Lead Removal from Water Solutions Using Alginate-Immobilized Peach Stone Particles

Abstract

Fruit processing industries generate millions of tons of organic waste annually, often improperly disposed of at open landfills. Based on the circular economy and waste management concepts, reusing these bio-waste materials is one of the future sustainable demands. Furthermore, recent investigations have shown that this material type can be reused as high-quality sorbents, with certain modifications that should be applied. Considering this, we have investigated the possible application of lignocellulosic waste-peach stones (Prunus Persica L.), immobilized in sodium alginate, as heavy metals sorbent. The immobilized particles (IPS) were utilized to remove metals from synthetic water solutions. Among all metals (Pb, Cu, Cd, and Zn), IPS has shown superior performance in Pb removal, governing further investigations. Dried IPS spheres were characterized by FTIR, SEM/EDX, and TG techniques. The batch reaction system investigated the effects of the contact time, initial Pb concentration, and mass-to-volume ratio. Optimized operational parameters were used in kinetic and isotherm studies. Obtained data were modeled using a nonlinear form of pseudo-first, pseudo-second, Elovich, Freundlich, and Langmuir equations. The results showed pseudo-second-order kinetics with Freundlich isotherm fitting Pb removal, indicating a heterogeneous IPS surface with the multilayer adsorption and adsorbed molecule interaction. As obtained from Langmuir isotherm, IPS particles have removed Pb by saturation capacity of80.40 mg Pb/g. These preliminary results indicate that IPS can be applied to purify waters contaminated with lead metal.