Effect of Voltage on the Treatment of Cyanide Wastewater by Three-dimensional Electrode

2017 ◽  
Vol 20 (4) ◽  
pp. 151-159 ◽  
Author(s):  
Di Yao ◽  
Yonghui Song ◽  
Shan Zhang ◽  
Yuhong Tian ◽  
Xinzhe Lan
Keyword(s):  
Wastewater Treatment ◽  
Reaction Mechanism ◽  
Heavy Metal Ions ◽  
Electrode Materials ◽  
Removal Rate ◽  
Three Dimensional ◽  
Electrolytic Deposition ◽  
Removal Rates ◽  
Concentration Of Ions ◽  
Scanning Electron

The effects of applied voltage on cyanide wastewater treatment by three-dimensional electrodes were primarily examined. The main electrodes were produced from self-made coal-based electrode materials, and activated carbon was used as a particle electrode to treat cyanide wastewater. Changes in the concentration of ions in wastewater were determined and analyzed through Scanning Electron Microscopy and Energy Dispersive Spectroscopy. Results show that voltage significantly affects wastewater treatment via the three-dimensional electrodes. In particular, the removal rate of the ions in wastewater increases as voltage increases. The reaction mechanism of the three-dimensional electrodes also varies at different voltages. At 1 V, the reaction mechanism of the three-dimensional electrodes involves electro-adsorption. The removal rates of CNT, Cu, Zn, SCN−, and CN− in wastewater are 31.81%, 53.04%, 36.11%, 29.05%, and 29.05%, respectively. The reaction mechanism of the three-dimensional electrodes includes electro-adsorption and enrichment precipitation when voltage is increased to 2 V. The three-dimensional electrode plays a significant role in electrolytic deposition when voltage is further increased to 3 and 4 V. Cu, Zn, and other heavy metal ions are reduced on the cathode and on the particle electrode surface, and the removal rates of CNT, Cu, Zn, SCN−, and CN− in wastewater are 93.94%, 95.22%, 97.23%, 99.38%, and 94.93%, respectively.

scholarly journals Enhanced Wastewater Treatment by Immobilized Enzymes

2021 ◽  
Author(s):  
Jakub Zdarta ◽  
Katarzyna Jankowska ◽  
Karolina Bachosz ◽  
Oliwia Degórska ◽  
Karolina Kaźmierczak ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Process Optimization ◽  
Organic Pollutants ◽  
Large Scale ◽  
Removal Rate ◽  
Immobilized Enzymes ◽  
Future Research ◽  
Process Conditions ◽  
Removal Rates ◽  
Catalytic Cycles

Abstract Purpose of Review In the presented review, we have summarized recent achievements on the use of immobilized oxidoreductases for biodegradation of hazardous organic pollutants including mainly dyes, pharmaceuticals, phenols, and bisphenols. In order to facilitate process optimization and achievement of high removal rates, effect of various process conditions on biodegradation has been highlighted and discussed. Recent Findings Current reports clearly show that immobilized oxidoreductases are capable of efficient conversion of organic pollutants, usually reaching over 90% of removal rate. Further, immobilized enzymes showed great recyclability potential, allowing their reuse in numerous of catalytic cycles. Summary Collected data clearly indicates immobilized oxidoreductases as an efficient biocatalytic tools for removal of hazardous phenolic compounds, making them a promising option for future water purification. Data shows, however, that both immobilization and biodegradation conditions affect conversion efficiency; therefore, process optimization is required to achieve high removal rates. Nevertheless, we have demonstrated future trends and highlighted several issues that have to be solved in the near-future research, to facilitate large-scale application of the immobilized oxidoreductases in wastewater treatment.

Efficiency of removal of nitrogen, phosphorus, and zinc from domestic wastewater by a constructed wetland system in rural areas: a case study

2008 ◽  
Vol 58 (12) ◽  
pp. 2427-2433 ◽  
Author(s):  
Kaoru Abe ◽  
Michio Komada ◽  
Akihito Ookuma
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetland ◽  
Rural Areas ◽  
Removal Rate ◽  
Domestic Wastewater ◽  
Removal Rates ◽  
Total N ◽  
Household Wastewater ◽  
Percentage Removal ◽  
Total P

The effluent from the combined household wastewater treatment facilities used in unsewered areas of Japan is generally high in nitrogen (N) and phosphorus (P). In Japan, environmental quality standards for zinc (Zn) pollution were enacted recently because of the toxicity of Zn to aquatic ecosystems. In 2004 a fallow paddy field at the Koibuchi College of Agriculture and Nutrition was converted into a surface-water-flow constructed wetland (500 m2) to clean the effluent from the combined household wastewater treatment facility of a dormitory (100 residents) before discharge to a pond. We evaluated N and P removal efficiencies and the fate of soluble Zn in the wetland from April 2006 to March 2007. Wetland influent contained an average of 18.3 mg L−1 total N and 1.86 mg L−1 total P. In the effluent from the wetland, average total N concentration was 10.3 mg L−1 and average total P was 0.90 mg L−1. Average removal rates were 0.37 g m−2 d−1 for total N and 0.050 g m−2 d−1 for total P (percentage removal rates of 40% and 48%, respectively). Soluble Zn concentration decreased from 0.041 in the influent to 0.023 mg L−1 after passing through the wetland. The average Zn removal rate during the year was 0.0007 g m−2 d−1 (percentage removal rate 37%).

Removal of selected non-steroidal anti-inflammatory drugs (NSAIDs), gemfibrozil, carbamazepine, b-blockers, trimethoprim and triclosan in conventional wastewater treatment plants in five EU countries and their discharge to the aquatic environment

2004 ◽  
Vol 50 (5) ◽  
pp. 253-260 ◽  
Author(s):  
N. Paxéus
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Aquatic Environment ◽  
Wastewater Treatment Plants ◽  
Removal Rate ◽  
Average Concentration ◽  
Operating Conditions ◽  
Removal Rates ◽  
Eu Countries ◽  
Acidic Drugs

The removal of commonly used pharmaceuticals (ibuprofen, naproxen, diclofenac, gemfibrozil, carbamazepine, atenolol, metoprolol and trimethoprim) and a biocide (triclosan) in operating wastewater treatment plants in five EU countries has been studied. Under normal operating conditions the acidic drugs and triclosan were partially removed with removal rates varying from ca. 20 to >95%. The highest removal rate was found for ibuprofen and triclosan (>90%) followed by naproxen (80%), gemfibrozil (55%) and diclofenac (39%). Ibuprofen undergoes an oxidative transformation to corresponding hydroxy- and carboxy- metabolites, which contributes to its high removal rate. Disturbances in the activated sludge process resulted in lower removal rates for all acidic drugs, mostly for diclofenac (<10% removed) but also for ibuprofen (<60% removed). The treatment of wastewaters by activated sludge usually did not result in any practical removal (<10%) of neutral carbamazepine or basic atenolol, metoprolol and trimethoprim. The removal rates of the investigated drugs and triclosan are discussed in terms of mechanisms responsible for their removal. Discharges of carbamazepine, diclofenac, gemfibrozil, naproxen, triclosan and trimethoprim from WWTPs to the aquatic environment, expressed as the average concentration in the effluent and the daily discharged quantity per person served by WWTPs were assessed.

scholarly journals Optimization for simultaneous removal of NH3-N and COD from coking wastewater via a three-dimensional electrode system with coal-based electrode materials by RSM method

2021 ◽  
Vol 10 (1) ◽  
pp. 756-767
Author(s):  
Ting Su ◽  
Wenwen Gao ◽  
Xiangdong Xing ◽  
Xinzhe Lan ◽  
Yonghui Song
Keyword(s):  
Applied Voltage ◽  
Processing Time ◽  
Electrode Materials ◽  
Removal Rate ◽  
Three Dimensional ◽  
Electrode System ◽  
Simultaneous Removal ◽  
Coking Wastewater ◽  
Plate Spacing ◽  
Electrode Plate

Abstract The present work demonstrated preparation of coal-based electrode materials (CEM)-derived low-rank coal for simultaneous removal of ammonia nitrogen (NH3-N) and chemical oxygen demand (COD) from coking wastewater by a three-dimensional electrode system (3DES). The influence of important parameters in 3DES such as processing time, applied voltage, electrode plate spacing, mass of commercially activated carbon (CAC), and initial pH were investigated. Based on the central composite design, the response surface method (RSM) was employed in order to optimize the variable parameters in removal process of pollutants. From the analysis of RSM, the optimum conditions for 3DES were 4.5 h of processing time, 5.5 V of applied voltage, 17 mm electrode plate spacing, 4.5 g CAC, and pH of 3 with higher simultaneous removal rate of COD (74.20%) and NH3-N (51.48%). Besides, the content of N element (4.9%) and N containing groups were traced by SEM-EDS and FTIR analysis in order to verify the removal effect. The experiment results showed the capability of CEM for electrode system removal of pollutants from coking wastewater and obtained considerable simultaneous removal rate of NH3-N and COD.

Electrochemical Reduction of Nitrate by Fe-Si Alloy Electrode

2011 ◽  
Vol 287-290 ◽  
pp. 1789-1794 ◽  
Author(s):  
Min Li ◽  
Yan Zhi Sun ◽  
Cai Ying Li ◽  
Ping Yu Wan
Keyword(s):  
Reaction Time ◽  
Electrochemical Reduction ◽  
Removal Efficiency ◽  
Current Density ◽  
Electrode Materials ◽  
Removal Rate ◽  
Three Dimensional ◽  
Electrochemical Catalysis ◽  
Test Conditions ◽  
Permeable Electrode

The present paper studies the removal of the nitrogen in the form of nitrate in water by electrochemical catalysis reduction. The influence of electrode materials and various test conditions on the removal efficiency was studied. The experimental results show that the removal rate of nitrate can reach above 90% by using a three-dimensional permeable electrode of Fe-Si alloy under the condition of flowrate of 600ml/h, current density of 10mA/cm2and reaction time of 2h.

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

A Scanning Electron Microscope Study of Isolated Guard Cells

1973 ◽  
Vol 31 ◽  
pp. 454-455 ◽  
Author(s):  
P. Dayanandan ◽  
P. B. Kaufman
Keyword(s):  
Electron Microscope ◽  
Electron Microscope Study ◽  
Three Dimensional ◽  
Guard Cells ◽  
Scanning Electron Microscope Study ◽  
Psilotum Nudum ◽  
Subsidiary Cells ◽  
Welwitschia Mirabilis ◽  
Cycas Revoluta ◽  
Scanning Electron

A three dimensional appreciation of the guard cell morphology coupled with ultrastjuctural studies should lead to a better understanding of their still obscure dynamics of movement. We have found the SEM of great value not only in studies of the surface details of stomata but also in resolving the structures and relationships that exist between the guard and subsidiary cells. We now report the isolation and SEM studies of guard cells from nine genera of plants.Guard cells were isolated from the following plants: Psilotum nudum, four species of Equisetum, Cycas revoluta, Ceratozamia sp., Pinus sylvestris, Ephedra cochuma, Welwitschia mirabilis, Euphorbia tirucalli and Allium cepa.

Scanning electron microscopy of freeze-fractured prescapular lymph node of caprine

1984 ◽  
Vol 42 ◽  
pp. 244-245
Author(s):  
O. Faroon ◽  
F. Al-Bagdadi ◽  
T. G. Snider ◽  
C. Titkemeyer
Keyword(s):  
Lymph Node ◽  
Lymph Nodes ◽  
Lymphatic System ◽  
Three Dimensional ◽  
Meat Products ◽  
The Body ◽  
Morphological Data ◽  
The World ◽  
Cellular Constituent ◽  
Scanning Electron

The lymphatic system is very important in the immunological activities of the body. Clinicians confirm the diagnosis of infectious diseases by palpating the involved cutaneous lymph node for changes in size, heat, and consistency. Clinical pathologists diagnose systemic diseases through biopsies of superficial lymph nodes. In many parts of the world the goat is considered as an important source of milk and meat products.The lymphatic system has been studied extensively. These studies lack precise information on the natural morphology of the lymph nodes and their vascular and cellular constituent. This is due to using improper technique for such studies. A few studies used the SEM, conducted by cutting the lymph node with a blade. The morphological data collected by this method are artificial and do not reflect the normal three dimensional surface of the examined area of the lymph node. SEM has been used to study the lymph vessels and lymph nodes of different animals. No information on the cutaneous lymph nodes of the goat has ever been collected using the scanning electron microscope.

Scanning Electron Microscopy and Electron Microprobe Analysis of Malignant Cell Cultures

1968 ◽  
Vol 26 ◽  
pp. 164-165
Author(s):  
R. I. Johnsson-Hegyeli ◽  
A. F. Hegyeli ◽  
D. K. Landstrom ◽  
W. C. Lane
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Cultures ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Three Dimensional ◽  
Malignant Cell ◽  
Interference Microscopy ◽  
Scanning Electron

Last year we reported on the use of reflected light interference microscopy (RLIM) for the direct color photography of the surfaces of living normal and malignant cell cultures without the use of replicas, fixatives, or stains. The surface topography of living cells was found to follow underlying cellular structures such as nuceloli, nuclear membranes, and cytoplasmic organelles, making possible the study of their three-dimensional relationships in time. The technique makes possible the direct examination of cells grown on opaque as well as transparent surfaces. The successful in situ electron microprobe analysis of the elemental composition and distribution within single tissue culture cells was also reported.This paper deals with the parallel and combined use of scanning electron microscopy (SEM) and the two previous techniques in a study of living and fixed cancer cells. All three studies can be carried out consecutively on the same experimental specimens without disturbing the cells or their structural relationships to each other and the surface on which they are grown. KB carcinoma cells were grown on glass coverslips in closed Leighto tubes as previously described. The cultures were photographed alive by means of RLIM, then fixed with a fixative modified from Sabatini, et al (1963).

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