الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Nanoparticles are clusters of atoms in the size of 1-100 nm. They are the building blocks of nanotechnology applications. Metal nanoparticles exhibit unique chemical, physical and biological multifunctional properties compared to their bulk parent materials so they can be utilized in a wide variety of novel applications in various fields such as nanofood, nanomedicine, nanobiotechnology and nanoelectronics.
The route of synthesis of nanoparticles controls their shape and size. Nanoparticles have shape and size-dependent properties, so there are increasing demand not only to researches related to applications of nanoparticles but also to researches related to the approaches of the synthesis of nanoparticles.
Production of nanoparticles by chemical and physical methods may have considerable drawbacks such as defective surface formation, low production rate, high cost, large energy requirement, and environmental defect, usage of toxic chemicals and formation of hazardous by-products that may have undesirable effects in pharmaceutical and biomedical applications. Hence, there is a growing need to develop clean, non-toxic, eco-friendly, and safe procedures for nanoparticles production.
Recycling of natural product waste is one of the most important innovative approaches to minimize or eliminate the use and/or generation of hazardous substances.
Silver nanoparticles have multi-field applications such as food industry ( like food packaging and biosensors for detection of pathogens and chemical contaminants ) , environment (like waste water treatment and water disinfection) , biomedical (like cancer therapy, diagnostics, cell imaging, biological implants , drug delivery, wound dressings, contraceptive devices, antimicrobials, therapeutics, drug-gene delivery and surgical instruments ) health care ( like Ultra violet protection and topical ointments ) , textile ( like UV blocking textiles and anti stain textiles) and catalysis (like fuel cell catalyst and hydrogen production catalyst).
Copper nanoparticles are known to be one of the multifunctional inorganic nanoparticles with effective antimicrobial activity against various bacterial and fungal strains.
Iron nanoparticles have been used in various fields, for food related applications they have been used for enzyme immobilization, protein purification and food analysis .
The aim of the present study was to use eco-friendly, rapid, and simple method for green synthesis of silver, copper and iron nanoparticles using natural, low cost, and non toxic reducing agents which are alternative to hazardous chemical reducing agents utilized in traditional chemical methods.
The present study reports the production of silver, copper and iron nanoparticles using ten aqueous extracts of pomegranate peel, banana peel, orange peel, tangerine peel , lemon peel, green tea leaves, Moringa oleifera leaves, black seeds, guava leaves and clove buds as reducing agents and 0.01 M silver nitrate,copper sulphate and ferric chloride solutions as chemical precursors. Each extract was added to AgNO3, CuSO4 and FeCl3 solutions separately in 1:1 proportion.
The synthesized particles were characterized by
Ultraviolet-visible spectroscopy
Particle Size Analyzer
X-Ray diffraction
Scanning electron microscope
Fourier transform infrared
The results of this study can be summerized as follows :
1- The synthesis of produced nanoparticles was primary confirmed by the change of color of chemical precursor.
2- UV-Vis Spectrophotometer showed :
Characteristic bands in reaction mixtures containing silver nitrate with all of plant extracts at wave length 440 – 480 nm.
Characteristic bands in reaction mixtures containing copper sulfate with all of plant extracts at wave length 455 – 485 nm except that contains tangrine peel extract show no characteristc band.
Characteristic bands in reaction mixtures containing ferric chloride with all of plant extracts at wave length 462 – 506 nm except that contains banana peel or tangrine peel extract show no characteristc band.
No characteristic band appears in controls containing chemical precursors (silver nitrate,copper sulfate or ferric chloride) .
3- Particle Size Analyzer showed that :
All plant extracts were found to be suitable for generation of silver nanoparticles particles of appreciable size except orange peel extract.
All plant extracts were found to be unsuitable for generation of copper nanoparticles of appreciable size except green tea and guava leaves that can produce copper nanoparticles with size 41.6 and 85.2 nm respectively.
Pomegranate peel, green tea, Moringa oleifera, guava leaves, and Clove buds extracts were found to have the ability to reduce iron ions to iron nanoparticles of appreciable size ( 67.7, 23.7 , 22.8 , 80.7 and 35.7 nm ) respectively while the other plant extracts were found to be unsuitable.
The X-Ray diffraction analysis showed that :
Silver nanoparticles synthesized from different plant extracts showed four distinct diffraction peaks at 38.06 o, 44.26 o, 64.5 o and 77.30 o .
Copper nanoparticles synthesized using diffrent plant extracts show no reflections assignable metalic copper.
Iron nanoparticles synthesized using diffrent plant extracts show no reflections assignable metalic iron .
4- SEM images revealed that the synthesized AgNps,CuNPs and FeNPs were distinct and scattered in distribution. They were spherical in shape .
5- Fourier transform infrared spectrum of most particles synthesized by reacting AgNO3,CuSO4 and FeCl3 with diffrent plant extracts showed several peaks mostley around at 3767.1,3398.69, 2926.11, 2112.12, 1708.99, 1383.01, 1055.1 and 572.88 cm-1 .
According to the results of this study it is concluded that:
1- Silver ,copper and iron nanoparticles were successfully obtained from bioreduction of silver nitrate, copper sulfate and ferric chloride respectively solutions using pomegranate peels ,banana peels, orange peels , tangerine peels, lemon peels, clove buds, green tea leaves, Moringa oleifera leaves, black seeds, and guava leaves using novel, simple, ecofriendly,single step ,economic , energy saving and fast method .
2- This eco-friendly method could be a competitive alternative method to traditional physical, chemical and even the microbial-mediated green synthesis of metal nanoparticles.
3- The plant extracts contain active biological components which have the ability to act as reducing,capping, size -controller and stabilizing agents.
4- The Fourier transform infrared results imply that the carboxyl (–C=O), hydroxyl (–OH) and amine (–NH) groups in plant extracts extracts are mainly involved in fabrication of silver, Copper and iron nanoparticles.
5- The X-Ray diffraction analysis showed that the Silver nanoparticles are crystalline in nature and have face-centered cubic geometry, while copper and iron nanoparticles are amorphous in nature.
6- The SEM images indicate the completion of the synthesis process of silver,copper and iron nanoparticles.
7- This method is economic because active biological components present in plant extracts their self act as a reducing, capping and stabilizing agent, thereby reducing the overall cost of the synthesis process.
8- This method is safe, clean and green chemistry – based route for production of nanoparticles because toxic chemicals and high energy are not used.
9- The rate of reduction for the synthesis of nanoparticles by this method was rapid where the reduction of chemical pecorsors (AgNO3, CuSO
10- 4 and FeCl3) by diffrent plant extracts completed within 5 minutes according to visual observations.
11- This approach supports the dual purpose of agricultural food waste management.
12- Recycling of natural product waste is one of the most important innovative approaches to minimize or eliminate the use and/or generation of hazardous substances.
13- The use of natural benign and renewable biological reducing agent could produce metal nanostructures in aqueous solutions avoiding the occurrence of hazardous and toxic solvents without need to external stabilizers.
14- Owing to varying composion of these ten plant extracts, the synthesyzied particles obtained also varied in size. PSA showed that the smallest particle size of silver nanoparticles was 9.5 nm that produced using pomegranate peel extract, while the smallest particle size of copper nanoparticles was 41.6 nm that produced using green tea leaves extract and the smallest particle size of iron nanoparticles was 22.8 nm that produced using Moringa oleifera leaves extract.
15- Green tea leaves and guava leaves extracts are the most suitable plant extracts because they have the ability to reduce AgNO3, CuSO4 and FeCl3.
16- Silver nitrate is the most easily reduced chemical precursor because it can be reduced by all plant extracts except orange peel extract.
17- This method is easily scaled up for large scale production of nanoparticles that may be well utilized in industrial, biomedical or environmental purposes. However, plant uptake and utilization of nanoparticles require more detailed research on many issues like uptake potential of various species, process of uptake and translocation and the activities of the nanoparticles at the cellular and molecular levels.
According to the results of this study it is recommended that :
1- A critical need in the field of nanotechnology is the development of reliable and eco-friendly processes for synthesis of metallic nanoparticles.
2- Further research is needed to purify and characterize the active biological components in plant extracts to understand their mode of action and possible interactions with produced nanoparticles.
3- Further research is needed to study factors affecting the size , shape and morphology of nanoparticles such as temperature, pH, and concentration of plant extract, content of plant extract and time of reaction.
4- There is a significant variation in chemical compositions of plant extract of same species when it collected from different locations of world and may lead to different results in different laboratories. This is the major drawback of the plant-mediated green synthesis of nanoparticles and there is need to resolve this problem. So further researches are needed to identify biomolecules present in the plant which are responsible for mediating the nanoparticles production for rapid single step protocol to overcome the above said problem.
5- There is insufficient funding for human health and safety research, and as a result there is currently limited understanding of the human health and safety risks associated with nanotechnology. so a stricter application of the precautionary principle with delayed marketing approval, enhanced labelling and additional safety data development requirements in relation to certain forms of nanotechnology are required .