Calcium Alginate Beads with Entrapped Iron Oxide Magnetic Nanoparticles Functionalized with Methionine-A Versatile Adsorbent for Arsenic Removal.

Surbhi Lilhare,Sónia A C Carabineiro,Ajaya K Singh,Sunitha B Mathew

doi:10.3390/nano11051345

Surbhi Lilhare, Sónia A C Carabineiro + Show 2 more

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https://doi.org/10.3390/nano11051345

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Abstract

A novel beads adsorbent, consisting of calcium alginate entrapped on magnetic nanoparticles functionalized with methionine (MFMNABs), was developed for effective elimination of arsenic from water. The material was characterized by FT-IR (Fourier Transform Infrared Spectroscopy), SEM (Scanning Electron Microscopic), XRD (X-ray Diffraction) and TEM (Transmission Electron Microscopy). The arsenic removal capacity of the material was studied by altering variables such as pH of the solution, contact time, adsorbent dose and adsorbate concentration. The maximal removal of As(III) was 99.56% under optimal conditions with an equilibrium time of 110 min and pH 7.0–7.5. The adsorption followed a second order kinetics and data best fitted the Langmuir isotherm with a correlation coefficient of R2 = 0.9890 and adsorption capacity (qm) of 6.6533 mg/g. The thermodynamic study showed entropy change (∆S) and enthalpy change (∆H) to be 34.32 J mol−1 K and 5.25 kJ mol−1, respectively. This study proved that it was feasible to treat an As(III) solution with MFMNABs. The synthesized adsorbent was cost-effective, environmentally friendly and versatile, compared to other adsorbents. The adsorption study was carried by low cost spectrophotometric method using N- bromosuccinimide and rhodamine-B developed in our laboratory.

Highlights

Arsenic is naturally present in the crust of Earth and has long been recognized as highly toxic and carcinogenic, affecting millions of humans in the world [1,2]
The X-ray diffraction (XRD) results show that the average size of the particles of Methionine Functionalized Magnetic Nanoparticles (MFMNPs) was 17.04 nm and after crosslinking with alginate, the mean size of the MFMNABs particles was reduced to 12.95 nm
(Figure 9B) and Temkin (Figure 9C) isotherm models to evaluate the best fit with the Langmuir isotherm model the bestare fit presented with a R2 =in

Summary

Introduction

Arsenic is naturally present in the crust of Earth and has long been recognized as highly toxic and carcinogenic, affecting millions of humans in the world [1,2]. Long-term exposure to arsenic gives symptoms such as vomiting, abdominal pain, diarrhea, severe gastrointestinal irritation, gastrointestinal damage, cardiac damage and several types of cancer [3]. It can result in vascular diseases like black foot disease [4,5]. Arsenic can be found in both organic and inorganic forms, as trivalent arsenite H2 AsO3 − ) and pentavalent arsenate (H3 AsO4 , HAsO4 2− , H2 AsO4 − or AsO4 3− ), of which the first form, As(III) is more noxious than As(V) [6]. Inorganic arsenic compounds are more harmful and toxic, compared to organic arsenic compounds [7]

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