Synthesis of Imprinted Polysiloxanes for Immobilization of Metal ions

2014 ◽  
Vol 1675 ◽  
pp. 209-214
Author(s):  
Adnan Mujahid ◽  
Faisal Amin ◽  
Tajamal Hussain ◽  
Naseer Iqbal ◽  
Asma Tufail Shah ◽  
...  

ABSTRACTImprinting is a well-established technique to induce recognition features in both organic and inorganic materials for a variety of target analytes. In this study, ion imprinted polysiloxanes with varying percentage of coupling agent i.e. 3-chloro propyl trimethoxy silane (CPTM) were synthesized by sol-gel method for imprinting of Cr3+. The imprinting of Cr3+ in cross-linked siloxane network was investigated by FT-IR which indicates the metal ion is coordinated with oxygen atoms of polysiloxanes. SEM images revealed that imprinted polysiloxanes possess uniform particles of submicron size. It was experienced that by increasing the concentration of CPTM up to 10% (v/v) substantially improves the binding capacity of polysiloxanes which allows us to recognized Cr3+ down to 50µg/L. Furthermore, the selectivity of Cr3+-imprinted polysiloxanes was evaluated by treating them with other competing metal ions of same concentration i.e. Cr6+, Pb2+ and Ni2+. In this regard, polysiloxanes showed much higher binding for imprint ion i.e. Cr3+ in comparison to above mentioned metal ions. Finally, the regenerated polysiloxanes were studied in order to reuse them thus, developing cost effective biomimetic sensor coatings.

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Abdussalam Salhin Mohamad Ali ◽  
Norfarhah Abdul Razak ◽  
Ismail Ab Rahman

Sorbent materials based on a hydrazone Schiff base compound, C14H11BrN4O4, were prepared either by immobilizing the ligand into sol-gel (SG1) or bonding to silica (SG2). The sorbent materials were characterized by FT-IR, EDX, SEM, TEM, and TGA. The sorption characteristics of a matrix of eight transition metal ions (Ag+, Cu2+, Co2+, Ni2+, Fe3+, Pb2+, Zn2+, and Mn2+) using batch method were studied. Several key parameters that affected the extraction efficiency such as pH, contact time, metal ions concentration, and gel size (for SGl) were investigated and optimized. Under the optimized conditions, the physically immobilized hydrazone sorbent (SG1) exhibits highest selectivity towards Ag+ions, while the chemically bonded hydrazone sorbent (SG2) exhibits high extraction for all metal ions tested. However, for practical applications such as the removal and preconcentration of Ag+, the physically immobilized sorbent (SG1) is preferred.


Biomimetics ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 38 ◽  
Author(s):  
Özgecan Erdem ◽  
Yeşeren Saylan ◽  
Müge Andaç ◽  
Adil Denizli

Aquatic and terrestrial environment and human health have been seriously threatened with the release of metal-containing wastewater by the rapid growth in the industry. There are various methods which have been used for removal of ions from the environment, such as membrane filtration, ion exchange, membrane assisted liquid extraction and adsorption. As a sort of special innovation, a polymerization technique, namely molecular imprinting is carried out by specific identification for the target by mixing it with a functional monomer. After the polymerization occurred, the target ion can be removed with suitable methods. At the end of this process, specific cavities, namely binding sites, are able to recognize target ions selectively. However, the selectivity of the molecularly imprinted polymer is variable not only because of the type of ligand but also charge, size coordination number, and geometry of the target ion. In this review, metal ion-imprinted polymeric materials that can be applied for metal ion removal from different sources are discussed and exemplified briefly with different metal ions.


2019 ◽  
Vol 20 (1) ◽  
pp. 16 ◽  
Author(s):  
Duha Hussien Attol ◽  
Hayder Hamied Mihsen

Rice husk ash (RHA) was used to prepare sodium silicate, which in turn was functionalized with 3-(chloropropyl)triethoxysilane employing the sol-gel technique to form RHACCl. Chloro group in RHACCl was replaced with iodo group forming RHACI. Ethylenediamine was immobilized on RHACI in order to prepare it for the reaction with salicylaldehyde to form a silica derivative-salen. FT-IR analysis indicated the presence of secondary amine and –NH and C=N absorption bands. XRD analysis revealed the occurrence of the broad diffused peak with maximum intensity at 22–23° (2θ). BET measurements showed also that the surface area of the prepared compound is 274.55 m2/g. Elemental analysis proved the existence of nitrogen in the structure of the prepared compound. The silica derivative-salen showed high potential for extraction and removal of heavy contaminating metal ions Ni(II), Cu(II), and Co(II) from aqueous solutions. The kinetic study demonstrates that the adsorption of the metal ions follows the pseudo-second order.


2014 ◽  
Vol 85 (4) ◽  
pp. 665-672 ◽  
Author(s):  
Ayse Tuygun Erdogan ◽  
Didem Nalbantgil ◽  
Feyza Ulkur ◽  
Fikrettin Sahin

ABSTRACT Objective:  To compare metal ion release from samples welded with silver soldering and laser welding when immersed into mouthwashes with different ingredients. Materials and Methods:  A total of 72 samples were prepared: 36 laser welded and 36 silver soldered. Four samples were chosen from each subgroup to study the morphologic changes on their surfaces via scanning electron microscopy (SEM). Each group was further divided into four groups where the samples were submerged into mouthwash containing sodium fluoride (NaF), mouthwash containing sodium fluoride + alcohol (NaF + alcohol), mouthwash containing chlorhexidine (CHX), or artificial saliva (AS) for 24 hours and removed thereafter. Subsequently, the metal ion release from the samples was measured with inductively coupled plasma mass spectrometry (ICP-MS). The metal ion release among the solutions and the welding methods were compared. The Kruskal-Wallis and analysis of variance (ANOVA) tests were used for the group comparisons, and post hoc Dunn multiple comparison test was utilized for the two group comparisons. Results:  The level of metal ion release from samples of silver soldering was higher than from samples of laser welding. Furthermore, greater amounts of nickel, chrome, and iron were released from silver soldering. With regard to the mouthwash solutions, the lowest amounts of metal ions were released in CHX, and the highest amounts of metal ions were released in NaF + alcohol. SEM images were in accord with these findings. Conclusions:  The laser welding should be preferred over silver soldering. CHX can be recommended for patients who have welded appliances for orthodontic reasons.


2013 ◽  
Vol 717 ◽  
pp. 108-112
Author(s):  
Noorzahan Begum ◽  
Md Fazlul Bari ◽  
Salmie Suhana Binti Che Abdullah ◽  
R.A. Khairel ◽  
N. Ahmed

A new solid phase extractant silica aerogel immobilized with Cyanex 301 {bis (2,4,4-trimethylpentyl) dithiophosphinic acid} (SAWC) was prepared via a sol-gel method and investigated for the extraction of Zn (II) from aqueous solution by a batch extraction technique. It is found that SAWC can extract about 100% zinc at equilibrium pH 1.7. Prepared SAWC was characterized by FT-IR, BET, EDX and SEM which proved the presence of Cyanex 301 into silica aerogel. Moreover, the material is also easily regenerated and reused in the subsequent removal of Zn (II) in five cycles. Therefore, it could be concluded that it may perform as a solid phase extractant in the extraction of metal ions from the aqueous solution.


Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 286 ◽  
Author(s):  
Radhia Msaadi ◽  
Gorkem Yilmaz ◽  
Andrit Allushi ◽  
Sena Hamadi ◽  
Salah Ammar ◽  
...  

There is an urgent demand worldwide for the development of highly selective adsorbents and sensors of heavy metal ions and other organic pollutants. Within these environmental and public health frameworks, we are combining the salient features of clays and chelatant polymers to design selective metal ion adsorbents. Towards this end, the ion imprinting approach has been used to develop a novel nanohybrid material for the selective separation of Cu2+ ions in an aqueous solution. The Cu2+-imprinted polymer/montmorillonite (IIP/Mt) and non-imprinted polymer/montmorillonite (NIP/Mt) nanocomposites were prepared by a radical photopolymerization process in visible light. The ion imprinting step was indeed important as the recognition of copper ions by IIP/Mt was significantly superior to that of NIP/Mt, i.e., the reference nanocomposite synthesized in the same way but in the absence of Cu2+ ions. The adsorption process as batch study was investigated under the experimental condition affecting same parameters such as contact time, concentration of metal ions, and pH. The adsorption capacity of Cu2+ ions is maximized at pH 5. Removal of Cu2+ ion achieved equilibrium within 15 min; the results obtained were found to be fitted by the pseudo-second-order kinetics model. The equilibrium process was well described by the Langmuir isothermal model and the maximum adsorption capacity was found to be 23.6 mg/g. This is the first report on the design of imprinted polymer nanocomposites using Type II radical initiators under visible light in the presence of clay intercalated with hydrogen donor diazonium. The method is original, simple and efficient; it opens up new horizons in the general domain of clay/polymer nanocomposites.


2019 ◽  
Author(s):  
Chem Int

An easy route for preparation emulsion of kaolinite (Al2Si2O5.4H2O) from Sweileh sand deposits, west Amman, Jordan by hydrochloric acid under continuous stirring for 4 h at room temperature was performed and nano kaolinite powder was used as an adsorbent for the removal of Cu(II), Zn(II) and Ni(II) ions. Nano kaolinite was characterized by XRD, FT-IR and SEM techniques. Effect of pH, adsorbent dose, initial metal ion concentration, contact time and temperature on adsorption process was examined. The negative values of ΔGo and the positive value of ΔHo revealed that the adsorption process was spontaneous and endothermic. The Langmuir isotherm model fitted well to metal ions adsorption data and the adsorption capacity. The kinetic data provided the best correlation of the adsorption with pseudo-second order kinetic model. In view of promising efficiency, the nano kaolinite can be employed for heavy metal ions adsorption.


2011 ◽  
Vol 9 (5) ◽  
pp. 932-940 ◽  
Author(s):  
Albena Detcheva ◽  
Paunka Vassileva ◽  
Ralitsa Georgieva ◽  
Dimitrinka Voykova ◽  
Tsvetelina Gerganova ◽  
...  

AbstractIn the present work the adsorption of some transition metal ions from aqueous solutions on a silica-based nanostructured hybrid material modified by aluminium was investigated. The novel organic-inorganic material was synthesized via a sol-gel method through hydrolysis and co-condensation reactions. Its structure was characterized by means of SEM, XRD and FTIR. Based on the data obtained the most probable cross-linking mechanism for the derived xerogel was proposed. The characterization of its texture parameters was carried out by low-temperature adsorption of nitrogen. The adsorption properties of this material with respect to Cu(II), Cr(III) and Pb(II) ions from single-component aqueous solutions and multi-component aqueous solutions containing also Cd(II) and Fe(III) were evaluated. The effect of contact time, acidity of initial solutions and metal ion concentrations was investigated using the batch method. Pseudo-first order, pseudo-second order and intraparticle diffusion models were used to analyze kinetic data. In all cases the adsorption was significantly affected by the pH value. Equilibrium modelling data were fitted to linear Langmuir, Freundlich and Dubinin-Radushkevich models. Best fit was observed for Langmuir model, which showed determination coefficients greater than 0.992 for all ions studied. The maximum adsorption capacities for single- and multi-component adsorption were calculated.


2018 ◽  
Vol 32 (08) ◽  
pp. 1850096 ◽  
Author(s):  
Esmaeil Pakizeh ◽  
Mahmood Moradi

Ferroelectric Pb(ZrTi)O3 (PZT) nanotubes were prepared by sol–gel method and porous anodic alumina (PAA) membrane using spin-coating technique. This method is based on filling-pyrolysis-filling process and the use of one-stage alumina membranes. One of the advantages of this method is its rapidity, which takes only 1 h time before the calcination step. The effect of repeated pores filling was investigated to get the required size of nanotubes. The field emission scanning electron microscope (FE-SEM) images were shown that the PZT nanotubes have inner diameters in the range of 65–90 nm and length of about 50–60 [Formula: see text]m. This means that the samples have a significant aspect ratio (700–800). Also the FE-SEM image confirmed that the highly ordered, hexagonally distributed PAA membranes with the pore diameter about 140–150 nm were formed. The X-ray diffraction (XRD) results showed that the PZT nanotubes have a tetragonal structure. The metal oxide bands like ZrO6 and TiO6 of the final PZT nanotubes were detected by Fourier transform infrared (FT-IR) analysis and confirmed the formation of perovskite structure. By using FT-IR spectroscopy and Kramers–Kronig transformation method, the optical constants like real [Formula: see text]([Formula: see text]) and imaginary [Formula: see text]([Formula: see text]) parts of dielectric function, extinction coefficient k([Formula: see text]) and refractive index n([Formula: see text]) were determined. It was shown that the optical constants of PZT nanotubes are different from PZT nanoparticles.


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