Electrocoagulation is the process of passing an electrical current through a solution of liquid and suspended particles to solidify or semi-solidify it.
The current generates a high temperature that is concentrated in the liquid, causing it to coagulate.
Water hardness causes plenty of issues in both life and business.
Iron, manganese, strontium and a few other metals, in addition to calcium and magnesium, can generate water hardness, although their amounts in proportion to calcium and magnesium can be ignored.
There are several methods for removing excess hardness, each with its own set of benefits and drawbacks.
Because of its simplicity, the electrochemical or electrocoagulation approach has attracted a lot of attention and is now used to eliminate a mixture of ions and organic debris.
What is the meaning of electrocoagulation in water?
In both home and commercial settings, hard water produces plenty of issues.
The development of sophisticated and cost-effective technology for softening hard and very hard waters is necessitated by the rising demand for high-quality water.
The electrocoagulation procedure is one of these methods (EC).
Electrocoagulation (EC) is an electrochemical water treatment technology that is employed in many different sectors.
Using an electrical charge to preserve contaminating particles, ions such as heavy metals and colloids in solution, the procedure destabilizes and aggregates them.
To destabilize the charges, the technique generally uses an anode and a cathode, both of which are stimulated by a DC power source.
This process isolates flocculated particulates from water, allowing them to be removed and replaced with pure water.
How does electrocoagulation work?
Traditionally, an electrochemical technique releases metal ions that produce coagulants, destabilize impurities and break emulsions by electrolytically oxidizing a sacrificial anode.
This coagulation produces flocculants, which float to the top and may be discarded.
Mechanism’s work of electrocoagulation in removing hardness
It consists of metal dissolution from the anode and the production of hydroxyl ions and hydrogen gas at the cathode.
Highly charged cations destabilize any colloidal particle by forming polyvalent poly hydroxide complexes.
These mixtures have a high adsorption capability and produce pollutant aggregates.
Hydrogen gas production improves mixing and, as a result, flocculation.
Following the formation of the flocs, the electrolytic gas creates a flotation action that pulls impurities to the floc-foam layer at the liquid surface.
Species can interact in a variety of different ways in solutions, including:
1. Aggregation owing to charge neutralization and migration to an oppositely charged electrode (electrophoresis).
2. The cation or hydroxyl ion (OH-) reacts with the pollutant to generate a precipitate.
3. The metallic cation reacts with OH- to create a hydroxide with excellent adsorption characteristics, causing the pollutant to attach to it (bridge coagulation).
4. The hydroxides rush through the water, forming bigger lattice-like structures (sweep coagulation).
5. Pollutants are oxidized into less harmful substances.
6. Electro-flotation removal and adherence to bubbles
Advantages and disadvantages
Advantages of EC
It may result in higher-quality water
Electrocoagulation is a method of water treatment that does not necessitate the use of chemicals.
This eliminates the risk of unwanted chemicals making their way into the effluent and leaving poisons and smells behind.
There is also no need for thickening, as there would be chemical coagulation, which lowers the initial cost of the procedure.
According to research from 2009, electrocoagulation can reduce the overall quantity of suspended solids in a solution by up to 99 percent
The solution can be used to recover metals
Metals found suspended in untreated water may not be completely worthless.
In reality, they may be beneficial; it’s simply that when they’re suspended in water, they become a problem.
Some water treatment processes are unable to effectively remove metals, thus they are destroyed or removed in other ways. Electrocoagulation is a unique procedure.
The technique may gather metals in a simpler form because it employs electrolysis to separate and coagulate liquids.
These metals can then be utilized for a variety of purposes.
It just needs a little amount of electrical current
In most circumstances, the coagulation equipment does not require much electricity to operate.
Green energy sources can readily provide this little amount of current.
Sludge production is minimal
EC generates relatively little sludge and is completely safe.
Because the only part of EC that demands the addition of chemicals is pH correction, there isn’t much to contribute to the amount of sludge generated.
Furthermore, even though the majority of the electrodes are sacrificial, they do not oxidize at a pace that supplies substantial quantities of the sludge.
It can process multiple contaminants in a single pass
At the start of the treatment process, treatment water often includes a variety of contaminants.
These include heavy metals, organic chemicals, insecticides, and colloidal solids.
To remove this many toxins, some treatment approaches employ numerous systems.
EC, on the other hand, may eliminate them in a single system with only a single step.
Produces effluent with reduced total dissolved solids (TDS)
In some circumstances, as compared to a traditional chemical coagulation process, EC can control raw water with lower amounts of total dissolved solids.
This low concentration is due to the lack of huge quantities of chemical additions.
Membrane fouling can also be significantly decreased by eliminating even the tiniest pollutants.
Because the membranes do not need to be replaced as frequently as they would ordinarily, this can save operational expenses in various applications.
Disadvantages of EC
Electrodes have a finite lifespan
Electrocoagulation necessitates the use of electrodes to provide electricity to the solution.
Unfortunately, the coagulation process is time-consuming and puts a lot of strain on the electrodes, resulting in wear and tear.
This implies that the electrodes must be cleaned and maintained regularly.
This may be a time-consuming and costly undertaking.
This also implies that the electrodes have a short lifespan and must be changed often.
It’s necessary to do some active fine-tuning
Because consistency is difficult to achieve, the process no longer qualifies as passive.
It’s not enough to just set up the equipment, turn it on and collect the effluent.
Instead, you’ll need a group of people who can actively fine-tune the equipment to obtain the best results.
References
[1] Wastewater Treatment Using Electrocoagulation, April, [online] available at: http://ajast.net/data/uploads/72023.pdf
[2] Removal of Hardness from Groundwater by Electro-coagulation Using Aluminum Electrode, September, [online] available at: https://utpedia.utp.edu.my/6055/1/FINAL%20DISSERTATION.pdf%20aizul.pdf
[3] Performance evaluation of electrocoagulation process using iron-rod electrodes for removing hardness from drinking water, 31 May, [online] available at: https://www.sciencedireccom/science/article/abs/pii/S0011916410000378
[4] Electrocoagulation, [online] available at: https://watercom/electrocoagulation/overview/
[5] Top 5 Advantages of Advanced Electrocoagulation Water Treatment, 5 March, [online] available at: https://genesiswaterteccom/blog-post/top-5-advantages-of-advanced-electrocoagulation-water-treatment/
[6] Review of Studies on Hardness Removal by Electrocoagulation,2017, [online] available at: https://www.ripublication.com/irph/ijert_spl17/ijertv10n1spl_59.pdf
[7] Advantages and disadvantages of electrocoagulation water treatment, 2 April, [online] available at: https://chemtech-us.com/advantages-and-disadvantages-of-electrocoagulation-water-treatment/
