Green Synthesis of Iron Nanoparticles Using Green Tea and Its Removal of Hexavalent Chromium

Abstract

Chromium (VI) is a ubiquitous groundwater contaminant and it is dangerous to both ecological and human health. Iron nanoparticles (nFe) have a large specific surface area and they are highly efficient in removing chromium (VI) from aqueous solution. However, since the traditional reductive synthesis of nFe is relatively expensive and often causes secondary pollution, it is necessary to develop a low-cost green synthetic method using plant extracts. Synthetic conditions are important for obtaining highly active chromium-removing nanomaterials. In this paper, a green tea extract was used to prepare nFe and the effects of synthetic conditions on subsequent remediation performance were investigated. The optimal conditions included a green tea extract/Fe2+ ratio of 1:2 (91.6%), a green tea extract temperature of 353 K (88.3%) and a synthetic temperature of 298 K (88.1%). Advanced material characterization techniques, including XPS, SEM-EDS, TEM, and Brunauer–Emmett–Teller (BET) confirmed that the average particle size was between 50–80 nm, with a specific surface area of 42.25 m2·g−1. Furthermore nFe had a core-shell structure, where Fe (0) constituted the core and a shell was composed of iron oxide. Finally, a mechanism for synthesizing nFe by green tea extract was proposed, providing a theoretical basis for optimized synthetic conditions for preparing nFe when using green tea extract.

Synergistic Anticandidal Activities of Greenly Synthesized ZnO Nanomaterials with Commercial Antifungal Agents against Candidal Infections

“…Phytochemical examination showed that caffeine, 1,3,5-benzenetriol, 1,2,3-benzenetriol, catechol, 1,1′-Biphenyl, 2-ethyl-, 6-Hydroxy-4,4,7a-trimethyl-5,6,7a-tetrahydrobenzofuran, and methoxy resorcinol were the main phytoconstituents of green tea extract which were thought to act as a reducing, biostabilizing and capping agents ( Table 1 ). Our findings were in agreement with those of an earlier study, which showed that caffeine, 1,2,3-benzenetriol and 1,3,5-benzenetriol in green tea extract operationalized as a reducing and capping agent for biogenic iron nanoparticles [ 31 ]. Another study found that the phytoconstituents such as caffeine, catechol, 1,2,3-benzenetriol, methoxy resorcinol, ethanone, and 1,3,5-benzenetriol acted as capping and reducing agents during the formulation of bimetallic Fe/Pd nanoparticles using an aqueous green tea extract [ 32 ].…”

Green synthesis and characterization of iron-oxide nanoparticles using Moringa oleifera: a potential protocol for use in low and middle income countries

“…In this regard, numerous Fe 3 O 4 -NP synthesis methods, for example, coprecipitation, the sol–gel method [ 4 ], hydrothermal synthesis [ 5 ], solid-state synthesis [ 6 ], flame spray synthesis [ 7 ], thermal decomposition [ 5 ], and solvothermal methods [ 8 ], have been adopted to produce nanoparticles with desired properties. However, such methods have had a number of limitations, including high production costs, toxic chemicals, and the production of hazardous byproducts [ 9 – 12 ]. This has necessitated research in green synthesis approaches in an effort to address the above issues caused by these conventional methods [ 13 ].…”

Variation in the Optical Properties of PEO-Based Composites via a Green Metal Complex: Macroscopic Measurements to Explain Microscopic Quantum Transport from the Valence Band to the Conduction Band

“…The stretching mode within the aromatic compounds is identified at 1480 cm −1 [ 39 , 40 ]. Within the 1440 to 1410 cm −1 range, a new wideband is recorded for both carbonate C-O stretch vibrations and carboxylic acid O-H in a bent plane [ 41 ]. For a number of compounds, including carboxylic acids, esters, and alcohols, a sharp and strong peak lies at 1036 cm −1 ; identifying the stretching modes of C-O and the stretching vibration peaks around1236 cm −1 originates from the C-N vibrations in aliphatic amine groups [ 39 , 40 ].…”