The main difference between aluminum chlorohydrate and polyaluminum chloride is that polyaluminium chloride has a higher aluminium content and lower water content than aluminium chlorohydrate.
Aluminum chlorohydrate (ACH) and polyaluminum chloride (PAC) are two distinct chemical compounds that share similarities due to their aluminum and chlorine content. However, they have vastly different purposes in various applications.
Key Areas Covered
1. What is Aluminum Chlorohydrate
– Definition, Features, Applications
2. What is Polyaluminum Chloride
– Definition, Features, Applications
3. Similarities Between Aluminum Chlorohydrate and Polyaluminum Chloride
– Outline of Common Features
4. Difference Between Aluminum Chlorohydrate and Polyaluminum Chloride
– Comparison of Key Differences
Key Terms
ACH, Aluminum Chlorohydrate, PAC, Polyaluminum Chloride
What is Aluminum Chlorohydrate
Aluminum chlorohydrate (ACH) is a group of specific aluminum salts with the general formula AlnCl(3n-m)(OH)m. This formula signifies the presence of aluminum (Al3+) ions, chloride (Cl-) ions, and hydroxide (OH-) ions in varying proportions. The specific composition of aluminum chlorohydrate may vary depending on its intended application and manufacturing process.
Aluminum chlorohydrate is typically found in the form of a colorless or white, odorless, and slightly acidic liquid solution. Its liquid form is convenient for handling and dosing in various applications. ACH is a low-basicity coagulant, meaning it contains a relatively low concentration of hydroxide ions (OH-). This results in a milder increase in pH when added to water compared to other coagulants. ACH is highly soluble in water, allowing for rapid dispersion and distribution in water treatment processes. Its solubility contributes to its effectiveness in coagulation.
Figure 1: Aluminum Salts
Applications of Aluminum Chlorohydrate
ACH is also known for its coagulation and flocculation capabilities. When added to water, it forms small, gelatinous flocs that capture and aggregate impurities and suspended particles, facilitating their removal during settling or filtration processes. ACH is widely used in municipal and industrial water treatment processes. It helps clarify water by coagulating and settling impurities, suspended solids, and colloidal particles. It is particularly effective in the treatment of turbid and challenging water sources.
Aluminum chlorohydrate is a key active ingredient in many antiperspirant and deodorant products. It works by forming a gel-like plug in the sweat ducts, reducing the flow of sweat to the skin’s surface and thereby helping control perspiration and odor. ACH is also utilized in cosmetics and personal care products for its astringent and skin-soothing properties. It is often found in products like toners and skin creams. In some fire retardant formulations, ACH can be used as a component to help reduce the flammability of materials. Moreover, ACH may be employed in various industrial processes where coagulation and settling of particles are necessary, such as the treatment of wastewater generated by industrial facilities.
What is Polyaluminium Chloride
Polyaluminium chloride, commonly abbreviated as PAC, is a chemical compound that plays a pivotal role in water treatment processes around the world. Polyaluminium chloride is a group of water-soluble inorganic polymers with the general formula Aln(OH)mCl(3n-m). In this formula, “n” represents the degree of polymerization, “m” denotes the number of chloride ions, and “OH” represents hydroxide ions. The specific composition of PAC can vary depending on its intended use and manufacturing process.
PAC is typically available in liquid form as a clear to slightly cloudy solution. It is also produced in solid forms, such as powder or granules, which can be dissolved in water as needed. Moreover, the basicity of PAC can vary depending on the manufacturing process and product formulation. High-basicity PAC contains more hydroxide ions (OH-) and can significantly increase the pH of water. Moreover, PAC is highly soluble in water, allowing for easy dispersion and mixing in water treatment processes.
Applications of Polyaluminium Chloride
PAC is renowned for its coagulation and flocculation properties. When added to water, it forms larger flocs, which capture and aggregate impurities, suspended solids, and colloidal particles. These flocs can then be easily removed during settling or filtration processes.
Moreover, PAC contains chloride ions (Cl-), which can affect the salinity of treated water. The chloride content may vary depending on the specific PAC product. PAC is extensively used in municipal and industrial water treatment processes. It effectively coagulates and settles impurities, turbidity, and suspended particles, resulting in improved water quality and clarity. PAC is often employed in the treatment of drinking water, wastewater, and industrial effluents.
PAC acts as a retention aid and drainage aid in the papermaking process. It helps improve the retention of fine particles and the drainage of water from the paper pulp, enhancing the efficiency of paper production.
In the textile industry, PAC is useful in wastewater treatment to remove dyes, chemicals, and other contaminants from textile effluents. PAC is also employed in the treatment of mine water and wastewater generated by mining and metallurgical processes, aiding in the removal of heavy metals and solids. PAC helps in the treatment of produced water and wastewater in the oil and gas sector to remove oil, suspended solids, and other impurities. It can also act as a flocculant in various chemical processes, such as the treatment of chemical effluents.
Similarities Between Aluminiumchlorohydrate and Polyaluminium Chloride
- ACH and PAC are water-soluble and readily dissolve in water.
- Both coagulants help in coagulation and flocculation purposes in water treatment.
Difference Between Aluminium Chlorohydrate and Polyaluminium Chloride
Definition
Aluminium chlorohydrate is a group of specific chemical compounds with the general formula AlnCl(3n-m)(OH)m, while polyaluminium chloride is a broader term that refers to a range of aluminum chloride compounds, primarily Aln(OH)mCl(3n-m).
Basicity
ACH is generally considered a low-basicity coagulant. It contains a relatively low concentration of hydroxide ions (OH-), resulting in a milder increase in pH when added to water. PAC can have varying levels of basicity, depending on the manufacturing process and product formulation. High-basicity PACs contain more hydroxide ions and can significantly raise the pH of water.
Aluminum Content
Aluminium chlorohydrate products typically have lower aluminum content compared to polyaluminium chloride.
Applications
ACH is effective in removing suspended particles, organic matter, and colloidal substances from water. It forms smaller flocs and provides good coagulation performance at lower dosages. PAC, especially the high-basicity variants, has superior coagulation and flocculation properties. It can effectively treat water with a wide range of impurities and is often useful with challenging water sources.
Conclusion
Aluminium chlorohydrate and polyaluminium chloride are two distinct chemical compounds that share similarities due to their aluminum and chlorine content. The main difference between aluminum chlorohydrate and polyaluminum chloride is that polyaluminium chloride has a higher aluminium content and lower water content than aluminium chlorohydrate.
Reference:
1. “Aluminium chlorohydrate.” Wikipedia. Wikipedia Foundation.
Image Courtesy:
1. “AlCl3 tricloruro di alluminio – aluminium chloride” By Xlollitox – Own work (CC BY 3.0) via Commons Wikimedia
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