Treating electroplating wastewater with polymeric ferric sulfate

Electroplating wastewater treatment: application of polymeric ferric sulfate
The generation of electroplating wastewater
Electroplating wastewater mainly comes from various links in the electroplating production process, including but not limited to:
Plating cleaning water: Before and after electroplating, the plated parts need to be cleaned, and these cleaning waters contain a large amount of plating solution residue.
Waste electroplating solution: After long-term use, the electroplating solution in the electroplating tank needs to be replaced or discharged due to changes in composition and accumulation of pollutants.
Other wastewater: This includes flushing workshop floors, scrubbing electrode plates, condensation water from ventilation equipment, as well as various tank liquids and drainage caused by leakage or improper operation management of plating tanks, such as "running, emitting, dripping, and leaking".
Equipment cooling water: Although the cooling water is not directly contaminated during use, it may contain a small amount of plating solution components due to contact with plating equipment.
Characteristics and hazards of electroplating wastewater
The water quality of electroplating wastewater is complex and the composition is difficult to control. The main characteristics include:
There are various types of pollutants: wastewater contains heavy metal ions such as chromium, cadmium, nickel, copper, zinc, gold, silver, and toxic substances such as cyanide.
Highly toxic: Heavy metal ions and cyanides in electroplating wastewater have carcinogenic, teratogenic, and mutagenic properties.
Difficult to handle: Due to the complex composition of electroplating wastewater, it needs to be classified and treated separately during the treatment process, which increases the difficulty of treatment.
The hazards of electroplating wastewater mainly manifest in its dual effects on the environment and human health. If pollutants such as heavy metal ions and cyanide in wastewater are discharged directly without treatment, they will cause long-term pollution to water bodies, soil, and ecological environment, affecting ecological balance and human health.
The principle and advantages of treating electroplating wastewater with polymeric ferric sulfate
Polymeric ferric sulfate has significant advantages in treating electroplating wastewater, and its principles and advantages are as follows:
Processing principle:
Coagulation precipitation: Using polymeric ferric sulfate as a coagulant, suspended solids and colloidal particles in electroplating wastewater lose their stability and coalesce into larger particles through mechanisms such as charge neutralization and adsorption bridging, which are then separated from the wastewater through precipitation.
Breaking effect: Electroplating wastewater often contains complex compounds that are difficult to treat, such as copper ammonia complexes. Polymeric ferric sulfate can react with these complexes, disrupting their stability and making them easier to remove.
advantage:
Efficient purification capability: Polyferric sulfate has the characteristics of fast hydrolysis rate, strong cohesion, high density of generated flocs, and fast settling rate, which can efficiently remove pollutants such as suspended solids, organic matter, sulfides, and heavy metal ions in electroplating wastewater.
Wide pH adaptability: It can achieve good purification effect in a wide pH range (generally 4-11, with the optimal pH range of 6-9), improving the flexibility and adaptability of treating electroplating wastewater with different pH values.
Low corrosiveness: Compared to other water purification agents, polymeric ferric sulfate has lower corrosiveness to treatment equipment, which is beneficial for extending the service life of equipment and reducing maintenance costs. However, it should be noted that polymeric ferric sulfate is an acidic substance and still has a certain degree of corrosiveness, so the processing equipment still needs to be treated with anti-corrosion measures.
Small sludge volume and easy dewatering: The sludge generated after treating electroplating wastewater with polymeric ferric sulfate has a small volume and is easy to dewater, making it convenient for subsequent treatment and disposal.
Environmental friendliness: Polyferric sulfate is a safe, non-toxic, and harmless water treatment chemical that does not cause secondary pollution to the environment after use. The wastewater treated with polymeric ferric sulfate contains almost no aluminum ions, which helps reduce the impact of wastewater on the environment and meets current environmental requirements.
Collaborative treatment: Polyferric sulfate can also be used in conjunction with other water purification agents or treatment methods to further improve the treatment efficiency of electroplating wastewater. For example, it can be combined with technologies such as activated carbon adsorption and membrane separation to achieve deep purification of various pollutants in wastewater.
In summary, polymeric ferric sulfate has significant advantages and broad application prospects in the treatment of electroplating wastewater, which is of great significance for protecting the environment and human health.