Hexavalent chromium wastewater treatment process
Hexavalent chromium wastewater is a common and serious industrial wastewater, which contains a large amount of hexavalent chromium ions, which is extremely harmful to the human body and the environment. Therefore, it is essential for the treatment of hexavalent chromium wastewater. This article will introduce the treatment process of hexavalent chromium wastewater in detail, including wastewater**, treatment methods, treatment processes and treatment effects.
1. Wastewater**.
Hexavalent chromium wastewater is mainly used in the production process of electroplating, metallurgy, tanning, chemical and other industries. In these processes, hexavalent chromium ions are usually discharged in the form of wastewater, causing serious pollution to the environment.
Second, the treatment method.
For the treatment of hexavalent chromium wastewater, common treatment methods include chemical precipitation, ion exchange, adsorption, electrolysis, etc. Each of these methods has its own advantages and disadvantages, and the choice of method depends on the nature of the wastewater and the treatment requirements.
1.Chemical precipitation.
The chemical precipitation method is to add chemical agents to the wastewater, so that the hexavalent chromium ions and the agent undergo a chemical reaction to generate insoluble precipitate, so as to achieve the purpose of removing hexavalent chromium ions. Commonly used chemical agents are hydroxides, sulfides, etc. This method is easy to operate and inexpensive, but the resulting precipitate needs to be further treated to avoid secondary contamination.
2.Ion exchange method.
The ion exchange method uses the ion exchange properties of the ion exchange resin to exchange the hexavalent chromium ions in the wastewater with other ions on the resin, so as to remove the hexavalent chromium ions. This method has a good treatment effect, but the equipment investment is large, the operation is complex, and the resin needs to be replaced regularly.
3.Adsorption method.
The adsorption method uses the adsorption performance of the adsorbent to adsorb the hexavalent chromium ions in the wastewater on the surface of the adsorbent, so as to achieve the purpose of removing hexavalent chromium ions. Commonly used adsorbents are activated carbon, bentonite, etc. This method is simple to operate and has good treatment effect, but the adsorbent needs to be replaced regularly and the cost is high.
4.Electrolysis.
The electrolysis method is to remove hexavalent chromium ions by electrolyzing the hexavalent chromium ions in the wastewater and causing them to undergo a redox reaction on the electrode. This method has good treatment effect, but the energy consumption is high, the equipment investment is large, and the operation is complex.
3. Processing process.
The treatment process for hexavalent chromium wastewater usually consists of three stages: pretreatment, main treatment and post-treatment.
1.Pre-treatment phase.
The pretreatment stage is mainly for the preliminary treatment of wastewater, such as adjusting the pH value of wastewater, removing suspended solids, etc. The purpose of this phase is to create the conditions for the subsequent major processing.
2.The main processing phase.
The main treatment stage is the core of hexavalent chromium wastewater treatment, and the above-mentioned chemical precipitation method, ion exchange method, adsorption method or electrolysis method are usually used to remove hexavalent chromium ions in wastewater. Choose the appropriate treatment method according to the nature of the wastewater and the treatment requirements.
3.Post-processing stage.
The post-treatment stage is mainly to further treat the treated wastewater, such as neutralization, sedimentation, filtration, etc., to ensure that the wastewater meets the discharge standard. In addition, it is also necessary to properly dispose of the sediment and waste residue generated during the treatment process to avoid secondary pollution.
Fourth, the treatment effect.
After proper treatment process, hexavalent chromium ions in hexavalent chromium wastewater can be effectively removed, and the treated wastewater can meet the national discharge standard. At the same time, the sediment and waste residue generated in the treatment process can also be properly disposed of to avoid secondary pollution to the environment.
Summary. Hexavalent chromium wastewater treatment is an important environmental protection work, which is of great significance for protecting human health and environmental safety. This paper introduces the treatment methods, treatment processes and treatment effects of hexavalent chromium wastewater, hoping to provide a useful reference for the treatment of hexavalent chromium wastewater. In practical applications, it is necessary to select the appropriate treatment method according to the nature and treatment requirements of the wastewater to ensure the best treatment effect. At the same time, it is also necessary to strengthen the maintenance and management of wastewater treatment facilities to ensure the normal operation of the facilities and the stability of the treatment effect.