Use of hen feathers to remove Reactive Black 5 and Basic Red 46 from aqueous solutions

This study aimed to determine the effectiveness of Reactive Black 5 (RB5) and Basic Red 46 (BR46) sorption on hen feathers (HF), being a post-slaughter waste from the poultry industry. The scope of the study included, i.a. FTIR spectra analysis of hen feathers, pH effect on dye sorption effectiveness, dye sorption kinetics (pseudo-first order model, pseudo-second order model, intramolecular diffusion model), and maximal sorption capacity of the sorbent (Langmuir 1 and 2 models, and Freundlich model). The effectiveness of RB5 sorption onto HF was the highest at pH 2 and that of BR46 - at pH 5. The time needed to reach RB5 and BR46 sorption equilibrium onto HF ranged from 180 to 210 min. The kinetics of dye sorption onto HF was best described by the pseudo-first order model, which indicates the typically physical nature of the sorption process. The constants determined from the intramolecular diffusion model demonstrated that RB5 and BR46 sorption onto HF proceeded in two main phases, differing in sorption intensity. The maximal sorption capacity of HF reached 5.19 mg/g for RB5 and 4.06 mg/g for BR46. The identical values of KC, K1, and K2 constants determined from the Langmuir 1 and Langmuir 2 models suggest that only one type of the sorption center played the key role in the sorption process.

Automated summary

This study investigated the sorption of RB5 and BR46 dyes on hen feathers, finding different sorption effectiveness at different pH levels. The kinetic study revealed that the sorption process followed a pseudo-first order model, and the sorbent had a maximal sorption capacity. The Langmuir models suggested only one type of sorption center played a key role in the sorption process.