- The main application of super absorbent polymer
- Correct selection method of polyacrylamide for mineral processing
- What is the degree of hydrolysis and ionic degree of polyacrylamide?
- What factors are related to the amount of polyacrylamide?
- Effect and distinction of polyacrylamide and decolorizing agent
- Causes and solutions of sludge whitening in sewage
- Application of polyacrylamide in the whole process of oil recovery
- Characteristics and application range of instant polyacrylamide
- Spray drying polyaluminum chloride -- Chinafloc-PAC
- Sludge dewatering process of polyacrylamide
1.The brief introduction of the water treatment agent
The water treatment agent is the necessary chemical agent in the treatment processing of the industrial waste water, the domestic waste water and sewage etc., by using these agents, the treated water can reach a certain water quality requirements. The main function of the water treatment agent is to control the formation of the water scale and the sludge, to reduce the foam, to reduce the material corrosion from the contact with the water, to remove the suspending solids and the toxic substances in the water, to achieve the deodorization and the decolorization effect and to soften the water etc. At present the demand on the water supply is increased dramatically around the world, while at the same time a variety of environmental regulations (the laws for the water purification and clarification) have been brought into effect more and more strictly, therefore, the demand for all kinds of efficient water treatment agents is growing very quickly. In our country, there is the contradiction between the increasing severe water shortage crisis and the very low production capacity of the water treatment agent, the quality of the water treatment agent can not be guaranteed, thereby, it is very urgent to speed up the development of the water treatment agent industry in China.
The water treatment agent includes the flocculant, the corrosion inhibitor, the scale inhibitor, the bactericide, the dispersing agent, the cleaning agent, the pre-filming agent, the defoaming agent, the decoloring agent, the bleaching agent, the chelating agent, the chelecting agent, the deoxidizing agent and the ion exchange resin etc.
The key point of the flocculation technology is the choice of the flocculant. The flocculant can be divided into the inorganic flocculant, the organic flocculant and the microbial flocculant.
2.1The inorganic flocculant
The low molecular inorganic flocculant includes the aluminum chloride, the aluminum sulfate, the ferric sulfate and the ferric chloride etc. the aggregation rate of the low molecular inorganic flocculant is slow, the flocs formed is small but with strong corrosion effect, so there is a big problem in the process of the water treatment. Now it is gradually replaced by the high polymer inorganic flocculant.
The high polymer inorganic flocculant is a new type of water treatment agent which is developed on the traditional aluminum salt and the ferric salt, it features the low price and the good water purification effect.
The Polyaluminium Chloride (PAC) has good coagulation performance, it can generate the large alum, it has the advantages like the less dosage, the high efficiency, the fast sedimentation and the wider applicable range in different water properties. It is mainly used for the purification of the drinking water and the industrial water supply. At the same time, it can also be used in the removal of the heavy metals such as the ion, the manganese, the chromium and the lead etc in the water, it can also be used to remove the fluoride and the oil in the water, therefore, it can be used in the treatment of a variety of industrial waste water.
The Polymeric Aluminum Ferric Chloride (PAFC) is a new type of high polymer inorganic water purification agent. The ratio of the aluminum and the ion in the PAFC is adjustable to adapt to the different water quality requirements. It has been practically applied in the purification treatment of the industrial waste water in the petrochemical industry, the steel industry and the coal industry. The practical application shows that this agent has high quality but with low price, it is a kind of innovative, high efficient and stable water purification agent with the wide application prospect. The comparison experiment shows that the PAFC has the better effect than the PAC in the water purification; but the dosing cost of the PAFC is much less than the PAC.
The Polymeric Ferric Sulfate (PFC) has good flocculation and adsorption effect, it is widely used in the treatment of the raw water, the drinking water, the tap water, the industrial water, the industrial waste water and the domestic sewage etc. The Polymeric Aluminum Sulfate (PAS) is a kind of most widely used coagulant, it is mainly used in the purification treatment of the drinking water and the industrial water.
The Polymeric Silicate is developed on the traditional polymeric silicic acid and the aluminum salt and the ferric salt. The highly polymerized silicic acid the metal ions can work together to produce a good coagulation effect. By combining the metal ion charge neutralization capacity and the polysilicic acid adsorption bridging ability together, it makes the composite products with the strong charge neutralization and the bridging effect to achieve the better water purifying effect. Theirs performance on the flocculating and the dewatering stabilization far exceeds the performance of the poly silicic acid and the poly metal ions. Comparing with the poly silicic acid, they not only improve the stability but also increase the ability of the charge neutralization. Comparing with the poly metal ions, they can enhance the bonding and bridging performance. As the representative of the composite inorganic polymer flocculants, that is the polymeric aluminum silicate sulfate (PASS), the polysilicate aluminum chloride (PASC) and the inorganic polymer composite flocculant ferrosilicon, has been successfully used in the treatment of the water supply, the industrial waste water and the urban sewage, now it has become the mainstream of the flocculant.
However, the relative molecular weight, the particle size and the flocculation bridging capability of the inorganic polymer flocculant is still much less than the organic flocculant, and there is an instability problem on its further hydrolysis reaction.