Synthesis, characterization and evaluation of amphoteric galactomannan derivative for the mitigation of malachite green and congo red dye from aqueous solution

Biopolymeric materials have been utilized for water treatment since ancient times. Consequently, novel sustainable, inexpensive and natural biobased alternatives have been explored persistently. Ampho-teric derivatives of galactomannans are still unex-plored and rarely used materials to treat industrial wastes. The present study was explored to synthesize and characterize the amphoteric derivative of galac-tomannan, obtained from Cassia tora seeds, by applying 'Taguchi design' (L'9), for its application in mitigation of cationic (Malachite green) and anionic (Congo red) dyes. The derivative was also studied for the conditioning of water using kaolin suspension. The results signify that the amphoteric derivative (anionic DS similar to 0.52 and cationic DS 0.197) is effective in maximum adsorption of Malachite green (73%) and Congo red (17%) dyes and as a flocculant at a minimum dose of 10 ppm. The amphoteric derivative was characterized by X-ray-diffraction, TG analysis and spectroscopic techniques. [GRAPHICS] .