From Feather to Adsorbent: Keratin Extraction, Chemical Modification, and Fe(III) Removal from Aqueous Solution

Abstract

In this work, feather keratin was extracted from the waste feather of chicken via alkyd pretreatment and reduction method, the extraction rate is above 85%. The molecular weight and aggregation morphology of feather keratin in an aqueous environment were characterized by 18-angle laser light scattering gel permeation chromatography and field emission transmission electron microscopy. The relationship between the structure and properties of feather keratin is discussed. The 1-(3-dimethylaminopropyl) -3-ethylcarbondiimide hydrochloride and N-hydroxysuccinimide were used as activation system and cross-linkage. The gallic acid was used as modification reagent and was bonded to feather keratin chains; meanwhile, feather keratin chains were cross-linked through covalent bonds obtained the novel adsorbent (named as GA-FK gel). The GA-FK gel was investigated by IR, SEM, TGA, XRD, and BET methods. The results indicated that GA molecules successfully bonded to feather keratin chains and cross-linked between feather keratin chains. The GA-FK gel was found to have a three-dimensional network structure with abundant mesopores. Its pore size range is 1.8~90 nm; average pore size is 19.6 nm. Its specific surface area is 7.17 m2·g−1. In addition, GA-FK gel was applied to remove Fe(III) in water. The maximum adsorption capacity was 319.0 mg·g−1. The adsorption process of GA-FK gel to Fe(III) presents a typical two-stage pattern accompanied with swelling. The adsorption kinetics of GA-FK gel to Fe(III) follows the quasi-second-order model, the adsorption isotherm follows the Freundlich model. Therefore, the adsorption mechanism is non-specific adsorption.

Keywords

• feather keratin
• biomass
• solid waste
• chemical modification
• adsorption property