Effects of catalysts on structural and adsorptive properties of iron oxide-silica nanocomposites

Ianăși, Cătălin; Ianăşi, Paula; Negrea, Adina; Ciopec, Mihaela; Ivankov, Oleksandr I.; Almásy, László; Putz, Ana-Maria

doi:10.1007/s11814-020-0675-2

Cited by 7 publications

(6 citation statements)

References 79 publications

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“…Taking into account the composition of the material (Fe(acac) 2 , ammonia and TEOS), several peaks are expected. The presented Raman spectra shows very low intensity peaks around 500 cm −1 and 1600 cm −1 , which are characteristic for the most abundant components, in our case the Fe-O and C-O bonds from the Fe(acac) 2 [ 52 , 53 ]. Others are expected to be found the Si-O bands, which in our case are overlapped with the already aforementioned bands [ 52 , 54 ].…”

Section: Resultsmentioning

confidence: 99%

Molybdate Recovery by Adsorption onto Silica Matrix and Iron Oxide Based Composites

Matusoiu

Negrea

Ciopec

et al. 2022

Gels

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Aggressive industrial development over the last century involved different heavy metals being used, including high quantities of molybdenum, which need to be treated before discharge in industrial waters. Molybdenum’s market price and industrial applicability make its recovery a big challenge. In the present study the possibility to recover molybdenum ions from aqueous solutions by adsorption on a composite material based on silica matrix and iron oxides—SiO2FexOy—was evaluated. Tests were performed in order to determine the influence of adsorbent material dose, initial solution pH, contact time and temperature over adsorption capacity of synthesized adsorbent material. For better understanding of the adsorption process, the obtained experimental data were modelled using Langmuir, Freundlich and Sips adsorption isotherms. Based on the obtained data, it can proved that the Sips isotherm was describing with better orderliness the studied process, obtaining a maximum adsorption capacity of 10.95 mg MoO42− for each gram of material. By modelling the studied adsorption process, it was proven that the pseudo-second order model is accurately describing the adsorption process. By fitting experimental data with Weber-Morris model, it was proven that MoO42− adsorption is a complex process, occurring in two different steps, one controlled by diffusion and the second one controlled by mass transfer. Further, studies were performed in order to determine the optimum pH value needed to obtain maximum adsorption capacity, but also to determine which are the adsorbed species. From pH and desorption studies, it was proven that molybdate adsorption is a physical process. In order to establish the adsorption mechanism, the thermodynamic parameters (ΔG0, ΔH0 and ΔS0) were determined.

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Section: Resultsmentioning

confidence: 99%

Molybdate Recovery by Adsorption onto Silica Matrix and Iron Oxide Based Composites

Matusoiu

Negrea

Ciopec

et al. 2022

Gels

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“…The linear fitting and the correlation coefficient of the pseudo-first-order and pseudosecond-order equations for the adsorption of Cr(VI) ions by M-PAS-GO are shown in Figure 7b,c and Table 2. The results indicate that the pseudo-second-order model is more suitable for describing the adsorption behavior of Cr(VI) ions when using GO and M-PAS-GO (R 2 > 0.99), which suggests that the rate-limiting step of adsorption is a chemisorption between the metals ions and binding sites of the M-PAS-GO and GO [13,14]. Therefore, it can be inferred that the adsorption of Cr(VI) on M-PAS-GO is mainly controlled by the chemical interaction between adsorbents and Cr(VI) ions.…”

Section: Effect Of Contact Time On Cr(vi) Adsorption By M-pas-gomentioning

confidence: 94%

“…Among these methods, the adsorption process has been most widely employed because of its high availability, easy operability, low cost and high efficiency. Various materials, such as biomaterials, metal oxides [9], nanomaterials [10], activated carbon [11] and fibrous [12] and mesoporous inorganic sorbents [13][14][15] have been applied to remove Cr(VI) from aqueous solutions. However, the adsorption ability of these materials for Cr(VI) in aqueous solution still need further improvement.…”

Section: Introductionmentioning

confidence: 99%

Effective Removal of Hexavalent Chromium from Aqueous Solutions Using Quaternary Ammonium-Functionalized Magnetic Graphene Oxide Composites

Huang,

Chen

et al. 2023

Separations

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Novel quaternary ammonium/magnetic graphene oxide composites (M-PAS-GO) that efficiently remove Cr(VI) ions were fabricated through the introduction of the (3-aminopropyl) triethoxysilane and Fe3O4 nanoparticles on the surface of GO, and then modified with n-butyl bromide. The fabricated M-PAS-GO was comprehensively characterized by SEM, TEM, EDX, XRD, Raman spectroscopy and FTIR, and the results manifest that the quaternary ammonium group was introduced onto the surface of GO. Under the reaction conditions of pH 3.20, temperature of 25 °C and M-PAS-GO dosage of 0.01 g/50 mL, 90% of 10 mg/L Cr(VI) ions were removed from the solution within 20 min. The kinetics study indicates that the adsorption process followed the pseudo-second-order model and was surface reaction-controlled. The thermodynamic parameters calculated from temperature-dependent adsorption isotherms suggest that the adsorption process was an exothermic and spontaneous process. The maximum adsorption capacities of Cr(VI) ions on M-PAS-GO composites calculated by the Langmuir model were 46.48 mg/g. Moreover, the reusability and stability of M-PAS-GO demonstrates its economic sustainability. This study suggests that M-PAS-GO is a potential candidate adsorbent for the separation of Cr(VI) from wastewater.

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“…The adsorption mechanism of Cr(VI) ions can be described in four steps: (1) protonation of active groups on the surface of the adsorbent; (2) adsorption of the metal ions on the protonated substrate and the metal ionic complexation; (3) Cr(VI) ions can be reduced by means of electron groups; and (4) chemical complexation, electrostatic attraction or cation exchange process are finally taking place [47]. The organic component of SC was the primary adsorbent of Cr(VI) ions, which is certified by adsorbent characterization (FT-IR, XRD and SEM).…”

Section: Mechanism For Adsorption Of Cr(vi) Ionsmentioning

confidence: 99%

Efficient Removal of Cr(VI) Ions in Petrochemical Wastewater Using Fe3O4@Saccharomyces cerevisiae Magnetic Nanocomposite

et al. 2022

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Saccharomyces cerevisiae (SC) is a widely available biobased source for function material. In this work, a kind of new efficient magnetic composite adsorbent containing Fe3O4 and SC was prepared successfully and used for the removal of Cr(VI) ions in petrochemical wastewater. The morphology and structure of this magnetic adsorbent were characterized with FT-IR, TG, XRD, VSM, SEM and XPS. The effect of the different factors such as pH, adsorption time, initial Cr(VI) ions concentration and adsorption temperature on the adsorption behavior were investigated. The results showed that 10%-Fe3O4@SC exhibited high removal rate, reutilization and large removal capacity. The corresponding removal capacity and removal rate could reach 128.03 mg/g and 96.02% when the pH value was 2, adsorption time was 180 min, and initial Cr(VI) ions concentration were 80 mg/L at 298 K. The kinetics followed the pseudo-first-order, which indicated that the adsorption behavior of 10%-Fe3O4@SC for Cr(VI) ions belonged to the physical adsorption and chemical adsorption co-existence. The thermodynamic study showed that the adsorption process was spontaneous and exothermic. It still showed better adsorption performance and reutilization after the fifth adsorption-desorption experiment. The possible mechanism of Cr(VI) ions adsorption onto the 10%-Fe3O4@SC magnetic adsorbent has been discussed. Hence, this new adsorbent will be a candidate for industry-level applications in petrochemical wastewater containing Cr(VI) ions.

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Effects of catalysts on structural and adsorptive properties of iron oxide-silica nanocomposites

Cited by 7 publications

References 79 publications

Molybdate Recovery by Adsorption onto Silica Matrix and Iron Oxide Based Composites

Molybdate Recovery by Adsorption onto Silica Matrix and Iron Oxide Based Composites

Effective Removal of Hexavalent Chromium from Aqueous Solutions Using Quaternary Ammonium-Functionalized Magnetic Graphene Oxide Composites

Efficient Removal of Cr(VI) Ions in Petrochemical Wastewater Using Fe3O4@Saccharomyces cerevisiae Magnetic Nanocomposite

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