Water soluble polyacrylamide-grafted carboxymethyl cellulose flocculant: Synthesis, characterization, and flocculation activity evaluation

In the current investigation, graft polymerization was conducted employing acrylamide (AM) and carboxymethyl cellulose (CMC) as the primary substrates. The influential variables assessed included the concentrations of AM and CMC, the reaction temperature, the reaction duration, and the initiator concentration. Additionally, parameters related to grafting, including grafting efficiency (GE%), grafting percentage (GP%), grafting yield (GY%), and grafting conversion (GC%), were determined. The optimal preparation parameters were also identified. Structural characterization techniques, including Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), point of zero charge determination, and energy-dispersive X-ray spectroscopy (EDX), were adopted to further validate the successful execution of the polymerization process. The flocculation performance was evaluated under the optimal grafting conditions, with significant factors such as flocculant volume, dosage, temperature, agitation speed, pH, clay concentration, and flocculation duration being thoroughly investigated. Furthermore, two coagulation-flocculation protocols were applied to treat bentonite suspension, with results indicating that polyacrylamide-grafted-carboxymethylcellulose (PAM-g-CMC) demonstrated a synergistic effect in turbidity reduction, accompanied by a notable reduction in the required dosage.