Study on Preparation of Modified Nano-TiO2 and its Application in Photocatalytic Treatment Wastewater Containing Cd2+

2011 ◽  
Vol 347-353 ◽  
pp. 733-737 ◽  
Author(s):  
Xiao Cai Yu ◽  
Peng Fei Zhu ◽  
Yue Xia Chen ◽  
Jun Wang ◽  
Zong Fu An

Nano-Sn0.25Ti0.75O2 was prepared with hydrothermal method using tetrabutyl titanate as one of the primary raw materials. The products were characterized by XRD and SEM, which revealed that the crystal structure of Sn4+-doped nano-TiO2 is rutile, and the nanoparticles diameter was 14.49nm. Photocatalytic treatment the machining wastewater containing cadmium ions with the UV excitation by Nano-Sn0.25Ti0.75O2 was investigated. The experimental results show that Nano-Sn0.25Ti0.75O2 can be used as photocatalyst to removal Cd2+ from the wastewater effectively with the UV excitation. The wastewater pH value, the initial concentration of Cd2+, the amount of catalyst,the reaction time and other factors affect the efficiency of photocatalytic treatment significantly. The optimization experimental conditions for photocatalytic treatment wastewater containing cadmium ions are as follows, when the concentration of Cd2+ in the wastewater is 20mg/L, amount of Sn0.25Ti0.75O2 is 2g/L, pH in wastewater is 7 and the photocatalytic reaction time is 2h, the removal rate of Cd2+ from the wastewater is up to 98.4%.

2012 ◽  
Vol 518-523 ◽  
pp. 121-124
Author(s):  
Hong Xia Xia ◽  
Qi Hong Zhu

This paper investigates the effect of Limonite/TiO2 combined microspheres dosage,solution pH, reaction time,light intensity on the removal rate of phenol in source water.Based on the single factor experiment, the experimental conditions are optimized by quadratic regression orthogonal rotation combination design.The quadratic orthogonal regression model of removal rate of phenol(y) to four factors of Limonite/TiO2 combined microspheres dosage(x1),pH(x2),reaction time (x3)and light intensity (x4) is established as Y=88.64+4.43X1+ 6.69X3+3.75X4-4.79X12-13.20X22-4.21X32-2.69X42+8.06X1X2-6.76X1X3-4.45X1X4.It can conclude from the model that when Limonite/TiO2 combined microspheres dosage is 1.5583g,solution pH value is 4.5095,reaction time is 102.12min,light intensity is 1710.8(x10 lux),the yield(y) reaches the maximal(95.83%) and consistent with the confirmatory experiment result..


2011 ◽  
Vol 694 ◽  
pp. 298-303 ◽  
Author(s):  
Mo Jie Sun ◽  
Peng Wang ◽  
Yu Han Shan ◽  
Chun Biao Zhang

In this paper, we made the nano-TiO2/glass composite electrode through the sol-gel method by using tetrabutyl titanate and anhydrous alcohol as the raw materials and the ITO conductive glass as the carrier. With the help of the photoelectric catalytic effect of TiO2 and the strong oxidation of Na2S2O8 as well as the computer application technology, we decomposed rapidly of the organophosphorous compounds and detected the total phosphorous (TP) on-line accurately. And then we characterized the TiO2 particles by SEM and analyzed the factors which influenced the decomposition and detection of TP by this method. The results show that the optimum experimental conditions of this method should be as follow: the concentration of Na2S2O8 is 0.03mol/L, UV illuminating time is 10 min, electrode voltage is 8V and the pH value should be in the alkaline zone. At last, it is validated the method is reliable and accurate for the decomposition of the organophosphorous by the recovery experiments and the comparative experiments between this method and national standard method.


2012 ◽  
Vol 476-478 ◽  
pp. 2001-2004
Author(s):  
Xiao Cai Yu ◽  
Peng Fei Zhu ◽  
Kui Sheng Song ◽  
Dong Dong Hu ◽  
Qian Du

The Fe3+-doped nano-TiO2 catalyst with various amounts of dopant Fe3+ irons was prepared by a sol-gel method. The products were characterized by XRD and SEM. The photocatalytic degradation of ammonia nitrogen in aquaculture wastewater was investigated by using Fe3+-doped nano-TiO2 under UV irradiation. In the experiment, the effect of Fe3+/TiO2 dosage, the ratio of dopant Fe3+, ammonia-N initial concentration, pH value, H2O2 volume concentration, and reaction time, respectively, on the removal of ammonia-N was investigated. The experimental results can be stated as follows: when the ratio of dopant Fe3+ was 0.25% wt, the dosage of Fe3+/TiO2 was 0.7 g/L, the initial concentration of ammonia-N was 10 mg/L, H2O2 volume fraction was 4 %, respectively, if the reaction time may last 4 h, the removal rate of ammonia-N was expected to reach 97.17 %.


2011 ◽  
Vol 197-198 ◽  
pp. 774-779
Author(s):  
Peng Fei Zhu ◽  
Xiao Cai Yu ◽  
Qian Du ◽  
Kui Sheng Song ◽  
Zhong Hua He

The nano-TiO2photocatalyst was prepared via sol-gel method, and the crystal structure and surface morphology were characterized by XRD and SEM. The photocatalytic degradation of ammonia-N in aquaculture wastewater was investigated by using nano-TiO2under UV irradiation. In the experiment, the effect of nano-TiO2dosage, ammonia-N initial concentration, pH value, H2O2volume concentration, and reaction time, respectively, on the removal of ammonia-N was investigated. On the basis of the results of these experimental data, an orthogonal array experimental design was used to select more efficient degradation condition. The optimal experimental conditions for photocatalytic degradation of ammonia-N can be stated as follows: when the concentration of ammonia-N was 20 mg/L, nano-TiO2catalyst dosage was 1.2 g/L, the pH value of solution was 5, H2O2volume fraction was 4 %, respectively, if the reaction time may last 3 h, the removal rate of ammonia-N was expected to reach 92.10 %.


2011 ◽  
Vol 347-353 ◽  
pp. 2351-2355 ◽  
Author(s):  
Xiao Cai Yu ◽  
Peng Fei Zhu ◽  
Min Zhang ◽  
Ji Yao Guo ◽  
Xv Zheng

The Sn4+-doped nano-TiO2 particles with various amounts of dopant Sn4+ irons was prepared by sol-gel method using tetrabutyl titanate(TEOT) as one of the primary raw materials at different calcination temperatures (400-700°C). The products were characterized by XRD and SEM, which revealed that the crystal structure of Sn4+-doped nano-TiO2 changes from anatase to rutile with the calcination temperature increasing, and the nanoparticles diameter was around 10-30 nm. The photocatalytic degradation of ammonia nitrogen in aquaculture wastewater was investigated by using Sn4+-doped nano-TiO2 under UV irradiation. The experimental results can be stated as follows: when the ratio of dopant Sn4+ was 3% wt, the calcination temperature of Sn4+-doped nano-TiO2 was 500 °C, the dosage of Sn4+-doped nano-TiO2 was 0.8 g/L, respectively, if the reaction time may last 4h, the removal rate of ammonia-N was expected to reach 87.13%.


2012 ◽  
Vol 610-613 ◽  
pp. 564-568 ◽  
Author(s):  
Kui Sheng Song ◽  
Xiao Cai Yu ◽  
Dong Dong Hu ◽  
Xu Zheng ◽  
Ji Yao Guo

Nano-ZnO photocatalyst was prepared using direct precipitation method .The crystal form, particle size and configuration characterization of the nano-ZnO prepared was characterized by XRD and SEM. The photocatalytic degradation of ammonia-N in aquaculture wastewater was investigated by using nano-ZnO under UV irradiation. The experimental results show that: nano-ZnO dosage, catalytic reaction time, initial ammonia-N concentration, H2O2volume concentration, pH value affect the efficiency of photocatalytic degradation significantly. On the basis of the results of these experimental data, the optimal experimental conditions for photocatalytic degradation of ammonia-N are tried through the orthogonal test. The optimization experimental conditions for photocatalytic degradation of ammonia-N in aquaculture wastewater are as follows, nano-ZnO catalyst dosage was 0.4 g/L, the pH value of solution was 10, H2O2volume fraction was 4 %, respectively, if the reaction time may last 1 h, the removal rate of ammonia-N was expected to reach 86.66 %.


2011 ◽  
Vol 197-198 ◽  
pp. 780-785 ◽  
Author(s):  
Xiao Cai Yu ◽  
Qian Du ◽  
Peng Fei Zhu ◽  
Dong Dong Hu ◽  
Li Yang

TiO2 can be used as a photocatalyst because of its semiconductor property. When TiO2 is doped with transition metal ions, its electronic properties may be modified. In this work, nanosized Sn4+-doped TiO2 (TiO2-Sn4+) particles have been synthesized by a sol-gel process at different temperature. Their microstructure and crystal structure depending on the calcination temperatures were investigated using XRD and SEM techniques. The photocatalytic degradation of diesel pollutants in seawater was investigated by using Sn4+-doped nanometer TiO2 under UV irradiation. In the experiment, the effect of different ratio of Sn4+ doped into TiO2, the effect of calcination temperature of Sn-doped nano-TiO2, the effect of Sn4+-doped nanometer TiO2 dosage, pH value and photocatalytic degradation reaction time, respectively, on the removal of diesel pollutants in seawater was investigated. On the basis of the results of these experimental data, the optimal experimental conditions for photocatalytic degradation of diesel are tried through the orthogonal test. The results reveal that when the ratio of Sn4+ doped into TiO2 was 3% wt, the calcination temperature of Sn-doped nano-TiO2 was 400°C, the Sn4+-doped nanometer TiO2 dosage was 1 g/L, pH value was 8 and photocatalytic degradation reaction time was 1.5h, respectively, the removal rate of diesel pollutants in seawater was expected to reach 88.00 %.


Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 359
Author(s):  
Liping Zhang ◽  
Shengnian Wu ◽  
Nan Zhang ◽  
Ruihan Yao ◽  
Eryong Wu

Salicylic hydroxamic acid is a novel flotation reagent used in mineral processing. However, it impacts the flotation wastewater leaving behind high chromaticity which limits its reuse and affects discharge for mining enterprises. This study researched ozonation catalyzed by the granular activated carbon (GAC) method to treat the chromaticity of the simulated mineral processing wastewater with salicylic hydroxamic acid. The effects of pH value, ozone (O3) concentration, GAC dosage, and reaction time on chromaticity and chemical oxygen demand (CODCr) removal were discussed. The results of individual ozonation experiments showed that the chromaticity removal ratio reached 79% and the effluent chromaticity exceeded the requirement of reuse and discharge when the optimal experimental conditions were pH value 3, ozone concentration 6 mg/L, and reaction time 40 min. The orthogonal experimental results of catalytic ozonation with GAC on chromaticity removal explained that the chromaticity removal ratio could reach 96.36% and the chromaticity of effluent was only 20 when the optimal level of experimental parameters was pH value 2.87, O3 concentration 6 mg/L, GAC dosage 0.06 g/L, reaction time 60 min respectively. The degradation pathway of salicylic hydroxamic acid by ozonation was also considered based on an analysis with ultraviolet absorption spectrum and high-performance liquid chromatography (HPLC).


1997 ◽  
Vol 36 (2-3) ◽  
pp. 263-270 ◽  
Author(s):  
Cheng-Nan Chang ◽  
Jih-Gaw Lin ◽  
Allen C. Chao ◽  
Bo-Chuan Cho ◽  
Ruey-Fang Yu

Acrylonitrile and styrene are used as the raw materials for manufacturing acrylic fiber, thus they are often found as pollutants in the petrochemical wastewater. This study utilizes ozone to decompose the organic nitrogen contained in acrylonitrile and styrene, and the oxidation process was monitored using on-line measurements of oxidation-reduction potential (ORP) and pH. The efficiency of organic nitrogen decomposition was also estimated based on the COD, organic nitrogen, TOC, ammonia-N, nitrite, and nitrate measurements. Both the initial pH and alkalinity are observed to affect the degradation rate of organic nitrogen. The acrylonitrile sample with the lowest initial pH value (i.e., 4.0) has a shorter t1/2 of 18.9 min and that for samples of the highest initial pH (i.e., 11) was 34 min. The alkalinity of one acrylonitrile sample was boosted by adding 500 mg/l CaCO3, to simulate the field ABS (Acrylonitrile-Butadiene-Styrene) wastewater effluent. It was observed that within a short ozone contact time, the acrylonitrile sample spiked with 500 mg/l CaCO3 had the highest COD decomposition rate of 0.411 min−1, or 1.3 times more than that for samples without addition of CaCO3. Results of the ozonation process can be fitted with a modified Nernst equation for the various pH conditions. Additionally, the ozone treated synthetic ABS sample shows a faster COD removal rate in the subsequent biological process than those samples without ozone treatment.


2014 ◽  
Vol 609-610 ◽  
pp. 311-316
Author(s):  
Xiao Cai Yu ◽  
Dong Dong Hu ◽  
Jin Fang Chen ◽  
Xiao Jie Jin ◽  
Xu Zheng

ZnO and Ag-droped ZnO photocatalysts with different Ag loadings (0.5, 1.0, 1.5, 2.0at%) and different calcination temperature (300, 400, 500, 600, 700°C) were synthesized by a sonochemical method. The morphology and crystal pattern of some prepared catalysts were characterized by XRD and SEM techniques which demonstrated that the prepared catalysts were of hexagonal wurtzite structure. Ag loadings, calcination temperature and other factors, dosage of photocatalyst, reaction time and pH value of seawater, were also taken into consideration in the procedure of photocatalytic degradation reaction under UV light. An orthogonal experiment was carried out to investigate the best combination of factors which can reach the best diesel pollution removal rate and the influence order of factors. Reaction time and dosage of catalyst were the most influential factors in this experiment, and the factor of calcination temperature was the weakest influential factor. The removal rate of diesel can up to 78% when the experiment was undertaken under the very conditions: the dosage of catalyst 2.0g/L, reaction time 2.0h, Ag loading of catalyst 1.0 at%, calcinations temperature 400°C and pH value 8.5.


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