Modification of silica nanoparticles by 2,4-dihydroxybenzaldehyde and 5-bromosalicylaldehyde as new nanocomposites for efficient removal and preconcentration of Cu(ii) and Cd(ii) ions from water, blood, and fish muscles

Abstract

Herein, silica nanoparticles were modified by 2,4-dihydroxybenzaldehyde and 5-bromosalicylaldehyde to produce new nanocomposites which were abbreviated as N₁ and N₂, respectively. The synthesized nanocomposites were used for efficient removal and preconcentration of Cu(II) and Cd(II) ions from water, blood, and fish muscles. FE-SEM, FT-IR, XRD, CHN elemental analysis, and nitrogen gas sorption analyzer were used to characterize the new nanocomposites. The XRD proved that the synthesized oxide is cristobalite with an average crystallite size of 54.80 nm. Due to the formation of the CN group, the intensity of the XRD peak at 2θ = 21.9° in the N₁ and N₂ nanocomposites decreased significantly. The FT-IR bands, which appeared at 1603 and 1629 cm⁻¹ in the N₁ and N₂ nanocomposites, are attributable to the bending vibration of CN and/or OH, respectively. Also, the FE-SEM analysis shows the morphology of the silica nanoparticles which were identified as spherical and rod-like with slight agglomeration while the N₁ and N₂ nanocomposites have flaky surfaces due to the formation of CN groups. The maximum Cu(II) ion adsorption capacities of the N₁ and N₂ nanocomposites are 64.81 and 40.93 mg g⁻¹, respectively. The maximum Cd(II) ion adsorption capacities of the N₁ and N₂ nanocomposites are 27.39 and 26.34 mg g⁻¹, respectively. The adsorption of Cu(II) or Cd(II) ions using the synthesized nanocomposites is spontaneous, chemical, exothermic, and well-matched with the Langmuir equilibrium isotherm. The recovery findings demonstrate that the preconcentration process is accurate, adaptable, and resulted in quantitative separation because % Recovery is more than 95%. Furthermore, the % RSD was less than 3.5%, indicating good reproducibility.