scholarly journals Effect of Chloride Ions on Electro-Coagulation to Treat Industrial Wastewater Containing Cu and Ni

2020 ◽  
Vol 12 (18) ◽  
pp. 7693
Author(s):  
Chien-Hung Huang ◽  
Shan-Yi Shen ◽  
Chiu-Wen Chen ◽  
Cheng-Di Dong ◽  
Mohanraj Kumar ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Ph Value ◽  
Electricity Consumption ◽  
Chloride Ions ◽  
Circuit Board ◽  
Treated Wastewater ◽  
Coagulation System ◽  
Initial Ph ◽  
Effects Of Ph ◽  
Electro Coagulation

A series of experiments with different NaCl concentrations added to the PCB (printed circuit board) wastewater were prepared to investigate the chloride effect on the formation of aluminum floc and removal efficiency of Cu and Ni. The effects of pH, current density, and different concentration of NaCl were studied and the results are discussed. Results imply that chloride ions are favored to avoid the passivation of the aluminum anode in the EC (electro-coagulation) system. Chloride ions used as the electrolyte can facilitate the release of Al3+, which results in the current efficiency of over 100% in the EC system. For the PCB factory’s wastewater, the EC system could remove Cu2+ and Ni2+ effectively (both Cu and Ni concentration of treated wastewater was less than 1.0 mg/L within three minutes). PCB wastewater’s pH value could maintain stably about 9.0 in the EC system when the initial pH value was around 2.5. The estimated electricity consumption for treating PCB wastewater by the EC process was about 0.894 kWh for each meter of cubic wastewater.

Bio-Treatment of APMP Effluent with Activated Sludge

2014 ◽  
Vol 675-677 ◽  
pp. 505-509
Author(s):  
Ting Zhi Liu ◽  
Hao Yu Wang ◽  
Shuai Li ◽  
Yuan Liu
Keyword(s):  
Activated Sludge ◽  
Ph Value ◽  
Effluent Treatment ◽  
Treated Wastewater ◽  
Process Conditions ◽  
Wood Extractives ◽  
Mechanical Pulp ◽  
Alkaline Peroxide ◽  
Initial Ph ◽  
Optimized Conditions

Aerobic activated sludge was more appropriate for APMP(Alkaline Peroxide Mechanical Pulp) effluent treatment than anaerobic processes because the high content of toxic wood extractives in the effluent. In this article, Eucalyptus APMP effluent was treated with activated sludge and the process conditions was optimized. The optimized conditions were: the initial pH value was 6.0, SV30of activated sludge was 35%, and loading volume of flask was 150ml (250ml flask), cultured shakily for 3 days at 35°Cand 150rpm. The removal of COD was 66.75%, from 4181mg/l to 1390mg/l, and the color of the effluent and treated water were 2541C.U. and 1557C.U. under the optimized conditions, respectively. In most cases, the color of treated wastewater was increased compared with the initial effluent, but the removal of COD was significant.

scholarly journals Adsorption-Oxidation Mechanism of δ-MnO2 to Remove Methylene Blue

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ge Yan ◽  
Pu Wang ◽  
Yuqian Li ◽  
Zhangjie Qin ◽  
Shuai Lan ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Adsorption Mechanism ◽  
Ph Value ◽  
Oxidation Mechanism ◽  
Superior Performance ◽  
Adsorption Ability ◽  
Initial Ph ◽  
Effects Of Ph ◽  
Ph Conditions ◽  
Positively Charged

The material, δ-MnO2, has exhibited superior performance on the removal of methylene blue (MB), but the process is significantly impacted by pH, and the impacting mechanism is still unclear. In this study, the effects of pH on the removal mechanism of MB using synthesized δ-MnO2 were investigated by distinguishing the adsorption and oxidation of MB by δ-MnO2 during the removal process in the dark. The results show that the total removal efficiency of MB by δ-MnO2 decreased significantly with an increase in the pH. MB could be removed by δ-MnO2 via an adsorption mechanism and oxidation mechanism, and the proportion of adsorptive removal and oxidative removal was different under different pH conditions. With an increase in the initial pH from 2.00 to 8.05, the redox potential of δ-MnO2 decreased, and its oxidation ability for the removal of MB also gradually decreased. In contrast, the surface negative charges of δ-MnO2 increased with an increase in the pH, and the adsorption ability towards positively charged MB also gradually increased. This indicates that the effects of pH on the removal of MB by δ-MnO2 are primarily dominated by its influence on the oxidation ability of δ-MnO2. In addition, it is further proved that the pH value has a significant effect on the oxidation and adsorption of MB on δ-MnO2. Moreover, the significant effects of pH on the oxidation of MB by δ-MnO2 are further demonstrated by observing the changes in Mn2+ and the UV-Vis spectra of intermediate products during the reaction, as well as the changes in the FTIR and XPS characterizations of δ-MnO2 after the reaction.

scholarly journals Removal of Trace Thallium from Industrial Wastewater by Fe0-Electrocoagulation

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 163 ◽  
Author(s):  
Xianghui Fu ◽  
Li Li ◽  
Guochao Yang ◽  
Xiangyang Xu ◽  
Lihua He ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Current Density ◽  
Industrial Wastewater ◽  
Ph Value ◽  
Operation Time ◽  
Single Step ◽  
Toxic Heavy Metal ◽  
Effective Removal ◽  
Initial Ph ◽  
Effects Of Ph

As thallium (Tl) is a highly toxic heavy metal, there are compulsory environmental regulations in many countries on minimizing its release. This research investigated the treatment of real industrial wastewater with low Tl(I) concentration by Fe0-electrocoagulation (Fe0-EC) in a batch aeration-forced pump cycle reactor. The effects of pH (7–12), current density (8.3–33.3 mA/cm2), dissolved oxygen (DO) in wastewater, and initial Tl(I) concentration (66–165 µg/L) on Tl(I) removal efficiency were investigated. The removal efficiency of Tl(I) is pH-dependent, to be exact, it increases significantly with pH rising from 8 to 11. Initial pH of influent and DO concentration were the key operation parameters which strongly affect Tl(I) removal. After the water sample with initial Tl(I) concentration of 115 µg/L was treated for 12 min by a single-step process at pH of 11 and current density of 16.7 mA/cm2, the residual Tl(I) concentration was decreased to beneath the emission limit in China (2 µg/L) with a low energy consumption of 0.82 kWh/m3. By prolonging the operation time, the concentration was further reduced to 0.5 µg/L or even lower. The main composition of the flocculent sludges is iron oxyhydroxide, yet its crystal structure varies dependent on pH value which may result in different Tl(I) removal efficiency. Feroxyhyte nanosheets generate in situ by Fe0-EC, which contributes to the rapid and effective removal of Tl(I), while the speedy oxidation under DO-enriched conditions benefits the feroxyhyte formation. The mechanism of Tl(I) removal by Fe0-EC is attributed to the combination of electrostatic attraction and the formation of inner-sphere complexes. As shown in the technical and mechanical studies, Fe0-EC technology is an effective method for low Tl concentration removal from wastewater.

DIP quality influenced by process water quality

TAPPI Journal ◽  
2014 ◽  
Vol 13 (9) ◽  
pp. 51-60
Author(s):  
DENNIS VOSS ◽  
HANS-JOACHIM PUTZ ◽  
SAMUEL SCHABEL
Keyword(s):  
Water Quality ◽  
Surface Tension ◽  
Ph Value ◽  
Water Hardness ◽  
Process Water ◽  
Test Results ◽  
Negative Effects ◽  
Water Parameters ◽  
Effects Of Ph ◽  
Contamination Levels

The need for deinking mills to reduce their fresh water consumption has resulted in higher loads of various contaminants in the process water. Lower recovered paper quality also leads to higher contamination levels in the mills. This higher load has an influence on achievable target brightness. The objective of the work was to determine and explain the main reasons for relatively poor deinked pulp quality or poor deinking potential based on the influence of recovered paper composition and process water quality. The process water parameters significantly affect the deinking potential of recovered paper. The test results showed the negative effects of increased water hardness. For standard recovered paper mixtures, flotation selectivity is higher with increasing flotation pH-value. Good results were realized for standard recovered paper with low hardness, low surface tension, and high pH-value. The results for recovered paper containing flexo newsprint could be slightly improved with low hardness, low surface tension, and low pH-value. The results of the test program using design of experiments showed interacting effects of pH-value and surface tension on luminosity and flotation selectivity.

Characteristics of Radiated Emission from a Printed Circuit Board with a Slit

2012 ◽  
Vol 132 (6) ◽  
pp. 404-410 ◽  
Author(s):  
Kenichi Nakayama ◽  
Kenichi Kagoshima ◽  
Shigeki Takeda
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Printed Circuit ◽  
Radiated Emission

Confirming the Signal Integrity in Transmission of Digital Signals on Microstrip Straight Circuits via the Eye Diagrams

2014 ◽  
Vol 5 (1) ◽  
pp. 737-741
Author(s):  
Alejandro Dueñas Jiménez ◽  
Francisco Jiménez Hernández
Keyword(s):  
Integrated Circuits ◽  
Printed Circuit Board ◽  
Signal Integrity ◽  
High Volume ◽  
Information Storage ◽  
Circuit Board ◽  
Electromagnetic Simulation ◽  
Electronic Systems ◽  
Digital Signals ◽  
Printed Circuit

Because of the high volume of processing, transmission, and information storage, electronic systems presently requires faster clock speeds tosynchronizethe integrated circuits. Presently the “speeds” on the connections of a printed circuit board (PCB) are in the order of the GHz. At these frequencies the behavior of the interconnects are more like that of a transmission line, and hence distortion, delay, and phase shift- effects caused by phenomena like cross talk, ringing and over shot are present and may be undesirable for the performance of a circuit or system.Some of these phrases were extracted from the chapter eight of book “2-D Electromagnetic Simulation of Passive Microstrip Circuits” from the corresponding author of this paper.

DIDACTIC MODEL OF LIFT

2018 ◽  
pp. 219-224
Author(s):  
Lubica Miková
Keyword(s):  
Printed Circuit Board ◽  
Base Plate ◽  
Educational Process ◽  
Circuit Board ◽  
Basic Knowledge ◽  
Practical Training ◽  
Target Setting ◽  
Lower Base ◽  
Complex Design ◽  
Starting Point

Urgency of the research. Mechatronics products become more sophisticated and complicated. Mechatronic engineers should be prepared for this complex design process. Practical experimental model helps improve educational process as preparing for practice. Target setting. Miniaturized model of the lift suitable for practical training on subjects focused to microcontrollers, sen-sors, actuators etc. Students have possibility to make practice on laboratory exercises, where they can verify theoretical knowledge obtained on lectures. The arrangement of the model has modular character, because of possibility to rearrange or adding of new function into model. The aim was to create minimized model of real lift with all functions and systems. Actual scientific researches and issues analysis. Many universities are oriented only to finished robotic kits and do not support creativity of students. Open access and open structure model missing in this field. There is a need for fast prototyping model, which allows the creation of new design of product. Uninvestigated parts of general matters defining. The question of the design of printed circuit board are uninvestigated, because they need more time than allows normal exercises. The research objective. The main aim of educational process is to educate engineers with basic knowledge, skills and handicraft. Practical models help as support devices for fulfil of this aim. All mechatronic students can practice a training on these practical models. They become as more skilled and well-oriented engineers.. The statement of basic materials. Construction consist of upper and lower base plate connected with four pillars used as linear guide for moving of lift cage. Lower base plate includes base microcontrollers boards, resistor network, power transis-tor array board, power supply terminals, relay modules, PWM module and signals terminals. Upper base plate consist of DC motor with gearing and screw mechanism for moving the lift cage. Conclusions. The model enables supports the creativity of the students. The starting point of the using of the model can be without any wired connections. Students should connect every part and try functionality of every function. The students receive the defined several problems and they have to analyze it and make any proposal for solution of defined problems.

Root Cause Analysis of a Connector Time-Delayed Fracture

2015 ◽  
Author(s):  
Prabjit Singh ◽  
Ying Yu ◽  
Robert E. Davis
Keyword(s):  
Printed Circuit Board ◽  
Ceramic Substrate ◽  
Circuit Board ◽  
Delayed Fracture ◽  
Ceramic Substrates ◽  
Printed Circuit ◽  
Root Cause ◽  
Chip Carrier ◽  
Electrical Connections ◽  
Grain Boundary Grooves

Abstract A land-grid array connector, electrically connecting an array of plated contact pads on a ceramic substrate chip carrier to plated contact pads on a printed circuit board (PCB), failed in a year after assembly due to time-delayed fracture of multiple C-shaped spring connectors. The land-grid-array connectors analyzed had arrays of connectors consisting of gold on nickel plated Be-Cu C-shaped springs in compression that made electrical connections between the pads on the ceramic substrates and the PCBs. Metallography, fractography and surface analyses revealed the root cause of the C-spring connector fracture to be plating solutions trapped in deep grain boundary grooves etched into the C-spring connectors during the pre-plating cleaning operation. The stress necessary for the stress corrosion cracking mechanism was provided by the C-spring connectors, in the land-grid array, being compressed between the ceramic substrate and the printed circuit board.

Application of Lock-in Thermography on PCB for Fault Localization and Validation of Failure Mechanism Due to External Discrete Component Variation

2010 ◽  
Author(s):  
William Ng ◽  
Kevin Weaver ◽  
Zachary Gemmill ◽  
Herve Deslandes ◽  
Rudolf Schlangen
Keyword(s):  
Failure Mechanism ◽  
Integrated Circuit ◽  
Printed Circuit Board ◽  
Hot Spot ◽  
Circuit Board ◽  
Discrete Component ◽  
Printed Circuit ◽  
Thermal Signature ◽  
Lock In

Abstract This paper demonstrates the use of a real time lock-in thermography (LIT) system to non-destructively characterize thermal events prior to the failing of an integrated circuit (IC) device. A case study using a packaged IC mounted on printed circuit board (PCB) is presented. The result validated the failing model by observing the thermal signature on the package. Subsequent analysis from the backside of the IC identified a hot spot in internal circuitry sensitive to varying value of external discrete component (inductor) on PCB.

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