Manyetik nanopartiküllerin analitik incelenmesi
The analytical examination of magnetic nanoparticles
Yazar: SEMANUR SARIBUĞA
Danışman: PROF. DR. BİRSEN  DEMİRATA  ÖZTÜRK
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Kimya Ana Bilim Dalı
Derece: Yüksek Lisans, 2014
Konu: Kimya = Chemistry

Özet:
Ağır metal sanayi günümüzde gitgide önem kazanmaktadır. Bunun yanında işlem sonrası açığa çıkan endüstriyel atık sular, tüm canlılar için çok zehirli ve tehlikeli olan kurşun, bakır, nikel, civa, arsenik, demir ve krom gibi ağır metaller içerirler. Ağır metallerin zehirleyici özellikleri ekosistemdeki tüm canlıları tehdit etmektedir. Bu elementleri eser miktarda da olsa içeren sular çeşitli faaliyetlerle besin zincirine girmektedir. 
Bu nedenle kirlilik kaynaklarından oluşan atık suların ağır metal içerikleri, çevreye verilmeden önce arıtılarak çeşitli su standartlarına göre izin verilen değerlerin altına düşürülmesi gerekmektedir. Bu çalışmada, atık sulardan ağır metal gideriminde kullanılmak amacıyla manyetik nanopartiküllerin sentezi amaçlanmıştır. Manyetik partiküllerin uygulanan manyetik alana cevap vererek istenilen şekilde hareket ettirilebilmeleri birçok uygulamada avantaj sağlamaktadır. Manyetik nanopartiküllerin manyetik çekim kuvveti yanında kompleks yaparak sinerjik etki yaratabilmesi için hümik asitle kaplanması tasarlanmıştır. Ayrıca nanopartiküllerin stabil kalması için antioksidan bileşiklerden yararlanılmıştır. Bu amaçla kuersetin ve hümik asit kaplı manyetik nanopartiküller ortak çöktürme yöntemiyle sentezlenerek seçici, kolay, ucuz ve çevre dostu bir yöntem geliştirildi. 
Sentez aşamasında ticari kuersetin kullanıldığı gibi yeşil çay ekstraktı da kullanılarak içerdiği kateşin ve kuersetinden faydalanıldı. Ayrıca yüzey aktif madde olarak sodyum dodesil sülfat (SDS) kullanılarak tanecik boyutuna etkisi araştırılmıştır.
Hümik asitin partikülde dış kabuk olarak kullanılmasının nedeni, demirin agregasyonu engellemesi ve fonksiyonel grupları (alkil, aromatik, karboksilik asit grupları) sayesinde metallerle kompleks oluşturma kapasitesinin fazla olmasıdır.
Bir antioksidan çeşidi olan kuersetin ise oluşan parçacığın oksitlenmesini engellemekte ve parçacığa antibakteriyel özellik katmaktadır. Böylelikle bir yandan sanayi atıksularından, sınır değerleri aşan ağır metaller giderilirken bir yandan da suda üremesi muhtemel bakterileri gidererek daha sağlıklı ve hijyenik sular kazandırılmış olur. 
Çalışmada nanopartikül sentez aşamasında; kullanılacak hümik asit ve kuersetin miktarları; ağır metal giderim analizleri için de pH, sıcaklık, zaman ve nanopartikül miktarları gibi parametreler değiştirilerek optimizasyon yapıldı. Parçacık karakterizasyonu UV spektrometresi, moleküler floresans spektrometresi, IR, SEM ve XRD kullanılarak yapıldı. Metal giderim deneyleri ise atomik absorbsiyon spektrometresinde gerçekleştirildi.

Abstract:
The prefix nano is used to denote one billionth. Here, nanometer defines one billionth of 1m or one millionth of 1 mm. Although there is not a specific definition of nanoparticles (NP's), generally they are called as particles from 1 nm to 100 nm. This size usually depends on the material, field or application used. NP's exist both in the realm of quantum and Newtonian physics.
The study of Nanotechnology is an interdisciplinary area between fundamental sciences which are physics, chemistry and biology and applied sciences which are electronics and materials.
Nanomaterial is a field that takes a materials science-based approach on nanotechnology. It studies materials with morphological features on the nanoscale, and especially those that have special properties stemming from their nanoscale dimensions. Nanoscale is usually defined as smaller than a one tenth of a micrometer in at least one dimension though sometimes includes up to a micrometer.
An important aspect of nanotechnology is the vastly increased ratio of surface area to volume present in many nanoscale materials, which makes possible new quantum mechanical effects. One example is the "quantum size effect" where the electronic properties of solids are altered with great reductions in particle size. Nanoparticles, take advantage of their dramatically increased surface area to volume ratio. An effect does not come into play by going from macro to micro dimensions. However, it becomes pronounced when the nanometer size range is reached.
Hundreds of products containing nanomaterials are already in use. Examples are batteries, coatings, anti-bacterial clothing etc. Nano innovation will be seen in many sectors including public health, employment and occupational safety and health, information society, industry, innovation, environment, energy, transport, security and space.
One of the kinds of nanomaterials is nanoparticles. There are numerous applications of nanoparticles. These applications can be classified as follows; industrial applications, biological applications, drug delivery, bioseparation, magnetic resonance imaging, hyperthermia, catalysis applications, environmental applications.
Nowadays, heavy metal industry is becoming more and more important. Besides; copper, nickel, mercury, arsenic, iron and chromium containing industrial waste is toxic and dangerous for all of the living organisms. The toxic effect of the heavy metals threatens not only human health but also all of the organisms in the ecosystem. The water that contains these elements in trace amounts attends to the food chain in different ways.
For this reason, source of the pollution of heavy metal content must be purified before letting to the ground water and must be below the allowed values. 
This study aims synthesize magnetic nanoparticles to remove the heavy metals from waste water. The motion of the magnetic nanoparticles under magnetic field gives some advantages for many applications. Coating the magnetic nanoparticles with the humic acid is designed to make complex under the magnetic field and create a synergic effect. For this purpose, quercetin and humic acid coated magnetic nanoparticles were synthesized with the co-precipitation method. The proposed method is selective, easy, cheap and environmentally friendly.
The usage of humic acid as the outer shell prevents the aggregation of iron and maintains a high capacity of complexion with metals as it carries functional groups (alkyl, aromatic, and carboxylic acid groups).
Quercetin, type of an antioxidant, prevents oxidation of the particles and gives anti-bacterial properties to the particles. Thus, the newly synthesized magnetic nanoparticles not only remove heavy metals exceeding the limit values from the industrial waste water but also prevent possible growth of bacteria in water.
In this study, parameters such as pH, temperature, time and amount of nanoparticle were optimized after the appropriate amounts of quercetin and humic acid used during the synthesis procedure had been decided. For the characterization of the synthesized particles, UV-Visible spectrophotometer, molecular fluorescence spectrometer, IR, SEM-EDX, XRD and Zeta potential equipments were used.
After characterization optimum conditions was determined and the synthesized nanoparticles was used for removing metals from the industrial wastewater. For this purpose the series of Copper and Nickel metal solutions was prepared and adsorption process was used. Adsorption process between metals and synthesized nanoparticles was investigated by using Atomic Absorption Spectrometer. According to their absorbance value calibration graph was obtained for each metal. After the adsorption particles were collected with a magnet. Final concentration values of each sample were calculated after the absorbance values were measured with the aid of the AAS. Final and initial values were used to calculate the removal percentage Optimization process was carried out for each metal. pH, particle mass and sorption time were obtained.  
After determination of optimum conditions, the mix solution was prepared and the portion of magnetic nanoparticles was put in the mix. Nanoparticles may be more selective for some of the metals. Then it can be specify for the real industrial wastewater 
For the next studies it may be intended to be observe smaller particles according to new easier methods While forming smaller particles surface area will be increased and the metal adsorption can be occur more efficient. The aim must be removing heavy metals from the natural waste water with the help of smaller amount of particles.
After adsorption, desorption process must be developed and the material can be used several times. So it contributes to have better environmental and economic conditions.
Magnetite nanoparticles may be studied with different antioxidants extracted from the plants. Not only removing heavy metals from the industrial wastewater but also removing bacterial contaminants to have healthier and cleaner water. And according to the results of this study it prevents environmental diseases and protects public health.