Drinking Water Grade Polyaluminum Chloride/PAC Water Purifier

 



1,Salinity.

The degree of hydroxylation or alkalization of a certain form in PAC (polyaluminum chloride) is called the degree of basicity or alkalinity. It is generally expressed by the molar ratio of aluminum hydroxide B=[OH]/[Al] percentage. The salinity is one of the most important indicators of polyaluminum chloride, which is closely related to the flocculation effect. The higher the raw water concentration and the higher the salinity, the better the flocculation effect.
 

3,alumina content.

The alumina content in PAC (polyaluminum chloride) is a measure of the effective components of the product, which has a certain relationship with the relative density of the solution. Generally speaking, the greater the relative density, the higher the alumina content. The viscosity of polyaluminum chloride is related to the alumina content, and the viscosity increases with the increase of alumina content.


1. It should be stored in a cool, ventilated, dry and clean warehouse. During transportation, it should be protected from rain and scorching sun, and deliquescence should be prevented.

2. Be careful when loading and unloading to prevent damage to the package. The storage period of liquid products is half a year, and the storage period of solid products is one year.

1. Boiling pyrolysis method The crystalline aluminum chloride is subjected to boiling pyrolysis at 170°C, and the released hydrogen chloride is absorbed into 20% recovered. Then add water at above 60°C to carry out ripening polymerization, and then solidify, dry and crush to obtain solid polyaluminum chloride finished product.

2. Aluminum ash method Add aluminum ash (the main components are aluminum oxide and metal aluminum) in a certain proportion into the reactor pre-added with washing water, slowly add  under stirring to carry out polycondensation reaction, and then mature and polymerize to pH The value is 4.2 to 4.5, the relative density of the solution is about 1.2, and the solution is settled to obtain liquid polyaluminum chloride. The liquid product is diluted and filtered, evaporated, concentrated and dried to obtain the solid polyaluminum chloride product.

The main purpose
1. Water treatment agent is mainly used for the purification of drinking water, industrial sewage and urban sewage, such as iron removal,al, radioactive pollution removal, floating oil removal, etc. Also used for industrial wastewater treatment, such as printing and dyeing wastewater. Also used in precision casting, medicine, paper rubber, leather, petroleum, chemicals, dyes.
2. Polyaluminum chloride is used as a water treatment agent in surface treatment.
3. Cosmetic raw materials.

water purification principle


The structure of the micelle electric double layer determines that the concentration of counter ions is the largest at the surface of the colloidal particles. The larger the distance from the surface of the colloidal particles, the lower the concentration of counter ions, which is finally equal to the ion concentration in the solution. When the electrolyte is added to the solution to increase the ion concentration in the solution, the thickness of the diffusion layer decreases.

When two colloidal particles approach each other, the zeta potential decreases due to the decrease in the thickness of the diffusion layer, so the mutual repulsion force between them decreases, that is, the repulsive force between the colloidal particles with high ion concentration in the solution is smaller than that with low ionic concentration. The suction force between the colloidal particles is not affected by the composition of the water phase, but due to the thinning of diffusion, the distance between them when they collide is reduced, so that the mutual suction force is larger. It can be seen that the resultant force of repulsion and attraction has changed from repulsion-based to suction-based (the repulsive potential energy has disappeared), and the colloidal particles can be rapidly aggregated. This mechanism can better explain the sedimentation phenomenon in the harbour. When the fresh water enters the sea water, the salt increases, the ion concentration increases, and the stability of the colloidal particles carried by the fresh water decreases, so the clay and other colloidal particles are easy to deposit in the harbour.

According to this mechanism, when the added electrolyte in the solution exceeds the critical agglomeration concentration for agglomeration by a large amount, there will be no more excess counterions entering the diffusion layer, and it is impossible to change the sign of the colloidal particles to re-stabilize the colloidal particles. Such a mechanism is based on the simple electrostatic phenomenon to explain the effect of electrolyte on the destabilization of colloidal particles, but it does not consider the effect of other properties (such as adsorption) in the destabilization process, so it cannot explain other complex destabilization phenomena, such as trivalent destabilization. If the amount of aluminum salt and iron salt as coagulant is too much, the coagulation effect will decrease, or even re-stabilize; another example, the polymer or polymer organic matter with the same electric number as the colloidal particles may have a good coagulation effect: the isoelectric state should be It has the best coagulation effect, but often in production practice, the coagulation effect is the least when the zeta potential is greater than zero.


For example, using Na+ and dodecyl ammonium ion (C12H25NH3+) to remove the turbidity caused by the negatively charged silver iodide solution, it is found that the destabilizing ability of the same monovalent organic amine ion is much greater than that of Na+, and Na+ is excessively added. Addition will not cause the colloidal particles to re-stabilize, but the organic amine ions do not. When the dosage exceeds a certain amount, the colloidal particles can be re-stabilized, indicating that the colloidal particles adsorb too many counter ions, so that the original negative charge is converted into a negative charge. positive charge. When the dosage of aluminum salt and iron salt is high, the phenomenon of re-stabilization and charge change will also occur. The above phenomenon is very suitable to be explained by the mechanism of adsorption charge neutralization.

adsorption bridging

The mechanism of adsorption and bridging mainly refers to the adsorption and bridging of polymer substances and colloidal particles. It can also be understood that two large colloidal particles of the same size are connected together because there is a colloidal particle of different size. Polymer flocculants have a linear structure, and they have chemical groups that can act on certain parts of the surface of the colloidal particles. When the high polymer is in contact with the colloidal particles, the groups can have a special reaction with the surface of the colloidal particles and adsorb each other. The rest of the polymer molecule is stretched in the solution and can be adsorbed with another colloidal particle with vacancies on the surface, so that the polymer acts as a bridge. If there are few colloidal particles, and the stretched part of the above-mentioned polymer cannot adhere to the second colloidal particle, this stretched part will be adsorbed on other parts by the original colloidal particles sooner or later, and the polymer cannot act as a bridge, and the colloidal particles will not be able to act as a bridge. is in a stable state again. When the dosage of polymer flocculant is too large, the surface of the colloidal particles will be saturated and re-stabilized. If the bridging and flocculated colloidal particles are subjected to vigorous and long-term stirring, the bridging polymer may be separated from the surface of another colloidal particle and re-rolled back to the original colloidal particle surface, resulting in a re-stable state.

The adsorption of polymers on the surface of colloidal particles comes from various physical and chemical interactions, such as van der Waals attraction, electrostatic attraction, hydrogen bonds, coordination bonds, etc., depending on the characteristics of the chemical structure of the polymer and the surface of the colloidal particles. This mechanism can explain the phenomenon that non-ionic or ionic polymer flocculants with the same charge can obtain good flocculation effect.



When metal salts (such as aluminum sulfate ) or metal oxides and hydroxides (such as lime) are used as coagulants, when the dosage is large enough to rapidly precipitate metal hydroxides (such as Al(OH)3, Fe(OH)3, Mg(OH)2, or metal carbonates such as CaCO3, the colloidal particles in the water can be caught by these precipitates as they form. When the precipitates are positively charged (Al(OH) 3 and Fe(OH)3 in the range of neutral and acidic pH), the precipitation rate can be accelerated by the presence of anions in the solution, such as silver sulfate ions. In addition, the colloidal particles themselves in the water can be formed as the precipitates of these metal oxides. Therefore, the optimal dosage of the coagulant is inversely proportional to the concentration of the material to be removed, that is, the more colloidal particles, the less the dosage of the metal coagulant.