Photocatalytic Treatment of MO in Water with BiOBr Photocatalyst

2011 ◽  
Vol 694 ◽  
pp. 554-558 ◽  
Author(s):  
Xiao Xia Zhao ◽  
Yan Wang ◽  
Zhu Qing Shi ◽  
Cai Mei Fan

The BiOBr catalyst prepared by the hydrolysis method was investigated with the X-ray diffractometry(XRD) and scanning electron microscope (SEM). The results show that the catalyst was the tetragonal primitive crystal structure and composed of homogeneous particles of fine ferrite plates. At the same time, the photocatalytic activity of BiOBr catalyst was evaluated by methylene orange (MO) in aqueous solution illuminated by Xenon lamp, and the degradation process parameters, such as initial concentration of MO, initial pH value and amount of BiOBr catalyst were discussed to the degradation rate of the MO. Under the following experimental conditions of C0=10mg/L, pH=8, m(BiOBr)=1.0g/L, MO can be entirely degraded after 2.5 hours.

NANO ◽  
2008 ◽  
Vol 03 (05) ◽  
pp. 317-322 ◽  
Author(s):  
ZHAOHUI LUO ◽  
KEIKO KATAYAMA-HIRAYAMA ◽  
KIMIAKI HIRAYAMA ◽  
TETSUYA AKITSU ◽  
HIDEHIRO KANEKO

Pyrene is a high molecular weight polycyclic aromatic hydrocarbon (PAH) that is found in water systems worldwide. It is harmful to living organisms, even when taken in very small amounts. The photocatalytic degradation of pyrene in porous Pt / TiO 2– SiO 2 photocatalyst (PPtPC) suspension under UV irradiation was investigated in this study. PPtPC was prepared by a simple heat treatment of the compacted powder mixtures of anatase TiO 2 and amorphous SiO 2 with camphor as a pore directing template, followed by coating platinum by the dip-coating method. X-ray diffraction (XRD), scanning electron microscopy (SEM) with an integrated energy-dispersive analysis of the X-ray (EDX) system, and Brunauer–Emmett–Teller (BET) were used to characterize PPtPC. The degradation kinetics of pyrene in different experimental conditions, such as initial concentration of pyrene, oxygen concentrations, pH, and temperature, were investigated. The durability of PPtPC was also tested. The results indicate that the structure of TiO 2 in PPtPC is anatase. The aggregated size of PPtPC is in the range of 10–100 μm, the mean pore diameter is 3 nm, and the BET surface area is 109 m2 g-1. The photocatalytic degradation process of pyrene follows pseudo-first-order kinetics. The rate constants increase as the initial concentration of pyrene and pH decrease. Higher temperature slightly enhances the rate constant. The dissolved oxygen in the photocatalytic degradation process is not as important as in the photolysis process. The recovered PPtPC still shows high photoactivity. This work suggests that PPtPC offers a promising method for high molecular weight PAH removal.


2019 ◽  
Vol 10 ◽  
pp. 1157-1165 ◽  
Author(s):  
Binjing Hu ◽  
Qiang Sun ◽  
Chengyi Zuo ◽  
Yunxin Pei ◽  
Siwei Yang ◽  
...  

A mild and simple method was developed to synthesize a highly efficient photocatalyst comprised of Ce-doped ZnO rods and optimal synthesis conditions were determined by testing samples with different Ce/ZnO molar ratios calcined at 500 °C for 3 hours via a one-step pyrolysis method. The photocatalytic activity was assessed by the degradation of a common dye pollutant found in wastewater, rhodamine B (RhB), using a sunlight simulator. The results showed that ZnO doped with 3% Ce exhibits the highest RhB degradation rate. To understand the crystal structure, elemental state, surface morphology and chemical composition, the photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and inductively coupled plasma emission spectroscopy (ICP), respectively. The newly developed, robust, field-only surface integral method was employed to explore the relationship between the remarkable catalytic effect and the catalyst shape and porous microstructure. The computational results showed that the dipole-like field covers the entire surface of the rod-like Ce-doped ZnO photocatalyst and is present over the entire range of wavelengths considered. The optimum degradation conditions were determined by orthogonal tests and range analysis, including the concentration of RhB and catalyst, pH value and temperature. The results indicate that the pH value is the main influential factor in the photocatalytic degradation process and the optimal experimental conditions to achieve the maximum degradation rate of 97.66% in 2 hours are as follows: concentration (RhB) = 10 mg/L, concentration (catalyst) = 0.7 g/L, pH 9.0 and T = 50 °C. These optimum conditions supply a helpful reference for large-scale wastewater degradation containing the common water contaminant RhB.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2518
Author(s):  
Dorota Kołodyńska ◽  
Yongming Ju ◽  
Małgorzata Franus ◽  
Wojciech Franus

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 529
Author(s):  
Hongjuan Zheng ◽  
Kongjun Zhu ◽  
Ayumu Onda ◽  
Kazumichi Yanagisawa

Eu(OH)3 with various shape-controlled morphologies and size, such as plate, rod, tube, prism and nanoparticles was successfully synthesized through simple hydrothermal reactions. The products were characterized by XRD (X-Ray Powder Diffraction), FE-SEM (Field Emission- Scanning Electron Microscopy) and TG (Thermogravimetry). The influence of the initial pH value of the starting solution and reaction temperature on the crystalline phase and morphology of the hydrothermal products was investigated. A possible formation process to control morphologies and size of europium products by changing the hydrothermal temperature and initial pH value of the starting solution was proposed.


2013 ◽  
Vol 743-744 ◽  
pp. 523-530 ◽  
Author(s):  
Jian Cui ◽  
Zhong Min Wang ◽  
Feng Lei Liu ◽  
Pei Bang Dai ◽  
Ran Chen ◽  
...  

Persimmon tannins (PT) were immobilized on a matrix of collagen fiber by cross-linking of glutaraldehyde. The adsorption behaviours to Cr (VI) on PT were investigated including the effects of initial pH, initial concentration of Cr (VI), temperature, adsorbent dosage, adsorption kinetics and the recycling performance of PT adsorbents. The results showed that pH value had a major influence in adsorption. PT showed a strong adsorbability to Cr (VI) in the pH range of 1.0 to 3.0, whereas the effect of temperature on the adsorption was comparatively weaker. The adsorption equilibrium could be well described by Freundlich equation. PT adsorption efficiency of Cr (VI) reached 98.04% and the maximum equilibrium adsorption capacity of Cr (VI) was up to 49.01 mg/g at 303 K with a pH value of 2.0, 100 mg/L of initial concentration of Cr (VI) and 0.1g of adsorbent dosage. The adsorption data could be well fitted by pseudo-second-order rate model. PT adsorbents were characterized by FTIR and EDS. The analysis indicated that the adsorption mechanism was mainly contributed by redox adsorption.


2012 ◽  
Vol 66 (12) ◽  
pp. 2539-2545 ◽  
Author(s):  
Xuening Fei ◽  
Lingyun Cao ◽  
Lifeng Zhou ◽  
Yingchun Gu ◽  
Xiaoyang Wang

Sepiolite, a natural nano-material, was chosen as a carrier to prepare supported nanoscale zero-valent iron (nZVI). The effects of preparation conditions, including mass ratio of nZVI and activated sepiolite and preparation pH value, on properties of the supported nZVI were investigated. The results showed that the optimal mass ratio of nZVI and sepiolite was 1.12:1 and the optimal pH value was 7. The supported nZVI was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS), and furthermore an analogy model of the supported nZVI was set up. Compared with the nZVI itself, the supported nZVI was more stable in air and possessed better water dispersibility, which were beneficial for the degradation of bromamine acid aqueous solution. The degradation characteristics, such as effects of supported nZVI dosage, initial concentration and initial pH value of the solution on the decolorization efficiency were also investigated. The results showed that in an acidic environment the supported nZVI with a dosage of 2 g/L showed high activity in the degradation of bromamine acid with an initial concentration of 1,000 mg/L, and the degree of decolorization could reach up to 98%.


2021 ◽  
Author(s):  
Rong Chen ◽  
Dan Zhao ◽  
Yanmao Dong ◽  
Chengrun Cai ◽  
Yan Yuan ◽  
...  

Abstract manganese doped iron oxychloride (Mn-FeOCl) was synthesized by partial pyrolysis method. The Mn-FeOCl was used as heterogeneous catalyst to activate permonosulfate (PMS) for the degradation of azo dye acid red B(ARB) for the first time. The Mn-FeOCl was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction spectroscopy (XRD). The effects of Mn-FeOCl dosage, PMS concentration, initial pH value, Cl ion concentration and humic acid (HA) dosage on the degradation of ARB by Mn-FeOCl/PMS were investigated. Results showed that the ARB was degraded effectively by Mn-FeOCl/PMS. The mineralization rate of ARB reached 42.5%. As the Mn-FeOCl dosage was 0.1g/L, PMS concentration was 1mmol/L, and ARB concentration was 0.05mmol/L, the degradation rate of ARB reached 99.4% in 30 minutes. With the increase of PMS dosage, Mn-FeOCl dosage, Cl− ion concentration and initial pH value, the decolorization effect of ARB increased. The reaction mechanism was analyzed by free radical quenching experiment and XPS. The main active species were determined as ·OH and SO4·− which generated by PMS activation. The SO4·−−was the main active species.


Author(s):  
Yanjun Liu ◽  
Xiaoqian Zheng ◽  
Shufen Zhang ◽  
Shujuan Sun

Abstract Heterogeneous photo-Fenton like catalysts with low cost, little hazardous, high effective and facile separation from aqueous solution were highly desirable. In this study, sludge-based catalysts combining nano Fe3O4-MnO2 and sludge activated carbon were successfully synthesized by high-temperature calcination method and then characterized. These synthetic materials were applied to remove ibuprofen in the heterogeneous photo-Fenton process. The preparation conditions of sludge-based catalysts optimized by orthogonal experiments were 2.0 M of ZnCl2, a temperature of 500 °C, a pyrolysis time of 60 min, and a sludge ratio: Fe3O4-MnO2 of 25:2. In batch experiments, the optimal experimental conditions were determined as catalyst dosage of 0.4 g·L−1, hydrogen peroxide concentration of 3.0 g·L−1, pH value of 3.3, and contact time of 2.5 h. The degradation rate Sludge/Fe3O4-MnO2 catalyst to ibuprofen is up to 95%. The removal process of ibuprofen fitted the pseudo-second-order kinetic model, and the photocatalytic degradation process was the main factor controlling the reaction rate. The catalytic mechanism was proposed according to the FTIR analysis and mass spectrometry product analysis, it was mainly attributed to the interaction between hydroxyl groups and benzene rings.


2014 ◽  
Vol 675-677 ◽  
pp. 154-157
Author(s):  
Ling Li ◽  
Hua Yan Zhang ◽  
Xiao Wei Li ◽  
Wen Ming Zhang

Chrome doped nanoTiO2transparent hydrosol was synthesized by a complexation-controlled hydrolysis method at room temperature. The absorbance spectrum and phase structure of samples were characterized by UV-Vis spectrophotometer, and X-ray diffraction, respectively. The photocatalytic activity by degradating acid red 3R dye was studied, and the results indicated that when nanoparticle doped with 0.5% Cr, the degradation rate exceeded 96% for 60 min under the sunlight.


2018 ◽  
Vol 150 ◽  
pp. 06035
Author(s):  
Muna Ibrahim ◽  
Essam A. Makky ◽  
Nina S. Azmi ◽  
Jamil Ismail

In this study, the effect of process parameters (incubation period, temperature, initial pH-value, concentration of PAHs in the medium, and bacterial inoculum size) on the biodegradation of PAHs using Mycobacteria confluentis was studied using One-Factor-At-a-Time (OFAT) method. From the results of the study, it was observed that the studied parameters had significant effects on the degradation process. The capability of Mycobacteria confluentis on the degradation of PAHs was found to be maximum when the initial pH of the PAH was 7, temperature 40 °, PAH concentration of 50 μL, bacterial concentration of 7.5 mL, and incubated for 3 to 5 days. This condition gave a PAH degradation percentage of 40 to 50 %, showing a similarity to most previous studies where the maximum percentage of degradation has been around 40 to 50 %. This study, therefore, concludes that Mycobacteria confluentis is a good PAHs degrader which can be of significant important in the management of oil polluted fields and environments.


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