Photocatalytic reduction of environmental pollutant Cr(VI) over some semiconductors under UV/visible light illumination

Khalil, Laila B.; Mourad, W.E.; Rophael, M.W.

doi:10.1016/s0926-3373(98)00020-4

Cited by 315 publications

(169 citation statements)

References 22 publications

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“…These results show that adsorption amounts of Cr(VI) through TiO 2 particles at low pH level was much more than neutral pH. The results have shown good agreement with previous works (Khalil et al, 1998;Chirwa et al, 2000;Colon et al, 2001;Uyguner and Bekbolet, 2004;Wang et al, 2008). The photocatalytic oxidation reaction depends on the amount of adsorption on the surface catalyst, therefore, at lower pH levels the reaction rate were highest.…”

Section: Adsorption On Tio 2 Surface Adsorption Of Cr(vi) On Tiosupporting

confidence: 89%

“…The pervious works show that final products of organophosphate degradation are phosphate, carbon dioxide and water. Moreover, several reports have been presented for the reduction of Cr(VI); the effects of important parameters such as pH values (Chirwa et al, 2000), titanium dioxide (TiO 2 ) dosage (Khalil et al, 1998), light intensities, dissolved oxygen levels and other operating conditions were investigated (Chenthamarakshan et al, 2000;Colon et al, 2001;Uyguner and Bekbolet, 2004;Wang et al, 2008). There is not any report on type of kinetic reaction rate and effect of different parameters on the TEP photocatalytic reaction rate.…”

Section: Adsorption Measurementsmentioning

confidence: 99%

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Decontamination of hexavalent chromium and tri-ethyl phosphate stimulants through photacatalytic oxidation

Fathizadeh

Fakhraee

Aroujalian

2011

Int. J. Environ. Sci. Technol.

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ABSTRACT:In this paper, the photocatalytic decontamination of hexavalent chromium and tri-ethyl phosphate, two important wastewater contaminants, are studied by the ultraviolet / nano-titanium dioxide process. The pH value and synergic effect between the oxidation of tri-ethyl phosphate and the reduction of hexavalent chromium were investigated in different concentrations of tri-ethyl phosphate and hexavalent chromium. Furthermore, the effects of ultraviolet and nano-titanium dioxide were investigated in a solution which contained tri-ethyl phosphate and hexavalent chromium. Results of adsorptions showed that hexavalent chromium was adsorbed better in acidic pH while the better adsorption for tri-ethyl phosphate was occurred in alkalinity pH. The reduction rate of hexavalent chromium was higher in acidic solutions while it was obtained at natural pH for tri-ethyl phosphate. In co-adsorption of hexavalent chromium and triethyl phosphate pollutants, tri-ethyl phosphate slightly increased adsorption of hexavalent chromium, but hexavalent chromium had no influence on the adsorption of tri-ethyl phosphate on nano-titanium dioxide particles. In contrast, triethyl phosphate has an improving effect on the reduction reaction rate of hexavalent chromium which increases with the interaction of the concentration of tri-ethyl phosphate in mixture. The same is true for the oxidation rate of tri-ethyl phosphate.

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Section: Adsorption On Tio 2 Surface Adsorption Of Cr(vi) On Tiosupporting

confidence: 89%

Section: Adsorption Measurementsmentioning

confidence: 99%

Decontamination of hexavalent chromium and tri-ethyl phosphate stimulants through photacatalytic oxidation

Fathizadeh

Fakhraee

Aroujalian

2011

Int. J. Environ. Sci. Technol.

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“…Sementara itu, toksisitas Cr(III) jauh lebih rendah bila dibandingkan dengan Cr(VI), yaitu sekitar 1/100 kalinya, sehingga untuk mengolah limbah krom maka Cr(VI) harus direduksi terlebih dahulu menjadi Cr(III). Disamping itu, Cr(III) mudah diendapkan atau diabsorpsi oleh senyawa-senyawa organik dan anorganik pada pH netral atau alkalin [1][2][3].…”

Section: Pendahuluanunclassified

“…Endapan yang terbentuk merupakan senyawa Cr(OH) 3 . Massa Cr(III) yang terrecovery dihitung dari selisih antara massa krom total sebelum di-recovery dengan massa krom total sesudah recovery.…”

Section: Hasil Dan Pembahasanunclassified

PENGOLAHAN LIMBAH ORGANIK (FENOL) DAN LOGAM BERAT (Cr6+ ATAU Pt4+) SECARA SIMULTAN DENGAN FOTOKATALIS TiO2, ZnO-TiO2, DAN CdS-TiO2 1. Pendahuluan

Slamet¹,

Arbianti²,

Daryanto³

2010

MST

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AbstrakDalam penelitian ini limbah logam berat (Cr dan Pt) dan organik (fenol) diolah secara simultan dengan metode fotokatalitik yang relatif masih baru, kemudian dilanjutkan dengan recovery terhadap logam berat Cr dan Pt. Percobaan fotokatalisis dilakukan meggunakan katalis berbasis TiO 2 dalam fotoreaktor batch. Recovery logam Cr dan Pt masingmasing dilakukan dengan metode presipitasi dan leaching. Hasil penelitian menunjukkan adanya efek sinergisme antara reduksi logam berat (Cr 6+ atau Pt 4+ ) dan oksidasi senyawa organik (fenol) pada sistem fotokatalitik, yaitu dapat meningkatkan konversi masing-masing. Penambahan dopan ZnO (loading optimal = 0,5% berat) dapat meningkatkan kinerja fotokatalis TiO 2 dalam mereduksi Cr(VI), meskipun tidak terlalu signifikan. Loading CdS (pada TiO 2 ) yang optimal adalah sebesar 1% berat, memberikan aktivitas tertinggi dengan konversi reduksi Cr(VI) dan oksidasi fenol masing-masing ≥ 97 % dan 93 %. Reduksi Platinum menggunakan fotokatalis 0,5%ZnO-TiO 2 dan 1%CdS-TiO 2 terbukti cukup efektif dengan konversi > 99 % selama 2 jam reaksi. Proses recovery Cr(III) mencapai hasil optimal pada pH = 9, dengan efisiensi recovery sebesar 91 %. Suhu leaching optimal pada proses recovery Pt adalah 100 o C, dengan efisiensi recovery sebesar 86 %. AbstractSimultaneous Treatment of Organic (Phenol) and Heavy Metal (Cr 6+ or Pt 4+ ) Wastes over TiO 2 , ZnO-TiO 2 and CdS-TiO 2 Photocatalysts. Treatment of heavy metal (Cr 6+ and Pt 4+ ) and organic (phenol) wastes has been studied using the relatively new method, i.e. simultaneous photocatalytic process over TiO 2 photocatalysts in the batch photoreactor. Following the photocatalytic reduction of the heavy metal wastes, recovery of Cr and Pt was carried out by precipitation and leaching method, respectively. The experimental results show that in the simultaneous photocatalytic system, there is a synergism effect between the photocatalytic reduction of heavy metal waste (Cr 6+ or Pt 4+ ) and the oxidation of organic waste (phenol), so that increasing the conversion of each other. Dopant of ZnO with the optimum loading (0.5 wt%) could slightly increase the performance of TiO 2 photocatalyst in photocatalytic treatment of the wastes. Whereas CdS dopant with the optimum loading of 1 wt% could significantly enhance the performance of TiO 2 photocatalyst in simultaneous Cr(VI) reduction and phenol oxidation with the highest conversion of ≥ 97 % and 93 %, respectively. Photocatalytic reduction of Pt(IV) under 0.5%ZnO-TiO 2 and 1%CdS-TiO 2 photocatalysts effectively occurred with a high conversion (> 99 %) in 2 hours irradiation of UV. The optimum precipitation condition of Cr(III) recovery was achieved at pH = 9, with the efficiency of recovery was 91 %. Optimum temperature of leaching process in Pt recovery was 100 o C, with the efficiency of recovery was 86 %.

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“…[11][12][13]. As a potential photocatalyst for the oxidation of pollutants, CeO 2 is less active than TiO 2 under UV irradiation [14][15][16]. But it can be activated by visible light [8].…”

Section: Introductionmentioning

confidence: 99%

A Highly Efficient and Stable Visible-Light Plasmonic Photocatalyst Ag-AgCl/CeO<sub>2</sub>

Wang¹,

Yang²,

Yu³

et al. 2011

WJNSE

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Noble metal Ag nanoparticles with unique surface plasmon resonance property have attracted much attention recently in the field of photocatalysis. Based on the advantages of Ag nanoparticles and semiconductor CeO 2 , a novel plasmonic photocatalyst Ag-AgCl/CeO 2 was prepared with a facile route. The as-prepared samples were characterized using scanning and transmission electron microscopy, X-ray photoelectron spectroscopy and UV-vis diffusion reflection spectroscopy. This metal-semiconductor nanocomposite plasmonic photocatalyst exhibited a high visible-light photocatalytic activity and good stability for photocatalytic degradation of methyl orange in water. Ag-AgCl/CeO 2 will be a potentially promising plasmonic photocatalysts for organic pollutant degradation and water purification.

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Photocatalytic reduction of environmental pollutant Cr(VI) over some semiconductors under UV/visible light illumination

Cited by 315 publications

References 22 publications

Decontamination of hexavalent chromium and tri-ethyl phosphate stimulants through photacatalytic oxidation

Decontamination of hexavalent chromium and tri-ethyl phosphate stimulants through photacatalytic oxidation

PENGOLAHAN LIMBAH ORGANIK (FENOL) DAN LOGAM BERAT (Cr6+ ATAU Pt4+) SECARA SIMULTAN DENGAN FOTOKATALIS TiO2, ZnO-TiO2, DAN CdS-TiO2 1. Pendahuluan

A Highly Efficient and Stable Visible-Light Plasmonic Photocatalyst Ag-AgCl/CeO<sub>2</sub>

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Photocatalytic reduction of environmental pollutant Cr(VI) over some semiconductors under UV/visible light illumination

Cited by 315 publications

References 22 publications

Decontamination of hexavalent chromium and tri-ethyl phosphate stimulants through photacatalytic oxidation

Decontamination of hexavalent chromium and tri-ethyl phosphate stimulants through photacatalytic oxidation

PENGOLAHAN LIMBAH ORGANIK (FENOL) DAN LOGAM BERAT (Cr6+ ATAU Pt4+) SECARA SIMULTAN DENGAN FOTOKATALIS TiO2, ZnO-TiO2, DAN CdS-TiO2 1. Pendahuluan

A Highly Efficient and Stable Visible-Light Plasmonic Photocatalyst Ag-AgCl/CeO&lt;sub&gt;2&lt;/sub&gt;

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A Highly Efficient and Stable Visible-Light Plasmonic Photocatalyst Ag-AgCl/CeO<sub>2</sub>