The role and use of polyaluminum chloride

Polyaluminum chloride (PAC) is a chemical compound that is widely used as a coagulant and flocculant in water treatment processes. It is derived from aluminum chloride by partially neutralizing it with a base such as hydrochloric acid. Here are the key roles and uses of polyaluminum chloride:

1. Water Treatment: PAC is primarily used in water treatment plants to clarify and purify water. It acts as a coagulant by destabilizing particles and colloids suspended in water. When PAC is added to water, it forms positively charged aluminum hydroxide flocs that attract and bind with negatively charged particles, such as dirt, organic matter, and suspended solids. This process helps to aggregate these impurities into larger particles, making them easier to remove through sedimentation or filtration.

2. Municipal and Industrial Water Treatment: PAC is commonly used in municipal water treatment facilities to improve the clarity and quality of drinking water. It effectively removes turbidity, color, odor, and various contaminants. It is also used in industrial water treatment processes, including wastewater treatment, to enhance the removal of pollutants and solids.

3. Paper and Pulp Industry: PAC finds applications in the paper and pulp industry. It is used as a retention and drainage aid to improve the efficiency of paper production. PAC helps to increase the retention of fine particles, fibers, and fillers in the paper pulp, resulting in improved paper quality and reduced water usage.

4. Textile Industry: In the textile industry, PAC is used as a dye-fixing agent. It helps to improve color fastness by enhancing the adsorption and fixation of dyes onto fabric fibers.

5. Oil and Gas Industry: PAC is employed in the oil and gas industry for the clarification of produced water, which is the wastewater generated during oil and gas extraction processes. It aids in the removal of suspended solids, oil, and grease from the produced water, facilitating its treatment and disposal.

It's worth noting that the specific formulation and application of PAC can vary depending on the water quality, treatment objectives, and regulations in different regions. The dosage and treatment methods may also differ based on the specific requirements of each application. Therefore, it is important to follow the guidelines and recommendations provided by water treatment professionals and regulatory authorities for the appropriate use of PAC.