Multiple nitrogen functionalized magnetic nanoparticles as an efficient adsorbent: synthesis, kinetics, isotherm and thermodynamic studies for the removal of rhodamine B from aqueous solution

Mike O Ojemaye,Anthony I Okoh

doi:10.1038/s41598-019-45293-x

Abstract

The continuous demand for clean and affordable water needed for the survival of man is now a major challenge globally. Therefore, the treatment of wastewater generated from printing, textile and dyeing industries containing soluble dyes like rhodamine B (Rh-B) is of utmost important. This study investigates the efficiency of new multifunctionalized superparamagnetic nanoparticles (MNP-Tppy) for the removal of cationic Rh-B from aqueous solution. To afford MNP-Tppy, the surface of MNP was covalently functionalized with terpyridine ligand to enable an anionic charge on the adsorbent. The results of characterization including Brunauer-Emmett-Teller (BET) analysis, thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), scanning electron microscope (SEM) and fourier transform infra–red spectroscopy (FTIR) indicate that this superparamagnetic nanoparticle functionalized with multiple nitrogen atoms was successfully synthesized. Adsorption experiments involving the effect of pH, time, temperature, adsorbent dose and adsorbate concentration show that the maximum adsorption of Rh-B using MNP-Tppy was observed at pH 9 and removal was observed to increase as solution pH increases. Similarly, time variation shows that adsorbate removal increases as adsorption time increases until the removal attained equilibrium at 15 min. Kinetic studies conducted among four kinetic models using the data obtained from effect of time indicate that the adsorption process can best be described by the pseudo-second order model. Isotherm studies conducted at three different temperatures revealed that Langmuir isotherm model fitted well for the equilibrium data with qm value of 113.64 mg g−1 and thermodynamic studies showed that the adsorption process involving the removal of Rh-B from aqueous solution by MNP-Tppy is spontaneous, endothermic and realistic in nature. Lastly, Reusability experiments indicate that MNP-Tppy can be regenerated and re-used.

Highlights

The heralding of multifunctional superparamagnetic nanomaterials with excellent chemical, physical, magnetic and biological characteristics has been a major topical issue in the field of science because of its importance in the conversion of energy[1,2], medicine[3], water treatment[4], catalysis[5] and so on
The effectiveness of the functionalized superparamagnetic nanoparticles for the removal of rhodamine B (Rh-B) from aqueous solution was evaluated by means of a batch adsorption experiment but prior to this; the characterization of this new material and ligand was carried out using a number of techniques so as to confirm the successful synthesis of this material
Multiple nitrogen functionalities from terpyridine ligand were introduced onto the surface of magnetic nanoparticles via covalent linkage to enable negatively charged adsorbent for the removal of a positively charged Rh-B by electrostatic interaction

Summary

Introduction

The heralding of multifunctional superparamagnetic nanomaterials with excellent chemical, physical, magnetic and biological characteristics has been a major topical issue in the field of science because of its importance in the conversion of energy[1,2], medicine[3], water treatment[4], catalysis[5] and so on. Www.nature.com/scientificreports power brought about by magnetic means, high stability, large surface area, ability to tune their pore sizes and volumes These properties qualify them as a great candidate for numerous applications because they are able to host different molecules with different functionalities, shapes and sizes. Adsorption due to its ease of operation, simplicity, low cost, reliability and effectiveness can overcome the challenges highlighted above and is recently been utilized for the removal of dyes from wastewater Cationic dyes such as rhodamine B (Rh-B) are widely used in the industry textile, dyeing and printing companies. Rhodamine B is a toxic substance and becomes very harmful to human and aquatic organisms upon the discharge of effluents contaminated with Rh-B to the environment[27]

Methods

Results

Conclusion