Tiyol-en hidrojellerinin sentezi: altın ve gümüş iyonlarının sulu ortamdan uzaklaştırılması

ÖZETTİYOL-EN HİDROJELLERİNİN SENTEZİ: ALTIN VE GÜMÜŞ İYONLARININ SULU ORTAMDAN UZAKLAŞTIRILMASIBu çalışmada Au(III) ve Ag(I) iyonlarının sulu çözeltilerden yeni thiol-ene hidrojelleriyle uzaklaştırılması araştırılmıştır. Bu çalışmada hazırlanan hidrojel formülasyonları ışıkla başlatılan tiyol-en katılma reaksiyonları ile hazırlanmış ve daha sonra karakterize edilmiştir. Hazırlanan hidrojellerin jelleşme yüzdelerinin %94’ten büyük olduğu belirlenmiştir. Hidrojellerin fotopolimerizasyon kinetiği gerçek zamanlı infrared spektroskopisi (RT-IR) ile incelenmiştir. Hidrojellerin fonksiyonel grupları seyreltilmiş toplam reflektans infrared spektroskopi (ATR-IR) ile araştırılmıştır. Hidrojellerin yüzey morfolojileri taramalı elektron mikroskobu (SEM) ile karakterize edilmiştir pH ve sıcaklığa bağlı hidrojellerin şişme yüzdeleri de incelenmiştir; örneğin, maksimum şişme yüzdesi değerleri pH=0,5’te 25°C’de elde edilmiştir.Au(III) ve Ag(I) adsorpsiyon verimine farklı parametrelerin etkisi detaylı olarak incelenmiştir. Au(III) ve Ag(I) iyonlarının en iyi adsorpsiyon davranışı pH=0,5’te F1 kodlu (P(Penta3MP4/PEGDA/HEMA)) ve H1 kodlu(P(Penta3MP4/PEGDA/AAc)) hidrojel formülasyonları ile sağlanmıştır. F1 hidrojeli ile Au(III) ve Ag(I) adsorpsiyonu sırasıyla 2 ve 24 saatte dengeye gelmiştir. H1 hidrojeli ile Au(III) ve Ag(I) iyonlarının adsorpsiyonu sırasıyla 5 ve 16 saatte dengeye gelmiştir. F1 hidrojeli ile Au(III) ve Ag(I) iyonlarının adsorpsiyonu ve H1 hidrojelleri ile Ag(I) iyonlarının adsorpsiyonu başlangıç iyon konsantrasyonu arttıkça artmış 500 mg L-1’de dengeye ulaşmıştır. Diğer yandan, H1 hidrojeli ile Au(III) adsorpsiyonu başlangıç iyon konsantrasyonu arttıkça artmış 750 mg L-1’de dengeye ulaşmıştır.Langmuir ve Freundlich izoterm modelleri deneysel verilere uygulanmıştır ve veriler F1 ve H1 hidrojelleri ile Au(III) ve Ag(I) iyonlarının adsorpsiyonunun Langmuir izoterm modeline uyduğu belirlenmiştir. Tiyol-en hidrojellerinin tekrar kullanılabilirliği araştırılmıştır ve elde edilen sonuçlar hidrojellerin en az 3 kez tekrar kullanılabileceğini göstermiştir. F1 ve H1 hidrojelleri ile Au(III) iyonları 50 kat derişiklendirilmiştir. F1 hidrojelleri ile Ag(I) iyonları 100 kat, H1 hidrojelleri ile 50 kat derişiklendirilmiştir.Optimum koşullarda yöntemin tekrarlanabilirliği incelenmiştir ve gözlenebilme sınırları belirlenmiştir. Geliştirilen yöntem, elektronik atıklara, röntgen filmi atıklarına ve Dikili Jeotermal Suyuna uygulanmış ve bu örneklerden Au(III) ve Ag(I) iyonlarının ayrılması ve Alevli Atomik Absorpsiyon Spektrofotometresinde (FAAS) belirlenmesi çalışmaları yapılmıştır.ABSTRACTSYNTHESIS OF THIOL-ENE HYDROGELS: REMOVAL OF GOLD AND SILVER IONS FROM AQUEOUS MEDIAIn this study, the removal of Au(III) and Ag(I) ions from aqueous solutions was investigated using novel thiol-ene hydrogels. The hydrogel formulations prepared in this study were cured via photo-initiated thiol-ene addition reactions and were lateron characterized. The gelation percentages of prepared hydrogels were higher than 94%. Photopolymerization kinetics of the hydrogels was investigated by real-time infrared spectroscopy (RT-IR). The functional groups of hydrogels were investigated by attenuated total reflectance infrared spectroscopy technique (ATR-IR). The surface morphologies of hydrogels were characterized by scanning electron microscopy (SEM). The influence of pH and temperature on swelling percentages of the hydrogels was also investigated; maximum swelling percentage values, for instance, are achieved at pH=0.5 and 25°C. The effects of different parameters on Au(III) and Ag(I) adsorption efficiencies were examined in detail. The highest adsorption efficiency for Au(III) and Ag(I) was achieved by using F1 (P(Penta3MP4/PEGDA/HEMA)) and H1 (P(Penta3MP4/PEGDA/AAc)) hydrogels at pH=0.5. Adsorption of Au(III) and Ag(I) was reached to the equilibrium by using F1 hydrogel at 2 and 24 hours, respectively. Adsorption of Au(III) and Ag(I) was reached to the equilibrium by using H1 hydrogel at 5 and 16 hours, respectively. It was observed that adsorption of Au(III) and Ag(I) ions by using F1 hydrogel and Ag(I) ions by H1 hydrogel increased with increasing initial metal concentration up to 500 mg L-1 and then reached equilibrium. On the other hand, Ag(I) adsorption by using H1 hydrogel increased with increasing initial metal concentration up to 750 mg L-1 and then reached equilibrium.Both Langmuir and Freundlich adsorption isotherm models were applied to the experimental data and equilibrium data were found to fit very well with Langmuir model for both Ag(I) and Au(III) adsorption by using F1 and H1 hydrogels. Reusability of the thiol-ene hydrogels was investigated and the results revealed that these hydrogels can be reused at least three times. Au(III) ions could be concentrated by 50-fold by using F1 and H1 hydrogels. Ag(I) ions could be concentrated by 100-fold by using F1 hydrogel and 50-fold by using H1 hydrogel. The repeatability of method at the optimum conditions was investigated and the detection limits were also determined. The method developed was applied to separation and determination of Au(III) and Ag(I) ions in electronic wastes, radiograph wastes, and Dikili Geothermal Water by Flame Atomic Absorption Spectrophotometer (FAAS)

2- akrilamido-2- metilpropan sulfonik asit bazlı hidrojellerle ağır metallerin adsorpsiyonu

ÖZET2-AKRİLAMİDO-2-METİLPROPAN SULFONİK ASİT BAZLI HİDROJELLERLE AĞIR METALLERİN ADSORPSİYONUHidrojeller sıvı ve katı arasında ara durumlarından dolayı önemli özellikler gösterirler. Ağır metal iyonlarının uzaklaştırılmasında ve geri kazanımı uygulamalarında su ve sulu çözeltileri absorlama ve depolama kabiliyeti hidrojelleri yegane madde yapar.Bu çalışmada, sulu çözeltilerden Pb(II) ve Cd(II) iyonlarının uzaklaştırılması amacıyla tiyoüre, guanidin ve üre modifiye 2-akrilamido-2-metilpropan sülfonik asid (AMPS) monomerleri sentezlendi. Sonra radikalik fotopolimerizasyonla Poli(Tiyoüre modifiye AMPS/Akrilik Asit/N-Vinil-2-Pirolidon/2-Hidroksietil Metakrilat) [P(AMPSTU/AAc/NVP/HEMA)] hidrojeli, Poli(Guanidin modifiye AMPS/ Akrilik Asit / N-Vinil-2-Pirolidon /2-Hidroksietil Metakrilat) [P(AMPSG/AAc/NVP/HEMA)] hidrojeli ve Poli(Üre modifiye AMPS/ Akrilik Asit / N-Vinil-2-Pirolidon /2-Hidroksietil Metakrilat) [P(AMPSU/AAc/NVP/HEMA)] hidrojeli hazırlandı. Monomer ve hidrojellerin yapıları Fourier Transform Infrared Spektroskopisi, Termal Gravimetrik Analiz, Taramalı Elektron Mikroskobu ile karakterize edildi.Hidrojellerin metal iyonlarını adsorplama kapasitesi üzerine pH, başlangıç metal iyon konsantrasyonu ve adsorpsiyon denge süresinin etkisi incelendi.Diğer metal iyonlarına karşı hidrojellerin seçiciliği incelendi. Hidrojellerle Pb(II), Cd(II), Hg(II) ve Au(III) iyonlarının yarışmalı adsorpsiyonunda sırasıyla P(AMPSTU/AAc/NVP/HEMA) hidrojeli için seçimlilik sırasının Pb(II)>Au(III) >Cd(II)>Hg(II) şeklinde, P(AMPSG/AAc/NVP/HEMA) hidrojeli için seçicilik Hg(II)>Pb(II)>Au(III)>Cd(II) ve P(AMPSU/AAc/NVP/HEMA) hidrojeli için Pb(II)>Au(III)>Cd(II)>Hg(II) şeklinde olduğu görüldü.Adsorpsiyon parametreleri Langmuir ve Freundlich izoterm modelleri kullanılarak tayin edildi. 0.5 M HNO3 çözeltisi kullanılmasıyla yapılan rejenerasyon işlemleri modifiye polimerlerin adsorpsiyon kapasitesinde kayıp olmaksızın beş kez kullanılabileceğini göstermiştir.ABSTRACTADSORPTION OF HEAVY METALS BY 2-ACRYLAMIDO-2-METHYLPROPAN SULFONIC ACID BASED HYDROGELS Hydrogels have special properties due to their intermediate state between a liquid and a solid. The ability to absorb and to store much water and water solutions make hydrogels unique materials for a variety of applications of removal and recovery of heavy metal ions In this study, thiourea, guanidine and urea modified 2-acrylamido-2-methylpropan sulfonic acid (AMPS) monomers were synthesized in order to remove Pb(II) and Cd(II) from aqueous solutions. Then Poly(Thiourea modified AMPS/Acrilic Acid/N-Vinyl-2-Pyrrolidone/2-Hydroxyethyl Methacrilate) [P(AMPSTU/AAc/NVP/HEMA)] hydrogels, Poly(Guanidine modified AMPS/Acrilic Acid/N-Vinyl-2-Pyrrolidone/2-Hydroxyethyl Methacrilate) [P(AMPSG/AAc/NVP/HEMA)] hydrogels, Poly(Thiourea modified AMPS/Acrilic Acid/N-Vinyl-2-Pyrrolidone/2-Hydroxyethyl Methacrilate) P(AMPSU/AAc/NVP/HEMA) hydrogels were prepared by radicalic photopolymerization. The structures of monomers and hydrogels were characterized by Fourier Transform Infrared Spectroscopy, Thermal Gravimetric Analysis and Scanning Electron Microscopy.The effect of pH, initial metal ion concentration and adsorption equilibrium time on the metal ion binding capacity of hydrogels was also investigated.The selectivity of the hydrogels towards the different metal ions was tested. The competitive adsorption of Pb(II), Cd(II), Hg(II), and Au(III) by hydrogels was found to be Pb(II)>Au(III)>Cd(II)>Hg(II) for P(AMPSTU/AAc/NVP/HEMA) hydrogels, Hg(II)>Pb(II)>Au(III)>Cd(II) for P(AMPSG/AAc/NVP/HEMA) hydrogels and Pb(II)>Au(III)>Cd(II)>Hg(II) for P(AMPSU/AAc/NVP/HEMA), respectively. The adsorption parameters were determined using both Langmuir and Freundlich isotherm models. A regeneration procedure by treatment with 0.5 M HNO3 solution showed that the modified polymers could be used five times without loss of their adsorption capacities

Controlled Sr( ii ) ion release from in situ crosslinking electroactive hydrogels with potential for the treatment of infections

The development of electrochemical stimuli-responsive drug delivery systems is of both academic and industrial interest due to the ease with which it is possible to trigger payload release, providing drug delivery in a controllable manner. Herein, the preparation of in situ forming hydrogels including electroactive polypyrrole nanoparticles (PPy-NPs) where Sr2+ ions are electrochemically loaded for electrically triggered release of Sr2+ ions is reported. The hydrogels were characterized by a variety of techniques including Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), cyclic voltammetry (CV), etc. The cytocompatibility towards human mesenchymal stem cells (MSCs) and fibroblasts were also studied. The Sr2+ ion loaded PEC-ALD/CS/PPy-NPs hydrogel showed no significant cytotoxicity towards human mesenchymal stem cells (MSCs) and fibroblasts. Sr2+ ions were electrochemically loaded and released from the electroactive hydrogels, and the application of an electrical stimulus enhanced the release of Sr2+ ions from gels by ca. 2–4 fold relative to the passive release control experiment. The antibacterial activity of Sr2+ ions against E. coli and S. aureus was demonstrated in vitro. Although these prototypical examples of Sr2+ loaded electroactive gels don't release sufficient Sr2+ ions to show antibacterial activity against E. coli and S. aureus, we believe future iterations with optimised physical properties of the gels will be capable of doing so

Equilibrium, kinetics, and thermodynamics of Pd(II) adsorption onto poly(m-aminobenzoic acid) chelating polymer

This study describes the equilibrium, kinetics, and thermodynamics of the palladium(II) (Pd(II)) adsorption onto poly(m-aminobenzoic acid) (p-mABA) chelating polymer. The p-mABA was synthesized by the oxidation reaction of m-aminobenzoic acid monomer with ammonium peroxydisulfate (APS). The synthesized p-mABA chelating polymer was characterized by FTIR spectroscopy, gel permeation chromatography (GPC), thermal analysis, potentiometric titration, and scanning electron microscopy (SEM) analysis methods. The effects of the acidity, temperature, and initial Pd(II) concentration on the adsorption were examined by using batch adsorption technique. The optimum acidity for the Pd(II) adsorption was determined as pH 2. In the equilibrium studies, it was found that the Pd(II) adsorption capacity of the polymer was to be 24.21 mg/g and the adsorption data fitted better to the Langmuir isotherm than the Freundlich isotherm. The kinetics of the adsorption fitted to pseudo-second-order kinetic model. In the thermodynamic evaluation of the adsorption, the G degrees values were calculated as -16.98 and -22.26 kJ/mol at 25-55 degrees C temperatures. The enthalpy (H degrees), entropy (S degrees), and the activation energy (E-a) were found as 35.40 kJ/mol, 176.05 J/mol K, and 61.71 kJ/mol, respectively. The adsorption of Pd(II) ions onto p-mABA was a spontaneous, endothermic, and chemical adsorption process which is governed by both ionic interaction and chelating mechanisms. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42533