Valorization of carnauba straw and cashew leaf as bioadsorbents to remove copper (II) ions from aqueous solution

This work proposes the use of cashew leaf (CL) and carnauba straw (CS) powders as natural bioadsorbents to remove cooper (II) ions from aqueous solution. The bioadsorbents were evaluated from physical nitrogen adsorption (BET), thermogravimetry (TGA), scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The parameters studied were: pH effects, bioadsorbent dose and particle size. The adsorption experiments for both powders showed a low equilibrium time of about 120 min. The adsorption kinetics followed for both bioadsorbents the pseudo-second order model. The experimental CS data were best adjusted by the Langmuir monolayer model while the CL data were adjusted for the Freundlich model. For the same experimental conditions, the maximum adsorption capacity of copper (II) was 9.51 mg/g and 1.73 mg/g for CS and CL powders, respectively. Therefore, the results described in this study value the use of native plant residues to remove copper (II) ions in order to provide a more suitable destination. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study utilized cashew leaf and carnauba straw as natural bioadsorbents to remove copper (II) ions from aqueous solution. Through various experiments, it was found that the maximum adsorption capacity of copper (II) ions differed between the two bioadsorbents.