Enhancing the organic dye adsorption on porous xerogels

Organic dye adsorption on mesoporous hybrid gels

“…For determination of the adsorption isotherms, the initial pH of the solutions is set to 2 because adsorption of ARS and PR on the similar gels is relatively high at this pH [13]. The experimental isotherm data and the isotherms predicted by the two isotherm models are shown in Fig.…”

“…Initial solution pH was fixed at 2 with dilute HCl solution, and ionic strength of the solution was maintained at 0.25 M KNO 3 . Dye concentration change was recorded on a UV-160A Shimadzu UV-vis spectrophotometer by measuring the solution absorbance at maximum absorption in suitable solutions: ARS at 420 nm in pH 2 solution; PR at 558 nm in pH 12 solu- tion [13]. The amount of dye adsorbed onto the gels (q, in micromoles per kilogram of gel) was calculated by a mass balance relationship:…”

Adsorption kinetics and mechanism of maxilon blue 5G dye on sepiolite from aqueous solutions

“…The removal of dye at higher pH values may be due to the abundance of OH-ions and because of electrostatic attraction between the negatively charged surface of adsorbent and the cationic dye molecules [34]. At higher pH, the surface of sepiolite particles may become negatively charged, which enhances the positively charged maxilon blue 5G cations through electrostatic forces of attraction.…”

Paper-like composites of cellulose acetate–organo-montmorillonite for removal of hazardous anionic dye in water

“…As a result, a decreased adsorption at high pH values was observed. This was due to the abundance of OH À ions in solution, leading to the ionic repulsion between the negatively charged surface and the anionic dye molecules [44].…”