Which method is used for the removal of zinc from water?

Lime softening or cation exchange is an effective method for removing zinc from water primarily because it involves chemical reactions that precipitate heavy metals like zinc from water. In lime softening, lime (calcium hydroxide) is added to the water, which raises the pH. This elevated pH causes zinc to precipitate as zinc hydroxide, which can then be removed through sedimentation or filtration. This method is particularly effective at treating water that contains hardness minerals and various dissolved metals by transforming them into less soluble forms that can be easily separated.

Cation exchange, on the other hand, specifically replaces undesired cations such as zinc with other less harmful cations, effectively reducing the concentration of zinc in the water. This technique is useful in water treatment applications where the presence of heavy metals must be minimized to meet safety and environmental standards.

While reverse osmosis is also effective at removing a wide variety of contaminants, including zinc, it works through a physical separation process and may not always be the primary choice for metals due to fouling and maintenance challenges. Carbon filtration primarily targets organic compounds and chlorine, thus is less effective for metals. Ultraviolet treatment is utilized for disinfection rather than chemical removal and would not eliminate metal contaminants like zinc