LAUSR

Abstract Buckwheat husks (Fagopyrum esculentum) modified with epichlorohydrin (ECH) and ammonia water (NH3*H2O) were tested as potential sorbent for Reactive Black 5 (RB5) dye. FTIR and pHPZC measurements were used to characterize sorbents. The influence of pH, contact time and concentration of the dye on RB5 sorption has been investigated. The FTIR spectra analysis confirmed the amination of polysaccharides and lignin in buckwheat husks modified with ammonia water. The effectiveness of RB5 sorption was the highest at pH 3. The sorption equilibrium time was from 240 to 300 min. Equilibrium data were well fitted to the Double Langmuir adsorption model. The maximum RB5 sorption capacity of modified buckwheat husks was Qmax = 85.18 mg/g, which was over 19 times higher than that of unmodified buckwheat husks (Qmax = 4.43 mg/g).