Adsorption of Scandium and Neodymium on Biochar Derived after Low-Temperature Pyrolysis of Sawdust

Komnitsas, Kostas; Zaharaki, Dimitra; Bartzas, Georgios; Alevizos, George

doi:10.3390/min7100200

Cited by 22 publications

(9 citation statements)

References 76 publications

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“…In the present study, the removal capacity of raw FA was also determined and found to be 38 mg•g −1 . However, the It was seen from the data that the pseudo-second-order model fits (R 2 values, 0.991-1) the experimental data very well for both the zeolites used, indicating that the reaction rate depended on the number of available active sites on the surface [32,49,50]. For the initial Cu(II) ion concentrations of 45 and 100 mg•L −1 , the removal capacity of ZFA1Na was 93 and 196 mg•g −1 , respectively; this capacity was significantly higher compared with the capacity (40-70 mg•g −1 ) calculated in an earlier study in which the removal of multiple metal ions, namely, Co(II), Cr(III), Ni(II), Zn(II), and Cu(II), was investigated with the use of zeolites [29].…”

Section: Evaluation Of Kinetic Modelsmentioning

confidence: 89%

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Synthesis of Zeolites from Greek Fly Ash and Assessment of Their Copper Removal Capacity

2020

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The objective of this study was to synthesize zeolites through fusion of lignite fly ash and NaOH or KOH pellets at 600 °C and assess their removal efficiency in terms of decontamination of solutions containing Cu(II) ions. The removal efficiency of the produced zeolites was tested in batch kinetic experiments using different zeolites and Cu(II) ion concentrations. Experimental data revealed that zeolites synthesized with the use of NaOH exhibited higher removal efficiency compared with those synthesized with the use of KOH. Kinetic data showed that the pseudo-second-order equations described well the removal process. Copper removal was mainly accomplished through the concerted action of chemisorption and intraparticle diffusion. Analytical techniques involving XRF, XRD, FTIR, SEM/EDS and XPS were used for the characterization and morphology analysis of the produced zeolites. SEM/EDS confirmed the presence of copper on the zeolite surface. XPS spectra of Cu2p at 934.3 eV proved the presence of Cu(II) oxidation state, confirming the possible formation of CuO and/or Cu-Cl.

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Section: Evaluation Of Kinetic Modelsmentioning

confidence: 89%

“…The linearized kinetic models investigated in this study were the pseudo-first (Equation ( 3)) and pseudo-second-order models (Equation ( 4)) [31,32]. log(q e − q t ) = log q e − k 1 t 2.303…”

Section: Kinetic Studiesmentioning

confidence: 99%

Synthesis of Zeolites from Greek Fly Ash and Assessment of Their Copper Removal Capacity

2020

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“…carboxylic, phenolic, and lactonic) on their surface, due to their amphoteric nature [37]. Those groups might be responsible for the pseudocapacitive reactions observed.…”

Section: Electrochemical Performance Of Activated Biocharsmentioning

confidence: 98%

“…In relation to pHPZC results, both activated biochars had the point of zero charge in the acid range. The pHPZC indicates the electrokinetic behavior of the material, which usually varies with the properties of the precursor and the type and temperature of pyrolysis [37]. The acid pHPZC means that mostly acid functional groups are connected to both materials' surface, but KOHBWB, having a much lower pHPZC (2.86),…”

Section: Physicochemical Characterizationmentioning

confidence: 99%

The conversion of wood residues, using pilot-scale technologies, into porous activated biochars for supercapacitors

et al. 2019

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In this study, activated biochar was produced using pilot-scale technologies of fast pyrolysis and activation to create desirable morphology, surface chemistry, and adsorptive properties for application in supercapacitors. First, residues from white birch were converted into biochar by fast pyrolysis (~ 450 °C). Then, physical (using CO2) or chemical (using KOH) activation was carried out in a homemade pilot-scale furnace at 900 °C. These synthesized materials presented distinct porosity structures: micro-/mesoporous (CO2 material) and highly microporous (KOH material), reaching surface areas of up to 1700 m 2 g-1. Electrochemical results showed that KOH-activated biochar had higher specific electrical capacitance in both acidic and neutral electrolytes with a maximum specific capacitance value of 350 and 118 F g-1 at 1 A g-1 , respectively; while, for CO2activated biochar, the maximum obtained values were 204 and 14 F g-1. The greater proportion of oxygenated and nitrogenated functional groups on the surface of the KOH activated biochar, along with its high surface area (with wider porosity), improved its performance as a supercapacitor electrode. Specifically, the low proportion of ultramicropores was determinant for its better electrochemical behavior, especially in the neutral electrolyte. Indeed, these results are similar to those found in the literature on the electrical capacitance of carbonaceous materials synthesized in a small-scale furnace. Thus, the chemical-activated biochar made from wood residues in pilot-scale furnaces is a promising material for use as electrodes for supercapacitors.

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“…The presence of polar groups on the surface of FA-H 2 O 2 is likely to give a considerable cation exchange capacity to the sorbents. The point of zero charge (PZC) was determined using the suspension and potentiometric titration methods [44,45]. In the case of FA/FA-H 2 O 2 , the value was found to be about 8.1/8.3.…”

Section: Influence Of Phmentioning

confidence: 99%

Novel Application of Mineral By-Products Obtained from the Combustion of Bituminous Coal–Fly Ash in Chemical Engineering

2020

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The aim of this work was the chemical modification of mineral by-products obtained from the combustion of bituminous coal (FA) treated with hydrogen peroxide (30%), used as an adsorbent for the removal of Cr(III) and Cd(II) ions and crystal violet (CV) from a mixture of heavy metal and organic dye in a solution containing either Cr(III)–CV or Cd(II)–CV. Fourier transform infrared (FT-IR), thermogravimetric analysis (TG), scanning electron microscopy–energy dispersive spectroscopy (SEM-EDS), and X-ray diffraction (XRD) analyses suggested that the mechanism of Cr(III)–CV or Cd(II)–CV sorption onto FA–H2O2 includes ion-exchange and surface adsorption processes. The effect of pH on the adsorption equilibrium was studied. The maximum adsorption was found for pH values of 9. The values of the reduced chi-square test (χ2/degree of freedom (DoF)) and the determination coefficient R2 obtained for the sorbate of the considered isotherms were compared. Studies of equilibrium in a bi-component system by means of the extended Langmuir (EL), extended Langmuir–Freundlich (ELF), and Jain–Snoeyink (JS) models were conducted. The estimation of parameters of sorption isotherms in a bi-component system, either Cr(III)–CV or Cd(II)–CV, showed that the best-fitting calculated values of experimental data for both sorbates were obtained with the JS model (Cr(III) or CV) and the EL model (Cd(II) or CV). The maximum monolayer adsorption capacities of FA–H2O2 were found to be 775, 570 and 433 mg·g−1 for Cr, Cd and CV, respectively. Purification water containing direct Cr(III) or Cd(II) ions and CV was made with 90%, 98% and 80% efficiency, respectively, after 1.5 h. It was found that the chemical enhancement of FA from coal combustion by H2O2 treatment yields an effective and economically feasible material in chemical engineering for the treatment of effluents containing basic dyes and Cr(III) and Cd(II) ions.

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Adsorption of Scandium and Neodymium on Biochar Derived after Low-Temperature Pyrolysis of Sawdust

Cited by 22 publications

References 76 publications

Synthesis of Zeolites from Greek Fly Ash and Assessment of Their Copper Removal Capacity

Synthesis of Zeolites from Greek Fly Ash and Assessment of Their Copper Removal Capacity

The conversion of wood residues, using pilot-scale technologies, into porous activated biochars for supercapacitors

Novel Application of Mineral By-Products Obtained from the Combustion of Bituminous Coal–Fly Ash in Chemical Engineering

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