Degradation of polyethylene glycol by Fenton reaction: a comparative study

2007 ◽  
Vol 55 (12) ◽  
pp. 83-87 ◽  
Author(s):  
R. Haseneder ◽  
B. Fdez-Navamuel ◽  
G. Härtel
Keyword(s):  
Polyethylene Glycol ◽  
Fenton Reaction ◽  
Heterogeneous System ◽  
Ph Value ◽  
Removal Rate ◽  
Heterogeneous Systems ◽  
Homogeneous System ◽  
Reduction Efficiency ◽  
Time Of Operation ◽  
Fenton System

Photochemical advanced oxidation processes (AOPs) utilising different Fenton systems were investigated in laboratory-scale experiments for the degradation of polyethylene glycol (PEG). The results of the study showed that the degradation rate of PEG was strongly accelerated by the homogeneous system, and this proved to be advantageous in comparison to the heterogeneous system. Between Fenton and photo-Fenton heterogeneous systems, the photo-Fenton process reached the highest removal rate of the organic compound, due to the enhanced reduction efficiency of Fe(III) to Fe(II) under UV-irradiation. The oxidation rate in the heterogeneous system was investigated using varying different parameters, such as the pH value, the concentration of hydrogen peroxide and the amount of Fe(OH)3 as the catalyst. For the homogeneous Fenton system the rate of degradation is significantly higher. At the same time of operation the elimination rates can be found to be 30% over the rates of the heterogeneous system. Optimising the typical influence parameters mentioned before, a degradation of about 93% of PEG can be achieved by using the homogeneous Fenton system.

Degradation of 4-chlorophenol mediated by Fe(III)-NTA in homogeneous and heterogeneous systems

2004 ◽  
Vol 49 (4) ◽  
pp. 123-128 ◽  
Author(s):  
O. Abida ◽  
C. Emilio ◽  
N. Quici ◽  
R. Gettar ◽  
M. Litter ◽  
...  
Keyword(s):  
Photochemical Reaction ◽  
Heterogeneous System ◽  
Reaction Rate ◽  
Heterogeneous Systems ◽  
Homogeneous System ◽  
Initial Reaction Rate ◽  
Initial Reaction ◽  
Iron Salt ◽  
Positive Role ◽  
Total Disappearance

In this work, the comparison of 4-chlorophenol (4-CP) degradation by two different AOT processes has been performed: a) a homogeneous system with Fe(III)-NTA (1:1 complex), b) a TiO2/Fe(III)-NTA heterogeneous system. In both cases, NTA appears to play a positive role in the photochemical reaction. In the homogeneous system, the iron salt is the only absorbing species and is proved to be able to photoinduce 4-CP degradation ([4-CP] = 0.1-0.2 mM, [FeNTA] = 0.3-0.9 mM, pH 4, λ = 365 nm). The progress of the reaction was positively affected by the FeNTA concentration, and the reaction kept going even after the total disappearance of FeNTA. However, 4-CP complete degradation requires the presence of oxygen, otherwise the reaction stops. In the heterogeneous system ([4-CP] = 2.0 mM, [FeNTA] = 1.0-2.0 mM, [TiO2] = 0.1 and 1.0 g L-1, pH 3, λ = 300-400 nm), an important effect of the complex on the degradation extent and on the initial reaction rate can be seen, which overcomes the effect of non-complexed Fe(III). This behaviour is more important at the highest TiO2 concentration.

scholarly journals Photo-assisted heterogeneous Fenton-like process for treatment of PNP wastewater

2020 ◽  
Vol 10 (1) ◽  
pp. 136-145 ◽  
Author(s):  
F. C. Ban ◽  
X. T. Zheng ◽  
H. Y. Zhang
Keyword(s):  
Kinetic Equation ◽  
Ph Value ◽  
Removal Rate ◽  
Optimum Process ◽  
Process Conditions ◽  
Order Kinetic ◽  
Heterogeneous Fenton ◽  
Solution Ph ◽  
Order Kinetic Model ◽  
Fenton System

Abstract The purpose of this study was to investigate the effect of photo-assisted heterogeneous Fenton on p-nitrophenol (PNP) wastewater treatment by a homemade reactor. Supported Fe-Ce/Al2O3 was used as a catalyst and H2O2 as an oxidant to treat simulated p-nitrophenol wastewater under ultraviolet light. The effects of H2O2 dosage, catalyst dosage, initial solution pH value, reaction temperature and reaction time on the removal rate of p-nitrophenol in a photo-assisted heterogeneous Fenton system were determined. According to the relation between the concentration of each component and time, the relation curve is fitted, and then the kinetic equation is established. Finally, we obtained the optimum process conditions to achieve the PNP wastewater removal rate of 98.7%. The degradation of the photo-assisted heterogeneous Fenton method conforms to the first-order kinetic model, and the kinetic equation is . Therefore, photo-assisted heterogeneous Fenton treatment of PNP wastewater is effective and can be used in the treatment of refractory wastewater.

scholarly journals HETEROGENEOUS SYSTEMS IN DIMENSIONS: LOWER SPECTRUM

2015 ◽  
Vol 57 (2) ◽  
pp. 150-165 ◽  
Author(s):  
PAOLO AMORE
Keyword(s):  
Boundary Conditions ◽  
Helmholtz Equation ◽  
Iterative Methods ◽  
Heterogeneous System ◽  
Heterogeneous Systems ◽  
Homogeneous System ◽  
Finite Region ◽  
Different Boundary Conditions ◽  
Lower Spectrum

The lower part of the spectrum of the Helmholtz equation for a heterogeneous system in a finite region in $d$ dimensions, where the solutions to the corresponding homogeneous system are known, can be systematically approximated by means of iterative methods. These methods only require the specification of an arbitrary ansatz and converge to the desired solution, regardless of the strength of the inhomogeneities, provided the ansatz has a finite overlap with it. In this paper, different boundary conditions at the borders of the domain are assumed, and some applications are used to illustrate the methods.

Decolorization of Mordant Red 15 Dye in Water by Potassium Ferrate (VI)

2013 ◽  
Vol 838-841 ◽  
pp. 2445-2448 ◽  
Author(s):  
Zheng Hua Wang ◽  
Bo Zhi Ren ◽  
Pu Wang
Keyword(s):  
Reaction Time ◽  
Fenton Reaction ◽  
Ph Value ◽  
Removal Rate ◽  
Dye Decolorization ◽  
High Ability ◽  
Potassium Ferrate ◽  
Optimum Conditions ◽  
Ph Values ◽  
Optimum Ph

Decolorization of the Mordant red 15 dye in water was investigated in laboratory-scale experiments using potassium ferrate (VI). The effect of corresponding parameters such as reaction time, concentration of potassium ferrate, pH values and the addition of H2O2 were considered in the experiments. The results indicated that about 78% dye decolorization was obtained in less than 30 min under optimum conditions. The pH values and concentration of ferrate (VI) were correlated with color removal rate of Mordant red 15 dye. The optimum pH value and ferrate (VI) concentration are 5 and 450 mg/L, respectively. Addition of H2O2 could initiate the Fenton reaction and result in 84.46% decolorization of dye in 30 min. Due to high ability of oxidizing and flocculation, potassium ferrate (VI) is an effect way for treatment of dyes in water.

Parameters for Measuring the Activity and Viability of Activated Sludge

1974 ◽  
Vol 9 (1) ◽  
pp. 235-249 ◽  
Author(s):  
S.G. Nutt ◽  
K.L. Murphy
Keyword(s):  
Organic Carbon ◽  
Activated Sludge ◽  
Biological System ◽  
Analytical Methods ◽  
Heterogeneous System ◽  
Removal Rate ◽  
Bacterial Species ◽  
Atp Content ◽  
Culture Studies ◽  
Activated Sludge System

Abstract Conventional wastewater parameters are accepted as inadequate estimates of the condition of activated sludge but numerous other indices have been suggested as specific measurements of the activity and viability of the biomass. Literature in the related fields of microbiology and biochemistry were reviewed in order to select the most appropriate activity parameters for application to a heterogeneous biological material. Modified analytical methods were applied to a well-controlled biological system containing a single predominant bacterial species to evaluate the relative merit of each as an indicator of viability and activity. The potential of each parameter in a complex heterogeneous system was determined by monitoring each index in a bench activated sludge system. The predominant culture studies indicated that the ATP content of the biomass and the dehydrogenase activity were potential indicators of cell viability in a simple system. However, in the complex activated sludge system, only the ATP content showed significant correlation to the organic carbon removal rate.

scholarly journals Enhancement of Iron-Based Photo-Driven Processes by the Presence of Catechol Moieties

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 372
Author(s):  
Javier Moreno-Andrés ◽  
Iván Vallés ◽  
Paula García-Negueroles ◽  
Lucas Santos-Juanes ◽  
Antonio Arques
Keyword(s):  
Fenton Reaction ◽  
Advanced Oxidation Processes ◽  
Salt Water ◽  
Degradation Process ◽  
Contaminants Of Emerging Concern ◽  
Low Salt ◽  
Aquaculture Industry ◽  
Iron Based ◽  
Ph Range ◽  
Fenton System

Photo-induced Advanced Oxidation Processes (AOPs) using H2O2 or S2O82− as radical precursors were assessed for the abatement of six different contaminants of emerging concern (CECs). In order to increase the efficiency of these AOPs at a wider pH range, the catechol organic functional compound was studied as a potential assistant in photo-driven iron-based processes. Different salinity regimes were also studied (in terms of Cl− concentration), namely low salt water (1 g·L−1) or a salt–water (30 g·L−1) matrix. Results obtained revealed that the presence of catechol could efficiently assist the photo-Fenton system and partly promote the photo-induced S2O82− system, which was highly dependent on salinity. Regarding the behavior of individual CECs, the photo-Fenton reaction was able to enhance the degradation of all six CECs, meanwhile the S2O82−-based process showed a moderate enhancement for acetaminophen, amoxicillin or clofibric acid. Finally, a response-surface methodology was employed to determine the effect of pH and catechol concentration on the different photo-driven processes. Catechol was removed during the degradation process. According to the results obtained, the presence of catechol in organic macromolecules can bring some advantages in water treatment for either freshwater (wastewater) or seawater (maritime or aquaculture industry).

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.

Synthesis and Application of Itaconic Acid Water-Coke Slurry Dispersant

2017 ◽  
Vol 896 ◽  
pp. 167-174 ◽  
Author(s):  
Zhi Yuan Yang ◽  
Zhuo Yue Meng ◽  
Zhi Hua Li ◽  
Si Tong Wang
Keyword(s):  
Surface Tension ◽  
Polyethylene Glycol ◽  
Itaconic Acid ◽  
High Performance ◽  
Ph Value ◽  
Raw Materials ◽  
Esterification Reaction ◽  
Solution Ph ◽  
Powder Surface ◽  
Coke Powder

Polyethylene glycol (PEG-200) and itaconic acid (IA) were used as raw materials to compound macromer through esterification reaction. A new type of specialized water-coke slurry dispersant was synthesized by copolymerization of microware, sodium methallyl sulfonate (SMAS) and maleic anhydride (MA). The experiment showed that the concentration of slurry could be reached to 63% with the dosage of 0.2%, and the apparent viscosity was 1140.3 mPa∙s. Through the analysis of the infrared, the dispersant was confirmed to have polyethylene glycol branched chain and hydrophilic functional groups such as carboxyl or sulfonic group. When the concentration of dispersant was 30 g/L, the surface tension of water could be decreased from 72.70 mN/m to 45.50 mN/m. Furthermore, when the solution pH value was 9, the Zeta potential of semi-coke powder surface could also be decreased from-13.38 mV to-25 mV with the addition of dispersant. Thus, this dispersant could increase electronegativity of semi-coke powder surface, enhance steric-hindrance effect and prevent the phenomenon of powder flocculation and gather. Meantime, it also could reinforce the semi-coke hydrophilic by reducing the surface tension of water effectively. And then, the high performance water-coke slurry could be obtained.

scholarly journals Numerical Simulation of Decontamination of Airborne Fission Products during In-Vessel Release Phase by Containment Spray

2018 ◽  
Vol 2018 ◽  
pp. 1-19
Author(s):  
Khurram Mehboob
Keyword(s):  
Droplet Size ◽  
Failure Time ◽  
Ph Value ◽  
Removal Rate ◽  
Droplet Diameter ◽  
Fission Products ◽  
Product Release ◽  
Spray System ◽  
Spray Solution ◽  
Proposed Model

The containment spray system (CSS) has a significant role in limiting the risk of radioactive exposure to the environment. In this work, the optimal droplet size and pH value of spray water to prevent the fission product release have been evaluated to improve the performance of the spray system during in-vessel release phase. A semikinetic model has been developed and implemented in MATLAB. The sensitivity and removal rate of airborne isotopes with the spray system have been simulated versus the spray activation and failure time, droplet size, and pH value. The alkaline (Na2S2O3) spray solution and spray water with pH 9.5 have similar scrubbing properties for iodine. However, the removal rate from the CSS has been found to be an approximately inverse square of droplet diameter (1/d2) for Na2S2O3 and higher pH of spray water. The numerical results showed that 450 μm–850 μm droplet with 9.5 pH and higher or the alkaline (Na2S2O3) solution with 0.2 m3/s–0.35 m3/s flow rate is optimal for effective scrubbing of in-containment fission products. The proposed model has been validated with TOSQAN experimental data.

scholarly journals Adsorption of aquatic Cd2+ using a combination of bacteria and modified carbon fiber

2017 ◽  
Vol 36 (3-4) ◽  
pp. 857-871 ◽  
Author(s):  
Chao Xue ◽  
Peishi Qi ◽  
Yunzhi Liu
Keyword(s):  
Aqueous Solution ◽  
Composite Material ◽  
Carbon Fiber ◽  
Active Sites ◽  
Ph Value ◽  
Removal Rate ◽  
Sorption Process ◽  
Acid Sites ◽  
Heterogeneous Distribution ◽  
Carbon Fiber Material

Batch experiments were conducted to investigate the capacity and mechanisms for adsorbing Cd2+ from aqueous solutions by the composite material. The composite material was manufactured with Plesiomonas shigelloides strain H5 and modified polyacrylonitrile-based carbon fiber. Experimental results showed that the surface areas of modified polyacrylonitrile-based carbon fiber increased by 58.54% and pore width increased by 40.19% compared with unmodified polyacrylonitrile-based carbon fiber. Boehm’s titration results show the surface acid sites of composite material were increased by 712% compared with unmodified polyacrylonitrile-based carbon fiber. The field emission scanning electron microscope results show P. shigelloides H5 can be grown on the surface of modified polyacrylonitrile-based carbon fiber closely. The equilibrium removal rate and sorption quantity of composite material were 71.56% and 7.126 mg g−1, respectively. With the pH value of aqueous solution increased, the removal rate of Cd2+ ions was also increased, but the change of temperature and ionic strength had no significant effect on the removal rate. Furthermore, the results showed the whole sorption process was a good fit to Lagergren pseudo-second-order model and Freundlich isotherms model. Therefore, the results infer that there was a heterogeneous distribution of active sites, and then the sorption process was chemical adsorption and multilayer adsorption. In a word, microbial composite carbon fiber material can adsorb Cd2+ ions from aqueous solution effectively, which might be helpful in wastewater treatment in the future.

Sign in / Sign up

Export Citation Format

Share Document