To reduce UV absorbance in crude glycerine below 15, use ion exchange resin purification combined with adsorption treatments such as activated carbon or bleaching clay. Optimizing temperature and solvent extraction (e.g., with methanol) can further improve removal of UV-absorbing impurities.

1) if i use only adsorption treatment, it will improve? or must need that resin?

2) can you explain to me how you do solvent extraction? is it after you putting the adsorption treatment? Abdelhak Maghchiche