Characterization and Evaluation of the Adsorption Behaviour of Salvadora Persica L. Leaves and Stems

Abstract

Used/Spent Salvadora persica L. leaves and stems constitute a major portion of the waste
generated by various foods and oil industries including laboratories of traditional
medicines. The valorization of this waste by applying it to the remediation of industrial
effluent may contribute to a cleaner and green environment. The quantitative removal of
toxic metals from wastewater has been demonstrated, which may be attributed to the
presence of various functional groups on the adsorbent. The probable active sites were
determined by a comparative study of the FTIR spectra of the metal laden adsorbent and
the free adsorbent. The adsorption behavior was found to be befitting to Langmuir model.
However, Freundlich and Dubinin and Radushkevich models have also found to be almost
befitting to the experimental data. The adsorption process was found to follow pseudo-first
order kinetic model. However, within contact time of 50 min, the pseudo-second-order
model and intraparticle diffusion model have also been followed. The evaluated
thermodynamic parameters suggest the spontaneous nature of adsorption. The biomass
was found to retain 98% of the sorption capacity up to 3 cycles. The proposed method
offers a very simple, low cost, effective and eco-friendly alternative methodology for the
determination and extraction of metal ions from wastewater samples.