Heterogeneous photo-Fenton Catalyst Research Articles

Prussian blue/TiO2 nanocomposites as a heterogeneous photo-Fenton catalyst for degradation of organic pollutants in water

The photo-Fenton process of PB/TiO2 to degrade pollutants was investigated with Mössbauer and EPR for the first time.

Removal of Rhodamine B with Fe-supported bentonite as heterogeneous photo-Fenton catalyst under visible irradiation

Fe-supported bentonite (Fe-B) was successfully fabricated as a low-cost heterogeneous catalyst for adsorption and visible light photo-Fenton degradation of Rhodamine B (RhB) from aqueous solution. The support of iron rendered a significant increase in specific surface area and a slight increase in interlayer spacing of bentonite, thus improving the adsorption performance of Fe-B. The maximum adsorption capacity of RhB onto Fe-B was calculated to be 227.27mgg−1 by the fitting of Langmuir adsorption isotherm. The catalytic activity of Fe-B was evaluated by the degradation of RhB (80mgL−1) in the presence of H2O2 under visible light irradiation. Light-emitting diodes (LED) lamps were used as visible light source as they are small in size, energy efficient, compact, have a relatively long life span, and can be facile to operate. The estimated quantum yield of photodegradation of RhB was calculated as (1.66±0.21)×10−2. The results showed that the Fe-B catalyst demonstrated good performance in the removal of RhB by combination of adsorption and degradation with optimum operating conditions of Fe-B 0.25gL−1, natural pH 4.2 and H2O2 12mM. The Fe-B catalyst retained high visible light photocatalytic activity toward RhB in a wide pH range from 3.0 to 9.0 and exhibited good chemical stability after five consecutive adsorption/degradation cycles.

Effects of Solvent Diols on the Synthesis of ZnFe2O4 Particles and Their Use as Heterogeneous Photo-Fenton Catalysts

A solvothermal method was used to prepare zinc ferrite spinel oxide (ZnFe2O4) using ethylene glycol and 1,4 butanediol as solvent diols, and the influence of diols on the physical properties of ZnFe2O4 particles was investigated. The produced particles were characterized by X-ray powder diffraction (XRD), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption isotherms, and the catalytic activity for the organic pollutant decomposition by heterogeneous photo-Fenton reaction was investigated. Both solvents produced particles with cubic spinel structure. Microporous and mesoporous structures were obtained when ethylene glycol and 1,4 butanediol were used as diols, respectively. A higher pore volume and surface area, as well as a higher catalytic activity for the pollutant degradation were found when 1,4 butanediol was used as solvent.

Fe-modified local clay as effective and reusable heterogeneous photo-Fenton catalyst for the decolorization of Acid Green 25

Locally sourced Bandar Baru clay (BBC) from Kedah in Malaysia was modified with NaCO3 and applied as catalyst support. Six different Fe supported BBC (Fe-BBC) catalysts were prepared with different calcination temperature (300–500°C) and time (4–6h) and their activities were tested on the decolorization of Acid Green 25 (AG25) pollutant dye. The best Fe-BBC was that calcined at 300°C for 4h, and it was characterized. The BET result showed increase in surface area and pore volume which was supported by the SEM result. The presence of the incorporated Fe in the catalyst was verified with EDX, XRD and FTIR techniques. The best experimental condition decolorized 99% of 50ppm (AG25) in 20min with 1.25g/L Fe-BBC300/4 and 6.7mM of hydrogen peroxide at pH 3. Its reusability after three cycles showed 97.5% decolorization of 50ppm of AG25. The versatility of Fe-BBC300/4 was also verified on the decolorization of Reactive Blue 4 and Direct Blue 71.

Synthesis and catalytic properties of La or Ce doped hydroxy-FeAl intercalated montmorillonite used as heterogeneous photo Fenton catalysts under sunlight irradiation

A series of La and Ce doped hydroxyl FeAl intercalated montmorillonite (FeAl-Mt) were prepared by a co-intercalation method for catalytic oxidation of Reactive Blue 19 (RB19) by a heterogeneous photo Fenton process under natural sunlight irradiation. The physicochemical properties of the obtained catalysts were deciphered by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS) and UV-vis diffuse reflectance spectroscopy (DRS). The results showed that Ce or La doped FeAl Keggin polyoxocations were intercalated into the gallery of montmorillonite and the physicochemical properties of intercalated FeAl Keggin polyoxocations were mildly changed after Ce or La doping, resulting in defects and lattice vacancies. The doping of Ce or La could effectively improve the catalytic performance of FeAl-Mt measured by heterogeneous photo Fenton degradation of RB19 catalyzed by the obtained products. The synergistic effect between the doped element and FeAl intercalated montmorillonite played a crucial role in the enhancement of heterogeneous catalytic activity under natural sunlight irradiation.

Heterogeneous photo-assisted Fenton catalytic removal of tetracycline using Fe-Ce pillared bentonite

In the present work, a novel heterogeneous photo-Fenton catalyst was prepared by iron and cerium pillared bentonite. The catalyst Fe-Ce/bentonite was characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM) methods. It is found that Fe and Ce intercalate into the silicate layers of bentonite successfully. Tetracycline was removed by heterogeneous photo-Fenton reaction using the catalyst in this work. The effects of different reaction systems, hydrogen peroxide concentration, initial pH, catalyst dosage, UV power and introduction of different anions on degradation were investigated in details. The stability of catalyst was investigated through recycling experiment. The results show that removal rate of tetracycline is 98.13% under the conditions of 15 mmol/L H2O2, 0.50 g/L catalyst dosage, initial pH 3.0, 11 W UV lamp power and 60 min reaction time. However, the removal rate decreases after adding some anions. The hydroxyl radical plays an important role in heterogeneous photo-assisted Fenton degradation of tetracycline. The catalyst is very stable and can be recycled many times.

Isomorphous substitution of Cr by Fe in MIL-101 framework and its application as a novel heterogeneous photo-Fenton catalyst for reactive dye degradation

Partial isomorphous substitution of Cr by Fe in the MIL-101 framework was achieved by direct synthesis using a hydrothermal method.

Preservation of Fe complexes into layered double hydroxides improves the efficiency and the chemical stability of Fe complexes used as heterogeneous photo-Fenton catalysts

Fe complexes ([Fe(Ox)3]3− and [Fe(Cit)2]3−) have been heterogenized through preservation into MgAl-layered double hydroxides (LDHs). The SEM images and N2 adsorption–desorption isotherm showed that the obtained products were mesoporous materials and the specific surface area of LDHs/Fe-complex composites were obviously greater than pristine LDHs, which is beneficial for the adsorption of organic pollutants. Measurement of adsorptive and heterogeneous photo-Fenton degradation of methylene blue (MB) suggested that the LDHs/Fe-complex composites had an excellent adsorption capacity at different pHs and the adsorption isotherm modeled well with the Langmuir equation. The enhancement of adsorption capacity may be attributed to the external hydroxyl groups of LDHs. MB was enriched on the surface of LDHs/Fe-complex composites, which favors MB degradation in situ. The obtained composites displayed an high photocatalytic activity in a pH range from 4.0 to 6.0 with dissolved Fe cation at a low concentration. Therefore, Fe complexes intercalated into LDHs can be an effective heterogeneous Fenton catalyst for oxidation of organic pollutants in a relatively wide pH range.

New Porphyrin/Fe-Loaded TiO2 Composites as Heterogeneous Photo-Fenton Catalysts for the Efficient Degradation of 4-Nitrophenol

A new class of porphyrin(Pp)/Fe co-loaded TiO2 composites opportunely prepared by impregnation of [5,10,15,20-tetra(4-tert-butylphenyl)] porphyrin (H2Pp) or Cu(II)[5,10,15,20-tetra(4-tert-butylphenyl)] porphyrin (CuPp) onto Fe-loaded TiO2 particles showed high activities by carrying out the degradation of 4-nitrophenol (4-NP) as probe reaction in aqueous suspension under heterogeneous photo-Fenton-like reactions by using UV-visible light. The combination of porphyrin-Fe-TiO2 in the presence of H2O2 showed to be more efficient than the simple bare TiO2 or Fe-TiO2.

Preparation of Grafted PTFE Fiber Metallic Complexes and Their Photocatalytic Degradation Abilities

Polyacrylic acid grafted polytetrafluoroethylene (PAA-g-PTFE) fibers were coordinated with Fe + ions and with a mixture of Cu + and Fe + ions to prepare PAA-g-PTFE Fe and Cu-Fe bimetallic complexes. The chemical structures and light adsorption properties of the complexes were characterized using Fourier transform infrared (FTIR) spectrometry and UV-Vis diffuse reflection spectroscopy (DRS), respectively. The complexes were used as heterogeneous photo-Fenton catalysts in the oxidative degradation of the azo dye, Reactive Blue 222, in different pH aqueous media. The results indicate that Fe + coordinates with six carboxyl groups grafted on the surface of PAA-g-PTFE in the presence or absence of Cu + ion, and improved light adsorption properties are achieved in the UV and visible regions. When both metal ions coexist in solution, the Cu ion coordinates more easily with PAA-g-PTFE than Fe to produce a PAA-g-PTFE Cu-Fe bimetallic complex. Moreover, PAA-g-PTFE Fe significantly increases the degradation of Reactive Blue 222 in the pH range 3-9 under visible irradiation. However, at high pH conditions (>7) the catalytic ability is reduced. Increasing the Fe content, and especially incorporating Cu ions in the complex, dramatically improves the catalytic reusability at high pH value. [Article] doi: 10.3866/PKU.WHXB201210152 www.whxb.pku.edu.cn 物理化学学报(Wuli Huaxue Xuebao) Acta Phys. -Chim. Sin. 2013, 29 (1), 157-166 January Received: August 20, 2012; Revised: October 15, 2012; Published on Web: October 15, 2012. ∗Corresponding author. Email: dyefib@yahoo.com.cn; Tel: +86-22-83955359. The project was supported by the Tianjin Municipal Science and Technology Committee for a Research Program of Application Foundation and Advanced Technology, China (11JCZDJ24600) and National Natural Science Foundation of China (20773093). 天津市应用基础与前沿技术重点研究计划(11JCZDJC24600)和国家自然科学基金(20773093)资助项目 C Editorial office of Acta Physico-Chimica Sinica 157 Vol.29 Acta Phys. -Chim. Sin. 2013

Heterogeneous photo-Fenton oxidation with natural clays for phenol and tyrosol remediation

Due to their excellent properties, clays have been widely used in several applications, particularly in catalysis. In this paper, three clays were used as heterogeneous photo-Fenton catalysts for phenol and tyrosol oxidations. Particular attention was given to the effect of the main operating conditions on the process performance. A total conversion was obtained for both organic pollutants with studied catalysts in 20 minutes reaction. For phenol, a total organic carbon (TOC) conversion of 93% was obtained using sieved and calcined smectite clay. The TOC conversion was 60% for tyrosol with the same catalyst. Clays were characterized by chemical analysis, BET, XRD, TPR and SEM.

Degradation of Acid Blue 29 in visible light radiation using iron modified mesoporous silica as heterogeneous Photo-Fenton catalyst

The evaluation of heterogeneous Fenton degradation on dye pollutant, Acid Blue 29 (AB29), has been investigated. The solid catalyst prepared by both sol–gel and incipient wetness impregnation methods was developed by occlusion of Fe3+ ions on synthesized mesoporous silica from sodium silicate. The prepared catalysts were characterized for their textural and surface morphology. High concentration of soluble metal precursor with 8.0wt% Fe3+ can be easily deposited on silica. The results showed that the Fe-SiO2 catalyst demonstrated good performance in the degradation of 50ppm Acid Blue 29 (AB29) which was nearly completed in 100min under visible light irradiation with optimum operating conditions at 0.4g Fe-SiO2/L, pH 3.0 and 10mM H2O2. A possible mechanism on visible light irradiated Fenton process was proposed. The catalyst is reusable over four consecutive cycles and minimal leaching of iron ions (<0.5ppm) was observed.

Decoloration of Acid Red 88 Using Synthetic-Zeolite-Based Iron as a Heterogeneous Photo-Fenton Catalyst

Decoloration and mineralization of an azo dye, Acid Red 88, were conducted using synthetic-zeolite-based Fe as a heterogeneous photo-Fenton catalyst in the presence of ultraviolet (UV) rays and H2O2. Under the optimal conditions (pH = 5.5, 17.6 mM H2O2, and 4 W m-2 UVC), 100% decoloration and 90% total organic carbon removal of 0.12 mM Acid Red 88 were achieved in 120 min. The effects of initial pH with time, as well as oxidation, were studied in a batch reactor. It was found that high decoloration was achieved using a heterogeneous Fenton method at pH 7 and lower. The catalyst also had the advantages of low leaching of Fe3+ ions and maintenance of a high decoloration in consecutive catalytic treatments. Zeolite-based Fe was successfully used repeatedly (up to three consecutive cycles) for decoloration. A high rate of decoloration was also achieved in the case of continuous operation, although <=0.4 mg L-1 of Fe were leached into the treated water.

Magnetic nickel ferrite as a heterogeneous photo-Fenton catalyst for the degradation of rhodamine B in the presence of oxalic acid

A magnetic species was synthesized in a 100mL Teflon-lined stainless steel autoclave at 180°C for 10h. The synthesized species was characterized by powder X-ray diffraction, transmission electron microscopy, scanning electronic microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and vibrating sample magnetometry at room temperature. The results showed that the synthesized species was nickel ferrite nanoparticles with diameters of approximately 10nm. The nanoparticles exhibited a photo-Fenton catalytic feature for the degradation of rhodamine B in the presence of oxalic acid. The effects of pH, oxalic acid concentration, and dosage of the catalyst, on the degradation rates of the dyes were examined. The optimal degradation rate was reached with 1.0mM oxalic acid at pH 3.0. Seven cyclic tests for rhodamine B degradation showed that the magnetic catalyst was very stable, recoverable, highly active, and easy to separate using an external magnet. Hence, this magnetic catalyst has potential use in organic pollutant removal.

Pillared montmorillonite supported ferric oxalate as heterogeneous photo-Fenton catalyst for degradation of amoxicillin

Degradation of amoxicillin (AMX) was achieved using pillared montmorillonite ferric oxalate (PMFeOx) catalyst in photo-Fenton process. The catalyst was prepared by aluminum pillaring of mild acid treated montmorillonite (MATM) clay followed by incorporation of ferric oxalate. The PMFeOx catalyst produced was characterized. XRD results revealed the intercalation of aluminum with an increase in basal spacing from 1.24 to ∼1.69 nm, the specific surface area also increased from 164.94 to 211.61 m 2 g −1. SEM images of PMFeOx showed the formation of irregular flaky morphology with random orientation. The FTIR profile at relevant wavenumbers detected intercalation of aluminum and incorporation of iron. The optimum condition that achieved 99.65% and 84.26% initial concentration reduction and COD removal respectively, for 40 ppm AMX solution was 15% excess H 2O 2 and 2.0 g PMFeOx catalyst loading at 40 °C in 10 min. The catalyst displayed good efficiency in degrading amoxicillin.

Photodegradation of thiacloprid using Fe/TiO2 as a heterogeneous photo-Fenton catalyst

Three Fe/TiO2 photocatalysts with different content of Fe (1.9, 7.2 and 13.9%, w/w) were synthesized by a simple deposition–precipitation method and characterized by XRD, SEM, N2 physisorption at 77K and Mössbauer spectroscopy. The characterization showed the presence of nano-sized Fe2O3 particles (less than 4nm) on the TiO2 support. The photocatalytic efficiency of the catalysts was examined on the example of thiacloprid (TCL) degradation under UV light irradiation in aqueous suspension in the presence/absence of H2O2. Since the efficiency of TCL degradation in the presence of H2O2 (heterogeneous photo-Fenton process) was more than two times higher, all other investigations were conducted in the presence of H2O2. The photocatalyst with 7.2%, w/w Fe (denoted as 7.2Fe/TiO2) appeared to be most efficient. The photocatalytic degradation studied under different operating conditions indicated that 0.5gL−1 of 7.2Fe/TiO2 was an optimal catalyst loading, and the optimal pH was 2.8. In the investigated range of initial concentrations of TCL (0.06–0.32mM) the photocatalytic degradation in the first stage of the reaction followed approximately a pseudo-first order kinetics. The suspended Fe/TiO2 spontaneously precipitated once the stirring of the reaction mixture was terminated (>90% after 15min). The results clearly demonstrated that 7.2Fe/TiO2 was stable and resistant to photocorrosion during the photocatalytic degradation of TCL. The higher efficiency of 7.2Fe/TiO2 compared to Degussa P25 under the optimal experimental conditions of TCL photodegradation, spontaneous precipitation of the suspension, possibility of reusing the catalyst, as well as an insignificant increase in the iron concentration in water solution, all this indicates the possibility of the practical application of this photocatalyst for water treatment.

Application of heterogenous catalyst of tris(1,10)-phenanthroline iron(II) loaded on zeolite for the photo-Fenton degradation of methylene blue

Abstract A heterogeneous photo-Fenton catalyst was prepared using the complex tris(1,10)-phenanthroline iron(II) loaded on the NaY type of zeolite. The catalyst displayed a feature of the photo-Fenton degradation of methylene blue, and a linear relationship between ln(C0/Ct) and reaction time was obtained, indicating the kinetic characteristics of a pseudo first-order reaction. The repeated cyclic experiments showed that the heterogeneous catalyst was stable and recoverable. Compared with the traditional homogeneous Fenton reagent, the heterogeneous catalyst has the advantage in the neutral or weakly basic medium used because the active component tris(1,10)-phenanthroline iron(II) is a stable chelate compound. The photo-Fenton degradation pathway for methylene blue was given based on the mass spectral data.

Impact of Inorganic Salts on Degradation of Azo Dye Using Fe (III)-Modified PAN Fiber Complex as Heterogeneous Fenton Catalyst

Fe (III)-amidoximated PAN fiber complex was prepared and used as a heterogeneous photo-Fenton catalyst for the oxidative degradation of Reactive Red 195 in water. The nature and concentration effect of inorganic salts on the dye degradation was investigated. Moreover, UV-Vis spectrum was also used to examine the decomposition process of the dye in the presence of the salt. The results indicated that the existence of the inorganic salts limited the photocatalytic degradation of the dye in water. Na2SO4 shows more strong inhibition effect on dye degradation than the other salts at the same conditions. UV-Vis spectrum demonstrated that the decomposition of the aromatic rings in the dye molecules was also reduced in the presence of the salt.

Degradation of Phenol Using the Mixed (Al-Fe) Pillared Bentonite as a Heterogeneous Photo-Fenton Catalyst

In this work the mixed Al-Fe pillared bentonite was developed and tested as a heterogeneous catalyst for the photo-Fenton oxidation of phenol under solar light irradiation. The structural characteristics of the catalyst were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The Al-Fe pillared clay exhibits higher basal distance than original bentonite. The effect of pH to the degradation of phenol and the reusability of the catalyst were addressed. The results of photocatalytic experiments indicate that the heterogeneous photo-Fenton process employing the Al-Fe pillared clay as a photocatalyst possesses a high potential for phenol degradation. During the photocatalytic reaction, the amount of iron leaching out increases as a function of time. Significantly lower concentration of Fe2+ and Fe3+ in the solution after the treatment could give a great advantage to the mixed Al-Fe pillared bentonite/H2O2 system over the homogeneous Fenton system. [DOI: 10.1380/ejssnt.2011.490]

Effect of alkali cations on heterogeneous photo-Fenton process mediated by Prussian blue colloids

This article evaluates Prussian blue (iron hexacyanoferrate) colloids as a heterogeneous photo-Fenton catalyst for the degradation of Rhodamine B. The emphasis is laid on the effects of alkali metal cations on the photo-Fenton process. The facts show that alkali cations strongly affect the degradation rate of organic species. The degradation rates of Rhodamine B, Malachite Green, and Methyl Orange in the presence of KCl, KNO 3, and K 2SO 4, respectively, are faster than their degradation rates in the presence of the corresponding sodium salts. The average degradation rates of Rhodamine B in 0.2 M KCl, NaCl, RbCl, and CsCl solution, decline in sequence, and the rate in KCl solution is greater than that without any salt added deliberately. Thus, potassium ions accelerate the degradation rate, but sodium, rubidium, and cesium ions slow the rate. The order of the rates is R K > R > R Na > R Rb > R Cs, which is consistent with that of the voltammetric oxidation currents of Prussian blue in the corresponding cation solutions. This phenomenon is attributed to the molecular recognition of the microstructure in Prussian blue nanoparticles to the alkali cations. The reaction mechanism of the photo-Fenton process has also been explored.