Poly aluminium chloride (PAC) has been making waves in the water treatment industry, especially when it comes to tackling the complexities of various types of industrial wastewater. In this article, we will explore the diverse and significant roles PAC plays in treating different kinds of industrial wastewater, highlighting its effectiveness and versatility.
Papermaking Wastewater
Papermaking wastewater is notorious for its high chemical oxygen demand (COD), suspended solids (SS), and colour. PAC works wonders in this scenario. When introduced into papermaking wastewater, it undergoes hydrolysis to produce a series of positively charged Al (OH) n m + species. These species can effectively adsorb and aggregate the negatively charged colloidal particles in the wastewater, such as those formed by dissolved lignin, cellulose, and other organic substances. Through electrostatic neutralization and adsorption bridging, PAC promotes the formation of large flocs. These flocs can easily settle or be filtered out, achieving a remarkable COD removal rate of up to 80–90% and a SS removal rate of over 90%, significantly improving the water quality and making it suitable for reuse or safe discharge.
Textile and Dyeing Wastewater
Textile and dyeing wastewater is highly polluting due to the presence of a wide variety of dyes, auxiliary agents, and other chemicals. Its high colour, COD, and complex composition pose significant challenges for treatment. PAC plays a crucial role in decolorization and COD removal. The positively charged Al (OH) n m + species generated by PAC can strongly adsorb the negatively charged dye molecules. Additionally, PAC can form a network structure with dyes and other pollutants through adsorption bridging, promoting their aggregation larger into particles. This leads to a decolorization rate of up to 70–80% and a COD removal rate of 60–70%, effectively reducing the pollution load of textile and dyeing wastewater.
Electroplating Wastewater
Electroplating wastewater contains high concentrations of heavy metal ions, such as chromium, nickel, copper, and zinc, which are highly toxic and pose severe threats to the environment and human health. PAC can effectively remove heavy metal ions from electroplating wastewater. It can form insoluble metal hydroxides with heavy metal ions through hydrolysis and precipitation reactions. PAC also has a strong adsorption capacity for heavy metal ions, which can be adsorbed onto its surface and removed along with the flocs. This reduces the heavy metal ion content in the wastewater to meet discharge standards and prevents heavy metal pollution.
Metallurgical Wastewater
Metallurgical wastewater contains a variety of pollutants, including heavy metal ions, suspended solids, and oil. PAC can be used to treat metallurgical wastewater by removing heavy metal ions through hydrolysis and precipitation reactions, similar to its action in electroplating wastewater. PAC can also effectively aggregate the suspended solids and oil in the wastewater into larger particles, facilitating their removal and thereby improving the water quality of metallurgical wastewater.
In summary, poly aluminium chloride demonstrates exceptional performance in treating various types of industrial wastewater. Whether it’s papermaking, textile, electroplating, or metallurgical wastewater, PAC effectively removes pollutants, reduces wastewater toxicity, and improves water quality. As environmental regulations become increasingly stringent and the demand for water resource protection grows, PAC is expected to play an even more important role in industrial wastewater treatment. It will continue to help industries address wastewater treatment challenges, achieve sustainable development, and contribute to the protection of water resources and the environment.
