Synthesis and characterization of ZSM-5 zeolite from rice husk ash and their adsorption of Pb2+ onto unmodified and surfactant-modified zeolite

► We used rice husk ash in synthesis of ZSM-5. ► Na+ cation plays a structure directing role as well as a charge balancing role. ► Higher Na2O content seems to be required to obtain pure ZSM-5. ► TPABr-zeolite in aqueous suspension (10 g/l) sorbed up to 85% of Pb2+ from solutions containing from 50 to 140 ppm Pb2+.