Decolorizer

Introduction

Decolorizer is a substance that can remove useless staining groups from wastewater or substance. Some industrial wastewater such as printing and dyeing wastewater has the characteristics of high chromaticity, large sewage, high toxicity and serious pollution. Therefore, it is necessary to undergo relevant treatment before discharge, among which decolorization treatment is one of the main treatment processes. Decolorization processing include several methods, and adding decolorizer into wastewater to achieve decoloring purpose get the widespread attention due to the advantages of economy, simplicity and effectivity. Nowadays, decolorizers are widely used in various industrial wastewater.

Fig. 1. The decolorization process of wastewater.

Classification

Decolorizer can be divided into physical decolorizer and chemical decolorizer.

• Physical decolorizer: Physical decolorizer refers to the substance that the chemical reaction will not occur when adding decolorizer into wastewater. Physical decolorizer includes activated carbon, coal cinder, natural mineral sorbents, ion exchange resins, fiber sorbents and others, which possesses the advantage of low cost and convenient operation.
• Chemical decolorizer: Chemical decolorizer has higher decolorization efficiency than physical decolorizer and can be divided into flocculating decolorizer and oxidizing decolorizer. Furthermore, flocculating decolorizer can be divided into organic flocculation decolorizer and inorganic flocculation decolorizer. Organic flocculation decolorizer has various types and it not only has high decolorization efficiency, but also has abilities of flocculation and degradation of COD. Therefore, it is the mainstream decolorization products at present. Inorganic flocculation decolorizer mainly includes polyferric sulfate, ferrous sulfate, polyaluminum chloride and so on. Oxidizing decolorizer is the oxidizing substances that can destroy colored group to remove chroma, including sodium hypochlorite, potassium permanganate, ozone, etc.

Applications

Decolorizers can be used for a variety of industrial wastewater treatments. Some examples are as follows:

• Printing and dyeing wastewater: Printing and dyeing wastewater is the main pollutant in the production process of the textile industry. A large number of dyes are used in the printing and dyeing process, so the residual dyes in the printing and dyeing wastewater are large, resulting in high chroma of the wastewater. With increasing awareness of people's environmental protection, the printing and dyeing wastewater discharge standards are becoming higher and higher. The treatment of printing and dyeing wastewater with decolorizers has been widely used due to its high efficiency and several advantages. Now, many studies have focused on this.

Fig. 2. The printing and dyeing wastewater with high chromaticity.

• Paper pulp making wastewater: Paper pulp making wastewater is a kind of wastewater with great difficulty in treatment. It not only has large discharge, but also has high COD content, complex composition and extremely high chroma. As an economical and simple water treatment technology, adding decolorizer is easy to be accepted by some pulp and paper enterprises due to its low technical requirements and small investment.
• High color reclaimed water: In order to alleviate the problem of water shortage, people pay more and more attention to the reuse of reclaimed water. If the chromaticity of reclaimed water after treatment fails to meet the relevant provisions of reclaimed water use, it will cause sensory discomfort and affect reuse. Adding decolorizer, especially organic flocculating decolorizer, can destroy the stability of dye molecules and make the dye molecules collide with each other to form larger flocs which is easily removed from the water by precipitation. Therefore, the excellent effect of decolorizer has attracted extensive attention.

Alfa Chemistry can offer you with various decolorizers. If you can't find the desired product in our product catalog, we also offer you with custom synthesis service. Please contact us, if you have any needs.