Removal of U(VI) from Leaching Process Wastewater by Zero-Valent Iron

2014 ◽  
Vol 539 ◽  
pp. 815-818
Author(s):  
Hua Zeng ◽  
Wei Ming Zhang ◽  
Yi Ran Li ◽  
Yuan Yuan Liu
Keyword(s):  
Iron Powder ◽  
Ph Value ◽  
Removal Rate ◽  
Zero Valent Iron ◽  
Removal Mechanism ◽  
Leaching Process ◽  
Process Wastewater ◽  
Better Than

The removing effectiveness of U(VI) in leaching process wastewater by Zero-valent iron (ZVI)(iron powder and waste scrap) has been studied. The effects of the dosage of ZVI, pH, shaking time and temperature on treatment effiency are investigated. The results showed that: ZVI has very good removal effect on U (VI), and when pH value of solution is 6, the dosage of ZVI is 1.5 g, the shaking time is 80 min, the removal rate reached 98.6%.The removing efficiency of iron powder is sightly better than waster scrap.Acorrding to the experiment, the optimum experiment conditions and the influence of these parameters are obtained. The removal mechanism of U(VI) in leaching process wastewater by ZVI is discussed.

Removal of Nonylphenol from Water by Ozone

2013 ◽  
Vol 859 ◽  
pp. 357-360 ◽  
Author(s):  
Xiao Dong Wang ◽  
Yang Lv ◽  
Meng Meng Li ◽  
Hong Ye Liu
Keyword(s):  
Reaction Time ◽  
Ozone Concentration ◽  
Degradation Rate ◽  
Ph Value ◽  
Removal Rate ◽  
Affecting Factors ◽  
Initial Concentration ◽  
Lower Temperature ◽  
Better Than

This study investigates the degradation of Nonylphenol. The degradation affecting factors including solution ozone dosage, initial concentration, pH, temperature and ultraviolet. The results indicated that when the ozone contents changes, the Nonylphenols degradation rate changes as well. The higher ozone concentration contribute to the faster degradation; With the increase of initial concentration of Nonylphenol, the removal rate of it decrease on the contrary, while with the initial concentration increases, the quality of unit ozone degradation of Nonylphenol is ascenting and then tend to a constant; The remove rate of Nonylphenol is improving when the pH value vary from 4.86~10.34. The effect of Nonylphenols ozonation in higher temperatures is better than it is in lower temperature; Ultraviolet radiation is also favorable for the removal of Nonylphenol as it can shorten the reaction time as well as reduce the amount of ozone.

scholarly journals Study of PFS and PAC coagulation effect on Pi River water

2021 ◽  
Vol 272 ◽  
pp. 01012
Author(s):  
Wan-Fen Wang
Keyword(s):  
Water Sample ◽  
River Water ◽  
Removal Efficiency ◽  
Aluminum Chloride ◽  
Ph Value ◽  
Removal Rate ◽  
Raw Water ◽  
Mass Ratio ◽  
Enhanced Coagulation ◽  
Better Than

Using poly-aluminum chloride (PAC) and poly-ferric sulfate (PFS) as coagulants, the effects of the dosage of PAC and PFS on the removal of turbidity, chromaticity and UV254* in water were investigated by using the method of enhanced coagulation. The results show that when the raw water is neutral and the turbidity is less than 20NTU, and the pH value does not decrease much after coagulation and sedimentation, PAC and PFS are separately added to 7.5mg/l, 35mg/l. The removal rate of turbidity and chromaticity in the water sample can reach 83.75% and 48.47%, respectively, but the removal rate of UV254* is less than 30%, the mass ratio of PAC to PFS is 1:1 to 6:1, the removal efficiency of turbidity and Chroma increased by about 10%, but the removal efficiency of UV254* did not change or even decreased, both PFS and PAC can effectively remove the turbidity and Chroma in the micro polluted Pi River, but the removal effect of UV254* is not good, and the removal effect of PAC is better than PFS.

Application of Polysilicate Ferric Flocculant in Treatment of Tanning Wastewater

2010 ◽  
Vol 113-116 ◽  
pp. 96-99 ◽  
Author(s):  
Zhi Hui Sui ◽  
Xin Zhao ◽  
Xu Mei Song
Keyword(s):  
Ph Value ◽  
Raw Materials ◽  
Removal Rate ◽  
Amorphous Polymer ◽  
Infrared Spectrometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Type ◽  
Polymer Flocculant ◽  
Better Than

A new type of inorganic polymer flocculant polysilicate ferric(PSF) was prepared by using pyrite slag as raw materials and used as flocculant in the treatment of tanning wastewater. The infrared spectrometry and X-ray diffraction had been adopted to characterize the product structure. The infrared spectrometry research indicates that Fe-O, Si-O-Fe and other groups exist in the PSF, which implies that chemical bonding reaction takes place between Fe and silicon in the PSF. X-ray diffraction analysis indicates that PSF is the amorphous polymer created upon mutual reaction between Fe3+ and PSi. The application experiment results show that the removal rate of S2-, SS, CODCr, Cr3+, and colority is 92.7%, 90.5%, 82.5％, 80.2% and 90.1% respectively in the condition where temperature is normal, pH value is 7.5 and dosage of the coagulant is 80mg/L. The flocculation effects of PSF in the treatment of tanning wastewater are much better than those of PAC and PFS.

Effects of physicochemical factors on Cr(VI) removal from leachate by zero-valent iron and α-Fe2O3 nanoparticles

2010 ◽  
Vol 61 (11) ◽  
pp. 2759-2767 ◽  
Author(s):  
T. Y. Liu ◽  
L. Zhao ◽  
X. Tan ◽  
S. J. Liu ◽  
J. J. Li ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
Ph Value ◽  
Removal Rate ◽  
Substantial Reduction ◽  
Chromium Concentration ◽  
Zero Valent Iron ◽  
Fe2o3 Nanoparticles ◽  
Pseudo First Order Reaction ◽  
Physicochemical Factors ◽  
Raw Wastewater

The effects of nanoparticle dosage, initial hexavalent chromium concentration, pH value, reaction temperature, and initial concentration of humic acid (HA) on chromate (CrO42−) removal from landfill leachate by nanoscale zero-valent iron (NZVI) and hematite (α-Fe2O3) nanoparticles were examined in the present investigations. The Cr(VI) removal rate decreased as the initial Cr(VI) concentration and the reaction temperature increased, whereas corresponding removal rate by NZVI was higher than that of α-Fe2O3. The optimum pH for the removal of Cr(VI) by NZVI was found to be 5.0 and more than 99.0% of Cr(VI) was removed within 5 h. However, the removal rate by α-Fe2O3 decreased as pH increased. Presence of HA resulted in substantial reduction in the rate and extent of Cr(VI) removal by NZVI, whereas Cr(VI) removal rate by α-Fe2O3 did not significantly decrease as HA concentration increased from 0.5 g/L to 3.0 g/L. Increasing the dosage of nanoparticles enhanced the rate constant and the removal of Cr(VI) by NZVI and α-Fe2O3 followed pseudo-first-order reaction kinetics. The information should be very useful for the successful application of NZVI and α-Fe2O3 for the treatment of groundwater or raw wastewater.

Removal of Bisphenol A from Water by Ozone

2013 ◽  
Vol 864-867 ◽  
pp. 155-160 ◽  
Author(s):  
Xiao Dong Wang ◽  
Yang Lv ◽  
Hong Ye Liu ◽  
Meng Meng Li
Keyword(s):  
Reaction Time ◽  
Bisphenol A ◽  
Degradation Rate ◽  
Ph Value ◽  
Removal Rate ◽  
Affecting Factors ◽  
Initial Concentration ◽  
Lower Temperature ◽  
Better Than

This study investigates the degradation of bisphenol A (BPA). The degradation affecting factors including solution ozone dosage, initial concentration, pH, temperature and ultraviolet. The results indicated that when the ozone contents changes, the BPAs degradation rate changes as well. The higher ozone concentration contribute to the faster degradation; With the increase of initial concentration of BPA, the removal rate of it decrease on the contrary, while with the initial concentration increases, the quality of unit ozone degradation of BPA is ascenting and then tend to a constant; The remove rate of BPA is improving when the pH value vary from 4.86~10.34. The effect of BPAs ozonation in higher temperatures is better than it is in lower temperature; Ultraviolet radiation is also favorable for the removal of BPA as it can shorten the reaction time as well as reduce the amount of ozone.

scholarly journals Image smoothing based on global sparsity decomposition and a variable parameter

2021 ◽  
Author(s):  
Xiang Ma ◽  
Xuemei Li ◽  
Yuanfeng Zhou ◽  
Caiming Zhang
Keyword(s):  
Removal Rate ◽  
Variable Parameter ◽  
Smoothing Parameter ◽  
Smoothing Effect ◽  
Image Smoothing ◽  
Sparse Decomposition ◽  
Alternating Direction ◽  
Texture Removal ◽  
Ideal Algorithm ◽  
Better Than

AbstractSmoothing images, especially with rich texture, is an important problem in computer vision. Obtaining an ideal result is difficult due to complexity, irregularity, and anisotropicity of the texture. Besides, some properties are shared by the texture and the structure in an image. It is a hard compromise to retain structure and simultaneously remove texture. To create an ideal algorithm for image smoothing, we face three problems. For images with rich textures, the smoothing effect should be enhanced. We should overcome inconsistency of smoothing results in different parts of the image. It is necessary to create a method to evaluate the smoothing effect. We apply texture pre-removal based on global sparse decomposition with a variable smoothing parameter to solve the first two problems. A parametric surface constructed by an improved Bessel method is used to determine the smoothing parameter. Three evaluation measures: edge integrity rate, texture removal rate, and gradient value distribution are proposed to cope with the third problem. We use the alternating direction method of multipliers to complete the whole algorithm and obtain the results. Experiments show that our algorithm is better than existing algorithms both visually and quantitatively. We also demonstrate our method’s ability in other applications such as clip-art compression artifact removal and content-aware image manipulation.

scholarly journals Lignocellulose@ Activated Clay Nanocomposite with Hierarchical Nanostructure Enhancing the Removal of Aqueous Zn(II)

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1710 ◽  
Author(s):  
Xiaotao Zhang ◽  
Yinan Hao ◽  
Zhangjing Chen ◽  
Yuhong An ◽  
Wanqi Zhang ◽  
...  
Keyword(s):  
Ph Value ◽  
Removal Rate ◽  
Weight Ratio ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Hierarchical Nanostructure ◽  
Desorption Temperature ◽  
Desorption Time ◽  
Adsorption Temperature ◽  
Hcl Concentration

A lignocellulose@ activated clay (Ln@AC) nanocomposite with a hierarchical nanostructure was successfully synthesized by the chemical intercalation reaction and applied in the removal of Zn(II) from an aqueous solution. Ln@AC was characterized by N2 adsorption/desorption isotherms and X-Ray Diffraction (XRD), scanning Electron Microscope (SEM), transmission Electron Microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis, and the results indicate that an intercalated–exfoliated hierarchical nanostructure was formed. The effects of different adsorption parameters on the Zn(II) removal rate (weight ratio of Ln to AC, Ln@AC dosage, initial Zn(II) concentration, pH value, adsorption temperature, and time) were investigated in detail. The equilibrium adsorption capacity reached 315.9 mg/g under optimal conditions (i.e., the weight ratio of Ln to AC of 3:1, Ln@AC dosage of 1 g/L, initial Zn(II) concentration of 600 mg/L, pH value of 6.8, adsorption temperature of 65 °C, and adsorption time of 50 min). The adsorption process was described by the pseudo-second-order kinetic model, Langmuir isotherm model, and the Elovich model. Moreover, Zn(II) could be easily eluted by HCl, and the effects of HCl concentration, desorption temperature, and ultrasonic desorption time on desorbed amount were tested. Desorption studies revealed that with an HCl concentration of 0.25 mol/L, desorption temperature of 70 °C, and ultrasonic desorption time of 20 min, the maximum desorption capacity and efficiency were achieved at 202.5 mg/g and 64.10%, respectively. Regeneration experimental results indicated that the Ln@AC exhibited a certain recyclable regeneration performance. Due to such outstanding features, the novel Ln@AC nanocomposite proved to have great adsorption potential for Zn(II) removal from wastewater, and exhibited an extremely significant amount of adsorbed Zn(II) when compared to conventional adsorbents.

Study on De-Nitrification of Improved Step-Feed Progress

2014 ◽  
Vol 703 ◽  
pp. 171-174
Author(s):  
Bing Wang ◽  
Yi Xiao ◽  
Shou Hui Tong ◽  
Lan Fang ◽  
Da Hai You ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Fluidized Bed ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Operating Conditions ◽  
Removal Mechanism ◽  
Aerobic Zone

Improved step-feed de-nitrification progress combined with biological fluidized bed was introduced in this study. The progress had good performance and capacity of de-nitrification and organic matter. The experiment result showed that the de-nitrification efficiency of the improved biological fluidized bed with step-feed process was higher than the fluidized bed A/O process under the same water quality and the operating conditions. When the influent proportion of each segment was equal, the system showed good nitrogen removal efficiency with the change of influent C/N ratio, HRT and sludge return ratio. The removal rate of TN reached up to 88.2%. It showed that the simultaneous nitrification and de-nitrification phenomenon happened in the aerobic zone. The nitrogen removal mechanism was also studied.

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