Hydrothermal Synthesis and Performance of Xanthan Gum‐Sodium p ‐Styrenesulfonate‐Sodium Alginate Ternary Anionic Flocculant for Dye Wastewater Treatment

Natural polysaccharide flocculants, with their green, safe, and renewable properties, represent a transition of sustainable development in the field of water treatment. However, they are confronted with challenges regarding their flocculation efficiency and feasibility under complex environmental factors. In this study, a ternary anionic flocculant of xanthan gum‐sodium p ‐styrenesulfonate‐sodium alginate (XSS) was synthesized by means of hydrothermal polymerization. The optimal synthesis conditions were determined with monomer ratio of 1:2:1, initiator dosage of 1.0 wt%, reaction time of 5 h, and reaction temperature of 65°C based on the flocculation efficiency of cationic dye methylene blue (MB). At an XSS concentration of 200 mg/L, the maximum removal efficiency toward 100 mg/L MB simulated wastewater reached 82.1%, due to its rich functional groups and negative charge. Moreover, it showed superior flocculation performance at a pH range of 4–10, temperatures between 10°C and 40°C, and with various inorganic salts of Na + , Ca 2 + , and Fe 3 + . Correlation analysis between the maximum removal efficiency and initial dye concentration indicates that charge neutralization is the dominant flocculation mechanism. The operating expense was calculated about 72% of that of an anionic polyacrylamide with comparable decolorization efficiency. The successful preparation of XSS provides a new approach for the utilization of natural polysaccharides for wastewater treatment in terms of environmental safety and high efficiency.