A Sustainable Approach to Ink Colorant Removal Using Modified Cellulose From Wastepaper

ABSTRACT This study reports the fabrication of cellulose‐based hydrogels for ink pigment removal using hydroxyethyl cellulose (HEC) and cellulose fibers (CF) recovered from office wastepaper. Cellulose was obtained through a mild chemical deinking process following the INGEDE method, while HEC was used as a soluble matrix to improve processability and network homogeneity. A series of HEC/CF hydrogels was prepared by glutaraldehyde (GA) crosslinking at different concentrations (0–5 wt%) and characterized using FTIR, TGA, SEM, and contact angle measurements. FTIR analysis confirmed network formation through reduced hydroxyl band intensity, while TGA revealed enhanced thermal stability with increasing crosslink density. SEM images showed a transition from interconnected porous morphologies at low GA content to denser structures at higher crosslinker levels, directly influencing swelling behavior. BET results indicated that the HCG5 hydrogel had a specific surface area of 13.6 m 2 g −1 , confirming its porous structure. Contact angle results indicated decreased surface hydrophilicity with increasing GA concentration. The hydrogels exhibited ultralight structures with high porosity and low apparent density, enabling rapid ink adsorption via capillary‐driven transport. Adsorption tests using synthetic magenta ink showed rapid dye removal, reaching optimal performance at pH 3 within 5 min. The hydrogel exhibited robust performance in real printing wastewater, achieving 72.91% colorant removal despite the complexity of the matrix, underscoring its high affinity toward printing‐derived pigments and its strong potential for scalable, sustainable industrial wastewater treatment applications. These results highlight the potential of wastepaper‐derived cellulose hydrogels as efficient and sustainable adsorbents for wastewater deinking and related environmental applications.