Green synthesis of a novel eco-friendly hydrochar from Pomegranate peels loaded with iron nanoparticles for the removal of copper ions and methylene blue from aqueous solutions

This study developed a novel eco-friendly and cost-effective bioadsorbent by synthesizing iron nanoparticles loaded onto hydrochar (FeNPs@HC). Pomegranate peels were used as feedstock for hydrochar (HC) production. The production of FeNPs@HC was done by hydrothermal carbonization process using the black solution of iron nanoparticles as a hydrothermal carbonization media. The FeNPs@HC was characterized using FTIR, Transmission electron microscope (TEM), Zeta potential techniques, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, SEM with EDX analysis, and Thermal analysis. The mean particle size of FeNPs and HC were similar to 28 and 196 nm, respectively. The batch experiments like initial concentration, contact time, solution temperature, adsorbent dosage, and pH on the adsorption capacity of the bioadsorbent for Cu (II) and MB were examined and determined. Maximum sorption capacity (q(m)) of Cu (II) and MB was 95.24 and 278 mg g (1). Different adsorption isotherms and kinetics models have been used for evaluating the adsorption process. The R-2 value obtained by Langmuir isotherm was the highest for Cu(II) = 0.997, while the R-2 value obtained by Freundlich isotherm is the highest for MB = 0.9957. The thermodynamic parameters have been determined for the adsorption process. The Delta G(0) values are negative, referring to the adsorption processes being spontaneous. The reusability of FeNPs@HC for removal Cu(II) and MB has been tested in four cycles and showed a good removal efficiency. The FeNPs@HC was successfully applied to actual wastewater samples. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study developed a novel eco-friendly and cost-effective bioadsorbent FeNPs@HC and characterized its adsorption capacity for Cu(II) and MB. The adsorption process followed the Langmuir and Freundlich adsorption isotherms and was found to be spontaneous. FeNPs@HC demonstrated efficient removal of Cu(II) and MB and showed good reusability after multiple cycles.