Acid Red-87 dye (Eosin) is an acidic dye
and is commonly used for dyeing wools, cotton, silk, leather, papers and nylon.
In the acidic dye
bath, the carboxyl ions of the fiber molecule main chain are converted to undissociated carboxyl groups due to addition of acid (HX) which makes silk fiber positively charged (+H3N-S-COOH) to take up an equivalent amount of acid anions X-, as shown in Scheme-2 .
This may be because of possible inefficient electron/cation recombination pathways and the acidic dye
adsorption environment .
The presence of the electron attracting groups in sulfonphthalein skeleton such as bromine atom increase the value of [K.sub.a] of the acidic dye
, which makes it even more electronegative, and due to the inductive effect, it will extract electrons, thus diminishing the carbon a electron density inducing a positive inductive effect and a structure having a relatively high energy that will be destabilizing the acidic dye
with respect to the anionic form (conjugate base); as the presence of bromine is electron attracting, this will disperse the charge and stabilize the anionic form, thus producing a stronger acidic dye
, and consequently the dissociation will be larger.
Refaat, "Removal of rhodamine B (a basic dye) and thoron (an acidic dye
) from dilute aqueous solutions and wastewater simulants by ion flotation," Water Research, vol.
In the present work, an effort has been made of verifying the capability of IJSP as a means of removal of acidic dye
, Acid Blue 25 (AB25), from the wastewater solutions, which are synthetic.
An acidic dye
(sunset yellow FCF) and a basic dye (malachite green) was removed by adsorption on chemically treated mangrove bark by Seey and Kassim .
This observation showed that an alkaline environment creates an anionic electrical environment, which naturally favored the acidic dye
Optimal formation of the complex is dependent on the ionization constants (pKa) as well as solubility characteristics for both the basic drug and acidic dye
; therefore, optimum complex formation is pH dependent and is characteristic of the analyte being tested.
 investigated that the biosorption of acidic dye
increased with increase in the concentration of salts by using wood shaving biomass.
In other words, increasing the initial dye concentration at higher chitosan content has led to improved removal of efficiency of acidic dye
A Hewlett Packard/Agilent 3D (Palo Alto, California) capillary electrophesis system, also equipped with a photodiode array detector, was chosen to perform all of the acidic dye