Functionalization of Synthesized Nanoporous Silica and Its Application in Malachite Green Removal from Contaminated Water

Abstract

Introduction: Nanoporous silica has received growing interest for its unique application potential in pollutant removal. Therefore, the development of a simple technique is required to synthesize and functionalize the nanoporous materials for industrial application. 
 Materials and Methods: The synthesis of nanoporous silica was investigated by the template sol-gel method, and it functionalized as an adsorbent for adsorption of malachite green. The morphology and structure of the prepared and functionalized nanoporous silica were studied using X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), and nitrogen adsorption-desorption technique. Subsequently, the effective parameters such as solution pH, contact time, and initial concentration on the adsorption process were optimized by adsorption tests. 
 Results: The results showed that high-order nanoporous silica had been produced with an average diameter of 20.12 nm and average pore volume of 1.04 cm3.g−1. It was found that the optimum parameters of pH, initial concentration and contact time for malachite green adsorption on nanoporous silica were 6.5, 10 mg.l-1, and 60 min, respectively. The experimental data confirmed the Freundlich model (R2 = 0.995) and the obtained kinetic data followed the pseudo-first-order equation. The maximum adsorption capacity calculated by Langmuir isotherm was found to be 116.3 mg.g-1. 
 Conclusion: The high adsorption capacity showed that the acid-functionalized nanoporous silica adsorbent can be used as an adequate adsorbent to remove malachite green from aquatic environments. The large surface area can be suggested that the silica nanoporous will have potential application prospects as the adsorbent.