<p>This study developed a novel composite polymer flocculant, polyaluminum zinc silicate-cationic guar gum (PSAZ-CGG) and investigated the effects of preparation conditions and flocculation parameters on the removal of Congo Red (CR) and Reactive Blue 19 (RB-19). The synthesized flocculant and flocs were characterized using techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy–energy dispersive spectroscopy (SEM/EDX), elemental analyzer (EA), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). These findings suggest the successful fabrication of the composite flocculant and its favorable flocculation performance. Single-factor flocculation experiments revealed maximum removal rates of 97.7% and 95% for CR and RB-19. The kinetic and isotherm data were better fitted by the pseudo-second-order and Langmuir models, respectively. These models were used as empirical tools to describe the apparent dye removal behavior. Furthermore, maximum uptake values of 454.55 mg g^− 1 (CR) and 393.33 mg g^− 1 (RB-19) were measured for the PSAZ-CGG composite in aqueous solution. XPS analysis further supports the interaction between PSAZ-CGG and the dye molecules during the flocculation process. The primary flocculation mechanisms are likely to include sweep flocculation, adsorption bridging, and charge neutralization. The recycling study further suggests that the flocculant possesses good chemical stability and eco-compatibility.</p> Graphical Abstract <p></p>