At what pH range does alum work best in water treatment?

At what pH range does alum work best in water treatment?

• A. 4.5-5.5
• B. 5.0-6.5
• C. 5.8-7.5
• D. 7.0-8.5

Answer: (C)

Alum, or aluminum sulfate, is commonly used in water treatment as a coagulant to assist in the removal of suspended particles. Its effectiveness is highly influenced by the pH level of the water being treated. The pH range of 5.8 to 7.5 is optimal for alum to function effectively because, within this range, the hydrolysis of aluminum ions occurs to form the appropriate species that facilitate coagulation. In this pH range, alum can better interact with colloidal particles, promoting their aggregation into larger flocs that can be easily removed from the water. When the pH is too low, alum may not produce effective floc formation, and when it is too high, the solubility of aluminum decreases, reducing its effectiveness as a coagulant. Therefore, managing the pH within this specific range ensures that alum can perform its role efficiently, leading to clearer and more treated water.

Alum, or aluminum sulfate, is commonly used in water treatment as a coagulant to assist in the removal of suspended particles. Its effectiveness is highly influenced by the pH level of the water being treated. The pH range of 5.8 to 7.5 is optimal for alum to function effectively because, within this range, the hydrolysis of aluminum ions occurs to form the appropriate species that facilitate coagulation.

In this pH range, alum can better interact with colloidal particles, promoting their aggregation into larger flocs that can be easily removed from the water. When the pH is too low, alum may not produce effective floc formation, and when it is too high, the solubility of aluminum decreases, reducing its effectiveness as a coagulant. Therefore, managing the pH within this specific range ensures that alum can perform its role efficiently, leading to clearer and more treated water.