Potentiality of mosambi (Citrus limetta) peel dust toward removal of Cr(VI) from aqueous solution: an optimization study

Abstract

Heavy metal has become a public health concern because of its tendency to accumulate in living organisms. The biosorptive removal of hexavalent chromium (Cr(VI)) from aqueous solution was investigated by using waste mosambi peel dust, and response surface methodology was applied as optimizing technique. The adsorbent was characterized by pHZPC, scanning electron microscope and Fourier transform infrared spectroscopy. The optimize condition for removal of Cr(VI) was recorded as follows: pH 2; dose: 0.5 g/50 mL; initial concentration: 5 mg/L; contact time: 30 min; agitation speed: 150 mg/L. The significance of independent variables and their interactions were tested by the analysis of variance and t test statistics. The adsorption data are nicely fitted with D–R isotherm and followed pseudo-second-order kinetic model. The monolayer adsorption capacity was recorded as 3.623 mg/g. Finally, thermodynamic results demonstrated that Cr(VI) adsorption is endothermic in nature and spontaneous. Therefore, the present results highlighted that mosambi peel dust is an efficient adsorbent and its versatility represents an eco-friendly alternative that can be implemented as agricultural waste management.