Which method can remove over 90% of sodium arsenate from water?

The method that can remove over 90% of sodium arsenate from water is filtration combined with ion exchange. This process is effective because it addresses the specific characteristics of arsenate, a form of arsenic commonly found in water.

Filtration acts as a physical barrier, removing larger particulates and certain dissolved substances from water. However, by itself, filtration may not be sufficient to remove dissolved ions like sodium arsenate effectively. This is where ion exchange comes into play. Ion exchange processes involve exchanging one type of ion in the water for another that is bound to resin beads in the system. Since arsenate ions can be exchanged for less harmful ions within this process, it ensures a significantly higher removal rate, often exceeding 90%.

Other methods mentioned, while useful in different contexts, may not achieve the same level of efficacy for sodium arsenate specifically. Simple sedimentation relies on gravity to settle out solids and is not effective for dissolved contaminants like sodium arsenate. Ozonation can help with certain organic contaminants or pathogens but is not as targeted or efficient for removing specific inorganic ions such as sodium arsenate. Biological treatment processes, while beneficial for degrading organic matter, are generally less effective at removing inorganic contaminants directly from water. Thus, the combination of filtration