flocculant
The effect of flocculant depends on the comprehensive action of many factors. The main factors affecting the flocculation effect are the properties of flocculant, the composition and composition of flocculant, the dosage of flocculant, the temperature and pH of water body, and the application conditions of flocculant. In order to simplify the influencing factors, some people regard the flocs as uniform spheres, but in fact, the size, shape, structure and other factors of flocs greatly affect the transportation and removal of flocs in the fluid.
For inorganic polymer flocculants, the greater the degree of polymerization, the greater the relative molecular weight, the better the flocculation effect; for organic polymer flocculants, in addition to the influence of the degree of polymerization, it also has a great relationship with the structure of the flocculant, such as the flocculation effect of linear structure flocculant is better than that of ring or branch chain structure flocculant, and the greater the relative molecular weight of the flocculant The more adsorption sites, the more charge carried, the stronger its neutralization ability, bridging ability and net catching effect.
In different environments, each flocculant has an optimal dosage, higher or lower than the optimal dosage will make the flocculation effect worse. When the dosage of flocculant is small, the flocculation is not complete, but when the dosage is too large, the colloid will be re stabilized, and the flocculation effect is also not good.
Some research results show that the optimal dosage of flocculant is about half of the amount when the surface of solid particles in water reaches saturation, because the bridging probability of macromolecular materials on solid particles is the largest. PH will affect the properties of flocculant and the surface charge of colloidal particles, so it will affect the adsorption, electric neutralization, hydrogen bonding between flocculant and colloidal particles.
disinfectant
Taking ClO2 as an example, the main factors affecting disinfectant are dosage of disinfectant, contact time and temperature of disinfectant.
>>>Dosage of disinfectant
Because ClO2 only selectively oxidizes with some organic compounds and degrades them into products mainly containing oxygen groups, no cyanide organic compounds are produced. Therefore, the higher the dosage of ClO2, the higher the bactericidal effect. However, with the increase of ClO2 dosage, its dissolution in water tends to be saturated. Excessive increase of ClO2 dosage will not only make a part of ClO2 gas insoluble in water and escape, increase the unnecessary loss of equipment and raw materials, but also lead to bad smell. Therefore, it is necessary to determine the appropriate dose through experiments.
>>>Contact time of disinfectant
The longer the contact time is, the better the killing effect of ClO2 is. But the contact time should not be too long. Otherwise, it will not only increase the load of the device and the loss of raw materials, but also produce by-products such as chlorite (ClO2 -) and low concentration chlorate (ClO3 -) in water, which will reduce the disinfection ability of ClO2. Therefore, the selection of disinfection time should consider the influence of other factors.
>>>Application temperature of disinfectant
The inactivation effect of ClO2 on bacteria increased with the increase of temperature. However, the solubility of ClO2 in water will decrease. If the temperature is too high, the content in the water will be reduced, and the effective concentration may not meet the requirements of killing all the bacteria in the sewage. Therefore, in the disinfection of hospital sewage, temperature should also be considered.
Corrosion inhibitor
There are many factors affecting the inhibition effect of corrosion inhibitor, the main factors are as follows.
>>>Properties and surface state of metal materials
Most of the inhibitors have specific inhibition effect on metal. In the same corrosion medium, adding the same inhibitor has different inhibition effect on different metal materials. Whether there are oil stains and corrosion products on the metal surface, and the surface roughness will affect the corrosion inhibition effect.
>>>Environmental media
1. Composition of medium. The composition of the medium is an important factor affecting the corrosion inhibition. Generally, corrosion inhibitors have strong environmental pertinence. The structure and properties of corrosion inhibitors must adapt to the environment and be able to disperse in the medium. Chemical reactions such as oxidation-reduction and neutralization should not occur in the medium, that is, the structure will not be damaged in the medium environment, and the properties will not change, so as to avoid the loss of corrosion inhibitors I lost.
2. PH of the environment. Most corrosion inhibitors have a suitable and effective pH range.
3. Flow velocity. When the protection effect is affected by the poor diffusion of the inhibitor, increasing the medium flow rate can make the inhibitor evenly diffuse to the metal surface, which is conducive to the growth of the inhibitor. When the flow rate increases, the inhibition rate may decrease, because with the increase of flow rate, the corrosion inhibitor is the activator of corrosion, and the corrosion is also accelerated. The effect of medium flow rate on the inhibition rate will be reversed at different concentrations.
4. Microorganism. There are many kinds of microorganisms, which can affect the corrosion and inhibition.
5. Temperature. Temperature has an important influence on the inhibition effect of corrosion inhibitor. The specific performance is as follows: in the lower temperature range, the inhibition effect is very good, with the increase of temperature, the inhibition effect decreases; in a certain range, the temperature has little effect on the inhibition effect, beyond a certain temperature, the inhibition effect decreases significantly; with the increase of temperature, the inhibition efficiency also increases.
>>>Concentration of corrosion inhibitor
From the practical use, from the principle of saving, we should ensure the effect and reduce the consumption of corrosion inhibitor to fully consider and confirm the dosage of corrosion inhibitor. There is a limit in the relationship between the inhibitor rate and concentration, that is, the inhibition effect is the best at a certain concentration, and the inhibition rate will decrease if the concentration is too low or too high.
