scholarly journals Electrochemical Removal of Chromium (VI) from Wastewater

2019 ◽  
Author(s):  
Hao Peng ◽  
Yumeng Leng ◽  
Jing Guo
Keyword(s):  
Reaction Temperature ◽  
Current Density ◽  
Reduction Rate ◽  
Reduction Process ◽  
Order Equation ◽  
First Order ◽  
Chromium Vi ◽  
Reduction Efficiency ◽  
Pseudo First Order ◽  
Electrochemical Removal

Removal of hexavalent chromium had attracted much more attention as it was a hazardous contaminant. Electrochemical reduction technology was applied to removal chromium (VI) from wastewater. The mechanism and parameters affect the reduction process were investigated. The results showed that the reduction efficiency was significantly affected by the concentration of H2SO4, current density and reaction temperature. And the reduction efficiency was up to 86.45% at concentration of H2SO4 of 100g/L, reaction temperature of 70 ℃, current density at 50 A/m2, reaction time at 180 min and stirring rate of 500 rpm. The reduction process of chromium (VI) was followed pseudo-first-order equation, and the reduction rate could be expressed as Kobs = k [H2SO4]1• [j] 4•exp-4170/RT.

scholarly journals Electrochemical Removal of Chromium (VI) from Wastewater

2019 ◽  
Vol 9 (6) ◽  
pp. 1156 ◽  
Author(s):  
Hao Peng ◽  
Yumeng Leng ◽  
Jing Guo
Keyword(s):  
Reaction Temperature ◽  
Current Density ◽  
Reduction Rate ◽  
Reduction Process ◽  
Order Equation ◽  
H2so4 Concentration ◽  
First Order ◽  
Chromium Vi ◽  
Reduction Efficiency ◽  
Electrochemical Removal

The removal of hexavalent chromium has attracted much attention as it is a hazardous contaminant. Electrochemical reduction technology was applied to remove chromium (VI) from wastewater. The mechanisms and parameters that affect the reduction process were investigated. The results showed that the reduction efficiency was significantly affected by the concentration of H2SO4, current density, and reaction temperature. The reduction efficiency was up to 86.45% at an H2SO4 concentration of 100 g/L, reaction temperature of 70 °C, current density at 50 A/m2, reaction time at 180 min, and stirring rate of 500 rpm. The reduction process of chromium (VI) followed a pseudo-first-order equation, and the reduction rate constant could be expressed as Kobs = k [H2SO4]1·[j]4·exp−4170/RT.

scholarly journals Electrocoagulation removal of anthraquinone dye Alizarin Red S from aqueous solution using aluminum electrodes: kinetics, isothermal and thermodynamics studies

2016 ◽  
Author(s):  
Abideen Idowu Adeogun ◽  
Ramesh Babu Balakrishnan
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Current Density ◽  
Alizarin Red S ◽  
Isotherm Models ◽  
Alizarin Red ◽  
Anthraquinone Dye ◽  
First Order ◽  
Electrocoagulation Process ◽  
Pseudo First Order

<span lang="EN-US">Electrocoagulation (EC) was used for the removal of anthraquinone dye, Alizarin Red S (ARS) from aqueous solution, the process was carried out in a batch electrochemical cell with Al electrodes in monopolar connection. The effects of some important parameters such as current density, pH, temperature and initial dye concentration, on the process were investigated. Equilibrium was attained after 10 minutes at 30 oC. Pseudo-first-order, pseudo-second-order, Elovic, and Avrami kinetic models were used to test the experimental data in order to elucidate the kinetic of the electrocoagulation process; pseudo-first-order and Avrami models best fitted the data. Experimental data were analyzed using six isotherm models: Langmuir, Freudlinch, Redlich–Peterson, Temkin, Dubinin–Radushkevich and Sips isotherms and it was found that the data fitted well with Dubinin–Radushkevich and Sips isotherm model. The study showed that the process depend on current density, temperature, pH and initial dye concentration. The calculated thermodynamics parameters (∆G<sup>o</sup>, ∆H<sup>o</sup> and ∆S<sup>o</sup>) indicated that the process is spontaneous and endothermic in nature.</span>

scholarly journals Oxidative Degradation of Amoxicillin in Aqueous Solution by Thermally Activated Persulfate

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Juanjuan Zhao ◽  
Yujiao Sun ◽  
Fachao Wu ◽  
Minjian Shi ◽  
Xurui Liu
Keyword(s):  
Aqueous Solution ◽  
Reaction Temperature ◽  
Oxidative Degradation ◽  
Water Remediation ◽  
Order Kinetic ◽  
Production Chain ◽  
First Order ◽  
Thermally Activated ◽  
Pseudo First Order ◽  
Activated Persulfate

Antibiotic residues and antibiotic resistance genes (ARGs) pose a great threat to public health and food security via the horizontal transfer in the food production chain. Oxidative degradation of amoxicillin (AMO) in aqueous solution by thermally activated persulfate (TAP) was investigated. The AMO degradation followed a pseudo-first-order kinetic model at all tested conditions. The pseudo-first-order rate constants of AMO degradation well-fitted the Arrhenius equation when the reaction temperature ranged from 35°C to 60°C, with the apparent activate energy of 126.9 kJ·mol−1. High reaction temperature, high initial persulfate concentration, low pH, high Cl− concentration, and humic acid (HA) concentration increased the AMO degradation efficiency. The EPR test demonstrated that both ·OH and SO4·− were generated in the TAP system, and the radical scavenging test identified that the predominant reactive radical species were SO4·− in aqueous solution without adjusting the solution pH. In groundwater and drinking water, AMO degradation suggested that TAP could be a reliable technology for water remediation contaminated by AMO in practice.

scholarly journals Effect of precursor type on the reduction of concentrated nitrate using zero-valent copper and sodium borohydride

2017 ◽  
Vol 77 (1) ◽  
pp. 114-122 ◽  
Author(s):  
Tihitinna Asmellash Belay ◽  
C. Y. Lin ◽  
H. M. Hsiao ◽  
M. F. Chang ◽  
J. C. Liu
Keyword(s):  
Particle Size ◽  
Surface Area ◽  
Sodium Borohydride ◽  
Reaction Rate ◽  
Reduction Rate ◽  
First Order ◽  
Reducing Conditions ◽  
Pseudo First Order

Abstract In this study, we demonstrated that the choice of precursor has a strong effect on the reduction of nitrate (NO3−) using zero-valent copper (Cu0) synthesized by sodium borohydride (NaBH4). Different precursors: CuSO4, CuO, Cu2O, Cu powder, and Cu mesh were used to reduce NO3− at 677 mg-N/L under the reducing conditions of NaBH4. Compared with the prehydrolyzed samples, those prepared without prehydrolysis exhibited lower reduction rates, longer times and higher concentrations of nitrite (NO2−) intermediate. It was found that one-time addition of NaBH4 resulted in higher reduction rate and less NO2− intermediate than two-step addition. Results showed that Cu0 from CuSO4 possessed the smallest particle size (890.9 nm), highest surface area (26.0 m2/g), and highest reaction rate (0.166 min−1). Values of pseudo-first-order constant (kobs) were in the order: CuSO4 &gt; CuO &gt; Cu2O &gt; Cu powder &gt;Cu mesh. However, values of surface area-normalized reaction rate (kSA) were approximately equal. It was proposed that NO3− was reduced to NO2− on Cu0, and then converted to NH4+ and N2, respectively; H2 generated from both NaBH4 hydration and Cu (II) reduction contributed to NO3− reduction as well.

Electrochemical Degradation of RDX in Aqueous Solution at Constructed Sb-Doped SnO2 Anode

2011 ◽  
Vol 396-398 ◽  
pp. 1803-1806
Author(s):  
Yong Chen ◽  
Lei Hong ◽  
Wei Shi ◽  
Wei Qing Han ◽  
Lian Jun Wang
Keyword(s):  
Aqueous Solution ◽  
Current Density ◽  
Order Reaction ◽  
Electrochemical Degradation ◽  
Kinetics Analysis ◽  
Pseudo First Order Reaction ◽  
Initial Concentration ◽  
First Order ◽  
Sno2 Electrode ◽  
Pseudo First Order

The constructed Sb-doped SnO2 electrode was obtained for electrochemical degradation of RDX. The influences of current density and initial concentration of RDX on electrochemical degradation of RDX were studied. Kinetics analysis shows that the electrochemical degradation of RDX follows the pseudo first-order reaction. The mechanism of electrochemical degradation of RDX was also discussed.

Adsorption Characteristics of L-Phenylalanine in Drinking Water by Granule Activated Carbon

2012 ◽  
Vol 610-613 ◽  
pp. 259-263 ◽  
Author(s):  
Fei Shang ◽  
Xiao Lv Zhou ◽  
Zhen Xing Zhou ◽  
Chen Yan Hu ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Order Equation ◽  
High Adsorption ◽  
Adsorption Time ◽  
First Order ◽  
Best Fitting ◽  
Pseudo First Order ◽  
High Adsorption Capacity

In this paper,granular activated carbon GAC was used to investigate the adsorption capacity and adsorption rate of a typical nitrogen-containing organic compounds L-phenylalanine. GAC shows a high adsorption capacity for the L-phenylalanine and the adsorption isotherms conform to with Langmuir model.The pseudo-first-order equation shows the best fitting for adsorption kinetics in L-phenylalanine adsorption by GAC. Besides the factors such as the temperature, adsorption time and activated carbon quantity were studied.

Decolourization of Methylene Blue by Persulfate

2013 ◽  
Vol 634-638 ◽  
pp. 76-80
Author(s):  
Wei Hu ◽  
Shen Xin Li ◽  
Cheng Duan Wang
Keyword(s):  
Methylene Blue ◽  
Ionic Strength ◽  
Uv Irradiation ◽  
Reaction Temperature ◽  
Uv Light ◽  
Kinetics Model ◽  
Dye Wastewater ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order

The decolourization of dye wastewater by persulfate was studied using methylene blue as a model dye wastewater. Effects of several parameters, such as dose of oxidant, ionic strength, pH, temperature and UV irradiation, were investigated in detail. The results showed that the decolourization reaction of methylene blue by persulfate could be fitted to a pseudo-first order kinetics model. In addition, when the oxidant amount used is 2 times of methylene blue, pH 3.43 and reaction temperature for 60°C, after uv light under the irradiation of 20 min, methylene blue decolorization rate can reach more than 98%. The results are useful for the treatment of dye wastewater.

scholarly journals Adsorption of Chromium (VI) by Cu (I)-MOF in Water: Optimization, Kinetics, and Thermodynamics

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hongxue Qi ◽  
Xianjun Niu ◽  
Haipeng Wu ◽  
Xiuping Liu ◽  
Yongqiang Chen
Keyword(s):  
Adsorption Capacity ◽  
Low Cost ◽  
Entropy Change ◽  
Maximum Adsorption Capacity ◽  
Sem Images ◽  
First Order ◽  
Chromium Vi ◽  
Function Change ◽  
Pseudo Second Order ◽  
Pseudo First Order

To investigate the adsorption behavior of Cu (I)-MOF material for chromium (VI) in water, the parameters of influencing adsorption were optimized and found as follows: the optimal pH was 6 for the adsorption of Cr (VI) by the Cu (I)-MOF, the optimal amount of adsorbent was 0.45 g·L−1, and the adsorption saturation time was within 180 min. Subsequently, the kinetics results were fitted by four models such as pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. Among them, the adsorption of chromium (VI) was more inclined to the pseudo-first-order model (Radj2 = 0.9230). Then, the isotherm data were fitted by Langmuir and Freundlich models. The results indicated that Langmuir isotherm was the excellent match model (Radj2 = 0.9827). It belongs to a monolayer adsorption, and the maximum adsorption capacity was 95.92 mg·g−1. Subsequently, the thermodynamic parameters of the adsorption were calculated as follows: enthalpy change (ΔHθ) was −8.583 kJ·mol−1, entropy change (ΔSθ) was −8.243 J·mol−1 K−1, and the Gibbs function change (ΔGθ) was less than zero in the temperature range of 288–328 K, indicating that the reaction was spontaneous. Finally, both the spectra of infrared and XPS supported the adsorption mechanism that belonged the ion exchange. The spectra of XRD and SEM images shown that the structure of Cu (I)-MOF remained stable for at least 3 cycles. In conclusion, Cu (I)-MOF material has a high adsorption capacity, good water stability, low cost, and easy to prepare in large quantities in practical application. It will be a promising adsorbent for the removal of Cr (VI) from water.

Reaction Performance of Propylene Carbonate Manufacturing by Using a Green Synthetic Route

2014 ◽  
Vol 1051 ◽  
pp. 289-293
Author(s):  
Richard Horng ◽  
Shin Ku Lee ◽  
Mei Lee Hwang ◽  
Hsin Ying Tsai
Keyword(s):  
Reduction Process ◽  
Kinetic Control ◽  
First Order ◽  
Kinetic Information ◽  
First Order Kinetics ◽  
Product Separation ◽  
Reaction Performance ◽  
Pseudo First Order ◽  
Fixation Reaction ◽  
Scale Reactor

The CO2 fixation reaction performance was carried out by using propylene oxide (PO) as reactant and medium and ionic liquid as catalyst. Through variation of reaction temperature, pressure and catalyst ratio and amount, it was found that the reaction was under kinetic control, for pressure ranging from 15 to 50 atm, rather than mass transfer control. From the kinetic data, it shows a pseudo first order kinetics with respect to PO concentration under constant CO2 pressure. The corresponding activation energy was calculated to be 9.152 kcal/mol. The reaction kinetics was independent of catalyst ratio and amount, yet the optimal catalyst ratio of [Bmim]Br/ZnCl2 is 2 for the fixation reaction. It is also a high conversion reaction, 96.0% (PO), with easier product separation, and as applied to industry for CO2 reduction process, its kinetic information would be very useful for future industrial scale reactor design.

Decolourization of Kiscolon Scarlet 2KN by Persulfate

2013 ◽  
Vol 864-867 ◽  
pp. 256-260
Author(s):  
Wei Hu ◽  
Shen Xin Li ◽  
Wang Ying ◽  
Cheng Duan Wang
Keyword(s):  
Uv Irradiation ◽  
Reaction Temperature ◽  
Kinetics Model ◽  
Dye Wastewater ◽  
First Order ◽  
Decolorization Rate ◽  
First Order Kinetics ◽  
Pseudo First Order

The decolourization of dye wastewater by persulfate was studied using kiscolon scarlet2KN as a model dye wastewater. Effects of several parameters, such as dose of oxidant, pH, temperature and UV irradiation, were investigated in detail. The results showed that the decolourization reaction of kiscolon scarlet2KN by persulfate could be fitted to a pseudo-first order kinetics model. In addition, when the oxidant amount used is 70 times of kiscolon scarlet2KN, pH 5.71 and reaction temperature for 70°C, kiscolon scarlet2KN decolorization rate can reach more than 98%. The results are useful for the treatment of dye wastewater.Keywords:Kiscolon scarlet 2KN, Decolourization, Persulfate

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