A kinetic model that describes removal of chromium VI from rinsing waters of the metal finishing industry by electrochemical processes

2000 ◽  
Vol 42 (5-6) ◽  
pp. 55-61 ◽  
Author(s):  
S.A. Martínez ◽  
M.G. Rodríguez ◽  
C. Barrera
Keyword(s):  
Reaction Rate ◽  
Treatment Time ◽  
Electrochemical Treatment ◽  
Ferrous Ions ◽  
Chromium Vi ◽  
Electrochemical Processes ◽  
Iron Salts ◽  
Sludge Characterization ◽  
Characterization Study ◽  
Electrode Passivation

A study was made to remove Chromium VI (Cr6+), present in large quantities in the rinsing waters from the plating industry, using electrochemical treatment. Large amount of Cr6+ are found. It was found that the reaction rate followed a variable kinetic order at concentrations up to 1700 mg Cr6+/L. It was also noticed that Cr6+ reduction depended on the ferrous ions (Fe2+) released at the anode, the cathode reactions and the acidic corrosion on electrodes. Iron salts produced electrode passivation and it caused a 50% increase in treatment time and power requirements. Eliminating the salt formation at the anode could reduce this effect. Using electrochemical processes it is possible to reuse treated waters in the rising stages of the plating industry owing to the fact that final Cr6+ concentration is less than 0.5 mg/L. Finally, a sludge characterization study revealed that residue generated in the process is not considered dangerous according to Mexican environmental protection standards.

scholarly journals Optimization of guava juice wastewater electrochemical treatment

2021 ◽  
Vol 10 (2) ◽  
pp. e41910212474
Author(s):  
Gilmar dos Santos ◽  
Joel Marques da Silva ◽  
Javier Alonso Villegas-Aragón ◽  
Silvanio Silvério Lopes da Costa ◽  
Joel Alonso Palomino-Romero
Keyword(s):  
Current Density ◽  
Aluminum Sulfate ◽  
Treatment Time ◽  
Electricity Consumption ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Cod Removal ◽  
Electrochemical Processes ◽  
Initial Ph ◽  
Consumption Rates

Wastewater from guava juice production was treated by two electrochemical processes: Electroflotation (EF) and Electrocoagulation (EC). Using Box-Behnken experimental design, these processes were optimized in order to find the values of treatment time, initial pH and current density that lead to the maximum chemical oxygen demand (COD) removal efficiencies. Aluminum electrodes were used in EC treatment and an iron cathode and a ruthenium dioxide / titanium dioxide anode were applied in EF treatment. EC treatment resulted in maximum COD removal of 60%, when treating the wastewater for 40 minutes, with initial pH 4.5 and current density of 35 A/m2. On the other hand, EF only removed 25% of the wastewater COD (treatment time 40 minutes, initial pH 7.0 and current density 45 A/m2). Aluminum sulfate addition improved the wastewater conductivity, lowering electricity consumption rates. Moreover, the treatment combining EF and this chemical coagulant lead to better results than the ones found when using EF alone.

scholarly journals A Comparative Electrochemical-Ozone Treatment for Removal of Phenolphthalein

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
V. M. García-Orozco ◽  
C. E. Barrera-Díaz ◽  
G. Roa-Morales ◽  
Ivonne Linares-Hernández
Keyword(s):  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Ozone Treatment ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Diamond Electrodes ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Electrochemical Processes ◽  
Density Values

The degradation of aqueous solutions containing phenolphthalein was carried out using ozone and electrochemical processes; the two different treatments were performed for 60 min at pH 3, pH 7, and pH 9. The electrochemical oxidation using boron-doped diamond electrodes processes was carried out using three current density values: 3.11 mA·cm−2, 6.22 mA·cm−2, and 9.33 mA·cm−2, whereas the ozone dose was constantly supplied at 5±0.5 mgL−1. An optimal degradation condition for the ozonation treatment is at alkaline pH, while the electrochemical treatment works better at acidic pH. The electrochemical process is twice better compared with ozonation.

scholarly journals Efficacy of Zhifei Kangfu Decoction in the Treatment of Infantile Pneumonia in the Recovery Period

2021 ◽  
Vol 271 ◽  
pp. 03031
Author(s):  
Yingying Zhang ◽  
Caihong Cao ◽  
Xin Guo ◽  
Haijun Shan
Keyword(s):  
Adverse Reaction ◽  
Reaction Rate ◽  
Treatment Time ◽  
Recovery Period ◽  
Research Work ◽  
Effective Rate ◽  
Control Group ◽  
Pediatric Pneumonia ◽  
The Difference ◽  
Experimental Group

The objective of this article is to explore the effect of applying Zhifei Kangfu Decoction on the treatment effect of patients during the recovery period of children with pneumonia. The method of this research is to take patients who were treated in our hospital from December 2019 to December 2020 as an example to carry out the research work. The researchers selected all patients in the recovery period of pediatric pneumonia, and the number was selected as 100 cases, who were divided into two groups, and the treatment methods used are conventional western medicine and Zhifei Kangfu Decoction treatment, who were named the control group and the experimental group, and the clinical treatment effects of the two groups of patients are compared and analyzed. The effective rate and adverse reaction rate of children in the experimental group were 96.00% and 4.00%, respectively. The effective rate and adverse reaction rate of children in the control group were 82.00% and 30.00%, respectively. Asthma, cough relieving, and treatment time were shorter than those of the control group, and the difference in the data was P<0.05, which was statistically significant. The experimental group had better results. The treatment of children in the recovery period of pneumonia and the application of Zhifei Kangfu Decoction can promote the improvement of clinical efficacy, reduce the incidence of adverse reactions in children, and have a positive significance in promoting the recovery of children.

Inhibited Antibiotic-Resistant and Electrochemical Treatment of Pharmaceutical Wastewater

2021 ◽  
pp. 1362-1383
Author(s):  
Isaiah Adesola Oke ◽  
Fehintola Ezekiel Oluwaseun ◽  
Justinah S. Amoko ◽  
Salihu Lukman ◽  
Adekunbi Enoch Adedayo
Keyword(s):  
Treatment Time ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Separation Distance ◽  
Electrochemical Process ◽  
Treatment Technique ◽  
Antibiotic Resistant ◽  
Industrial Wastewaters ◽  
Chemical Treatments ◽  
Treatment Conditions

The main aim of this chapter is to conduct a simple literature review on treatment wastewaters from pharmaceutical and related industries and establish efficacies of electrochemical treatment technique in removing selected pollutants form raw wastewater. Synthetic (simulated) wastewaters were prepared using standard methods. Fractional factorial (2K - P -1) experiments were utilized at random to determine influence of selected factors (separation distance between the electrodes, volume of the wastewater used, applied current, temperature of the wastewater, treatment time, concentration of the pollutant, concentration calcium of hypochrite (Ca(OCl)2) added and depth of the electrode into the wastewater used) on efficiency of electrochemical process in removing Biochemical Oxygen Demand concentration at five (BOD5). Industrial wastewaters were collected from industrial sources within the country (Nigeria). The industrial wastewaters collected were subjected to electrochemical treatment and chemical treatments individually and in combinations under specified treatment conditions.

Electrochemical Treatment of Wastewater

2020 ◽  
pp. 133-156
Author(s):  
Isaiah Adesola Oke ◽  
Lukman Salihu ◽  
Aladesanmi Temitope A. ◽  
Fehintola Ezekiel Oluwaseun ◽  
Amoko S. Justinah ◽  
...  
Keyword(s):  
Organic Contaminants ◽  
Environmental Pollutants ◽  
Rotating Disk ◽  
Electrochemical Treatment ◽  
Economic Implications ◽  
Oxidation Processes ◽  
Treatment Techniques ◽  
Electrochemical Processes ◽  
Bipolar Mode ◽  
Exchange Unit

This chapter presents an overview of over 529 articles on designs, models, laboratory setups, and applications of electrochemical processes from 1973 to 2017 with particular attention paid to the removal of emerging environmental pollutants. The chapter demonstrates that electrochemical and advanced oxidation processes are efficient despite the economic implications of the technologies. The electrodes in use arranged from monopolar to bipolar mode, which varies from the electroplating baths, recalcitrant organic contaminants, and eluates of an ion-exchange unit and the number of electrodes in a stack to a variant of rotating cathode cell. Application of the process can be in the form of a static anode and a rotating disk cathode. The narrow spacing between the electrodes in the pump cells allow the entrance of the effluent and effective wastewater treatment. It was concluded that electrochemical treatment techniques have a variety of laboratory setups and a wider range of applications.

scholarly journals Inactivation of Escherichia coli Cells in Aqueous Solution by Atmospheric-Pressure N2, He, Air, and O2Microplasmas

2015 ◽  
Vol 81 (15) ◽  
pp. 5257-5265 ◽  
Author(s):  
Renwu Zhou ◽  
Xianhui Zhang ◽  
Zhenhua Bi ◽  
Zichao Zong ◽  
Jinhai Niu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Aqueous Solution ◽  
Atmospheric Pressure ◽  
Reaction Rate ◽  
Treatment Time ◽  
Process Analysis ◽  
Content Type ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Plasma Treatment Time

ABSTRACTAtmospheric-pressure N2, He, air, and O2microplasma arrays have been used to inactivateEscherichia colicells suspended in aqueous solution. Measurements show that the efficiency of inactivation ofE. colicells is strongly dependent on the feed gases used, the plasma treatment time, and the discharge power. Compared to atmospheric-pressure N2and He microplasma arrays, air and O2microplasma arrays may be utilized to more efficiently killE. colicells in aqueous solution. The efficiencies of inactivation ofE. colicells in water can be well described by using the chemical reaction rate model, where reactive oxygen species play a crucial role in the inactivation process. Analysis indicates that plasma-generated reactive species can react withE. colicells in water by direct or indirect interactions.

A Mechanistic Study on the Electrocoagulation of Silica Nanoparticles from Polishing Wastewater

2006 ◽  
Vol 1 (3) ◽  
Author(s):  
W. Den ◽  
C. Huang ◽  
H.-C. Ke
Keyword(s):  
Reaction Time ◽  
Zeta Potential ◽  
Continuous Flow ◽  
The Other ◽  
Mechanistic Study ◽  
Iron Hydroxides ◽  
Ferrous Ions ◽  
Silica Removal ◽  
Sludge Characterization ◽  
Oppositely Charged

The removal mechanisms involved in the continuous-flow electrocoagulation for the treatment of a polishing wastewater containing negatively charged silica particles are described in the report. The mechanisms are derived from the experimental measurement of pH, zeta-potential and turbidity as a function of reaction time, as well as from the sludge characterization. Two types of distinct mechanisms are proposed, one involving particle destabilization by oppositely charged ferrous ions, the other involving a complexation or physical bridging by iron hydroxides/hydroxyl complexes. The former mechanism is apparently responsible for the formation of “surface sludge”, whereas the latter mechanism is responsible for the sediment sludge. Both mechanisms are important to the silica removal based on the measurement of sludge quantity.

Oxidation of DL-penicillamine by chromium(VI). Kinetics of formation of the thioester intermediate

1994 ◽  
Vol 72 (7) ◽  
pp. 1637-1644 ◽  
Author(s):  
Joaquin F. Perez-Benito ◽  
Driss Lamrhari ◽  
Conchita Arias
Keyword(s):  
Reaction Rate ◽  
Aqueous Media ◽  
Bimolecular Reaction ◽  
Spectrophotometric Detection ◽  
State Behavior ◽  
Chromium Vi ◽  
Specific Effects ◽  
Kinetics Of Formation ◽  
Kinetics Of ◽  
Catalytic Power

The kinetics of formation of the thioester involved as an intermediate in the reaction between chromium(VI) and DL-penicillamine in aqueous media (pH = 1–8) containing different buffers (acetate, citrate, and phosphate) has been studied by monitoring the disappearance of chromium(VI) at 370 nm and application of the initial-rates method. The initial rate is directly proportional to the initial concentrations of both oxidant and reductant, and the rate vs. pH plots show bell-shaped profiles. The reaction is catalyzed by the buffer present in the medium, the catalytic power of each buffer increasing in the order acetate < citrate < phosphate. This is explained in terms of a mechanism involving the formation of a complex between the acidic form of the buffer and HCrO4− previous to the formation of the thioester. Potassium chloride and sodium sulfate do not seem to have important specific effects on the reaction rate, their effect being that of an acceleration of the reaction as the ionic strength increases. On the contrary, the sulfates of magnesium, manganese(II), and zinc (the latter only in the presence of acetate buffer) have specific effects, indicating the probable formation of several complexes. The spectrophotometric detection of the thioester at 430 nm has allowed to confirm some of the conclusions extracted from the measurement of initial rates, and suggests that this intermediate might approach a steady-state behavior in the three buffers at pH > 6.25, and also that a bimolecular reaction with DL-penicillamine might be involved in its destruction.

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