scholarly journals Facile Preparation of ZnO Nanoparticles and Ag/ZnO Nanocomposite and Their Photocatalytic Activities under Visible Light

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Thi Anh Tuyet Pham ◽  
Van Anh Tran ◽  
Van Duong Le ◽  
Minh Viet Nguyen ◽  
Duc Duc Truong ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Zno Nanoparticles ◽  
Pore Volume ◽  
High Surface ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Order Kinetic ◽  
Solution Ph

Zinc oxide (ZnO) has been known as an excellent photocatalyst for the degradation of a variety of organic pollutants under UV irradiation. This work describes a synthesis of ZnO nanoparticles via a facile precipitation method, and Ag was doped into Ag/ZnO nanocomposite to improve the photocatalytic degradation of BPA under visible light irradiation. The obtained ZnO nanoparticles were 20 nm in size and had a relatively high surface area and pore volume, 26.2 m2/g and 0.48 cm3/g, respectively. The deposition of Ag led to a decrease in the surface area, pore volume, and band gap energy ( E g ) of ZnO nanoparticles. However, the photocatalytic activity of Ag/ZnO composite in the case increased. The performance of ZnO was compared with Ag/ZnO composites at the different molar ratios, and the kinetic reaction of BPA in these catalysts was investigated by the first-order kinetic model. The sample of Ag/ZnO-10 composite had the highest catalytic activity and showed the degradation efficiency, reaction rate, and degradation capacity of 100% in 120 min, 0.014 min-1, and 40 mg/g, respectively. In comparison, the effects of Ag/ZnO molar ratio, catalyst dosage, solution pH, and concentration of BPA on photocatalytic degradation were investigated. Additionally, the photocatalytic performance of Ag/ZnO-10 composite was evaluated by the degradation of other persistent organic compounds such as phenol, tartrazine, and methylene blue and compared to other catalysts in literature.

High Surface Area SnO2 -Ta2 O5 Composite for Visible Light-driven Photocatalytic Degradation of an Organic Dye

2018 ◽  
Vol 94 (4) ◽  
pp. 633-640 ◽  
Author(s):  
Bharath Velaga ◽  
Pradeep P. Shanbogh ◽  
Diptikanta Swain ◽  
Chandrabhas Narayana ◽  
Nalini G. Sundaram
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Organic Dye ◽  
Visible Light Driven

scholarly journals Visible light-induced photocatalytic degradation of gas-phase acetaldehyde with platinum/reduced titanium oxide-loaded carbon paper

RSC Advances ◽  
2017 ◽  
Vol 7 (80) ◽  
pp. 50693-50700 ◽  
Author(s):  
Soonhyun Kim ◽  
Minsun Kim ◽  
Ha-Young Lee ◽  
Jong-Sung Yu
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Gas Phase ◽  
Surface Area ◽  
Titanium Oxide ◽  
Visible Light Irradiation ◽  
High Surface ◽  
High Surface Area ◽  
Air Pollutant ◽  
Carbon Paper

A simply fabricated, high-surface-area substrate in a highly efficient photocatalyst for the degradation of air pollutant under visible light irradiation.

scholarly journals High-surface-area activated red mud for efficient removal of methylene blue from wastewater

2017 ◽  
Vol 36 (1-2) ◽  
pp. 62-79 ◽  
Author(s):  
Zhong-Pan Hu ◽  
Ze-Min Gao ◽  
Xinying Liu ◽  
Zhong-Yong Yuan
Keyword(s):  
Methylene Blue ◽  
Surface Area ◽  
Red Mud ◽  
High Surface ◽  
High Surface Area ◽  
Influence Factors ◽  
Interaction Mechanism ◽  
Precipitation Method ◽  
Order Kinetic ◽  
Alkaline Conditions

Red mud was activated by a digestion–precipitation method, resulting in a mesostructure with high surface area, and the activated red mud was further used as the adsorbent for methylene blue removal. The physicochemical properties of the resultant samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry analysis, and nitrogen sorption techniques. Batch studies were measured to investigate the influence factors including adsorbent dosage, contact time, pH, and initial concentration. It was revealed that the activated red mud was highly efficient for removal of methylene blue. Adsorption experiments were found to be better achieved in faintly acidic and alkaline conditions, where the adsorption capacity of activated red mud and activated red mud-200 reached 232 and 274 mg/g at pH 7.0, respectively. Langmuir, Freundlich, Temkin isotherms, and pseudo-second-order kinetic model fitted the experimental data well, demonstrating an electrostatic interaction mechanism.

Visible light assisted photocatalytic degradation of acid red 88 using Au–ZnO nanophotocatalysts

2009 ◽  
Vol 60 (6) ◽  
pp. 1589-1596 ◽  
Author(s):  
Panneer Selvam Sathish Kumar ◽  
Michael Ruby Raj ◽  
Sambandam Anandan ◽  
Meifang Zhou ◽  
Muthupandian Ashokkumar
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Zno Nanoparticles ◽  
Analytical Techniques ◽  
Electron Acceptors ◽  
Precipitation Method ◽  
Light Illumination ◽  
Photogenerated Electrons ◽  
Visible Light Illumination ◽  
Oxide Particles

Photocatalytic degradation of acid red 88 (AR88) in aqueous suspensions of Au–ZnO nanoparticles under visible light illumination was studied in order to evaluate various effects of the Au deposition on the ZnO photocatalytic activity. Au–ZnO nanoparticles were prepared by deposition precipitation method and characterized by different analytical techniques. In Au–ZnO system, all gold nanoparticles were tethered on the surface of zinc oxide particles. This enhanced the AR88 adsorption on the Au–ZnO surface and acted as electron traps which is the main reason for significant enhancement in the AR88 photodegradation under visible light illumination compared to ZnO alone. Further in the presence of electron acceptors complete decolorization of the dye was observed, which might be due to immediate trapping of the photogenerated electrons by electron acceptors.

scholarly journals One-post Solvothermal Synthesis of Bismuth Oxybromides for Efficient Visible-light Photocatalytic Degradation of Methyl Parahydroxybenzoate: Effects of Alkaline and Reaction Medium

2020 ◽  
Vol 01 ◽  
Author(s):  
Jiaxiu Xiao ◽  
Xiaoting Zhang ◽  
Yaoyao Huang ◽  
Xiuling Luo ◽  
Xin Xiao
Keyword(s):  
Ethylene Glycol ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Environmental Remediation ◽  
High Efficiency ◽  
High Surface ◽  
Reaction Medium ◽  
Bandgap Energy ◽  
Potential Candidate

Background: The development of high-efficiency visible-light-active photocatalysts to eliminate emerging contaminants is of great significance for environmental remediation and personal safety. Methods: In this work, BiOBr and two oxygen-rich bismuth oxybromide (Bi4O5Br2-EG and Bi4O5Br2-H2O) were synthesized by solvothermal method through the reaction of Bi3+ and Br- in different reaction medium (ethylene glycol or water) and alkali conditions. The composition, structure, morphology, light absorption, surface area, and surface feature of the synthetic bismuth oxybromides were systematically characterized. Due to the presence of ethylene glycol and OH-, the Bi4O5Br2-EG preferentially exposes the 010 facets. The formation of hierarchical flower-like structures of Bi4O5Br2- EG can be elucidated by the dissolution-recrystallization-growth mechanism. The bismuth oxybromides were then used for photocatalytic degradation of methyl parahydroxybenzoate (a commonly used preservative but exposes endocrine disrupting activity) under visible-light irradiation. Results: Since Bi4O5Br2-EG has a satisfactory band structure (bandgap energy ~2.61 eV, valence band potential +2.45 V), high surface area (49.0 m2g-1), and negatively charged surface, its photocatalytic removal efficiency of MPHB is 46.5 and 41.2 times that of BiOBr and Bi4O5Br2-H2O, respectively. During the photodegradation reaction, holes and superoxide radicals were recognized as the key reactive oxide species. Conclusion: In addition, the as-synthesized Bi4O5Br2-EG is stable and easy to reuse, suggesting it is a potential candidate for wastewater treatment.

scholarly journals Adsorption of Basic Brown and Chrysophenine from Water Solution by Magnesium Silicate Gel

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Zhun Zhao ◽  
Zhenhua Li ◽  
Penglei Cui ◽  
Shengli Li ◽  
Lingqian Kong
Keyword(s):  
Surface Area ◽  
Adsorption Equilibrium ◽  
Water Solution ◽  
High Surface ◽  
High Surface Area ◽  
Freundlich Isotherm ◽  
Magnesium Silicate ◽  
Order Kinetic ◽  
Solution Ph ◽  
Average Pore

Noncrystalline, high surface area magnesium silicate gel was successfully prepared by hydrothermal method. Such product was characterized by BET and XRD to determine surface area 576.4 m2·g−1, average pore width 2.76 nm, and amorphous surface. The adsorption behaviors of Basic Brown and Chrysophenine on magnesium silicate gel were investigated through changing initial concentration, adsorbent dosage, solution pH, contact time, and temperature. The experimental data was analyzed by the adsorption isotherms and kinetics. The results showed the adsorption progress was fast for Basic Brown, and the adsorption equilibrium was finished in 2 h, while the adsorption equilibrium of Chrysophenine was finished in 7 h. Freundlich isotherm model and second-order kinetic models described the adsorption process very well.

scholarly journals Enhanced photocatalytic degradation performance of bisphenol A over TiO2-SiO2 photocatalyst by improving specific surface area under simulation natural light

2020 ◽  
Vol 9 (4) ◽  
pp. 49-57
Author(s):  
Minh-Vien Le ◽  
Tai Huynh Huu ◽  
Oanh Nguyen Thi Kieu ◽  
Thang Ngo Manh ◽  
Suong Ho Thi Ngoc
Keyword(s):  
Bisphenol A ◽  
Specific Surface ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Specific Surface Area ◽  
Organic Pollutant ◽  
Molar Ratio ◽  
Natural Light ◽  
Solution Ph ◽  
Initial Concentration

The application of natural light in photocatalytic process is a potential energy source. In this study, TiO2-SiO2 nanoparticles with outstandingly enhanced photocatalytic activity have been fabricated by sol-gel method. The prepared photocatalysts with different molar ratio of TiO2:SiO2 as 100:0; 95:5; 85:15 and 75:25 were denoted as TiO2, TS5, TS15 and TS25, respectively. Characterization of these photocatalysts was evaluated using transmission electron microscopy (TEM), X-ray diffraction (XRD), N2 Adsorption and Desorption isotherms method (Brunauer–Emmet–Teller, BET). The specific surface area was improved in TiO2-SiO2 photocatalyst namely 193.9 m2.g-1 (at molar ratio of TiO2:SiO2 of 95:5) compared to 33.6 m2.g-1 of TiO2. The crystallite size was calculated around 5 nm from XRD data and uniform particle size distribution was observed in TEM image. The photocatalytic experiments were performed with bisphenol A (BPA) as model compound of organic pollutant. The effect of various operation parameters such as initial concentration, initial solution pH and photocatalyst dosage has been investigated. The kinetic studies of the photocatalytic degradation BPA over TS5 followed the pseudo-first order (k=1.09×10-2 min-1) and degradation yield to be 82.4% BPA, at pH6.23, initial concentration to be 10 ppm and photocatalyst dosage to be 1.0 g.L-1. The photocatalyst TS5 maintained activity after four cycles and remained 78%. The TiO2-SiO2 composite photocatalyst has shown to be a promising heterogeneous photocatalyst for organic degradation.

scholarly journals Municipal Leachate Treatment by Fenton Process: Effect of Some Variable and Kinetics

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mohammad Ahmadian ◽  
Sohyla Reshadat ◽  
Nader Yousefi ◽  
Seyed Hamed Mirhossieni ◽  
Mohammad Reza Zare ◽  
...  
Keyword(s):  
Reaction Time ◽  
Color Removal ◽  
Molar Ratio ◽  
Order Kinetic ◽  
Fenton Process ◽  
Solution Ph ◽  
Leachate Treatment ◽  
First Order ◽  
Order Kinetic Model ◽  
Better Than

Due to complex composition of leachate, the comprehensive leachate treatment methods have been not demonstrated. Moreover, the improper management of leachate can lead to many environmental problems. The aim of this study was application of Fenton process for decreasing the major pollutants of landfill leachate on Kermanshah city. The leachate was collected from Kermanshah landfill site and treated by Fenton process. The effect of various parameters including solution pH, Fe2+and H2O2dosage, Fe2+/H2O2molar ratio, and reaction time was investigated. The result showed that with increasing Fe2+and H2O2dosage, Fe2+/H2O2molar ratio, and reaction time, the COD, TOC, TSS, and color removal increased. The maximum COD, TOC, TSS, and color removal were obtained at low pH (pH: 3). The kinetic data were analyzed in term of zero-order, first-order, and second-order expressions. First-order kinetic model described the removal of COD, TOC, TSS, and color from leachate better than two other kinetic models. In spite of extremely difficulty of leachate treatment, the previous results seem rather encouraging on the application of Fenton’s oxidation.

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