Facile hydrogen peroxide modification of activated carbon particles produced by potassium hydroxide activation for removal of heavy metals from aqueous solutions

Abstract

Here, the activated carbon (AC) was first produced by potassium hydroxide (KOH) activation from pistachio shells. Subsequently, the obtained AC was modified with hydrogen peroxide (H2O2) activation. Cu (II) and Zn (II) ions adsorption using the KOH-AC-H2O2 was carried out from wastewater. The correlation coefficient (R2) values in the adsorption of KOH-AC-H2O2 and Cu (II) and Zn (II) showed compliance with the Langmuir isotherm model. The maximum adsorption capacities (Qm) with Cu (II) and Zn (II) from the Langmuir isotherm model at 30 °C for KOH + AC-H2O2 were 212.76 mg/g and 12.00 mg/g, respectively. The pHpzc of the H2O2-modified adsorbent was 7.58. However, the pHpzc of the KOH-AC adsorbent was 8.82 The resulting KOH-AC and KOH-AC-H2O2 samples were characterized by X-Ray diffraction (XRD), thermogravimetric/differential (TG-DTA), scanning electron microscope (SEM), Fourier transforms infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS), and nitrogen adsorption/desorption analyses. SEM analyses confirmed that the surface of the AC samples obtained was highly porous. At the same time, FTIR and EDS analyses showed the formation of oxygenated groups on the AC surface. In the kinetic experiments, the pseudo-second-order model was suitable for the adsorption of Cu (II) and Zn (II). The low-cost and environmentally friendly adsorbent obtained as a result of the modification of H2O2 with KOH-AC has improved the removal ability of heavy metals.