Читать книгу Groundwater Geochemistry - Группа авторов - Страница 124

The ion exchange method has been employed to eliminate both cationic and anionic impurities from water. It has many advantages, such as high treatment capacity, high removal efficiency, and fast kinetics (Rahimizadeh and Liaghatb 2015). The resin used may be either synthetic or natural solid resin (synthetic resins are comparatively more effective) (Alyüz and Veli 2009). As the solution containing heavy metal passes through the cations column, metal ions are exchanged for the hydrogen ions on the resin. The uptake of heavy metal ions by ion‐exchange resins is affected by certain variables such as pH, temperature, initial metal concentration, and contact time (Gode and Pehlivan 2006). Ionic charge also plays an important role in the ion‐exchange process. In contrast to resin, natural zeolites also exhibit good cation exchange capacities for heavy metal ions under different experimental conditions. Clinoptilolite is one of the most frequently studied natural zeolites that has received extensive attention due to its selectivity for heavy metals (Doula 2009). Although there are many reports on the use of zeolites and montmorillonites as ion‐exchange resin to decontaminate heavy metal, they are limited at present compared with the synthetic resins and the application of zeolites is on the laboratory experimental scale.