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Sodium diphosphate tetrabasic cross-linked chitosan magnetic nanoparticles for environmental remediation of selected dye from wastewater

Sylvanus Bisaba Ruvubu and Indrajit Roy

Department of Chemistry, University of Delhi, Delhi, India

Received: 7 June 2023 Accepted: 4 October 2023

Abstract:

In this study, sodium diphosphate tetrabasic was utilized to modify the chitosan magnetic nanoparticles. The product was then employed for removal of the malachite green dye in water. Co-precipitation method was used to create the chitosan magnetic sodium diphosphate tetrabasic nanoadsorbent. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, field scanning electron microscopy (FE-SEM) and vibrating sample magnetometer (VSM) were used to characterize the synthesized magnetic nanoadsorbent. In order to find the ideal circumstances for the adsorption process, it was then researched how several parameters, such as pH, initial concentration of malachite green and the adsorbent’s dosage, affect adsorption performance. The prepared chitosan magnetic nanoadsorbent with sodium diphosphate tetrabasic modification revealed semi-crystalline nanocomposite on both (FE-SEM) and (SEM). The effective functional groups that were confirmed on FTIR to have contributed to the adsorption of malachite green include chitosan amino group (NH₂). Phosphate group (PO₄) of tetrabasic sodium diphosphate serves as additional active sites for adsorption. Hydroxyl groups (OH) of chitosan and magnetic nanoparticles are other effective functional groups for MG adsorption. These hydroxyl groups form hydrogen bonds with malachite green and contribute to adsorption. The chitosan nanoparticles exhibited super-paramagnetic characteristics with attestable coercivity levels (Hc) of 15 extendable up to 20 (Oe). The removal efficiency of about 99% malachite green dye (MG) was shown by the prepared nanoadsorbent. Langmuir and Freundlich isotherm models gave successful prediction regarding adsorption efficiency using the malachite green. The findings demonstrated that the adsorption pattern was properly explained by both the Freundlich (R² = 0.902) and Langmuir (R² = 0.994) models with Langmuir model (R² = 0.994) being most pronounced. The Langmuir model was used to achieve the greatest capacity for malachite green retention of 3.94 mg g⁻¹. The kinetic experiments simulated by second-order kinetic model R² (0.990) fitted better adsorption than first-order kinetics R² (0.910). The desorption studies to regenerate the nanoadsorbent after eluting the malachite were based on increase in polarity. Based polarity water was confirmed to be the most prominent desorbing agent for malachite green (ethanol < acetone < methanol < water).

Keywords: Sodium diphosphate tetrabasic; Chitosan; Magnetic nanoparticles; Environmental remediation; Dye adsorptions

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03132-4

Chemical Papers 78 (2) 937–961 (2024)