Photocatalytic removal of Cr(VI) with illuminated TiO2

Yang, Jae‐Kyu; Lee, S.M.; Farrokhi, Mehrdad; Giahi, Omid; Shirzad‐Siboni, Mehdi

doi:10.1080/19443994.2012.677564

Cited by 66 publications

(29 citation statements)

References 35 publications

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“…Hence, activation of the diatomite surface becomes necessary for removal process optimization. Photocatalytic nature of TiO 2 has been utilized in the environmental remediation studies (Hanaor et al 2011;Hanaor and Sorrell 2014;Yang et al 2012;Lasek et al 2012;Kujawa et al 2013;Kamegawa et al 2013). Wu et al (2009) reported visible light-induced photocatalytic inactivation of bacteria with nitrogen-doped TiO 2 .…”

Section: Introductionmentioning

confidence: 99%

Adsorption isotherm studies of Cu (II) and Co (II) in high concentration aqueous solutions on photocatalytically modified diatomaceous ceramic adsorbents

2017

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Photocatalytically modified ceramic adsorbents were synthesized for the removal of high concentration Cu (II) and Co (II) ions from their aqueous solutions. The raw material, diatomaceous aluminosilicate mineral was modified using silver and anatase titanium oxide nanoparticles. Batch adsorption experiment was carried out on the targeted metal ions and the results were analyzed by the Langmuir and Freundlich equation at different concentrations (100-1000 mg/l) and the characteristic parameters for each adsorption isotherm were determined. As-received raw materials do not exhibit any sorption capacity for high concentration Cu 2? and Co 2? adsorbates. However, the adsorption isotherms for modified diatomaceous ceramic adsorbents could be fitted well by the Langmuir model for both Cu 2? and Co 2? with correlation coefficient (R) of up to 0.99953. The highest and lowest monolayer coverage (q max ) were 121.803 and 31.289 mg/g for Cu 2? and Co 2? , respectively. The separation factor (R L ) in the experiment was less than one (\1), indicating that the adsorption of metal ions on the Ag-TiO 2 -modified ceramic adsorbent is favorable. The highest adsorption capacity (K f ) and intensity (n) constants obtained from Freundlich model are 38.832 (Cu 2? on ZEO-T) and 5.801 (Co 2? on STOX-Z).

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Section: Introductionmentioning

confidence: 99%

Adsorption isotherm studies of Cu (II) and Co (II) in high concentration aqueous solutions on photocatalytically modified diatomaceous ceramic adsorbents

2017

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“…The removal of Cr(VI) using a TiO 2 catalyst has been favored at lower solution pH values due to an increased potential difference between the conduction band of TiO 2 and Cr(VI)/Cr(III) and the anionic-type adsorption of Cr(VI) onto the surface of TiO 2 (Yang et al 2012a). The reaction can be accelerated by the addition of organic compounds that act as scavengers of holes or HO•, such as citric acid (Kabra et al 2009;Wang et al 2008), humic acid, oxalate, ethylenediaminetetraacetic acid, nitrilotriacetic acid, phenol (Yang et al 2012b), and isopropyl alcohol (Pifferi et al 2013).…”

Section: Photocatalytic Reduction Of Cr(vi) With Tio 2 -Based Semiconmentioning

confidence: 98%

“…Table 7.5 describes some recent studies on the removal of Cr (VI) using TiO 2 -modified catalysts. The semiconductor commonly used for the photocatalytic removal of Cr(VI) has been the slurry form of Degussa P25, and the process has been based on the use of UV radiation (Yang et al 2012a(Yang et al , 2012b or solar light (Kabra et al 2009). Very few studies have considered the reduction of Cr (VI) using immobilized TiO 2 nanoparticles.…”

Section: Photocatalytic Reduction Of Cr(vi) With Tio 2 -Based Semiconmentioning

confidence: 99%

Application of Semiconductor Photocatalytic Materials for the Removal of Inorganic Compounds from Wastewater

Guzmán-Mar

Villanueva-Rodríguez

Hinojosa‐Reyes

2014

Photocatalytic Semiconductors

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A wide range of inorganic pollutants are sensitive to photochemical transformation on the surface of catalysts. The major inorganic wastewater pollutants treated by this process include cyanide-containing waste and heavy metal pollutants, such as arsenic species and hexavalent chromium. Heterogeneous photocatalysis has been explored as an alternative technology for inorganic ion removal offering satisfactory results. The photocatalytic removal of inorganic pollutants usually has two types of mechanisms: oxidation and reduction.In this chapter, the photocatalytic activities of various semiconductor materials for inorganic ion removal have been compiled and reviewed. The key advancements on the preparation of semiconductor materials tested for the removal of inorganic ions at low-level concentrations from natural water evaluating the matrix effects are also highlighted and discussed. In particular, the chapter focuses on enhancing the degradation efficiency; maximizing the use of illumination wavelength in the visible light region to develop solar active photocatalysts; the ease of separation from treated water, which is always of great interest; and improving the retrieval and reuse of semiconductors.

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“…The temporal photocatalytic decay of Cr(VI) concentration has been shown to obey the pseudo-first order rate kinetics [6,25,26]:…”

Section: Photocatalytic Reduction Of Cr(vi)mentioning

confidence: 99%

“…In general, the studies covered many aspects of photocatalysis includ-ing the influence of the (a) type of photocatalyst [4,5,6,7], (b) irradiation intensity [8], (c) photocatalyst loading [9], (d) Cr(VI) pollutant concentration [9], (e) solution pH [10], and (f) addition of radical scavengers [11] on the rate of reduction of Cr(VI) to Cr(III) with the objective of optimizing the process. The findings indicate that (a) the rate of reduction increases but photoefficiency decreases with increasing irradiance, (b) the percentage of Cr(VI) photoreduced increases to a maximum and then decrease with increasing photocatalyst loading, (c) the rate of reduction increases but percentage of Cr(VI) reduced decreases with increasing Cr(VI) concentration, and (d) the rate of reduction decreases with increasing pH.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Reduction of Aqueous Cr(VI) with CdS under Visible Light Irradiation: Effect of Particle Size

Makama

Salmiaton

Saion

et al. 2016

Bull. Chem. React. Eng. Catal.

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Stringent environmental standards have made the removal of Cr(VI) from water an important problem for environmental scientist and engineering. Heterogeneous photocatalysis using suspended photocatalyst is an interesting technique to consider for this application. In this work, the influence of particle size of suspended CdS on the photocatalytic reduction of aqueous Cr(VI) ion was investigated. The efficiency of Cr(VI) reduction was monitored through UV-visible analysis. The experimental results showed that the nanoparticle size has a dramatic effect on the adsorption and reduction of Cr(VI). As surface area increased from 44.2±0.6 to 98.7±0.5 m 2 /g due to particle size reduction, the rate of Cr(VI) reduction nearly doubled in the first 20 min of visible light irradiation. The results evidenced the inverse relationship between the apparent reduction rate constant and the CdS particle size. Conversely, the half-life (t1/2) period of the photocatalytic reduction has a direct relationship with CdS particle sizes.

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Photocatalytic removal of Cr(VI) with illuminated TiO2

Cited by 66 publications

References 35 publications

Adsorption isotherm studies of Cu (II) and Co (II) in high concentration aqueous solutions on photocatalytically modified diatomaceous ceramic adsorbents

Adsorption isotherm studies of Cu (II) and Co (II) in high concentration aqueous solutions on photocatalytically modified diatomaceous ceramic adsorbents

Application of Semiconductor Photocatalytic Materials for the Removal of Inorganic Compounds from Wastewater

Photocatalytic Reduction of Aqueous Cr(VI) with CdS under Visible Light Irradiation: Effect of Particle Size

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