Functionalized polymethyl methacrylate-modified dialdehyde guar gum containing hydrazide groups for effective removal and enrichment of dyes, ion, and oil/water separation

Highlights: • A novel multifunctional polymethacryloyl hydrazone modified guar gum adsorption material was prepared. • Dyes and heavy metal ions can be effectively simultaneously adsorbed. • As-prepared adsorbent exhibited high adsorption capacity for dyes and heavy metal ions. • The adsorbent possessed excellent anti-interference ability by external conditions. • The adsorbent displayed high separation efficiency for oil/water emulsions. In the study, a novel polymethacryloyl hydrazone modified guar gum adsorption material (GSA) was prepared via condensation between polyhydrazide and dialdehyde guar gum. GSA exhibited an abundant porous structure, higher selectivity for cationic pollutants in high-concentration wastewater like methylene blue (MB), malachite green (MG) dyes, and Cu²⁺. Under optimized experimental conditions, the maximum equilibrium adsorption capacity of MB, MG, and Cu²⁺ were 1418.36 mg/g, 1375.58 mg/g, and 196 mg/g, respectively. Adsorption isotherms and kinetics were well fitted with the Langmuir isotherm model and pseudo-second-order kinetic model. The thermodynamic analysis demonstrated that the adsorption process was endothermic, feasible, and spontaneous. Correspondently, the adsorption mechanism was explored by FTIR, SEM-EDS and XPS. The adsorbent was employed in disposing of local sewage water. Additionally, GSA successfully achieves efficient water/oil separation in different salt concentrations with a separation efficiency exceeding 99%.