation time and initial dye concentration. The sorption isotherms are analyzed by using the Langmuir and Freundlich models. The results indicate that acidic solutions support the adsorption of the studied dyes with the use of OP. Adsorption kinetic models are analyzed by using the pseudo-first order, pseudo-second order and intraparticle diffusion equations. The results show that the order equation fits the experimental data very well. The effect of the adsorbent surface is analyzed by using scanning electron microscopy (SEM), with the SEM images showing a reasonable agreement with the adsorption measurements.