Rhodamine b dye

Rhodamine B is a organic compound and it is a basic dye. In paper mill it is used as dye for making pink color paper. The chemical formula of Rhodamine B is C₂₈H₃₁N₂O₃Cl. The IUPAC name of the compound is [9-(2-carboxyphenyl)-6-(diethylamino)xanthen-3-ylidene]-diethylazanium-chloride. It contains amino, imino and carboxylic group and has a xanthene structure. Physically it looks like dark reddish purple or brown powder. The pKa value is about 3.1. It is also known as Basic Violet 10, Brilliant Pink B, Basic rose red etc.

Solubility of Rhodamine b dye

Rhodamine B is water soluble compound. The solubility of it in water is approximately 15g/l.

Lab test

There are three tests done in the lab to see the quality of the colors. The three tests are Back water Number, Water fastness and Light fastness. To test the color at first we need to make dye solution. Take 0.25g dye sample into the 250 ml volumetric flask and fill up to the mark with distill water for making 0.1% solution. Then we make hand sheet with adding the color and sizing chemical.

Back water Number

To test Back water Number take the specific amount of pulp and add the sample Rhodamine B dye and sizing chemicals. Then filter the some portion of the stock before making the hand sheet and collect the filtrate.  By the coloration amount of the filtrate we calculate the Back water Number.

Water fastness

Firstly, cut off a part of the created hand sheet just similar to filter paper size. Then, this sheet is soaked by keeping into two filter papers. After that it is placed between two glasses sheet for overnight. Then the two filter papers are dried in oven and calculate the Water fastness by the coloration of the filter papers.

Light fastness

Cut a half of the created hand sheet and placed in sunlight for 12 hours. Then, calculate the Light fastness by the coloration of the sheet.

Environmental effects

Rhodamine B is an organic dye, so it can creates environmental and biological problems. It has limited effects on human – may cause skin irritation and damage to eyes, whereas has some evidence of carcinogenicity in animals. The wastewater that contains Rhodamine B dye must be treated before discharge to the environment; otherwise it will damage ecological environment.