Table of Contents
In dispersed clay slurries, flocculation occurs after mechanical agitation ceases and the dispersed clay platelets spontaneously form flocs because of attractions between negative face charges and positive edge charges.
Which cation causes flocculation Why?
Clay particles usually possess net negative charge and therefore they electrostatically attract positively charged ions, such as Ca2+ cations, which form bridges, holding the particles together. Therefore, these cations can induce flocculation of clay particles.
How can flocculation be prevented?
When particles of a suspension come close together they can form aggregates called flocculates which will settle more rapidly. To prevent that we often coat the particle with a charged surfactant. The charge (Zeta potential) acts to keep the particles separate and prevent flocculation.
Why is gypsum added to soil?
Adding gypsum to the soil reduces erosion by increasing the ability of soil to soak up water after precipitation, thus reducing runoff. Gypsum application also improves soil aeration and water percolation through the soil profile.
What makes a good flocculant?
Polymers are useful as flocculants because they are robust molecules and sometimes carry charges. Because they are so large, small particles can get trapped in the curves of the polymer causing them to accumulate a mass heavy enough to prevent their retention in solution.
What is the importance of soil pH in soil analysis?
Why is pH important? Soil pH is important because it influences several soil factors affecting plant growth, such as (1) soil bacteria, (2) nutrient leaching, (3) nutrient availability, (4) toxic elements, and (5) soil structure.
Does flocculant affect pH?
Because flocculants can affect the pH level, you’ll want to start out with it at about 7.0 so you can make sure your sanitizer keeps working at maximum efficiency.
Which soil is not treated with gypsum?
Now that we have ascertained what gypsum is, it’s natural to question, “Is gypsum good for the soil?” Since it reduces salt levels in soil, it is effective in coastal and arid regions. However, it doesn’t work in sandy soils and it can deposit an excess of calcium in regions where the mineral is already abundant.
What does flocculation do to water?
Flocculation is a water treatment process where solids form larger clusters, or flocs, to be removed from water. This process can happen spontaneously, or with the help of chemical agents. It is a common method of stormwater treatment, wastewater treatment, and in the purification of drinking water.
Which ion causes dispersion in soil?
The type of cations present in the soil solution determine whether a soil is dispersed or flocculated. Sodium cations cause dispersion while calcium, magnesium, aluminium, and hydrogen ions promote flocculation (encourage the soil components to stick together).
How can you tell if soil is dispersive?
There are 3 ways to identify dispersive soils:
- measure the exchangeable sodium percentage (ESP) as part of a standard soil test (measures sodicity)
- use a simple soil dispersion test.
- observe visual indicators of moderate or severely dispersive topsoils.
Why is it important to treat flocculation in water?
While coagulation can remove particles and some dissolved matter, the water may still contain pathogens. It is, however, an important primary step in the water treatment process, because coagulation removes many of the particles, such as dissolved organic carbon, that make water difficult to disinfect.
What is the principle of flocculation?
Coagulation – flocculation is physico-chemical process that facilitates the agglomeration of fine particles (colloids) contained in water to form a floc that can be easily filtered from water. Effluent (waste water) must be treated before it is discharged or before the water is re-used.
Is alum a coagulant or flocculant?
To accomplish this, the water is treated with aluminum sulfate, commonly called alum, which serves as a flocculant. Raw water often holds tiny suspended particles that are very difficult for a filter to catch. Alum causes them to clump together so that they can settle out of the water or be easily trapped by a filter.
Why is it important to treat drinking water by flocculation?
Flocculation-Chlorination The combination of particle removal and disinfection appears to produce high removal rates of bacteria, viruses, and protozoa, even in highly turbid waters. There is considerable evidence that the system has reduced diarrheal disease significantly in various locations.
Is flocculation good for soil?
Soil aggregates are cemented clusters of sand, silt, and clay particles. Flocculation is important because water moves mostly in large pores between aggregates. Also, plant roots grow mainly between aggregates.
What chemicals are flocculants?
A flocculants are usually organic chemicals added to wastewater to enhance flocculation, such chemicals are alum, aluminium chlorohydrate, aluminium sulphate etc.
Why is flocculation important?
Used water can contain significant amounts of suspended particulate matter, which often takes long to sediment. Flocculation expedites sedimentation and ensures efficient solid/liquid separation.
What is difference between flocculation and Deflocculation?
The key difference between flocculation and deflocculation is that flocculation is the formation of flocs by the clumping of fine particles, whereas deflocculation is the dispersion of flocs to form a stable colloid. Flocculation refers to the formation of clumps from fine particles in a colloid.
What can be used as a flocculant?
The following natural products are used as flocculants:
- Chitosan.
- Isinglass.
- Moringa oleifera seeds (Horseradish Tree)
- Gelatin.
- Strychnos potatorum seeds (Nirmali nut tree)
- Guar gum.
- Alginates (brown seaweed extracts)
How do you dissolve flocculant?
Bleach or sodium hypochlorite can be used to break down polyacrylamide-based flocculants.
Why does sodium cause dispersion?
Effects of Sodium and Sodicity on Soil Physical Properties Sodium has the opposite effect of salinity on soils. The forces that bind clay particles together are disrupted when too many large sodium ions come between them. When this separation occurs, the clay particles expand, causing swelling and soil dispersion.
Does lime Flocculate clay soil?
Lime is considered to be a soil conditioner. It can be used to raise the pH of a soil to make it less acidic. It will also flocculate clay particles so they will form crumbs rather than clods.
What is the difference between flocculant and coagulant?
Depending on the charge and chemical composition of your wastewater, flocculants can either be used on their own or in combination with coagulants. Flocculants differ from coagulants in that they are often polymers, whereas coagulants are typically salts.
