Facile Removal of Congo Red using Mahua (Madhuca longifolia) Seeds, A Low Cost Adsorbent

Abstract

Indiscriminate use of dyes in various industrial sectors pollutes water and poses threat to mankind. Since dyes are non bio-degradable under ambient condition, various scavenging technologies were employed from time to time. Mahua fruits offer useful seeds which are found to be a cost effective scavenger of congo red dye from contaminated water. Batch adsorption tests were conducted to evaluate the effect of adsorbent dose (10-90 mg), contact time (10-60 min), agitation speed (100-180 rpm), pH, interference and concentration variation (10-80 ppm) at room temperature. Characterization of Mahua Seeds (MS) was done using FTIR, SEM, proximate analysis and Zero point charge (ZPC). Kinetic study suggested the mechanism follows intraparticle diffusion with R 2 value of 0.978 and rate constant of 0.697mg/g.min 0 .5 . Maximum adsorption capacity was found to be 32 mg/g. Isotherm study revealed that Freundlich model is best fit with R 2 value of 0.998.The calculated value of ZPC was 7.21. Regeneration was achieved up to 88% with aqueous NaOH. Adsorption thermodynamic data revealed the process to be spontaneous, feasible and exothermic in nature. Column experiments suggest feasibility of the material for large scale operation.