Synthesis Of Zero-valent Iron Nanoparticles Research Articles

Green synthesis of zero-valent iron nanoparticles by Cleistocalyx operculatus leaf extract using microfluidic device for degradation of the Rhodamine B dye

Environmental pollution, in particular, the wastewater from the textile and dyeing production process is causing serious issues for the ecosystem and humans. It has been well-demonstrated that zero-valent iron nanoparticles (nZVI) are one of the most promising materials in the treatment of environmental pollutants. In this work, the Cleistocalyx operculatus leaf extract was employed as a green reductant for the synthesis of the nZVIs nanoparticles from iron ions precursor. Notably, a microfluidic device was also used as micro-reactor for the synthesis process of the nanoparticles, making it easy to control and optimise the morphologies and sizes of nZVI. The morphology and crystallinity of nZVI were characterised by scanning electron microscopy (SEM) and x-ray diffraction (XRD), respectively. The nZVIs prepared in a microfluidic reactor using Cleistocalyx operculatus leaf extract as reductant were in plate-like structure with the thickness of around 5 nm and the diameter in range of hundred nanometers. The removal efficiency of Rhodamin B (RhB) dye by the prepared nZVI was determined by ultraviolet-visible (UV–vis) spectroscopy. The results showed that the nZVI revealed high removal performance toward RhB with removal efficiency of higher than 90% after 30 min of treatment. The effects of dye’s concentration, time, and pH solution on the treatment performance of RhB were also studied.

Plant-Derived Iron Nanoparticles for Removal of Heavy Metals

Nanoparticle synthesis has seen exponential development recently as its characteristics of high surface area, high rate of adsorption, and easy, cost-effective synthesis have been exploited for the purpose of ground water purification via the removal of organic and inorganic compounds, along with the removal of heavy metals and microbes. The synthesis of Zero-Valent Iron Nanoparticles (ZVI NPs) by green methods has proved to be environmentally friendly in many ways as it employs the use of naturally occurring plant extracts. These nanoparticles have large surface areas and efficiently remove heavy metals. The reducing potential of these ZVI NPs is mostly −0.44 V, thus allowing them to reduce heavy metal compounds such as cadmium, lead, zinc, copper, and arsenic present in wastewater. Irradiated nanoparticles have also exhibited antimicrobial resistance and adsorption. It is also observed that nanoparticles show a higher rate of efficacy at a lower pH. The adsorbent, which is ZVI NPs in this case, when present in large doses reduces heavy metal compounds rapidly and effectively.

Synthesis of Zero-Valent Iron Nanoparticles for Ultrasonic Assisted Dye Removal: Modeling and Optimization.


 
 
 
 
 
 
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Green synthesis of zero-valent iron nanoparticles and loading effect on activated carbon for furfural adsorption

The adsorption techniques are extensively used in dyes, metronidazole, aniline, wastewater treatment methods to remove certain pollutants. Furfural is organic in nature, considered a pollutant having a toxic effect on humans and their environment and especially aquatic species. Due to distinct characteristics of the adsorption technique, this technique can be utilized to adsorb furfural efficiently. As an environmentally friendly technique, the pomegranate peel was used to synthesized activated carbon and nanostructure of zerovalent iron impregnated on the synthesized activated carbon. The physicochemical and crystallinity characterization was done using Fourier transmission infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and Field emission scanning electron microscopy (FESEM). The nanoparticles are porous in structure having 821.74 m2/g specified surface area. The maximum amount of the adsorbent pores in the range of 3.08 nm shows the microporous structure and enhancement in adsorption capacity. The effects of increment in concentration of adsorbent, pH, reaction contact time and adsorbent dose, isothermal and kinetic behaviour were investigated. At the UV wavelength of 227 nm furfural adsorption was detected. The separation of the furfural from the aqueous solution was calculated at the 1 h reaction time at the composite dosage of 4 g/L, 250 mg/L adsorbent concentration and pH kept at 7. The 81.87% is the maximum removal attained by the nanocomposite in comparison to the activated carbon is 62.06%. Furfural adsorption was also analyzed by using the equations of isothermal and kinetics models. The adsorption process analysis depends on the Freundlich isotherm and Intra-particle diffusion than the other models. The maximum adsorbent of the composite was determined by the Langmuir model which is 222.22 mg/g. The furfural removal enhances as the adsorbent dose enhances. The developed zerovalent iron nanoparticles incorporated on activated carbon (AC/nZVI) from pomegranate peel extract are feasible as an efficient and inexpensive adsorbent to eliminate furfural from a liquid solution.

Facile green synthesis of zero-valent iron nanoparticles using barberry leaf extract (GnZVI@BLE) for photocatalytic reduction of hexavalent chromium

In this study, zero-valent iron (GnZVI) was synthesized using barberry leaf extract (GnZVI@BLE). The physicochemical properties of the final products were characterized by FT-IR, SEM, TEM, and EDS techniques. The results of TEM analysis showed that the obtained iron zero-valent nanoparticles with a diameter between 20 and 40 nm and shell-core structures were successfully synthesized. The results of FT-IR confirmed the presence of various functional groups. The photocatalytic activity of synthesized nanoparticles was investigated by reduction of hexavalent chromium. Laboratory data showed that the presence of GnZVI@BLE as a nanocatalyst in the photocatalytic process could be reduction the hexavalent chromium (Cr (VI)). Photocatalytic data revealed that, when the dosage of nanoparticles was 0.675 g/L, the reduction efficiency of hexavalent chromium was 100%. The kinetics of the reaction follows a pseudo-second-order equation. The constant of reaction rate was 0.4 at pH 2 and 0.5 g/L concentration of GnZVI@BLE.

Effects of ionic surfactants on the nucleation and growth of cyanidin 3,5-di-O-glucoside capped zerovalent iron nanoparticles

Cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS) were chosen to establish the role of ionic micelles on the morphology of cyanidin 3,5-di-O-glucoside (cyanin) assisted synthesis of zerovalent iron nanoparticles. Nucleation and growth process depends upon the presence of CTAB and SDS. CTAB exhibited catalytic sub-, post- and dilution-micellar effect for the nucleation and growth process of FeNPs formation in the present investigations. Nucleation process of FeNPs formation was inhibited in presence of SDS. The different role of SDS (inhibition) and CTAB (catalysis) micelles might be due to the strong electrostatic attraction and repulsion with Fe3+ ions and cyanin. The reduction rates of Fe3+ ions by cyanin were found to be 3.9 × 10−3, 10.2 × 10−3, and 2.6 × 10−3 s−1 for aqueous, CTAB and SDS, respectively. Transmission electron microscopic images indicate that the FeNPs are roughly spherical and poly dispersed.

Performance of Mulberry Leaves Mediated Green Synthesis Zero-Valent Iron Nanoparticles in Dye Removal

The nanomaterials especially be made of iron, are tapering off the environmental pollution in a sufficiently great way which is worthy for attention. Green synthesis of iron nanoparticles through the extraction of the natural products or wastes has been developed in a way that is more sustainable than the chemical routes associated with several limitations. The mulberry leaves, which are easy available in nature, were chosen for plant-mediated green synthesis of zero-valent iron nanoparticles (nZVI). The characterization of the synthesized nanoparticles was performed with the used of dynamic light scattering (DLS), scanning electron microscope (SEM), and Fourier Transform Infrared Spectroscopy (FTIR). The polyphenols content of the mulberry leaf can be used to synthesize the iron nanoparticles. The iron nanoparticles can be used as the Fenton-like catalyst to enhance the efficiency of dyes degradation. Meanwhile, the iron nanoparticles can be removed by its magnetic properties after the degradation of pollutants which can be reused in subsequent environmental remediation. The efficiency of dyes degradation by the synthesized iron nanoparticles, was investigated by UV-visible spectroscopy (UV-vis). The cationic and anionic model dyes were used to investigate the ability of the synthesized iron nanoparticles in degradation of dye molecules. Methylene Blue was used as the model for cationic dye whereas Methyl Orange was chosen as anionic model dye. The percentage removal of respective dyes was investigated at the different period of time. The work investigated the magnetic and catalytic bi-functionalities of the synthesized iron nanoparticles.

Leaf-extract mediated zero-valent iron for oxidation of Arsenic (III): Preparation, characterization and kinetics

In recent years, leaf-extract mediated green synthesis of zero-valent iron nanoparticles is gaining much popularity as it is cost effective and an eco-friendly alternative to chemically synthesized zero-valent iron. The present study reports the synthesis and characterization of nanoscale zero-valent iron particles obtained from various leaf extracts viz. eucalyptus (Eucalyptus globulus), mango (Mangifera indica), jamun (Syzygium cumini) and guava (Psidium guajava). The synthesized nanoparticles were characterized on the basis of size distribution, UV–Vis absorption spectroscopy, Fourier transform infrared spectroscopy, Field emission scanning electron microscopy and powder X-ray diffractometer. This study further investigates the potential of these nanoparticles for oxidation of arsenite (1000 µg/L) at various pH (3, 7 and 9). Results indicate that green nanoparticles synthesized from guava leaves were capable of oxidising As(III) to As(V) at all investigated pH values, the kinetics of which varied depending on the pH. As(III) oxidation kinetic model fitted well to first order with Kobs values of 0.3444 s−1, 0.0482 s−1 and 0.0155 s−1 for pH 3, 7 and 9 respectively. This study provides a novel mechanism for oxidation of arsenite to arsenate, thus providing an effective and sustainable solution for remediation of toxic trivalent arsenic.

Chromium adsorption from aqueous solution using novel green nanocomposite: Adsorbent characterization, isotherm, kinetic and thermodynamic investigation

In this study, Peganum harmala seed was used as a precursor for the preparation of powdered activated carbon (PAC). In addition, the plant extract was used for the synthesis of zero-valent iron nanoparticles (GnZVI). Then GnZVI was loaded on PAC and used as a novel green nanocomposite to adsorb hexavalent chromium from aqueous solutions. In order to synthesize activated carbon and nanoparticles, ultrasonic waves were used as a new tool for carbon activation and nanoparticle preparation. TEM images were used to show the synthesis of iron nanoparticles with a size of <60nm. Based on the results of FESEM test, it was found that the surface of the produced activated carbon had many pores which indicated the effective role of ultrasonic waves in the process of activation. EDAX analysis was used to confirm the loading of GnZVI on PAC; based on the results, Fe was present on PAC after loading GnZVI. In addition, the FTIR range confirmed the role of hydroxyl groups generated by organic compounds in the synthesis of nanoparticles. BET test showed that after the loading of Iron nanoparticles the specific surface area of activated carbon reduced from 442m2/g to 107m2/g. The results of adsorption tests showed that the loading of GnZVI resulted in an increase in the adsorption capacity of hexavalent chromium. Equilibrium adsorption test showed that laboratory data were well-fitted with Langmuir model and kinetic experimental data were consistent with Ho pseudo-second order model; moreover, intraparticle diffusion and film diffusion were the mechanisms involved in the adsorption process. Thermodynamic data on adsorption showed that the adsorption process was endothermic and spontaneous; furthermore, with increasing the temperature, the removal efficiency of chromium increased too.

Scale-up synthesis of zero-valent iron nanoparticles and their applications for synergistic degradation of pollutants with sodium borohydride

The scale-up synthesis of nZVI (zero-valent iron nanoparticles) was optimized by response surface modeling (RSM). The synthesized nZVI was employed for synergistic degradation of metronidazole (MNZ) or methyl orange (MO) in the presence of sodium borohydride (NaBH4). Key parameters such as initial MNZ or MO concentration, nZVI concentration, and NaBH4 concentration for MNZ or MO removal process was optimized using central composite design (CCD). Under the optimized conditions (nZVI concentration: 150mg/L; NaBH4:0.1M; interaction time: 25min for MNZ and 30min for MO; and MNZ or MO initial concentration: 40mg/L), the removal was synergistically increased to 100% (MNZ) and 98.07±1.1% (MO). When nZVI was applied without NaBH4, the removal of MNZ and MO were 50.62±0.28 and 43.72±0.29%, respectively. In the presence of NaBH4 alone, the removal of MNZ or MO was 6.5±1.1% and 4.2±0.7%, respectively. Addition of NaBH4 was found to enhance the remediation ability of nZVI. The MNZ or MO degradation followed pseudo–first–order kinetics. The degradation mechanism was studied by UV–visible spectroscopy, XRD, SEM-EDX, FT-IR, and BET analyses. The applicability of the process was tested with MNZ-spiked or MO-spiked lake water and ground water samples.

Biosynthesis of Iron Nanoparticles Using Tie Guanyin Tea Extract for Degradation of Bromothymol Blue

Facile synthesis of zero-valent iron nanoparticles has been developed using Tie Guanyin tea extract as reducing and stabilizing agent. The characterization carried out by UV-Vis, SEM, TEM, XRD, and FTIR techniques has identified the successful synthesis of the zero-valent iron nanoparticles. It is evident from the TEM result that spherical zero-valent iron nanoparticles with average size of 6.58±0.76 nm have been obtained through biological method in this study. FTIR spectrum demonstrates that the polyphenols play an important role in the synthetic process. Diffraction peak at 2θ of 44.9° and 49.1° in XRD spectrum explains the existence of the iron nanoparticles. Additionally, effect of concentration of iron nanoparticles and concentration of bromothymol blue on the kinetic rate constants during the degradation process was studied.

Controllable synthesis, characterization, and magnetic properties of nanoscale zerovalent iron with specific high Brunauer–Emmett–Teller surface area

This article reports a novel approach for the controllable synthesis of nanoscale zerovalent iron (NZVI) particles with specific high Brunauer- Emmett-Teller (BET) surface areas. Borohydride reduction is a primary and effective liquid phase reduction method for the synthesis of zerovalent iron nanoparticles. However, previous methods for syn- thesizing NZVI did not suggest a standard technique for controlling the size of particles during the synthesis process; in addition, previous literature generally reported that NZVI had a BET surface area of \37 m 2 /g. In this communication, a novel approach for the controllable synthesis of NZVI particles with specific high BET surface areas is presented. As a result, the BET surface areas of the NZVI particles synthesized increased to 47.49 and 62.48 m 2 /g, and the particle sizes decreased to 5-40 and 3-30 nm. Additionally, the physical and chem- ical properties of the synthesized NZVI particles were investigated by a series of characterizations, and magnetic analysis indicated that the synthesized NZVI particles had super-paramagnetic properties.