Study of the current waveform effect on the formation of cathode deposits during direct electrolysis. Part 2. Electrolysis of sea water

2021 ◽  
pp. 33-40
Author(s):  
И.В. Пчельников ◽  
Т.Т.З. Нгуен ◽  
Л.Н. Фесенко
Keyword(s):  
Sodium Hypochlorite ◽  
Mineral Water ◽  
Sea Water ◽  
Salt Water ◽  
Reverse Current ◽  
Oxide Coating ◽  
Raw Material ◽  
Sodium Hypochlorite Solution ◽  
High Concentration ◽  
Direct Electrolysis

Поваренная соль является сырьем для получения гипохлорита натрия, при этом затраты на ее приобретение и доставку составляют до 25–30% от общей стоимости произведенного дезинфектанта. Альтернативным сырьем для получения гипохлорита натрия могут быть хлориды, содержащиеся в природной минеральной воде, например подземной, морской и океанической. Минеральная вода будет сырьем для получения раствора гипохлорита натрия достаточно высокой концентрации, который можно затем добавлять в обрабатываемую воду. Опыт эксплуатации установок «ХЛОРЭФС» производства ООО НПП «ЭКОФЕС» показал, что основная проблема надежности работы электролизеров связана с образованием отложений солей жесткости: карбоната кальция на поверхности катодного электрода и гидроксида магния на поверхности катодов электролизера. Это приводит к негативному режиму электролиза, росту напряжения, перегреву и короблению электродной системы, разрушению оксидного покрытия анодов и т. д. Приведены результаты исследований прямого электролиза постоянным и реверсным током соленой воды Южно-Вьетнамского моря. В испытаниях оценивали влияние реверсного тока в сравнении с постоянным током на снижение образования нерастворимых веществ на катодах электролизера, а также определяли технологические параметры электролиза. Выход хлора по току для морской воды был выше 100% в реверсном режиме с плотностью тока 100 А/м2. Sodium chloride is a raw material for the production of sodium hypochlorite; however, the cost of its purchase and delivery is up to 25–30% of the total cost of the disinfectant produced. An alternative raw material for the production of sodium hypochlorite can be chlorides present in natural mineral water, e. g., underground, sea and oceanic water. Mineral water will be the raw material for obtaining sodium hypochlorite solution of a sufficiently high concentration that can then be added to the treated water. The experience of operating CHLOREFS units manufactured by EKOFES SPE LLC showed that the main problem related to the electrolyzer operation reliability is associated with the formation of deposits of hardness salts – calcium carbonate on the surface of the cathodic electrode, and magnesium hydroxide on the surface of the electrolyzer cathodes. This results in a negative electrolysis regime, an increase in voltage, overheating and warping of the electrode system, destruction of the oxide coating of the anodes, etc. The results of studies of direct electrolysis by direct and reverse current of salt water of the South Vietnam Sea are presented. During the tests the effect of reverse current in comparison with direct current on the reduction of the formation of insoluble substances on the cathodes of the electrolyzer was estimated, and besides, the electrolysis process parameters were determined. The current chlorine yield for seawater was above 100% in the reverse mode with a current density of 100 A/m2.

Study of the current waveform effect on the formation of cathode deposits during direct electrolysis Part 1. Electrolysis of fresh water

2021 ◽  
pp. 18-25
Author(s):  
И.В. Пчельников ◽  
Т.Т.З. Нгуен ◽  
Л.Н. Фесенко
Keyword(s):  
Fresh Water ◽  
Sodium Hypochlorite ◽  
Direct Current ◽  
Water Oxidation ◽  
Tap Water ◽  
Reverse Current ◽  
Raw Material ◽  
Half Cycle ◽  
Current Output ◽  
Direct Electrolysis

При электрохимической обработке хлоридсодержащих природных вод в бездиафрагменном электролизере образуются соли хлорноватистой кислоты, проявляющие окислительные свойства. Этот процесс широко используется для производства дезинфицирующих растворов на основе гипохлорита натрия. Сырьем для производства гипохлорита натрия могут быть не только искусственно приготовленные солевые растворы, но и природные минеральные воды, содержащие хлориды. Электролиз таких растворов приводит к образованию на катоде электролизера нерастворимых солей кальция и магния, что препятствует массообмену в межэлектродном пространстве, а также к возникновению аварийных ситуаций. В первой части статьи приведены результаты исследований прямого электролиза постоянным и реверсным током пресной воды г. Донгхой, Республика Вьетнам. В проведенных испытаниях определяли влияние реверсного тока в сравнении с постоянным током на снижение образования нерастворимых веществ на катодах электролизера. Эксперименты показали преимущество реверсного тока над постоянным. Так, при электролизе реверсным током продолжительностью периода до 6 часов масса отложений на электродах не увеличивалась, а на постоянном токе накапливалась с момента начала электролиза. Это связано с тем, что осадок, образующийся в катодный полупериод, растворяется в анодный полупериод кислотой – продуктом окисления воды. Выход хлора по току для водопроводной воды составил не более 23% с плотностью тока 100 А/м2. During the electrochemical processing of chloride-containing natural water in a membraneless electrolyzer, salts of hypochlorous acid are formed that are exhibiting oxidizing properties. This process is widely used for the production of sodium hypochlorite disinfectants. The raw material for the production of sodium hypochlorite can be not only artificially prepared saline solutions, but also natural mineral water containing chlorides. The electrolysis of such solutions results in the formation of insoluble calcium and magnesium salts at the cathode of the electrolyzer thus inhibiting mass transfer in the interelectrode space and the occurrence of emergency situations. The first part of the article presents the results of studies of direct electrolysis of fresh water with constant and reverse current in Dong Hoi city, Republic of Vietnam. In the conducted tests the effect of reverse current in comparison with direct current on the reduction of the formation of insoluble substances at the cathodes of the electrolyzer was determined. The experiments have shown the advantage of reverse current over direct current. So, during the electrolysis with reverse current for a period of up to 6 hours, the amount of deposits on the electrodes did not increase, however, with direct current the deposits accumulated from the very beginning of the electrolysis process. This is due to the fact that the precipitate formed during the cathodic half cycle is dissolved during the anodic half cycle by acid, a product of water oxidation. The current output of chlorine for tap water was no more than 23% with a current density of 100 A/m2.

Исследование прямого электролиза воды Вьетнамского моря при производстве гипохлорита натрия

2019 ◽  
pp. 4-9
Author(s):  
Igor, Pchel’nikov ◽  
A. Terikov ◽  
T.T.Z. Nguen ◽  
S. Shchukin
Keyword(s):  
Sodium Hypochlorite ◽  
Natural Waters ◽  
Sea Water ◽  
Specific Energy Consumption ◽  
Economic Feasibility ◽  
Raw Material ◽  
Active Chlorine ◽  
Main Process ◽  
The Cost ◽  
Direct Electrolysis

Electrochemical sodium hypochlorite is used at water supply facilities all around the world. The use of natural waters containing chlorides as a raw material is very promising since it greatly simplifies the process flow scheme for producing sodium hypochlorite. Direct electrolysis technology can be retrofitted into the existing water treatment schemes without significant changes. The use of natural water containing chlorides eliminates the purchase of salt which reduces the cost of the finished product. The results of studies of direct electrolysis of water in the Vietnam Sea are presented. During the experiments the effect of seawater flow rate and current density on the concentration of active chlorine in the resulting sodium hypochlorite, the change in the current chlorine yield and the specific energy consumption per 1 kg of generated active chlorine were determined. The main process parameters are determined that provide for producing sodium hypochlorite by direct electrolysis of sea water using an iridiumruthenium oxide titanium anode as electrodes. It was shown that the current chlorine yield reaches maximum values (85 90) at an active chlorine concentration in the product of 2 0.2 g/dm3 which motivate the technological and economic feasibility of obtaining sodium hypochlorite from sea (ocean) water.Электрохимический гипохлорит натрия применяется на объектах водоснабжения во всем мире. В качестве сырья перспективно использование природных вод, содержащих хлориды, что существенно упрощает технологическую схему получения гипохлорита натрия. Технология прямого электролиза может встраиваться в действующие схемы водоподготовки без их существенного изменения. Применение природных вод, содержащих хлориды, позволяет отказаться от покупки поваренной соли, что снижает стоимость готового продукта. Представлены результаты исследований прямого электролиза воды Вьетнамского моря. В ходе экспериментов определяли влияние расхода морской воды и плотности тока на концентрацию активного хлора в получаемом гипохлорите натрия, изменение величины выхода хлора по току и удельный расход электроэнергии на 1 кг образующегося активного хлора. Определены основные технологические параметры, позволяющие получать гипохлорит натрия прямым электролизом морской воды с использованием в качестве электродов оксидный иридиеворутений титановый анод. Показано, что выход хлора по току достигает максимальных значений (85 90) при концентрации активного хлора в продукте 2 0,2 г/дм3, что обусловливает технологическую и экономическую целесообразность получения гипохлорита натрия из морской (океанской) воды.

scholarly journals A new concept for marine environmental sustainability through recovery of magnesium carbonate from traditional salt production wastewater

2018 ◽  
Vol 2 (2) ◽  
pp. 93-99
Author(s):  
Mirna Apriani ◽  
Wahyono Hadi ◽  
Ali Masduqi
Keyword(s):  
Environmental Sustainability ◽  
Sea Water ◽  
Magnesium Carbonate ◽  
Raw Material ◽  
Ion Concentration ◽  
High Concentration ◽  
Wastewater Disposal ◽  
Material Characteristics ◽  
Potential Strategy ◽  
Marine Environmental

Environmental sustainability influenced social and economy sustainability. Without sustainably productive environment to provide resource foundation, it would difficult having sustainable society. Sustainable economy depends on sustainable raw material, energy and environmental resources. This work discussed about environmental sustainability in marine especially utilizing sea water as raw material for salt. This work started to investigate raw material characteristics and salt quality. The raw material characteristics represented high concentration for sodium, chloride, calcium and polluted by trace metal. According SEM-EDX result, salt contains lead and cooper. Salt farmer income is influenced by the salt quality, the higher its quality the bigger income received. Indirectly, economy in coastal was influenced by sea water quality. This is what encourages the research to achieve marine environmental sustainability in coastal area. The aims of this study are to review and categorize indicator for marine environmental sustainability into Driver-Pressure-States-Impacts-Response (DPSIR) and provide strategies suggestion for support environmental sustainability.  DPSIR indicators are utilizing sea water, wastewater discharge into sea, increasing of sea water ion concentration, mangrove growth disruption, regulation for salt wastewater disposal direct to the sea. Recovery magnesium from salt wastewater is potential strategy to protect marine environment and to support economy-social sustainability.

scholarly journals THE USE OF SUNLIGHT FOR SUSPENSION OF SALT WATER WITH CONVERGEN CONVERSION LENS

Tibuana ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 56-60
Author(s):  
Titik Koesdijati
Keyword(s):  
Confidence Interval ◽  
Sea Water ◽  
Raw Materials ◽  
Salt Water ◽  
Sea Salt ◽  
Raw Material ◽  
The Sun ◽  
Convex Lens ◽  
Water Salt ◽  
Made In

Salt in the main need for humans, In the process of shrinkage of salt products become the expected result is always increased because in the islands of Madura who have high salt income can be utilized. Light focus can be used through convex convex lens to increase sea water shrinkage so as to accelerate evaporation as well Get shrinkage of salt water salt raw material quickly. From observations made in May - June 2017 can be obtained data focusing light through convex convex lens is by focusing the sun on convex lens that is directed at sea water, so it can shrink the water faster. Acquisition of water depreciation using the tool obtained 95,000 cc / 95 liters, while 47.000 cc / 47 liters obtained from without tools. From this study it can be concluded that the value obtained yields a positive value, where the use of the tool from the volume of each volume filled 100 liters with a ratio of 1: 1 from the analysis obtained from using a tool faster 56% using tools with upper 14322.90 Of the 99% confidence interval received. So from the shrinkage using a faster tool, the depreciation of sea salt raw materials with convergent convex lenses can be applied directly as a technological reasoning.

scholarly journals Evaluation of the influence of UV radiation and sodium hypochlorite on the shelf life of strawberries

2021 ◽  
Vol 10 (11) ◽  
pp. e134101119311
Author(s):  
Amanda Eri Anze ◽  
Ana Claudia Granato Malpass ◽  
Geoffroy Roger Pointer Malpass ◽  
Monica Hitomi Okura
Keyword(s):  
Shelf Life ◽  
Uv Radiation ◽  
Sodium Hypochlorite ◽  
Uv Light ◽  
Raw Material ◽  
Life Extension ◽  
Sodium Hypochlorite Solution ◽  
Hypochlorite Solution ◽  
The Relationship ◽  
Plastic Containers

It is common to combine methods to increase the shelf life of a raw material or product. In this study, we sought to understand the relationship between ultraviolet (UV) radiation and sodium hypochlorite (NaOCl) in attenuating the proliferation of fungus and its deteriorating effect on strawberries. The UV light intensities of 125, 250 and 400 Watts (W) and sodium hypochlorite were tested in concentrations 0.5, 1.0 and 1.5 ppm. The strawberries were sprayed with sodium hypochlorite solutions and then kept for 1 minute in UV light chambers, to then be stored in transparent sealed plastic containers. The strawberry samples with the longest life were those that were sprayed with 0.5 and 1.0 ppm sodium hypochlorite solution combined with exposure to 125 W UV light. These samples had a shelf-life extension of about five days compared to strawberries without any kind of treatment. Thus, it is possible to state that this combination is efficient in cleaning the fruit without causing damage.

Investigational Studies on Quantity of Salinity in Netravati River Estuary Sand-Coastal Karnataka

2018 ◽  
Vol 6 (6) ◽  
pp. 46
Author(s):  
Raveesha P ◽  
K. E. Prakash ◽  
B. T. Suresh Babu
Keyword(s):  
Brackish Water ◽  
Sea Water ◽  
Salt Water ◽  
Construction Material ◽  
Salt Content ◽  
River Estuary ◽  
Sand Sample ◽  
River Sand ◽  
Natural Aggregates

The salt water mixes with fresh water and forms brackish water. The brackish water contains some quantity of salt, but not equal to sea water. Salinity determines the geographic distribution of the number of marshes found in estuary. Hence salinity is a very important environmental factor in estuary system. Sand is one major natural aggregate, required in construction industry mainly for the manufacture of concrete. The availability of good river sand is reduced due to salinity. The quality of sand available from estuarine regions is adversely affected due to this reason. It is the responsibility of engineers to check the quality of sand and its strength parameters before using it for any construction purpose. Presence of salt content in natural aggregates or manufactured aggregates is the cause for corrosion in steel. In this study the amount of salinity present in estuary sand was determined. Three different methods were used to determine the salinity in different seasonal variations. The sand sample collected nearer to the sea was found to be high in salinity in all methods.  It can be concluded that care should be taken before we use estuary sand as a construction material due to the presence of salinity.

Evaluation of Heavy Metal Contents in Mudflat Solar Salt, Salt Water, and Sea Water in the Nationwide Salt Pan

2012 ◽  
Vol 41 (7) ◽  
pp. 1014-1019 ◽  
Author(s):  
Hag-Lyeol Kim ◽  
Young-Joo Yoo ◽  
In-Sun Lee ◽  
Gang-Hee Ko ◽  
In-Cheol Kim
Keyword(s):  
Heavy Metal ◽  
Sea Water ◽  
Salt Water ◽  
Solar Salt ◽  
Metal Contents ◽  
Salt Pan

MEASURES FOR ENVIRONMENT CONSERVATION IN ENCLOSED COASTAL SEAS

2017 ◽  
Author(s):  
Keizo Negi ◽  
Keizo Negi ◽  
Takuya Ishikawa ◽  
Takuya Ishikawa ◽  
Kenichiro Iba ◽  
...  
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Water Mass ◽  
Sea Water ◽  
Red Tide ◽  
Water Environment ◽  
Quality Standard ◽  
Tokyo Bay ◽  
View Point ◽  
High Concentration

Japan experienced serious water pollution during the period of high economic growth in 1960s. It was also the period that we had such damages to human health, fishery and living conditions due to red tide as much of chemicals, organic materials and the like flowing into the seas along the growing population and industries in the coastal areas. Notable in those days was the issues of environment conservation in the enclosed coastal seas where pollutants were prone to accumulate inside due to low level of water circulation, resulting in the issues including red tide and oxygen-deficient water mass. In responding to these issues, we implemented countermeasures like effluent control with the Water Pollution Control Law and improvement/expansion of sewage facilities. In the extensive enclosed coastal seas of Tokyo Bay, Ise Bay and the Seto Inland Sea, the three areas of high concentration of population, we implemented water quality total reduction in seven terms from 1979, reducing the total quantities of pollutant load of COD, TN and TP. Sea water quality hence has been on an improvement trend as a whole along the steady reduction of pollutants from the land. We however recognize that there are differences in improvement by sea area such as red tide and oxygen-deficient water mass continue to occur in some areas. Meanwhile, it has been pointed out that bio-diversity and bio-productivity should be secured through conservation/creation of tidal flats and seaweed beds in the view point of “Bountiful Sea” To work at these challenges, through the studies depending on the circumstances of the water environment in the enclosed coastal seas, we composed “The Policy of Desirable State of 8th TPLCS” in 2015. We have also added the sediment DO into the water quality standard related to the life-environmental items in view of the preservation of aquatic creatures in the enclosed water areas. Important from now on, along the Policy, is to proceed with necessary measures to improve water quality with good considerations of differences by area in the view point of “Beautiful and bountiful Sea”.

scholarly journals A study on highly concentrated lactic acid and the synthesis of lactide from its solution

2021 ◽  
pp. 174751982110210
Author(s):  
Xiaolong Xu ◽  
Lijuan Liu
Keyword(s):  
Lactic Acid ◽  
Acid Solution ◽  
Concentration Distribution ◽  
Raw Material ◽  
High Concentration ◽  
Composition Distribution ◽  
Lactic Acid Solution ◽  
H Nmr ◽  
Back Titration ◽  
Condensed Water

Lactic acid is an important platform compound used as raw material for the production of lactide and polylactic acid. However, its concentration and composition distribution are not as simple as those of common compounds. In this work, the mass concentration distribution of highly concentrated lactic acid is determined by back titration. The components of highly concentrated lactic acid, crude lactide, and polymer after the reaction are analyzed by HPLC. Different concentrations of lactic acid solution were prepared for the synthesis of lactide and its content in the product was determined by 1H NMR analysis. We found that lactide is more easily produced from high-concentration lactic acid solution with which the condensed water is easier to release. Hence, the removal of condensed water is crucial to the formation of lactide, although it is not directly formed by esterification of two molecules of lactic acid.

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