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    Öğe
    Facile hydrogen peroxide modification of activated carbon particles produced by potassium hydroxide activation for removal of heavy metals from aqueous solutions
    (Elsevier Science Sa, 2023) Murtazaoglu, Cetin; Tegin, Ibrahim; Saka, Cafer
    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 degrees 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-ACH2O2 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.
  • [ X ]
    Öğe
    Phosphorus-doped porous carbon particles based on biomass for efficient adsorption performance of Cu2+ and Zn2+ from aqueous solutions: thermodynamics, isotherms, kinetics, and mechanism
    (Springer Heidelberg, 2023) Saka, Cafer; Tegin, Ibrahim; Murtazaoglu, Cetin
    In this study, the fabrication of two-step phosphorus-doped porous carbon particles for adsorbent design based on low-cost biomass is performed for heavy metal removal. In the first step, activated carbon is produced from pistachio shells as biomass by activation of potassium hydroxide (KOH) (PSAC/KOH). In the second step, as a result of the activation of the obtained PSAC/KOH with phosphoric acid (H3PO4), phosphorus (P)-doped PSAC/KOH is obtained. Removal of Cu2+ and Zn2+ ions from environmental waters is carried out with P-doped PSAC/KOH. EDS, ICP-OES, and FTIR analyses showed that the P atom was doped on the AC surface. It is possible that the absorption of Cu2+ and Zn2+ will increase with the complexes that may form between the phosphorus-containing groups of the modified sample and the metal ions. For P atoms are less electronegative than C atoms, in possible C-P bonds, the P atom will have a positive charge density and the carbon atoms will have a negative charge density. Thus, Lewis base sites are formed on carbon atoms. Lewis base sites serve as important active sites in this adsorption application. The maximum adsorption capacities (Qm) of 136.38 mg/g and 12.57 mg/g at 30 degrees C of Cu2+ and Zn2+ removal are obtained with P-doped PSAC/KOH, respectively.