Adsorption study for removal of sunset yellow by ethylenediamine-modified peanut husk

摘要

Peanut husk crosslinked with epichlorohydrin, followed by modification with ethylenediamine, was used as a new adsorbent for removal of sunset yellow from aqueous solution. Factors affecting the adsorption characteristics of the said adsorbent, namely, pH value, adsorption time, temperature, and concentration of initial sunset yellow were dealt with in the whole experiments in a batch system. It was concluded that the maximum adsorption capacity of this adsorbent for sunset yellow was 117.7 mg/g at 313 K, which was improved 4.3 times as much as that of the unmodified peanut husk. The Langmuir isotherm model could provide a better description for the adsorption equilibrium when compared with the Freundlich model under the conditions of the present study. The calculated thermodynamic parameters showed that the adsorption of sunset yellow onto peanut husk biomass was feasible, spontaneous, and endothermic under examined conditions. Due to the examination of controlling mechanisms of the process, the Largergren-first-order model, the pseudosecond- order model, and the intra-particle diffusion model were used to correlate the kinetic data. It was found that the intra-particle diffusion is the significant controlling step under the experimental conditions. It showed that the peanut husk modified with ethylenediamine had good performance for removal of sunset yellow and could be used as a highly efficient biomass adsorbent to treat dyes-containing wastewater.