The Photocatalytic Degradation of Methylene Blue Wastewater with Nanoscale Ferric Oxide as Catalyst

2011 ◽  
Vol 356-360 ◽  
pp. 1813-1818
Author(s):  
Yi Ren Zhu ◽  
Guang Chao Li ◽  
Qian Ping Zhang ◽  
Chong Tang

Nanoscale Ferric Oxide was prepared from natural hematite and characterized. Using it as catalyst, methylene blue-simulated wastewater was treated by photocatalytic degradation with high-voltage mercury lamp and sunlight as excitation light source. Main factors, including the preparation conditions and dosage of ferric oxide, pH value, reaction time and initial concentration of simulated wastewater, and their influence to treatment effect were discussed. Test results showed that at a pulverization time of 1.5h, calcination time of 2h at 500°C, initial methylene blue (MB) concentration of 20mg/L, pH=2 and a ferric oxide dosage of 0.01g/30ml, for both high-voltage mercury lamp and sunlight, MB wastewater was degraded effectively in lab-scale experiment; after 5h’s radiation, MB concentrations were reduced from 20mg/L to 0.51mg/L and 9.18mg/L respectively. With sunlight as the radiation light source, an enlarged experiment was done on a custom-built device, and MB concentration was reduced from 20mg/L to 0.11mg/L, which was significantly better than treatment results from lab-scale experiments and UV radiation. MB photocatatytic degradation reactions at different initial concentrations were in accordance with Lagergren’s pseudo-first-order kinetic equation. Spectral analysis of degradation products showed that MB molecules were degraded to inorganic ions.

2011 ◽  
Vol 1 (1) ◽  
pp. 45-51 ◽  
Author(s):  
L. V. Jian-xiao ◽  
Cui Ying ◽  
Xie Guo-hong ◽  
Zhou Ling-yun ◽  
Wang Su-fen

Methylene blue simulated wastewater was treated with a UV-H2O2 combined system. Influences of factors such as reaction time, initial pH value and H2O2 dosage were investigated, and the reaction kinetics of the process was explored. Results showed that the degradation of methylene blue happened only in the presence of both conditions: UV irradiation and H2O2 addition. Initial pH and H2O2 dosage had a remarkable influence on the degradation efficiency. Through several groups of univariate experiments, the optimum pH and H2O2 dosage of the photolysis process were found to be 4–5 and 0.165 mL 30% H2O2 per milligram of methylene blue, respectively. The photolysis process was relatively fast at the initial stage and, 20 min later, it was approximately in accordance with the first-order kinetic equation.


Author(s):  
Irem Firtina Ertis ◽  
Ismail Boz

Abstract Sb-CdS catalysts with good crystalline structure were prepared by chemical precipitation and hydrothermal method. The results showed that hydrothermal treatment is an effective method to prepare CdS based catalysts of hexagonal structure. Single Sb2S3 catalyst has spherical and Sb doped CdS catalysts have hexagonal structure. Sb doped CdS which is prepared by Na2S with chemical precipitation, has cubic structure. The band gap energies of Sb doped CdS photocatalysts were estimated using UV-visible reflectance spectra to be about the range of 2.35–2.57 eV. In particular, the photoluminescence (PL) spectra show enhancing emission peaks that strongly decrease with a doping Sb where the catalyst was prepared with ethylenediamine (EDA) and thioacetamide (TAA), has shown the lowest luminescence intensity. Photocatalytic degradation of methylene blue was carried out using Sb doped and Sb2S3-CdS binary catalysts under a 400 W medium-pressure mercury lamp of visible light irradiation (λ>420 nm). Higher photocatalytic degradation was achieved by adding Sb to CdS catalyst with using hydrothermal method and EDA as coordinating agent compare with the other catalysts. In this case the photocatalytic degradation of the Sb-CdS-EDA-TAA photocatalyst after 4 h irradiation time was about 84 %.


2017 ◽  
Vol 863 ◽  
pp. 20-25 ◽  
Author(s):  
Jing Li Gao ◽  
Ying Hui Han ◽  
Yu Juan Li ◽  
Xiao Hong Zhang

Photocatalytic degradation kinetics of methylene blue in aqueous solution was systematically investigated using Ti-based composite material as the photocatalyst. The single-variable-at-a-time ( SVAT) method was employed. It studied the individual and synergistic effects of several classical parameters on photocatalytic efficiencies. The kinetic mechanism was systematically explored. The kinetics effects of the doping amount of La and N, calcination temperature and time, light intensity were studied in detail. The factors on the degradation of MB were in accordance with the pseudo first order kinetic model. This kinetic model followed the Langmuir–Hinshelwood model. The best preparation conditions were found in the experiments. It is proved that the Ti-based composite material is an effective adsorbent for the degradation of dye contaminated water.


2010 ◽  
Vol 25 (1) ◽  
pp. 134-140 ◽  
Author(s):  
Yen-Pei Fu ◽  
Wen-Ku Chang ◽  
Hsin-Chao Wang ◽  
Chung-Wen Liu ◽  
Cheng-Hsiung Lin

In the current research, we successfully prepared TiO2/Ni–Cu–Zn ferrite composite powder for magnetic photocatalyst. The core Ni–Cu–Zn ferrite powder was synthesized using the steel pickling liquor and the waste solution of electroplating as the starting materials. The shell TiO2 nanocrystal was prepared by sol-gel hydrolysis precipitation of titanium isopropoxide [Ti(OC3H7)4] on the Ni–Cu–Zn ferrite powder followed by heat treatment. From transmission electron microscopy (TEM) image, the thickness of the titania shell was found to be approximately 5 nm. The core of Ni–Cu–Zn ferrite is spherical or elliptical shape, and the particle size of the core is in the range of 70–110 nm. The magnetic Ni–Cu–Zn ferrite nanopowder is uniformly encapsulated in a titania layer forming core-shell structure of TiO2/Ni–Cu–Zn ferrite powder. The degradation efficiency for methylene blue (MB) increases with magnetic photocatalyst (TiO2/Ni–Cu–Zn ferrite powder) content. When the magnetic photocatalyst content is 0.40 g in 150 mL of MB, the photocatalytic activity reached the largest value. With a further increase in the content of magnetic photocatalyst, the degradation efficiency slightly decreased. This occurs because the ultraviolet (UV) illumination is covered by catalysts, which were suspended in the methylene blue solution and resulted in the inhibition in the photocatalytic reaction. The photocatalytic degradation result for the relationship between MB concentration and illumination revealed a pseudo first-order kinetic model of the degradation with the limiting rate constant of 1.717 mg/L·min and equilibrium adsorption constant 0.0627 L/mg. Furthermore, the Langmuir–Hinshelwood model can be used to describe the degradation reaction, which suggests that the rate-determining step is surface reaction rather than adsorption is in photocatalytic degradation.


2012 ◽  
Vol 430-432 ◽  
pp. 1040-1043
Author(s):  
Jiang Liu ◽  
Zheng Xian Ma ◽  
Shuai Liang

Experiment of photocatalytic degradation was conducted through using tetra-n-butyl titanate and ethyl alcohol as raw material, adopting sol-gol method to prepare photocatalyst of nano-TiO2 and using methylene blue solution as analogue dye wastewater. The influences of hydrolyzing temperature, PH value, different water addition, and different speed of adding drops were investigated, as well as the reuse rate of photocatalyst.


Author(s):  
Doan Van Dat ◽  
Nguyen Hoai Thuong ◽  
Tran Thi Kieu Ngan ◽  
Le Thi Thanh Nhi ◽  
Dao My Uyen ◽  
...  

In this study, magnetic carboxylate-rich carbon material (Fe3O4@CRC) was synthesized via a low-temperature carbonization method and applied as an adsorbent for adsorption of Ni(II) ions and methylene blue (MB) in aqueous solution. The synthesized Fe3O4@CRC was characterized by various techniques (XRD, FTIR, FE-SEM, TEM, EDX, VSM, and BET). The adsorption kinetics, isotherms, thermodynamics, and the effects of key adsorption factors, including the pH value, initial adsorbate concentration, contact time, adsorbent dose and temperature were investigated in detail. The results showed that Fe3O4@CRC exhibited a high adsorption capacity for MB and Ni(II) with the maximum adsorption capacity of 187.26 mg/g and 106.75 mg/g, respectively. The adsorption of MB and Ni(II) on Fe3O4@CRC was a spontaneous and endothermic process, and was best described with the first-order kinetic model, Freundlich (for MB) and Langmuir (for Ni(II)) isotherm models. In addition, Fe3O4@CRC could maintain a high adsorption capacity after many consecutive cycles. Therefore, the Fe3O4@CRC material can be used as a highly efficient adsorbent for the removal of heavy metals and dyes from wastewater due to the advantages of high adsorption performance, easy separation, and good reusability.  


Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1293 ◽  
Author(s):  
Xuejuan Shi ◽  
Xiaoxiao Zhang ◽  
Liang Ma ◽  
Chunhui Xiang ◽  
Lili Li

Chitosan/cellulose acetate (CS/CA) used as a biopolymer systema, with the addition of TiO2 as photocatalyst (C-T/CA) were fabricated by alternating electrospinning/electrospraying technology. The uniform dispersion of TiO2 and its recovery after the removal of methyl orange (MO) was achieved by incorporating TiO2 in CS electrosprayed hemispheres. The effects of pH values, contact time, and the amount of TiO2 on adsorption and photocatalytic degradation for MO of the C-T/CA were investigated in detail. When TiO2 content was 3 wt %, the highest MO removal amount for fiber membranes (C-T-3/CA) reached 98% at pH value 4 and MO concentration of 40 mg/L. According to the data analysis, the pseudo-second-order kinetic and Freundlich isotherm model were well fitted to kinetic and equilibrium data of MO removal. Especially for C-T-3/CA, the fiber membrane exhibited multiple layers of adsorption. All these results indicated that adsorption caused by electrostatic interaction and photocatalytic degradation were involved in the MO removal process. This work provides a potential method for developing a novel photocatalyst with excellent catalytic activity, adsorbing capability and recycling use.


2011 ◽  
Vol 80-81 ◽  
pp. 55-59
Author(s):  
Xu Dong Lu ◽  
Cheng Zhi Jiang ◽  
Xiao Hui Zhu

The 0.05%Gd3+ /0.4%Eu3+ co-doped TiO2 composite nanopowders have been prepared by sol-gel method and characterized by the techniques such as XRD, SEM/EDAX. The photocatalytic degradation of Methylene blue in aqueous solution was used as a probe reaction to evaluate their photocatalytic activity. The results show that the 0.05%Gd3+ /0.4%Eu3+ co-doped TiO2 are only structuresd by anatase phase with grain sizes of about 16nm at 540 °C for 4 h. The photocatalutic degradation of Methylene blue was 96.7% in 120 min of irradiation when the pH value was 9.


Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 49
Author(s):  
Maha S. Elsayed ◽  
Inas A. Ahmed ◽  
Dina M. D. Bader ◽  
Asaad F. Hassan

In this study, zinc oxide nanoparticles (ZnO) and nanohydroxyapatite (NHAP) were prepared in the presence of date palm pits extract (DPPE) and eggshells, respectively. Another four nanocomposites were prepared from ZnO and NHAP in different ratios (ZP13, ZP14, ZP15, and ZP16). DPPE and all nanomaterials were characterized using GC-MS, zeta potentials, particle size distributions, XRD, TEM, EDX, FTIR, and pHPZC. The characterization techniques confirmed the good distribution of ZnO nanoparticles on the surface of NHAP in the prepared composites. Particles were found to be in the size range of 42.3–66.1 nm. The DPPE analysis confirmed the presence of various natural chemical compounds which act as capping agents for nanoparticles. All the prepared samples were applied in the adsorption and photocatalytic degradation of methylene blue under different conditions. ZP14 exhibited the maximum adsorption capacity (596.1 mg/g) at pH 8, with 1.8 g/L as the adsorbent dosage, after 24 h of shaking time, and the static adsorption kinetic process followed a PSO kinetic model. The photocatalytic activity of ZP14 reached 91% after 100 min of illumination at a lower MB concentration (20 mg/L), at pH 8, using 1.5 g/L as the photocatalyst dosage, at 25 °C. The photocatalytic degradation of MB obeyed the Langmuir–Hinshelwood first-order kinetic model, and the photocatalyst reusability exhibited a slight loss in activity (~4%) after five cycles of application.


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