Surface modification of Artocarpus odoratissimus leaves using NaOH, SDS and EDTA to enhance adsorption of toxic crystal violet dye

This study investigates the possibility of enhancing Artocarpus odoratissimus leaves (TL) through surface modification with a base, NaOH (TLN), a surfactant, SDS (TLS) and a chelating agent, EDTA (TLE). The adsorption of crystal violet (CV) dye onto all the three modified TL was achieved at 2.5 hours with no pH adjustment required. Of the six isotherm models used, the Langmuir model best described the adsorption process for TLN and TLE with correlation coefficient (R (2)) of 0.997 and 0.996, respectively, while the Temkin model best described the adsorption using TLS (R (2) = 0.937). Maximum adsorption capacity (q(max) ) provided by the Langmuir model was 476.5 mg g(-1), 108.8 mg g(-1)and 78.8 mg g(-1)for TLN,TLS and TLN, respectively, with the latter adsorbent giving the lowest q(max) value. The pseudo second-order kinetics model fitted closely with the experimental data for the three adsorbents. Based on the Weber-Morris model, intra-particle diffusion could be the rate-determining step for TLS and TLE, but not for TLN. Spent TL was successfully regenerated and reused, maintaining good adsorption towards CV even after the 4(th) cycle. Thus, surface modified TL proved to be a good method for enhancing adsorption towards CV and possesses great potential as possible adsorbents for the treatment of dye wastewater.