Modification of bio-zeolite greenly synthesized from rice husk and application in adsorptive removal of herbicide glyphosate

In this study, the bio-zeolite (BZ) was successfully fabricated by solvothermal method from the rice husk. The fabricated BZ was thoroughly characterized by SEM, XRD, XRF, BET, and FT-IR. The BZ characteristics were demonstrated with a homogenous, porous, and crystal structure, a uniform round edge shape, a SiO2/Al2O3 ratio of about 2.65, a specific surface area of 3.31 m2 g−1, and specific linkages of Si–O–Al, Si–O–Si, and Si–OH. Subsequently, the BZ particles were modified by the adsorption of a cationic surfactant CTAB. Then CTAB@BZ was applied as an effective adsorbent to remove the herbicide glyphosate (GP) from aqueous solutions. The GP removal variables were optimized at 10 mM CTAB, pH 5, free ionic strength, 1 mg mL−1 BZ dosage, and 60 min contact time. The GP removal efficiency was more significantly enhanced by greater than 90 % with the surface modification. The GP adsorption isotherm was accorded to the pseudo-second-order model with multiple-adsorbed layer formation. The GP adsorption mechanisms were the main surface adsorption due to the major CTAB-GP electrostatic attractions. [Display omitted] •Zeolite (BZ) fabricated from rice husk was modified by cationic surfactant CTAB.•Optimal variables to remove the GP were found at pH 5, free ionic strength.•GP multiple layers were formed based on mainly CTAB-GP electrostatic attractions.•GP adsorption isotherm was well-followed to the pseudo-second-order model.