Efficient Removal of Methylene Blue by Sodium Alginate‐Carboxymethyl Cellulose‐Kaolin Composite Microbeads

ABSTRACT With the rapid advancement of the printing and dyeing industry, water pollution has emerged as a prominent environmental issue, particularly dye wastewater. In order to construct polymeric adsorbents with rich functional groups for efficient adsorption of dye wastewater, hydrogel spherical adsorbent SA/CMC‐Kaolin was prepared by using sodium alginate (SA) as the hydrogel skeleton material, carboxymethyl cellulose (CMC) and kaolin as the strength‐reinforcing materials. FT‐IR, SEM, XRD, and TG were utilized for comprehensive characterization of the microbeads' characteristics and adsorption mechanism. SA/CMC‐K composite microbeads were investigated for the adsorption characteristics of methylene blue (MB) in aqueous solution. Adsorption kinetics and thermodynamic models were employed to analyze the adsorption process. Under optimal conditions, SA/CMC‐K microbeads demonstrated superior adsorption efficiency for MB, with a maximum adsorption capacity of 84.63 mg/g, a bio‐based adsorbent with a high adsorption capacity. The adsorption process exhibited better agreement with the Langmuir isotherm equation and the pseudo‐second‐order kinetic model. Besides, SA/CMC‐K composite microbeads maintained 71.74% adsorption efficiency after five cycles. Overall, the prepared microbeads, which are economical and environmentally friendly, are promising for the absorption of dye wastewater.