scholarly journals INVESTIGATION OF ELECTROCHEMICAL COLOR REMOVAL FROM ORGANIZED INDUSTRIAL DISTRICT (OID) WASTEWATER TREATMENT PLANTS USING NEW GENERATION Sn/Sb/Ni-Ti ANODES

2018 ◽  
Vol 21 (2) ◽  
pp. 106-112
Keyword(s):  
Energy Consumption ◽  
Current Efficiency ◽  
Current Density ◽  
Wastewater Treatment Plants ◽  
Salt Content ◽  
Color Removal ◽  
Ozone Production ◽  
Ambient Conditions ◽  
Operational Parameters ◽  
Oxidation Efficiency

<p>In this study, the application of Sn/Sb/Ni-Ti electrodes for the treatment of waste streams were investigated which is promising for ozone production by electrolysis of water because of their stability and high potential for ozone evolution reaction. These series of anodes have a high electrochemical ozone generation potential at ambient conditions (approximately up to 40% current efficiency). But using and testing of these novel anodes for real wastewater are too limited in the literature. Titanium mesh substrate coated with Sn/Sb/Ni-Ti alloy was used as anode immersed in wastewater at room temperature with platinized titanium cathode. These electrodes used for COD and color removal from OID wastewater in Inegol, Bursa, Turkey. Five operational parameters were evaluated for electrochemical COD and color removal processes, such as pH, salt content, applied voltage/current, current efficiency and contact time. Experimental results showed that after 30 min the electrochemical oxidation efficiency of COD and color could reach up to 98% and 99% respectively at pH 8.2 and temperature of 25°C as the optimum conditions. Current density observed as the most effective parameter for COD and color removal efficiencies. The lowest energy consumption was between 10-25 mA cm-2 of current density with only 0.6 kWh gCOD−1, while the highest energy consumption was 100 mA cm-2 of current density with 9.12 kWh gCOD−1 . The optimum current density value has been found as 50 mA cm-2 with 4.05 kWh gCOD−1 . These results were also supported with ANOVA test.</p>

scholarly journals Selective Recovery of Tellurium from the Tellurium-Bearing Sodium Carbonate Slag by Sodium Sulfide Leaching Followed by Cyclone Electrowinning

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1176
Author(s):  
Zhipeng Xu ◽  
Zoujiang Li ◽  
Dong Li ◽  
Xueyi Guo ◽  
Ying Yang ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Current Efficiency ◽  
Sodium Carbonate ◽  
Flow Rate ◽  
Current Density ◽  
Sodium Sulfide ◽  
Cell Voltage ◽  
Promising Alternative ◽  
Selective Recovery ◽  
Solid Ratio

The rigorous environmental requirements promote the development of new processes with short and clean technical routes for recycling tellurium from tellurium-bearing sodium carbonate slag. In this paper, a novel process for selective recovery of tellurium from the sodium carbonate slag by sodium sulfide leaching, followed by cyclone electrowinning, was proposed. 88% of tellurium was selectively extracted in 40 g/L Na2S solution at 50 °C for 60 min with a liquid to solid ratio of 8:1 mL/g, while antimony, lead and bismuth were enriched in the leaching residue. Tellurium in the leach liquor was efficiently electrodeposited by cyclone electrowinning without purification. The effects of current density, temperature and flow rate of the electrolyte on current efficiency, tellurium recovery, cell voltage, energy consumption, surface morphology, and crystallographic orientations were systematically investigated. 91.81% of current efficiency and 95.47% of tellurium recovery were achieved at current density of 80 A/m2, electrolyte temperature of 45 °C and electrolyte flow rate of 400 L/h. The energy consumption was as low as 1.81 kWh/kg. A total of 99.38% purity of compact tellurium deposits were obtained. Therefore, the proposed process may serve as a promising alternative for recovering tellurium from tellurium-bearing sodium carbonate slag.

scholarly journals Influence of current density and temperature in the zinc electroplating process at sulfate-based acid solution: study on process efficiency and coating morphology

2021 ◽  
Vol 17 (10) ◽  
Author(s):  
Gabriel Abelha Carrijo Gonçalves ◽  
Pedro Manoel Silveira Campos ◽  
Tácia Costa Veloso ◽  
Vera Rosa Capelossi
Keyword(s):  
Carbon Steel ◽  
Current Efficiency ◽  
Current Density ◽  
Bath Temperature ◽  
Sem Analysis ◽  
Process Efficiency ◽  
Operational Parameters ◽  
Zinc Deposition ◽  
Coating Morphology ◽  
Electroplating Process

Zinc as a metallic coating is a common strategy to protect the carbon steel against corrosion. The most common process of zinc deposition is known as electroplating. Because of the high toxicity of cyanide-based baths, the interest in acid baths has grown, but they present many challenges to be overcome. Several operational parameters and bath constitution – such as current density, pH, and zinc concentration – can impact the current efficiency, deposit quality, and coating morphology. In this work, the process efficiency and the coating morphology were evaluated on electroplated AISI 1008 carbon steel samples. The current density and temperature were individually varied on a range from 7.5 mA.cm-2 to 30.5 mA.cm-2, and from 40 °C to 60 °C, respectively. The process efficiency was evaluated by current efficiency (eC). The surface morphology was analyzed by both optical microscopy (OM) and scanning electron microscopy (SEM). Varying the bath temperature did not promote impacts in the current efficiency, which remained in all temperatures evaluated over 95%. On the other hand, increasing the current density, increased the current efficiency, starting from (85 ± 2)% at 7.5 mA.cm-2 to (92 ± 2)% at 19.0 mA.cm-2, and (95 ± 1)% at 30.5 mA.cm-2. Through OM and SEM analysis, the increase in the temperature tended to turn the coating rougher, and the sample was not completely covered at 7.5 mA.cm-2. Therefore, we recommend the use of a temperature between 40 °C and 50 °C associated with a current density of 30.5 mA.cm-2.

Current Efficiency and Energy Consumption of Electrochemical Oxidation for Ammonia Removal from Coking Wastewater Using Boron-Doped Diamond Electrodes

2013 ◽  
Vol 295-298 ◽  
pp. 1327-1332 ◽  
Author(s):  
Chun Rong Wang ◽  
Sha Chang ◽  
Min Ye ◽  
Qin Yi Ren
Keyword(s):  
Energy Consumption ◽  
Current Efficiency ◽  
Current Density ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Ammonia Removal ◽  
Ion Concentration ◽  
Coking Wastewater ◽  
Concentration Increase ◽  
Density Decrease

The electrochemical treatment of ammonia using born-doped diamond (BDD) as advanced treatment of coking wastewater was investigated. The effects of chloride ion concentration and current density on current efficiency and energy consumption were also analyzed. The results show that the current efficiency increases with chloride ion concentration increase and current density decrease. And 30% of current efficiency is obtained when current density is less than 19.7mA cm-2, and it decreases above 19.7mA cm-2. The energy consumption decreases with the chloride ion concentration increase and current density decrease. And energy consumption of 0.50kWh g-1 and ammonia removal rate of 84.7% can be achieved at initial ammonia concentration of 100mg L-1, chloride concentration of 900mg L-1 and current density of 29.6mA cm-2.Therefore, BDD electrodes have high current efficiency and low energy consumption, which attributed to its high oxygen evolution overvoltage (2.6V vs. SCE) and low chloride evolution overvoltage (1.5V vs. SCE).

Electro-Crystallization of Antimony from Acidic and Alkaline Baths in Diaphragm-Less Cell

2013 ◽  
Vol 828 ◽  
pp. 65-72 ◽  
Author(s):  
Chinmaya Kumar Sarangi ◽  
Ayonbala Baral ◽  
Jayasmita Panigrahi ◽  
Kali Sanjay ◽  
Tondepu Subbaiah ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Current Efficiency ◽  
Current Density ◽  
Cathodic Current ◽  
Antimony Concentration ◽  
Morphological Studies ◽  
Alkaline Bath ◽  
Alkaline Baths ◽  
Acidic Bath

Studies based on electrocrystallization of antimony were carried out to evaluate the effects of current density and antimony concentration in the electrolytic bath on cathodic current efficiency, energy consumption, and quality of the deposits during electrowinning of antimony from Sb2O3-HCl and Sb2S3-NaOH systems. In acidic bath, current efficiency for electrodeposition of antimony increases with the increase in current density till 150 A/m2, beyond which it follows a trend of gradual diminution. On varying antimony concentration in the bath, current efficiency was found to improve significantly and the optimum antimony concentration in Sb2O3-HCl system was evaluated to be about 60 g/L. In alkaline bath, current efficiency was observed to be maximum at 50 A/m2and further, with the increase in current density it progressively decreases. However, energy consumption for electrowinning of antimony in both of the baths gradually increases with the increase in current density. At a current density less than 150 A/m2, alkaline bath was found to be more current efficient in comparison to the acidic bath. Crystallographic studies by XRD, imaging by optical microscopic technique and morphological studies by SEM were also carried out to differentiate antimony deposits obtained from acidic and alkaline baths.

scholarly journals A novel gradient current density output mode for effective electrochemical oxidative degradation of dye wastewater by boron-doped diamond (BDD) anode

2020 ◽  
Vol 82 (10) ◽  
pp. 2085-2097
Author(s):  
Ting Liu ◽  
Dongtian Miao ◽  
Guoshuai Liu ◽  
Qiuping Wei ◽  
Kechao Zhou ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Current Efficiency ◽  
Current Density ◽  
High Energy ◽  
Molecular Structures ◽  
Constant Current ◽  
Dye Wastewater ◽  
Output Process ◽  
Boron Doped Diamond ◽  
General Applicability

Abstract In order to solve the problems of high energy consumption and low current efficiency in electrochemical oxidation (EO) degradation under the traditional constant output process (COP), a gradient output process (GOP) of current density is proposed in this paper. That is, the current density is gradually reduced in a fixed degradation time, and the Reactive Blue 19 simulated dye wastewater was used as the degradation target. The general applicability of the process was further confirmed by studying the optimal gradient current density output parameters, the dye concentration, electrolyte concentration and other dye compounds with different molecular structures. The corresponding results show that the chemical oxygen demand (COD) removal (78%) and the color removal (100%) under the GOP are similar to those in the COP, and the overall energy consumption is reduced by about 50% compared with that in the traditional constant current mode. Moreover, the current efficiency in the middle and late stages of EO process has increased by 8.6 times compared with COP.

Recovery of Heavy Metal from Scrap Metal Pickling Wastewater by Electrolysis

1993 ◽  
Vol 28 (7) ◽  
pp. 223-229 ◽  
Author(s):  
Ju-Sheng Huang ◽  
I-Chung Lee ◽  
Biing-Jauh Lin
Keyword(s):  
Energy Consumption ◽  
Current Efficiency ◽  
Deposition Rate ◽  
Current Density ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Copper Ion ◽  
Surface Loading ◽  
Electro Deposition ◽  
Continuous Flow Reactors

When the influent surface loading of copper ion in the four-stage continuous-flow reactors of electrolysis were controlled at 143.9, 94.0, 52.7 and 33.2 mg/min-dm2, respectively, and current density were controlled at 3.9, 2.6, 1.3 and 1.3A/dm2, respectively, the concentration of copper decreased from 13,900 to l,900mg/l (i.e., the electro-deposition rate of copper were 2,700, 2,240, 1,500 and 750 mg/dm2-h, respectively). The purity of copper depositing on the cathode reached over 98%. When the current density was ranged from 1.3 to 3.9A/dm2, the electro-deposition rate of copper increased with the increasing current density. However, when the current density was raised above 5.2 A/dm2, the electro-deposition rate of copper decreased with the increasing current density. The increase of current density decreased the current efficiency and increased the specific energy consumption. The increase of influent surface loading of copper ion increased the current efficiency and decreased the specific energy consumption.

scholarly journals Forecasting Energy Consumption of Wastewater Treatment Plants with a Transfer Learning Approach for Sustainable Cities

Electronics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1149
Author(s):  
Pedro Oliveira ◽  
Bruno Fernandes ◽  
Cesar Analide ◽  
Paulo Novais
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Transfer Learning ◽  
Short Term Memory ◽  
Wastewater Treatment Plants ◽  
Learning Approach ◽  
Sustainable Cities ◽  
Short Term ◽  
Long Short Term Memory ◽  
Gated Recurrent Units

A major challenge of today’s society is to make large urban centres more sustainable. Improving the energy efficiency of the various infrastructures that make up cities is one aspect being considered when improving their sustainability, with Wastewater Treatment Plants (WWTPs) being one of them. Consequently, this study aims to conceive, tune, and evaluate a set of candidate deep learning models with the goal being to forecast the energy consumption of a WWTP, following a recursive multi-step approach. Three distinct types of models were experimented, in particular, Long Short-Term Memory networks (LSTMs), Gated Recurrent Units (GRUs), and uni-dimensional Convolutional Neural Networks (CNNs). Uni- and multi-variate settings were evaluated, as well as different methods for handling outliers. Promising forecasting results were obtained by CNN-based models, being this difference statistically significant when compared to LSTMs and GRUs, with the best model presenting an approximate overall error of 630 kWh when on a multi-variate setting. Finally, to overcome the problem of data scarcity in WWTPs, transfer learning processes were implemented, with promising results being achieved when using a pre-trained uni-variate CNN model, with the overall error reducing to 325 kWh.

Performance evaluation of different wastewater treatment technologies operating in a developing country

2011 ◽  
Vol 1 (1) ◽  
pp. 37-56 ◽  
Author(s):  
Sílvia C. Oliveira ◽  
Marcos von Sperling
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Septic Tank ◽  
Operational Parameters ◽  
Technical Literature ◽  
Effluent Quality ◽  
Loading Rates ◽  
Treatment Processes ◽  
Treatment Technologies ◽  
Uasb Reactors

This article analyses the performance of 166 wastewater treatment plants operating in Brazil, comprising six different treatment processes: septic tank + anaerobic filter, facultative pond, anaerobic pond + facultative pond, activated sludge, UASB reactors alone, UASB reactors followed by post-treatment. The study evaluates and compares the observed effluent quality and the removal efficiencies in terms of BOD, COD, TSS, TN, TP and FC with typical values reported in the technical literature. In view of the large performance variability observed, the existence of a relationship between design/operational parameters and treatment performance was investigated. From the results obtained, no consistent relationship between loading rates and effluent quality was found. The influence of loading rates differed from plant to plant, and the effluent quality was dictated by several combined factors related to design and operation.

Optimization for white organic light-emitting diode based on DCJTB as color conversion layer

2018 ◽  
Vol 32 (27) ◽  
pp. 1850299
Author(s):  
Pei Wang ◽  
Zhen Wang ◽  
Ai Chen ◽  
Jia-Feng Xie ◽  
Xin Zheng
Keyword(s):  
Current Efficiency ◽  
Current Density ◽  
White Light ◽  
Power Efficiency ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
High Efficient ◽  
Color Conversion

In this paper, combining phosphorescence and fluorescence to form white light was realized based on DCJTB:PMMA/ITO/NPB/TCTA/FIrpic:TCTA/TPBi/Ir(ppy)3:TPBi/TPBi/Cs2CO3/Al. The effects of red fluorescence on this white light device was studied by adjusting the concentration of DCJTB. The study shows that the device with a DCJTB concentration of 0.7% in the color conversion layer (CCL) generates a peak current efficiency and power efficiency of 23.4 cd ⋅ A[Formula: see text] and 7.5 lm ⋅ W[Formula: see text], respectively. And it is closest to the equal-energy white point of (0.33, 0.33) which shows a CIE (Commission Internationale de L’Eclairage) coordinate of (0.35, 0.43) and a color rendering index (CRI) of 70 at current density of 10 mA ⋅ cm[Formula: see text]. In order to improve the efficiency, we design and fabricate both high efficient and pure white organic light-emitting diode (WOLED) by replacing the single blue emission layer (EML) with double EMLs of FIrpic:TCTA and FIrpic:TPBi. The further study shows that, when the layers of EML is three and the concentration of DCJTB at 0.7%, the device exhibits good performance specifically, at current density of 10 mA ⋅ cm[Formula: see text], the current efficiency of 28.2 cd ⋅ A[Formula: see text] (power efficiency of 10.3 lm ⋅ W[Formula: see text]), and the CIE coordinate of (0.33, 0.31) (CRI of 80.38).

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