Amaranthus dubius leaf extract ( Muthukumar et al.,2015), used to synthesis iron nanoparticles because it contains various photochemicals like amaranthine, isoamaranthine, phenols, flavonoids, and lysine that are used as reducing agents(Yizhong et al., 2003; Jannathul et al., 2014). 20 gm of leaves were heated with 100 mL distilled water at 50 °C for 45 min then filtered through a Whatmann filter paper and stored at 4 °C for further use. Solution of leaf extract 40 ml adds to 50 ml of 0.5 M FeCl3 solution. The leaf extract pH 6 adjusted using 0.1 N HCl and 0.1 N NaOH was added drop wise to the FeCl3 solution with continuously stirring for 90 minute. Precipitates were washed with absolute ethanol, then dried in an oven at 60 °C for 180 min and stored in sealed bottles under dry condition. The antioxidant activity increased from 34.2 to 94.9 by increase mass of leaves from 5 to 20 g per 100 ml of water. Also an antioxidant activity increases with temperature from 40 to 50 °C, temperature above 50 °C shows that decreased antioxidant activity from 94.9 to 52%. The heating time exceeded 45 min can degrade the antioxidant compound and less than 45 min was not enough for extraction. The zeta-potential value increased from −44 to −66 mV indicate stability of the particles. SEM studies confirmed that FeNps were roughly spherical in shape and size range from 60 to 300 nm. The PSA result showed leaf extract FeNps and sodium borohydride FeNps used as reducing agent size ranges varying from 58 to 530 nm and 105 to 2300 nm, respectively. And have less agglomeration even after 1 month than sodium borohydride FeNps.
Murraya koenigii (curry leaves) used to synthesis Iron Oxide Nanoparticles (Sundaresan et al., 2014). Four grams of powdered leaf obtained by washed Curry leaves with deionized water then dried at room temperature for 24 hours was mixed with 100 mL distilled water and boiling at 100 °C for 5 min.
The Whatman no. 1 filter paper used to filter leaf extract then was stored at 4 °C. 3 mL of extract was added to 7 mL of 1 mM FeSO4 solution and stirred on magnetic stirrer for 5 min. Centrifugate the result at (15,000 rpm, 20 °C) for 20 min, then washed several times with distilled water and dried at a hot air oven. The colour change from transparent yellow to black colour indicate synthesis of Nanoparticles.
The UV–visible spectra showed two absorption peaks were detected at 284 and 315 nm because of a single surface plasmon resonance (SPR) band. FTIR analysis identify that the synthesized iron oxide nanoparticles surrounded by polyphenols, proteins and amines.SEM images reveal that the morphology of the nanoparticles was appeared to be a porous, spongelike form. TEM image show that morphology of iron oxide nanoparticles was spherical along with some irregular shape. Dynamic light scattering analysis found size of nanoparticles 61nm. The iron oxide nanoparticles and FeSO4 used to study its effects on fermentative hydrogen production using C. acetobutylicum NCIM 2337.
Syzygium aromaticum (clove) used to synthesis of Zero Valent Iron Nanoparticles (Monalisa et al.,2013). Clove Buds were washed with triple distilled water. Then cut into small pieces and put in 10 ml of sterile distilled water and heated at 70-80°C for 2-3 minutes. Then filtered extract by Whatman’s No.1 filter paper. The filtrate was collected in a conical flask by standard sterilized filtration method at 4°C. The 1:1 proportion of freshly prepared 0.001 M aqueous of FeCl3 solution and extract were mixed with constant stirring at 50-60°C. Adding 1% of chitosan and 1% of PVA to stabilize Iron Nanoparticles (FeNps). Formation of (FeNps) accompanied by reduced of pH from high acidic to low acidic 4.22 to 1.88. SEM studies confirmed that (FeNps) were dispersed spheres having diameters around 100 nm. The UV visible spectroscopy of the synthesized (FeNps) were in the range of 216-265 nm because of surface Plasmon resonance (SPR) of nanoparticles.
α-Fe2O3 Nanoparticles were synthesized from curcuma and tea leaves (Alagiri et al., 2014) • which act as reducing and stabilizing agent. 10 ml of the tea extract was added into the iron, nitrate solution prepared by dissolved 1 mm of iron (III) nitrate nonahydrate in 100 ml of distilled water and continued for magnetic stirring around 6 h and mixture was stirred by magnetic stirring at 50°C for 24 h. In case of synthesis by curcuma, 0.1 g of curcuma was added to 20 mL of distilled water with continues stirring for 6 h then 40 mL of iron (III) nitrate nonahydrate (1 mM) was added into the above mixture with vigorous stirring at 50° C for 24 h. The tow product solution were centrifuged at 15,000 rpm for 20 min and washed several times and dried in a vacuum at 70°C. The dried product was calcined at 200°C for 4 h to obtain the nanoparticles. XRD results show that α-Fe2O3 nanoparticles are phase pure and well crystallinity with crystallite size 4 and 5 nm for α-Fe2O3 from curcuma and tea extract, respectively. SEM result showed that samples possess spherical-like shape with uniform size distribution. The photocatalytic activity of α-Fe2O3 nanoparticles was used in photocatalytic application as in measuring photocatalytic degradation of methyl orange (MO) dye in distilled water under the illumination of visible light which is measured every 30 min irradiation time. The color of the MO solution changed into colorless within 120 min of illumination time and the concentrations of MO solutions changes as a function of illumination time.
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