Encapsulation of NiS and ZnS in analcime nanoparticles as novel nanocomposites for the effective photocatalytic degradation of orange G and methylene blue dyes

Abstract

ABSTRACT Encapsulation of semiconductor materials in zeolites is one of the important types of composites that have been used as photocatalysts in the degradation of several organic dyes. The high surface area and uniform porous structure of the zeolite particles prevent the coagulation of the catalyst and ensure its stability and dispersion. The strong polarised electrostatic field of zeolites can decrease the energy consumption needed to facilitate the electrons transfer from the valence band to the conduction band. So, in this paper, ethylenediaminetetraacetic acid disodium salt dihydrate was used as an organic template to hydrothermally synthesise analcime nanoparticles. Besides, NiS and ZnS were encapsulated in the analcime nanoparticles as novel photocatalysts for the efficient degradation of orange G and methylene blue dyes. EDX, XRD, FE-SEM, FT-IR, HR-TEM, diffuse reflectance spectrophotometer, and nitrogen gas sorption instruments were used to characterise the novel photocatalysts. The XRD results confirmed that the encapsulation of NiS or ZnS in the analcime nanoparticles led to a decrease in the intensity of the peaks only without affecting their positions. The FE-SEM images confirmed that the encapsulation of NiS or ZnS in the analcime nanoparticles changed the surface of the analcime from small spherical particles into large spherical particles, in addition to the presence of irregular shapes. Besides, the nitrogen gas sorption analyser confirmed that the encapsulation of NiS or ZnS in the analcime nanoparticles led to an increase in average pore radius and total pore volume and a decrease in BET surface area. The percentage of photocatalytic degradation of orange G dye using NiS/analcime and ZnS/analcime composites is 63.60 and 70.50%, respectively. The percentage of photocatalytic degradation of methylene blue dye using NiS/analcime and ZnS/analcime composites is 88.76 and 98.31%, respectively.