Activated carbon Another performance of adsorption capacity is decolorization capacity. Activated carbon has the magical ability to turn colored liquid into light color or colorless, which is actually caused by the reason that activated carbon absorbs pigment molecules in colored liquid. Because of this characteristic, activated carbon is widely used in the production process of brown sugar to white sugar in the sugar industry. Take two transparent cups, put pure water in one cup, and then drop a drop of red ink (any pigment that is easy to observe but does not change the nature of the water can be used here, such as blue ink, printer color ink, but ink and carbon ink cannot be used). After mixing evenly, pour half of the colored water into another cup for comparison.

There are two types of activated carbon: intermittent operation and continuous operation:

1) Intermittent operation is commonly used for the large and small scale use of powdered activated carbon. The equipment used is: containers, filters, mixers, etc. with different sizes of barrels, tanks, troughs, etc. There are various types of filters, such as ordinary filter, vacuum filter or pressurized filter.

2) Continuous operation is often used for large-scale production using granular activated carbon. The equipment and devices include:

a. The fixed bed is a method that uses activated carbon as the filling layer, and the fluid flows continuously from above or below for adsorption, because the activated carbon in this equipment is fixed during operation. The fixed bed has single bed, multi bed series connection and multi bed parallel connection according to the fluid volume and processing requirements.

b. Moving bed refers to the intermittent moving adsorption mode of activated carbon. The fluid to be treated flows in from the bottom of the adsorption tower, contacts with the activated carbon countercurrent, and the treated fluid flows out from the top of the tower.

c. Mobile bed, which is a continuous mobile bed adsorption method, decolorizes sugar at an early stage. The activated carbon forms an expansion layer or fluidized state in the tower, contacts more with the fluid entering from the bottom of the tower, and then continuously discharges out of the tower. If the fluid flow rate is too large, the expansion rate of activated carbon in the tower will increase, and the laminar movement cannot be maintained, so the flow rate must be strictly adjusted.