Effect and distinction of polyacrylamide and decolorizing agent

 

 

The use of polyacrylamide and decolorizing agent is different, decolorizing agent is mainly used to remove dissolved organic matter in water, and cationic PAM in coordination with decolorizing agent is mainly used as a coagulant aid, then, what is the difference between polyacrylamide and decolorizing agent.

First of all, the principle of polyacrylamide and decolorization agent is different, the principle of decolorization agent is through chemical bonding, electrical neutralization to form small flocs, which requires decolorization agent must maintain good solubility, can ensure the rapid diffusion in water, and the full impact of organic molecules in wastewater contact reaction; At the same time, it is necessary to have the appropriate charge density, which requires that the molecular chain of decolorizer should not be too long.

For decolorizing agent is polymer, various raw materials in the reaction condition, by controlling the temperature to keep the decolorizing agent product form appropriate molecular weight, molecular weight, then the molecular chain of decolorizing agent is very long, can reduce rate of diffusion and solubility decreased, especially in the low temperature (below 5 degrees) will be layered white, affect the use; Also reduced the charge density of the decolorizing agent, affect the chemical bonds with cooperation, reduce its use effect, if the smaller molecular weight, so the reactive group on the molecular chain, rarely affect chemical bonds with cooperation, also reduces the chance of collisions with organic, formation of flocs is very small, can make the processed water residue many tiny suspended solids, affect water quality.

Second, polyacrylamide and decolorizing agent viscosity can be changed by additives, due to the determination of decolorizing agent raw materials and process, the viscosity produced is not more than 200cps, generally in 100- 150CPS, these can be achieved by controlling the temperature of the reaction, but if you want to further increase the viscosity, must add thickener to achieve, This is like detergent, detergent just to make the viscosity is also very low, then why use so thick, is the addition of the thickener, decolorization agent is the same, add a thickener, can be decolorization agent viscosity up to 500cps, but the effect is still the same as without the thickener, and even worse, Because the addition of thickening agent will react with part of the active group of decolorization agent, or shield the active group.

Third, the viscosity is too high will reduce the decolorization effect of decolorization agent, decolorization agent is to active group and electrical neutralization, if the viscosity is very high, then it is necessary to consume a lot of active group to form a long molecular chain; At the same time, the long molecular chain will reduce the charge density, high viscosity will reduce its water solubility, in winter, it is easy to delamination and whitening, affecting the use.

Fourth, the influence of the viscosity of decolorizing agent on the decoloring effect can be neglected, the bleaching of decolorizing agent is mainly depends on the molecular chain of the reactive group on the keys with cooperation and electrical neutralization, other adsorption bridge and the trap effect is limited, only when high concentrations of the pollutants in the water, the adsorption bridging and the trap effect to produce certain effect.

But in practice, decolorization agent is generally used in the biochemical pond after the water, the COD at this time is about 100mg/L, and decolorization agent is generally used with polyaluminum, do not need decolorization agent to play a strong adsorption bridge and precipitation trap role.

 

tag:

cationic polyacrylamide,anionic flocculant,nonionic polyacrylamide,flocculant,pam.