Application of nano-silica particles generated from offshore white sandstone for cadmium ions elimination from aqueous media

The overall goal of this investigation was to produce nano-silica particles from white sandstone and control Cd(II) pollution from various aqueous matrixes. The generated nanoparticles have spherical morphology with a surface area of 298.71 m(2)/g and a size of 30-40 nm. Based on the ANOVA findings, pH, temperature, nano-adsorbent quantity, initial cadmium concentration, and contact time parameters were effective (p-value < 0.05) in the Cd(II) adsorption process. The experimental results had a good agreement with the Freundlich model. According to response surface methodology data, the maximum efficiency (98.74%) of cadmium elimination by nano-silica obtained at a temperature of 25 degrees C, Cd(II) content of 5 mg/L, contact time of 10 min, nano-silica dose of 0.67 g/L, and pH of 6.14. The maximum Cd(II) attraction onto white sandstone and nano-silica was 42.97 mg/g and 55.13 mg/g, respectively. The exothermic and spontaneous behavior was observed for the adsorption of Cd(II) onto nano-silica particles. The silica nanoparticles had a good ability to adsorb-desorb cadmium ions up to 8 steps. The pseudo-second-order was suitably modeled kinetic data. Nano-silica particle was applied for controlling Cd ions from shipbuilding industry wastewaters. (C) 2020 Elsevier B.V. All rights reserved.