Constructing sustainable keratin/algae biohydrogels for efficient removal of aniline blue via a pre-extrusion induced self-crosslinking strategy

Two environmentally friendly hierarchical porous biohydrogels, honeycomb keratin hydrogel (HKH) and spongy keratin-algae hydrogel (SKAH), were fabricated using an extrusion approach by using extruded keratin with or without algae. The extruded keratin exhibits exceptional self-crosslinking properties, making the biohydrogels behave with excellent adsorption performance for aniline blue dye removal from wastewater. In addition, the SKAH demonstrated a significantly higher maximum uptake capacity of 442.56 mg/g, surpassing that of the HKH (134.63 mg/g). This enhancement can be attributed to the looser porous structure of the SKAH, which enables better exposure of active groups within the material, which indicates the introduction of algae led to noticeable variations in the microstructure and performance of the adsorbent. Systematic investigation on the adsorption performance of isotherm and kinetics analyses indicated that chemisorption played a predominant role in governing the overall rate of adsorption. Overall, this extrusion approach allows for a simplified and non-toxic method of synthesizing these biohydrogels without the need for additional chemical reagents or biocross-linkers, promoting their eco-friendliness and reducing potential environmental impacts. The unique feature presents significant opportunity to fabricate sustainable and eco-friendly biohydrogel adsorbent for wastewater treatment.