Rapid selective adsorption of hazardous dyes using charge controlled NiO layers encapsulated SiO2 core-shell nanostructures

Abstract

SiO2/NiO based composites possess extra ordinary chemical stability for employment in catalytic adsorption. In this study, we report on, SiO2/layered NiO nanocomposite processed through successive ionic layer adsorption and reaction (SILAR) process using appropriate surfactant as a template along. The nanocomposites have been synthesized with different concentration of cationic (Ni2+) and anionic (OH-) solution. The surface morphology, structural behavior, surface area and absorption properties were analyzed by XRD, FE-SEM, TEM, BET, FTIR and UV–vis studies. The nitrogen absorption-desorption curve shows that the composite exhibits the larger surface area (576.71 m2/g) in comparison to NiO (89.75 m2/g) and SiO2 (245.2 m2/g). The synthesized nanocomposites were examined for the elimination of Rhodamine B (RhB). The adsorption efficiency of the composite was observed to be 99.5% within 6 min and also, investigated as a function of contact time, adsorbent dosage, effect of initial concentration, selectivity, recyclability and reusability. Additionally, the kinetics and isotherms were evaluated to understand the surface interactions among the adsorbent and adsorbate. The nanocomposite was well-known to obey pseudo-second order kinetics (R2 = 0.99) and follow monolayer adsorption with maximum adsorption capacity of 35.33 mg/g. The studies approved the processed composite effectively adsorbed Rhodamine B, suggesting them as a better adsorbent in other frontiers.