Journal of Hazardous Materials, Vol.364, 206-217, 2019
Performance of surfactant-modified *BEA-type zeolite nanosponges for the removal of nitrate in contaminated water: Effect of the external surface
Hierarchical *BEA-type nanosponges zeolite with a high external surface area (116 m(2).g(-1)) and small crystal size, synthesized in the presence of a dual-porogenic organic compound, were modified with a cationic surfactant (HDTMA Br-+(-): hexadecyltrimethyl ammonium bromide) in order to create a new anion exchanger system: the surfactant-modified zeolite nanosponges (SMZ(NS)). For comparison, two other surfactant-modified *BEA-type zeolite materials, SMZ(MC) and SMZ(NC), were obtained by modifying the synthesized conventional micron-size microcrytals and nanocrystals *BEA-type zeolite with HDTMA Br-+(-), respectively. Textural and structural properties were determined for the three prepared materials using N-2 adsorption/desorption analysis, XRD, SEM, and TEM. Nitrate adsorption isotherms were drawn in a large concentration range [0.8-24.2 mmol.L-1] and fitted with Langmuir isotherm model. The maximum nitrate removal capacity (1338 mmol.Kg(-1)/83 mg.g(-1)) was obtained for SMZ(NS) material. This value is the highest ever observed for nitrate removal using surfactant-modified zeolite. The nitrate removal kinetics were fitted with the pseudo second-order model for both materials SMZ(NS) and SMZ(NC).
Keywords:Zeolite;Hierarchical materials;Surfactant modified zeolite;Nitrate adsorption;Molecular decontamination