Microwave initiated synthesis and application of polyacrylic acid grafted carboxymethyl cellulose

► CMC-g-PAA was synthesized by 'microwave initiated method'. ► FTIR spectroscopy provided experimental proof of the proposed mechanism of synthesis. ► Synthesized grades were studied for efficacy as flocculant for river water clarification. ► CMC-g-PAA showed higher flocculation efficacy than CMC as well as alum. ► higher the percentage grafting of CMC-g-PAA, higher is its flocculation efficacy.