Copper-containing wastewater is a common industrial wastewater that contains a large amount of copper ions, which causes serious harm to the environment and ecology. In order to effectively treat copper-containing wastewater, chemical treatment methods are widely used. In this paper, the principles, steps, advantages and disadvantages of chemical treatment methods for copper-containing wastewater are introduced, in order to provide reference for research and practice in related fields.
1. The principle of chemical treatment methods.
The principle of the chemical treatment method is to add chemical agents to the wastewater, so that the copper ions and the agent have a chemical reaction to generate water-insoluble precipitates or complexes, so as to achieve the purpose of removing copper ions. Commonly used chemicals include hydroxides, sulfides, carbonates, etc.
Second, the steps of the chemical treatment method.
1.Regulate the pH value of wastewater: The pH value of wastewater is an important factor affecting the removal effect of copper ions. Generally speaking, when the pH value of the wastewater is between 8-10, the removal of copper ions is better. Therefore, in actual operation, it is necessary to add an appropriate amount of acid or alkali according to the pH value of the wastewater to adjust the pH value of the wastewater to a suitable range.
2.Add chemicals: add an appropriate amount of sodium sulfide or remover to the wastewater to make the copper ions react with the agent. The amount of chemicals added should be determined according to the concentration of copper ions in the wastewater and the type of chemicals, and the optimal amount of chemicals should be determined by experiments.
3.Precipitation and separation: After the flocculant is added, the copper ions in the wastewater will react with the agent to flocculate to form a precipitate or complex that is insoluble in water. In this case, the sediment or complex needs to be separated from the wastewater by means of sedimentation and separation. Commonly used precipitation and separation methods include static precipitation, centrifugal separation, etc.
4.Treatment of treated wastewater: After chemical treatment, copper ions are effectively removed from the wastewater, but the wastewater may also contain other contaminants. Therefore, the treated wastewater needs to be further treated, such as filtration, adsorption, etc., to ensure that the wastewater meets the discharge standard.
The processing equation is as follows:
cu2+ +2naoh → cu(oh)2↓ +2na+