1. Physical and chemical methods The physical and chemical methods for removing heavy metals in water include adsorption, ion exchange, microfiltration, reverse osmosis and electrodialysis. Among these methods, adsorption is one of the commonly used methods; There are many kinds of adsorbents, including activated carbon, clay, fly ash, peat, bark, chitin, moss, seaweed, rice husk and so on. Among them, activated carbon has a special porous structure, huge surface area and high adsorption capacity, which is undoubtedly the most widely used adsorbent for removing heavy metals from water. However, its non-selectivity, high quality and high cost limit its use.

2 Chemical methods Among chemical methods such as chemical precipitation, redox method and electrochemical method, chemical precipitation is one of the classic methods to remove heavy metal pollutants.

Recently, the research focus of removing heavy metals from water has shifted to the field of biological purification, because biological purification of heavy metals has the characteristics of low cost, simplicity and no secondary pollution, with ideal effect and good application prospect.

3. 1 Removal of heavy metals from water by biological materials

3.2 Using microorganisms to remove heavy metals from water

3.3 Use plants to remove heavy metals from water

3.4 Use aquatic animals to remove heavy metals from water.

There are many literatures in this field. You can download it directly from your school's book website and search for "removing heavy metal pollution in water".