What are the electrochemical water treatment methods?
The most common electrochemical water treatment methods are electrochemical oxidation used for mineralization of organic pollutants, water disinfection, removal of cyanides, and sulfides; electrochemical reduction used for metals recovery and transformation of persistent organic compounds to less toxic forms;
What factors affect the efficiency of electrochemical water treatment?
The efficiency of electrochemical water treatments depends on the electrode material, nature and temperature of electrolyte solution, rate-limiting step of electrode reaction kinetics, etc. This chapter summarizes the information on water pollutants and electrochemical phenomena used in water treatment processes.
What is electrocoagulation in water treatment?
Electrocoagulation in Water Treatment - What Is it? Electrocoagulation? Electrocoagulation (EC) is an electrochemical water treatment process used by a variety of industries. The process destabilizes and aggregates contaminant particles, ions such as heavy metals, and colloids, using an electrical charge to hold them in solution.
What is an electrochemical process?
Traditionally, the electrochemical process electrolytically oxidizes a sacrificial anode to release metal ions that form coagulants, destabilizing contaminants, and breaking emulsions. This coagulation forms flocculants that float to the surface for removal. An electrochemical process offers outstanding benefits when compared to other technologies:
What is electrochemical process for wastewater treatment?
Electrochemical treatment is very efficient and reduces process detention times thereby allowing smaller plants. Sea water or brine is mixed with the screened sewage in an appropriate ratio, then passed through an electrolysis cell rather similar to that used for hypochlorite production.
What is electrochemical disinfection?
Electrochemical disinfection—a method in which chemical oxidants are generated in situ via redox reactions on the surface of an electrode—has attracted increased attention in recent years as an alternative to traditional chemical dosing disinfection methods.
What is electrochemical coagulation?
Electrocoagulation (EC) is an electrochemical water treatment process used by a variety of industries. The process destabilizes and aggregates contaminant particles, ions such as heavy metals, and colloids, using an electrical charge to hold them in solution.
What are two benefits of using an electrochemical membrane in the water treatment process?
Regarding the treatment of (waste)water, electrochemical processes have various advantages over other methods. They are robust, easy to operate and flexible in case of fluctuating wastewater streams. In addition, a relatively broad spectrum of organic and inorganic impurities can be removed.
What is electrochemical treatment?
Electrochemical water treatment systems utilize electricity to induce the removal of dissolved contaminants in the water. Positively charged contaminants such as calcium, magnesium, sodium, lead and uranium are called cations.
How does electrolysis sterilize water?
Electrolysis to Purify Waste Water Based on the same scientific concept as water purification tablets, this technology splits hydrogen and oxygen gas killing pathogens at the same time. As byproducts, it creates pure water, hydrogen, oxygen, and solid waste, which can easily be dealt with in a safe manner.
What is advanced oxidation process in wastewater treatment?
Advanced oxidation processes (AOPs), in a broad sense, are a set of chemical treatment procedures designed to remove organic (and sometimes inorganic) materials in water and wastewater by oxidation through reactions with hydroxyl radicals (·OH).
What are floc particles?
Floc is a small, loosely aggregated mass of flocculent material suspended in or precipitated from a liquid. It consists of finely divided suspended particles in a larger, usually gelatinous particle, the result of physical attraction or adhesion to a coagulant compound.
What is the role of electrodes in electrocoagulation?
Consumable metal plates, such as iron or aluminum, are usually used as sacrificial electrodes to continuously produce ions in the water. The released ions neutralize the charges of the particles and thereby initiate coagulation.
What are the disadvantages of oxidation?
The disadvantages of oxidation is, it causes rusting of Iron and Corrosion of many metals. Advantage: Oxidation is helpful in the digestion, blood circulation and several other process in our body.
What are the disadvantages of wastewater treatment?
Wastewater treatment plants are not suited to every home and have some disadvantages which need to be considered by anyone considering installing a system.Routine servicing required. ... More council approvals required. ... Smelly. ... Bacteria. ... Space. ... Installation costs. ... Power. ... Sporadic use.More items...
What are the advantages and disadvantages of coagulation process in waste water treatment?
AdvantagesIt can lead to better quality effluent. Electrocoagulation treats water without the need for chemicals. ... Metals can be recovered from the solution. ... It only requires a low level of electrical current. ... Electrodes are impermanent. ... Many different factors can affect results. ... Active fine-tuning is required.
Why are electrochemicals so scarce?
However, electrochemical products are currently scarce in the market because of the relative unfamiliarity to the technology as well as the enormous competition of other water treatment methods.
Is electrolysis good for water?
Although this technology is not in full use today, the cost and performance advantages will eventually pan out to the wider use of electrochemical techniques in the future.
What are the advantages of electrochemical water treatment?
Traditional water treatment methods can no longer comply with tightening environmental standards. Electrochemical water treatment methods have a number of advantages over conventional methods such as compact reactor vessels, high pollutant removal efficiencies, no additional chemicals for process operation, broad area of applicability, insensitivity to toxic compound, and decreased formation or the total absence of secondary wastes generation. Electrochemical processes are accompanied by electrode reactions caused by the passage of electric current. The efficiency of electrochemical water treatments depends on the electrode material, nature and temperature of electrolyte solution, rate-limiting step of electrode reaction kinetics, etc. This chapter summarizes the information on water pollutants and electrochemical phenomena used in water treatment processes.
What is electrochemical process?
Electrochemical processes are accompanied by electrode reactions caused by the passage of electric current. The efficiency of electrochemical water treatments depends on the electrode material, nature and temperature of electrolyte solution, rate-limiting step of electrode reaction kinetics, etc. This chapter summarizes ...
What is the purpose of electrochemical methods?
The only prerequisite for the use of electrochemical methods is to preliminarily remove large particles and other physical inclusion from water, which is usually made in conventional treatment as well. When this condition is satisfied, electrochemical methods can remove any kind of pollutants, including organic and inorganic compounds, ...
What is the difference between electrodeionization and capacitive deionization?
Electrodeionization combines two desalination processes into one, which are electrodialysis and ion exchange, and as a result provides even deeper demineralization rates. Capacitive deionization is an energy-efficient method allowing simultaneous water desalination and recuperation of electric energy.
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Equipment & Solutions
Capacity range 2 – 76 l/h, 320 – 12 bar. The plunger metering pump Sigma/ 2 (Basic Type) is an extremely robust plunger metering pump with high-performance plunger and the option to adjust the pump capacity in 0.2% increments.
What are the benefits of electrochemical processes?
An electrochemical process offers outstanding benefits when compared to other technologies: 1 Can treat both process and waste water 2 Treats a wide range of contaminants 3 Operation uses safe, simple equipment 4 Typically, no need for chemical treatment 5 Can typically reuse electrocoagulation-treated waters, minimizing waste
What is the process of separating flocculated materials from water?
The process traditionally utilizes an anode and a cathode, stimulated by a DC power source to destabilize the charges. This operation separates flocculated materials from water, allowing those materials to be removed, leaving clear water.
What is the largest detractor in electrocoagulation?
Perhaps its largest detractor is passivation. During the electrocoagulation process, electrodes become coated and fouled with a non-conducting oxide, especially when processing wastewater with high concentrations of dissolved solids and scaling compounds.
What is the name of the coagulating agent formed when aluminum hydrolyzes?
Hydroxides: e.g., aluminum hydroxide (a polymeric hydroxide formed when aluminum hydrolyzes) is an excellent coagulating agent. Oxyhydroxides.
What is electrochemical technology?
Electrochemical technologies have been investigated as the effluent treatment processes for over a century. Fundamental as well as engineering researches have established the electrochemical deposition technology in metal recovery or heavy metal-effluent treatment.
How does pH affect electrocoagulation?
The effects of pH of water or wastewater on electrocoagulation are reflected by the current efficiency as well as the solubility of metal hydroxides. When there are chloride ions present, the release of chlorine also would be affected. It is generally found that the aluminum current efficiencies are higher at either acidic or alkaline condition than at neutral. The treatment performance depends on the nature of the pollutants with the best pollutant removal found near pH of 7. The power consumption is, however, higher at neutral pH due to the variation of conductivity. When conductivity is high, pH effect is not significant.
How does electrooxidation occur?
Electrooxidation of pollutants can also occur directly on anodes by generating physically adsorbed “active oxygen” (adsorbed hydroxyl radicals, OH) or chemisorbed “active oxygen” (oxygen in the oxide lattice, MO x+1)
How does electrocoagulation work?
Electrocoagulation involves the generation of coagulants in situ by dissolving electrically either aluminum or iron ions from respectively aluminum or iron electrodes. The metal ions generation takes place at the anode, hydrogen gas is released from the cathode. The hydrogen gas would also help to float the flocculated particles out of the water. This process sometimes is called electrofloculation. It is schematically shown in Fig. 10. The electrodes can be arranged in a mono-polar or bi-polar mode. The materials can be aluminum or iron in plate form or packed form of scraps such as steel turnings, millings, etc.
When was electrolysis first used?
Using electricity to treat water was first proposed in UK in 1889 [1]. The application of electrolysis in mineral beneficiation was patented by Elmore in 1904 [2]. Electrocoagulation (EC) with aluminum and iron electrodes was patented in the US in 1909.
What is electrolytic recovery?
The electrolytic recovery of metals here involves two steps: collection of heavy metals and stripping of the collected metals. The collection step involves plating and the stripping can be accomplished chemically or electrochemically. Nowadays, metal powders can be formed on the surface of carbon cathodes. Therefore, physical separation is sufficient. The metals recovered can be of quite high purity.
What are the different types of reactors used in metal recovery?
There are quite a few types of reactors found applications in metal recovery, from very basic reactors such as tank cells, plate and frame cells, rotating cells, to complicated three-dimensional reactor systems like fluidized bed, packed bed cell, or porous carbon packing cells.
Abstract
The process of improving water quality for the desired purpose is generally referred to as water treatment. This may involve desalination or purification of water by removing specific pollutants, salts, ions, or other species.
Acknowledgments
BB acknowledges the DST support for awarding the women scientist project (Grant no.: SR/WOS-A/CS-17/2017). RKG acknowledges financial assistance from the Department of Science and Technology (DST), India, through the INSPIRE Faculty Award (Project no. IFA-13 ENG-57) and Grant no. DST/TM/WTI/2K16/23 (G).
10.1. Introduction
Water crisis is the highest global risk as announced by the World Economic Forum in January 2016, which impacts the society intensively.
10.2. Common techniques for industrial wastewater treatment
Over the years, many technologies of wastewater treatment or pollutant removal have been developed. Commonly, they are used to remove solid particles such as metals, organic matter, colloids, and other nutrients and can be considered as a combination of chemical, physical, and/or biological methods.
10.3. Potency of electrochemical technique in wastewater treatment
Industrial electrochemistry faced tremendous support in clean water technology development as these processes produce clean and environmentally friendly products.
10.4. Conclusion
In summary, electrochemical techniques have gained wide attention in wastewater treatment, purification, and separation technologies. They have been regarded as cleaner than many other membrane-based and physiochemical technologies since electron acts as the main reagent and they do not produce solid residue.
What is an electrolytic reaction?
Electrolytic process. Reactions in which chemical changes occur on the passage of an electrical current. Electrolytic cells are driven by an external source of electrical energy. A flow of electrons drives non- spontaneous (ΔG ≥ 0) redox reactions.
What are some examples of inert and reactive electrodes?
Inert and Reactive Electrode. ■ Inert Electrodes do not react with the product produced or dissolved in the electrolyte. Carbon and platinum are examples of inert electrodes. ■ Reactive electrodes can react or dissolve in the electrolyte. Copper, silver and mercury are examples of reactive electrodes. 1/23/2019 6.
What is the operation of a galvanic cell?
The operation of a galvanic (or voltaic) cell is opposite to that of an electrolytic cell. In a galvanic cell, electrical energy is produced by a chemical redox reaction, instead of a chemical reaction being produced by electricity. The classic example of a redox reaction for a galvanic cell is the reaction between aqueous solutions of zinc (Zn) ...
