Development of α- and γ-Fe₂O₃decorated graphene oxides for glyphosate removal from water

Abstract

In this study, the proposed adsorbent composed of graphene oxide (GO) functionalized by magnetic nanoparticles of iron oxide (α-γ-FeO) was obtained by a simple ultrasonication process. This new material was used for the removal of glyphosate in water. The nanoparticulated iron oxide used was synthesized by means of a modified sol-gel method, which does not use organic solvents. The adsorbent material (GO-α-γ-FeO) obtained was characterized by magnetic measurements, and it can be proved that it has superparamagnetic properties, allowing fast and efficient magnetic separation. The equilibrium time for the adsorption of glyphosate when using GO-α-γ-FeO was 2 hours and the maximum removal was 92% at 15°C, with a maximum adsorption capacity of 46.8 mg g. Langmuir model and pseudo-second-order kinetic model correlated satisfactorily to the experimental data. The thermodynamic parameters showed that the adsorption of glyphosate on GO-α-γ-FeO was spontaneous, exothermic and thermodynamically favorable at temperature of 15-45°C. Thus the adsorbent material GO-α-γ-FeO proposed in this study is considered a good candidate to be used in the removal of glyphosate from aqueous solutions, presenting high adsorption capacity, low cost and magnetic properties that facilitate the separation of the adsorbent material.

Biogenic α-Fe2O3 Nanoparticles Enhance the Biological Activity of Trichoderma against the Plant Pathogen Sclerotinia sclerotiorum

“…XRD analysis revealed the formation of a crystalline structure in the NPFe (Figure B). Peaks at 2θ values close to 28.0, 32.7, 40.0, 52.8, and 58.3° corresponded to the (012), (104), (113), (116), and (018) crystallographic planes characteristic of hematite (α-Fe 2 O 3 , JCPDS code 882359), − confirming the synthesis of hematite nanoparticles from FeCl 3 and T. harzianum.…”

Mycosynthesized Fe2O3 nanoparticles diminish brown rot of apple whilst maintaining composition and pertinent organoleptic properties

“…XRD analysis of this study revealed the small size (17.78 nm) and crystalline nature of mycosynthesized NPs. Previous studies have proved that the small size and crystalline nature of NPs provide them strong antimicrobial properties (Santos et al, 2019). Nanoparticles with small size (5–20 nm) work as excellent antimicrobial agents (Hoag et al, 2009).…”

Molecular theory of glyphosate adsorption to pH-responsive polymer layers

“…Methods of glyphosate removal currently include chemical precipitation (Liu et al 2013), advanced oxidation (Lan et al 2016;Xing et al 2018), membrane filtration (Song et al 2013), biodegradation (Loperena et al 2007), and physical adsorption (Zhou et al 2017;Santos et al 2017;Guo et al 2018;Zavareh et al 2018). Glyphosate adsorption to resins (Zhou et al 2017), graphene oxides (Santos et al 2017), starch (Guo et al 2018), and zeolites (Zavareh et al 2018) has been investigated. Removal methods involving physical adsorption are generally efficient and more environmentally friendly (Zhou et al 2017); however, because these methods are generally based on electrostatic attractions between the substrate and the herbicide, adsorption is highly affected by the solution composition.…”