The application status of activated alumina in water treatment. In water treatment, activated alumina is used to adsorb some or several pollutants in wastewater in order to recover or remove them, so as to purify the wastewater. Using its adsorption capacity for material separation has a long history. Scientific researchers at home and abroad have done a lot of research work in this field. At present, activated alumina adsorbent has been widely used in chemical industry, environmental protection, medicine and health, bioengineering and other fields. In terms of chemical industry and environmental protection, activated alumina is mainly used to purify waste gas, recover solvents (especially corrosive chlorinated hydrocarbons, reactive solvents and low boiling point solvents) and remove trace pollutants from water. The application scope of the latter includes decolorization, deodorization, removal of heavy metals, removal of various dissolved organic matter and radioactive elements. In the treatment process, activated alumina can be used as pretreatment of ion exchange, membrane separation and other methods to remove organic matter, colloid and residual chlorine. It can also be used as advanced treatment means after secondary treatment to ensure the quality of reclaimed water. Using adsorption method for water treatment has the advantages of wide application range, good treatment effect, recyclable useful materials and reusable adsorbents. With the continuous improvement of the performance of existing activated alumina adsorbents and the successful development of new adsorbents, the application prospect of activated alumina in water treatment will be broader.
Activated alumina adsorbent is the key factor to determine the high-efficiency adsorption treatment process. In a broad sense, all solids have adsorption capacity, but only porous materials or finely ground materials have large surface area. Industrial adsorbents must also meet the following requirements:
1. Strong adsorption capacity;
2. Good adsorption selectivity;
3. Low adsorption equilibrium concentration;
4. Easy regeneration and reuse;
5. Good mechanical strength;
6. Stable chemical properties;
It is difficult for general industrial adsorbents to meet these six requirements at the same time. Therefore, different adsorbents should be selected according to different occasions in the process of adsorption treatment. At present, the adsorbents that can be used for water treatment include activated carbon, activated alumina, modified starch adsorbent, modified cellulose adsorbent, modified lignin adsorbent, modified chitosan adsorbent and other agents and materials that can absorb pollutants.