scholarly journals Bioinspired ZnO-Based Solar Photocatalysts for the Efficient Decontamination of Persistent Organic Pollutants and Hexavalent Chromium in Wastewater

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 974 ◽  
Author(s):  
Albert Serrà ◽  
Elvira Gómez ◽  
Laetitia Philippe
Keyword(s):  
Methylene Blue ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Photocatalytic Performance ◽  
Synergistic Effects ◽  
Light Trapping ◽  
Visible Region ◽  
Active Surface ◽  
Good Ability ◽  
Visible Light Driven

Biomimetic/bioinspired engineering and sulfidation processes are effective strategies for improving the visible light-driven photocatalytic performance of ZnO photocatalysts. A facile electrodeposition process in high oxygen-flux conditions was used to synthesize well-defined fractal micro/nanoferns, consequently increasing the photocatalyst’s light-trapping capability and the accessible active surface. Next, a simple sulfidation process was used to form a thin layer of ZnS, producing ZnO@ZnS core@shell micro/nanoferns, thereby tuning the optoelectronic properties and extending the photoresponse to the visible region. The ZnO@ZnS micro/nanoferns exhibited clear superiority over other ZnO photocatalysts in the photooxidation of persistent organic pollutants (POPs) and the photoreduction of Cr(VI). Their excellent photocatalytic performance allowed the photodegradation under UV-filtered sunlight of nearly 97% of methylene blue after 60 min; the mineralization of >98% of a mixture of methylene blue, 4-nitrophenol, and rhodamine-B after 210 min; and the removal of nearly 65% of Cr(VI) after 180 min. In addition, the ZnO@ZnS micro/nanoferns demonstrated a good ability to decontaminate an inorganic-organic bipollutant system, with promising potential to leverage synergistic effects. Finally, these micro/nanoferns presented great recyclability and reusability for both photooxidation and photoremediation processes. These findings support that sulfidation and biomimetic engineering can be a superior route for designing efficient sunlight-driven ZnO-photocatalysts for water decontamination.

scholarly journals The Photocatalytic and Antibacterial Performance of Nitrogen-Doped TiO2: Surface-Structure Dependence and Silver-Deposition Effect

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2261 ◽  
Author(s):  
Abdul Wafi ◽  
Erzsébet Szabó-Bárdos ◽  
Ottó Horváth ◽  
Mihály Pósfai ◽  
Éva Makó ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Surface Area ◽  
Photocatalytic Performance ◽  
Visible Region ◽  
Bet Surface Area ◽  
Doped Tio2 ◽  
X Ray ◽  
Nitrogen Doped ◽  
Visible Light Driven

Catalysts for visible-light-driven oxidative cleaning processes and antibacterial applications (also in the dark) were developed. In order to extend the photoactivity of titanium dioxide into the visible region, nitrogen-doped TiO2 catalysts with hollow and non-hollow structures were synthesized by co-precipitation (NT-A) and sol–gel (NT-U) methods, respectively. To increase their photocatalytic and antibacterial efficiencies, various amounts of silver were successfully loaded on the surfaces of these catalysts by using a facile photo-deposition technique. Their physical and chemical properties were evaluated by using scanning electron microscopy (SEM), transmission electron microscopy–energy dispersive X-ray spectroscopy (TEM–EDS), Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD), and diffuse reflectance spectra (DRS). The photocatalytic performances of the synthesized catalysts were examined in coumarin and 1,4-hydroquinone solutions. The results showed that the hollow structure of NT-A played an important role in obtaining high specific surface area and appreciable photoactivity. In addition, Ag-loading on the surface of non-hollow structured NT-U could double the photocatalytic performance with an optimum Ag concentration of 10−6 mol g−1, while a slight but monotonous decrease was caused in this respect for the hollow surface of NTA upon increasing Ag concentration. Comparing the catalysts with different structures regarding the photocatalytic performance, silverized non-hollow NT-U proved competitive with the hollow NT-A catalyst without Ag-loading for efficient visible-light-driven photocatalytic oxidative degradations. The former one, due to the silver nanoparticles on the catalyst surface, displayed an appreciable antibacterial activity, which was comparable to that of a reference material practically applied for disinfection in polymer coatings.

scholarly journals Facile synthesis of mesoporous titanium dioxide doped by Ag-coated graphene with enhanced visible-light photocatalytic performance for methylene blue degradation

RSC Advances ◽  
2017 ◽  
Vol 7 (41) ◽  
pp. 25314-25324 ◽  
Author(s):  
Lin Xiao ◽  
Li Youji ◽  
Chen Feitai ◽  
Xu Peng ◽  
Li Ming
Keyword(s):  
Methylene Blue ◽  
Titanium Dioxide ◽  
Visible Light ◽  
Photocatalytic Performance ◽  
Solvothermal Method ◽  
Sol Gel ◽  
Facile Synthesis ◽  
Methylene Blue Degradation ◽  
Visible Light Driven ◽  
Visible Light Photocatalytic

A highly efficient and elaborately structured visible-light-driven catalyst composed of mesoporous TiO2 (MT) doped with Ag+-coated graphene (MT-Ag/GR) has been successfully fabricated by a sol–gel and solvothermal method.

scholarly journals Graphene oxide and Ag engulfed TiO2 nanotube arrays for enhanced electron mobility and visible-light-driven photocatalytic performance

2014 ◽  
Vol 2 (15) ◽  
pp. 5315-5322 ◽  
Author(s):  
Lan Ching Sim ◽  
Kah Hon Leong ◽  
Shaliza Ibrahim ◽  
Pichiah Saravanan
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Visible Light ◽  
Electron Mobility ◽  
Photocatalytic Performance ◽  
Visible Region ◽  
Tio2 Nanotube Arrays ◽  
Nanotube Arrays ◽  
Ternary Composite ◽  
Visible Light Driven

GO–Ag–TNTs, a ternary composite was synthesized. Both Ag and GO well contributed to enhance the photocatalytic activity in the visible region.

Hydrothermal formation of N/Ti3+ codoped multiphasic (brookite–anatase–rutile) TiO2 heterojunctions with enhanced visible light driven photocatalytic performance

2017 ◽  
Vol 46 (45) ◽  
pp. 15727-15735 ◽  
Author(s):  
Mingxuan Sun ◽  
Yuanyuan Kong ◽  
Yalin Fang ◽  
Swati Sood ◽  
Yuan Yao ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Performance ◽  
Rutile Tio2 ◽  
Visible Light Photocatalytic Activity ◽  
Visible Light Driven ◽  
Visible Light Photocatalytic

Multiphasic TiO2 heterojunctions codoped with N and Ti3+ were fabricated and their enhanced visible light photocatalytic activity for the degradation of methylene blue was demonstrated.

Facile fabrication of a NiO/Ag3PO4 Z-scheme photocatalyst with enhanced visible-light-driven photocatalytic activity

2020 ◽  
Vol 44 (29) ◽  
pp. 12806-12814 ◽  
Author(s):  
Ning Li ◽  
Yanlei He ◽  
Jiajia Lian ◽  
Qingyun Liu ◽  
Xianxi Zhang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Organic Pollutants ◽  
Photocatalytic Performance ◽  
Visible Light Driven ◽  
Facile Fabrication

The photocatalytic performance of Z-scheme NiO/Ag/Ag3PO4 was evaluated by degrading organic pollutants under visible light.

scholarly journals Removal of emerging persistent organic pollutants (Em-POPs) model compounds from water using a natural porous material functionalized with graphene-based products

2020 ◽  
Vol 3 (1) ◽  
pp. 416-427
Author(s):  
Donald Boehm ◽  
Alice Lecus ◽  
Hai-Feng Zhang ◽  
David Garman ◽  
Marcia R. Silva
Keyword(s):  
Methylene Blue ◽  
Graphene Oxide ◽  
Activated Carbon ◽  
Porous Material ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Sodium Fluorescein ◽  
Vacuum Deposition ◽  
Model Compounds ◽  
Carbon Regeneration

Abstract This study focuses on the removal of three model compounds, classified as emerging persistent organic pollutants (Em-POPs), from water using a modified version of natural Australian zeolite. Following a series of subsequent treatments and vacuum deposition of graphene oxide (GO), both chemical and physical properties of the adsorbent were characterized. The GO-coated zeolite was tested for the removal of methylene blue (MB), disperse blue 26 (DB26), and sodium fluorescein (NaFn). Results show excellent removal capability for MB and DB26 dyes and decent removal for NaFn when compared to commercially available products such as granular activated carbon. Regeneration of the adsorbent showed virtually no loss in adsorptive performance after two cycles, with MB and DB26.

Photocatalytic degradation of persistent organic pollutants under visible irradiation by TiO2 catalysts sensitized with Zn(II) and Co(II) tetracarboxy-phthalocyanines

2016 ◽  
Vol 20 (08n11) ◽  
pp. 1190-1199 ◽  
Author(s):  
Yaghub Mahmiani ◽  
Altuğ Mert Sevim ◽  
Ahmet Gül
Keyword(s):  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Diffuse Reflectance Spectroscopy ◽  
Aqueous Media ◽  
Visible Region ◽  
Gas Chromatography Mass Spectrometry ◽  
Infrared Spectrometry ◽  
Visible Irradiation ◽  
The Difference

Photo-excitation under visible light has been an important step to acquire solar-driven TiO2 photocatalysts and dye sensitization has been used frequently to extend the optical response of TiO2 into the visible region. In the present work, new heterogeneous photocatalysts were prepared by anchoring carboxylic acid substituted Zn(II) and Co(II) phthalocyanines onto polycrystalline TiO2 surface and their photocatalytic activities were investigated. Due to covalent bonding of carboxy-terminated molecules onto TiO[Formula: see text]semiconductors, we synthesized symmetric 4-hydroxybenzoic acid-bearing metallophthalocyanines as dye sensitizer molecules. Heterogeneous composites having titanium dioxide and metallophthalocyanines anchored via CO–O–TiO2 bonds were characterized by using X-ray diffraction (XRD), Fourier-transform infrared spectrometry (FT-IR), and ultraviolet-visible diffuse reflectance spectroscopy. The optimum loading value of the dyes on TiO2 were 0.98 [Formula: see text]mol/g TiO2 for CoPc and 0.86 [Formula: see text]mol/g TiO2 for ZnPc, nearly independent of the amount of TiO2 used. These newly obtained heterogeneous photocatalysts were employed in the photocatalytic degradation of 4-chlorophenol(4-CP), chlorobenzene(CB) and 1,2,4-trichlorobenzen(TCB) in aqueous media under visible irradiation. Gas chromatography-mass spectrometry (GC-MS) was used for quantitation. The new photocatalysts showed excellent activities with visible-region irradiation in the photocatalytic degradation of persistent organic pollutants (POPs) as compared to the control experiments used with untreated TiO2 and the difference was attributed to the cooperation of the two elements, namely TiO2 and MPc. Experiments show that in two hours nearly complete degradation of POPs were observed.

scholarly journals Synthesis of biomass-supported CuNi zero-valent nanoparticles through wetness co-impregnation method for the removal of carcinogenic dyes and nitroarene

2020 ◽  
Vol 9 (1) ◽  
pp. 237-247
Author(s):  
Shah Hussain ◽  
Hani S. H. Mohammed Ali ◽  
Shahid Ali Khan ◽  
Aliya Farooq ◽  
Najla bint Saud Al-Saud ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Methyl Orange ◽  
Elemental Composition ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Rhodamine B ◽  
Congo Red ◽  
Chemical Reduction ◽  
Impregnation Method ◽  
Crystalline Peak

AbstractStabilization of zero-valent CuNi nanoparticles (NPs) supported on Cicer arietenum (CP) is reported here for the reduction and removal of persistent organic pollutants. The functional groups and interactions of NPs with the CP were determined by ATR-FTIR. The crystallinity, morphology, and the elemental composition of the samples were determined through powder XRD, FESEM, and EDS techniques, respectively. The XRD spectrum displayed a sharp crystalline peak at 43.9 for CuNi. The Cu and Ni zero-valent NPs displayed a peak at almost the same region, and thus, both the peaks are merged and appeared as a single peak. The chemical reduction/degradation of eight model pollutants, viz., 2-nitrophenol (ONP), 3-nitrophenol (MNP), 4-nitrophenol (PNP), 2,4-dinitrophenol (DNP), methyl orange (MO), congo red (CR), methylene blue (MB), and rhodamine B (RB) were carried out in the presence of NaBH4. The kapp value of 0.1 mM 4NP was highest which was 1.8 × 10−1 min−1 while the slowest rate was observed for CR and RB with kapp 5.5 × 10−3 and 5.4 × 10−3 min−1 respectively. This article helps in the removal of toxic organic pollutants through green supported NPs.

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