There is no doubt that water-absorbing materials play an important role in all aspects of life and production. In addition to toilet paper, sponge, and cotton, what other absorbent materials can you name?
This article will introduce some common absorbent materials on the market.
Types of water absorption
Physical water absorption
Physical water absorption is similar to a molecular sieve, which uses cavities to adsorb. Therefore, the ability to adsorb depends on the average radius of the cavity, and the adsorption capacity is positively related to the specific surface area.
Therefore, the disadvantages of this physical water absorption are obvious: the water cannot be effectively locked after water absorption, and the water absorption is limited.
The water-absorbing materials in this way are Cotton, Toilet paper, Sponge, and Activated carbon.
Chemical water absorption
Chemical water-absorbing materials use the material itself to chemically react with water to absorb water.
It is characterized by fast water absorption, and usually cannot be used again after water absorption.
The water-absorbing materials in this way are Calcium Oxide, Anhydrous calcium chloride, and Soda-lime.
Polymer absorbent material
Polymer absorbent material is an advanced physical absorbent material (using a combination of physical and chemical methods to absorb water). Water absorption is achieved through the principle of high concentration of hydrophilic groups and molecular sieves. This method uses chemical properties, but no chemical reaction occurs, so it can repeatedly absorb water after the improvement.
The water-absorbing materials in this way are polyvinyl alcohol, sodium polyacrylate, and potassium polyacrylate (used in agricultural water retention agents).
Top 3 absorbent materials
#3 Calcium Oxide
The water absorption rate can be about 35% of its own weight.
Calcium oxide is usually formed by the thermal decomposition of materials (such as limestone or shells) containing calcium carbonate CaCO3 in the lime kiln.
Calcium oxide is an alkaline oxide, and it reacts with water to form calcium hydroxide (slaked lime). This violent reaction emits a lot of heat and can even make water boil.
Calcium oxide has a high affinity for water and is a more effective desiccant than silica gel. The reaction of calcium oxide with water is related to an increase in its volume by at least 2.5 times.
#2 Anhydrous calcium chloride
The water absorption rate can reach more than 300% of its own weight.
The main raw materials of calcium chloride desiccant are high-quality calcium carbonate and hydrochloric acid, which are refined by reaction synthesis, filtration, evaporation concentration, and drying process.
Calcium chloride dehumidifier has the functions of adsorption activity, static dehumidification, and deodorization. Not only the adsorption speed is fast, the adsorption capacity is high, but it is also non-toxic, odorless, non-contact corrosion, and non-environmental pollution. Especially for the human body, it is widely used in oil seals, optical drugs, Health food, and military products.
Calcium chloride has the physical properties of high-solubility liquor, high-solubility heat, and strong hygroscopicity. It can only combine with crystal water and can absorb a lot of moisture. So the raw material of calcium chloride desiccant is made of calcium chloride.
Application range: Used for soda ash production. Anhydrous calcium chloride particles are commonly used as desiccants to fill the drying tube. Calcium chloride to dry macroalgae (or seaweed ash) can be used for soda ash production. Household dehumidifiers: Some household dehumidifiers use calcium chloride to absorb moisture in the air. Dryer or dehydrator for gases and organic liquids: Calcium chloride can also be used as a desiccant or dehydrator for gases and organic liquids.
Because calcium chloride is neutral, it can dry acidic or alkaline gases and organic liquids, and can also produce a small amount of gas in the laboratory, such as nitrogen, oxygen, hydrogen, hydrogen chloride, sulfur dioxide, carbon dioxide, nitrogen dioxide, etc. Used for bandage first aid: Anhydrous calcium chloride as a water-absorbing agent has been approved by FDA for bandage first aid, and its role is to ensure that the wound is dry.
#1 Sodium polyacrylate (SAP)
Sodium polyacrylate is a functional polymer material. It can absorb water up to several hundred times its own weight. As an important absorbent material, SAP is applied to every aspect of our lives.
The water absorption (purified water) of conventional sodium polyacrylate is hundreds of times that of its own, and the improved product can reach thousands of times.
Adjustable water absorption speed.
Through post-processing in the production process, the water absorption speed of the finished product can be controlled according to the purpose. When used as an external water-stop material for cables, sodium polyacrylate can absorb water and swell very quickly, effectively preventing water from entering the inside of the cable.
Sodium polyacrylate does not generate heat or produce toxic substances during the entire process of absorbing water, and can be decomposed in the natural environment.
As we see, Sodium polyacrylate is an amazing material. It can be applied to all aspects of life to absorb & hold water.
- It’s not a good choice to use sodium polyacrylate retaining water in the soil for plants. As another superabsorbent polymer, potassium polyacrylate is mainly used as a water-retaining agent for plants in agriculture.
- Common sodium polyacrylate does not absorb oil.
It’s mainly used in Hygiene Products such as Diapers, Sanitary Napkins, Nursing pads, and Pet pads, etc.
The single sheets of Ice packs are activated by placing them in fresh tap water.
Water Absorbent Pad
SAP brings a new, specially developed absorbent layer that helps consumers simulate a dry process in vacuum packaging – with amazing results.
Gel Polymer Beads
Water beads are made of SAP. It can absorb a large amount of water and turn into a bigger ball.
Used in waterproof tape and waterproof ointment for use in optical fiber cables.
SAP in an anti-flood bag absorbs the water completely in 3 to 5 minutes when meets water and the bag will inflate quickly. Before absorbing water, the bag is small and light.
SAP Drilling Mud Additive (SNA-505) which is a new environmental protection product with good water-absorbable and swellable properties, can effectively against lost circulation.
-It with fibrous shapes potentially can be used to make high.
-Can be used as an internal sealant in cement-based materials.
-A special use of SOCO Polymer in concrete could be as a controlled release agent.
SAP is a cost-saving alternative to other bulk solidifiers, including Portland cement, kiln dust, corn-cobs, sawdust, or other commodity absorbents.