Use of nanomaterials in the pretreatment of water samples for environmental analysis

The challenge of providing clean drinking water is of enormous relevance in today’s human civilization, being essential for human consumption, but also for agriculture, livestock and several industrial applications. In addition to remediation strategies, the accurate monitoring of pollutants in water sup-plies, which most of the times are present at low concentrations, is a critical challenge. The usual low concentration of target analytes, the presence of in-terferents and the incompatibility of the sample matrix with instrumental techniques and detectors are the main reasons that renders sample preparation a relevant part of environmental monitoring strategies. The discovery and ap-plication of new nanomaterials allowed improvements on the pretreatment of water samples, with benefits in terms of speed, reliability and sensitivity in analysis. In this chapter, the use of nanomaterials in solid-phase extraction (SPE) protocols for water samples pretreatment for environmental monitoring is addressed. The most used nanomaterials, including metallic nanoparticles, metal organic frameworks, molecularly imprinted polymers, carbon-based nanomaterials, silica-based nanoparticles and nanocomposites are described, and their applications and advantages overviewed. Main gaps are identified and new directions on the field are suggested.publishe

Oxidative polymerization of 4-[(4-phenylazo-phenyimino)-methyl]-phenol catalyzed by horseradish peroxidase

Schiff base derivate 4-[(4-phenylazo-phenyimino)-methyl]-phenol (4-PPMP) monomer was synthesized by condensation reaction and the chemical structure of the monomer has been characterized by UV-vis, FT-IR, H-1 NMR spectroscopies. 4-PPMP readily dissolves in 1,4-dioxane, THF, DMF, diethyl ether, chloroform and DMSO. Its solubility in methanol and ethanol is much lower. Enzymatic oxidative polymerization of azobenzene derivate 4-[(4-phenylazo-phenyimino)-methyl]-phenol using horseradish peroxidase (HRP) in the presence of hydrogen peroxide as catalyst and oxidizing agent was carried out in various solvents (acetone, methanol, ethanol, N,N-DMF, and 1,4-dioxane) and phosphate buffers (pH 6, 6.8, 7, and 7.2) at room temperature. Studies have shown that a black polymer having a melting point of 290 degrees C was successfully produced in good yields by utilizing aqueous 1,4-dioxane as the solvent at pH 6. Poly(4-[(4-phenylazo-phenyimino)-methyl]-phenol) P(4-PPMP) shows good solubility in 1,4-dioxane, DMF and DMSO but it is only sparingly soluble in chloroform, THF, methanol and ethanol. P-(4-PPMP) is insoluble in diethyl ether. Characterization of P-(4-PPMP) was carried out via UV-vis, FT-IR, H-1 NMR, elemental analysis and SEC measurements. The number-average molecular weight (M-n), weight-average molecular weight (M-w) and polydispersity index (PDI) of the polymer were determined to be 7970.4, 8146.2 and 1.02 g mol(-1), respectively. FT-IR and H-1 NMR studies confirmed the presence of phenylene and oxyphenylene units with in the polymer backbone. The optical band gaps (E-g) of 4-PPMP and P-(4-PPMP) were calculated as 3.69 and 3.36eV, respectively. (C) 2009 Elsevier B.V. All rights reserved

Synthesis, characterization, thermal stability and electrochemical properties of ortho-imine-functionalized oligophenol via enzymatic oxidative polycondensation

WOS: 000439781600002Ortho-imine functionalized oligophenol was synthesized via enzymatic polymerization of 2-((4-nitrophenylimino) methyl) phenol (NPIMP). Enzymatic polymerization was catalyzed by Horseradish peroxidase (HRP) enzyme and hydrogen peroxide (H2O2) oxidizer yielded oligophenol with imine functionality on the side-chain. Effects of various factors including reaction pH, temperature and solvent system on the polymerization were studied. Optimum polymerization with the highest yield (96 %) and number-average molecular weight (M-n = 7300 g/mol, degree of polymerization approximate to 30) was accomplished using equivolume mixture of acetone/pH 7.0 phosphate buffer medium at 35 degrees C in 24 h under air. Characterization of the resulting oligomer was accomplished by ultraviolet-visible spectroscopy (UV-Vis), fourier transform infrared spectroscopy (FT-IR), H-1 and C-13 nuclear magnetic resonance (H-1 and C-13 NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), cyclic voltammetry (CV) and gel permeation chromatography (GPC). The polymerization involved elimination of hydrogen from NPIMP, and the oligomer possessed phenolic -OH end groups. The oligomer backbone was composed of oxyphenylene and phenylene repeat units. The optical band gaps (Eg) of NPIMP and oligo(NPIMP) were measured as 3.21 and 3.39 Eg, respectively. Thermal stability of the oligo(NPIMP) was also found to be relatively high, and lost 5 % of its mass at 175 degrees C and lost 50 % of its mass at 600 degrees C.Scientific and Technological Research Council of Turkey (TUBITAK) [115Z482]This research was partially supported by the Scientific and Technological Research Council of Turkey (TUBITAK) (115Z482)

Synthesis and Characterization of Conducting Copolymers of Thiophene Derivatives

Electrochemical copolymerizations of N1,N2-bis(thiophen-3-ylmethylene)benzene-1,2-diamine (TMBD), 4-methyl-N1,N2-bis (thiophen-3-ylmethylene)benzene-1,2-diamine (MTMBD) and 4-nitro-N1,N2-bis(thiophen-3-ylmethylene)benzene-1,2-diamine (NTMBD) with 3,4-ethylenedioxy thiophene (EDOT) were carried out in CH3CN/LiClO4 (0.1M) solvent-electrolyte couple via potentiodynamic electrolysis. The resulting copolymers were characterized by cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The conductivity measurements of copolymers and PEDOT were carried out by the four-probe technique

Synthesis, characterization and optoelectrochemical properties of poly(1,6-bis(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)hexane) and its copolymer with EDOT

WOS: 000259690500009A new polythiophene derivative was synthesized by electrochemical oxidative polymerization of 1,6-bis(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)hexane (TPH). The structure of the monomer was elucidated by H-1, C-13, MR and mass analyses. The polymer P(TPH) and its copolymer with 3,4-ethylenedioxythiophene (P(TPH-co-EDOT)) were synthesized via potentiostatic electrochemical polymerization. Characterizations of the resulting polymers were performed by cyclic voltammetry (CV), FTIR, UV-vis spectroscopies; and conductivity measurements. Moreover, the spectroelectrochemical and electrochromic properties of the polymer films were investigated. While P(TPH) has only three colors in oxidized and neutral states (blue, green and yellow), its copolymer with EDOT has five different colors (purple, red, light gray, green, and blue). Optical contrast and switching time of the polymer film were improved via copolymerization. It was found that with increasing applied potential the amount of PEDOT in the copolymer composition increases and band gap (E-g) of the copolymer decreases. (C) 2008 Elsevier B.V. All rights reserved.TUBA; DOSAP program METU; [DPT-2005K120580]The authors gratefully thank TUBA, DPT-2005K120580 grants and DOSAP program METU

Synthesis and characterization of oligosalicylaldehyde-based epoxy resins

WOS: 000237134100012The synthesis of a new epoxy resin of oligosalicylaldehyde by the reaction with epichlorohydrin is reported. New resin's epoxy value and chlorine content were determined and found to be 25 % and 1 %, respectively. The characterization of the new resin was instrumented by FTIR, H-1 NMR, scanning electron microscopy, and thermal gravimetric analyses. TGA results showed that the cured epoxy resin has a good resistance to thermal decomposition. The mass losses of cured epoxy resin were found to be 5 %, 10 %, 50 % at 175 degrees C, 240 degrees C and 400 degrees C, respectively. On the curing procedure the resin was cured with polyethylenepolyamine at 25 degrees C for 8 h and 100 degrees C for 1.5 h. The FTIR spectrum of new epoxy resin gave the peak of oxirane ring a (nu) over bar = 918 cm(-1)

Synthesis, Characterization and Optoelectrochemical Properties of Poly(2,5-di(thiophen-2-yl)-1-(4-(thiophen-3-yl)phenyl)-1H-pyrrole-co-EDOT)

A new polythiophene derivative was synthesized by electrochemical oxidative polymerization of 2,5-di( thiophen-2-yl)-1-(4-(thiophen-3-yl) phenyl)-1H-pyrrole (TTPP). The structure of the monomer was evaluated by H-1-NMR and FT-IR. The polymer (P(TTPP)) and its co-polymer with 3,4-ethylenedioxythiophene (P(TTPP-co-EDOT)) were synthesized via potentiostatic electrochemical polymerization. The resulting polymers were characterized by cyclic voltammetry (CV), FT-IR, SEM and UV-Vis spectroscopy, and conductivity measurements. Also, the spectroelectrochemical and electrochromic properties of P(TTPP-co- EDOT) were investigated. While P(TTPP) reveals no electrochromic activity, its co-polymer with EDOT has two different colours (yellow and blue). Optical contrast, switching time, lambda(max) and band gap (E-g) of (P(TTPP-co-EDOT)) were determined. (C) Koninklijke Brill NV, Leiden, 201

Synthesis and characterization of conducting copolymer of (N (1),N (3)-bis(thiophene-3-ylmethylene)benzene-1,3-diamine-co-3,4-ethylenedioxythiophene)

Electrochemical copolymerization of N (1),N (3)-bis(thiophene-3-ylmethylene)benzene-1,3-diamine (TMBA) with 3,4-ethylenedioxythiophene (EDOT) was carried out in a CH3CN/LiClO4 (0.1 M) solvent-electrolyte via potentiodynamic electrolysis. Chemical structure of the monomer was determined by nuclear magnetic resonance (H-1 NMR) and Fourier transform infrared (FTIR) spectroscopy. The resulting copolymer was characterized by cyclic voltammetry (CV), FTIR, scanning electron microscopy (SEM), and thermogravimetry analyses (TGA). Conductivity measurements of the copolymer and PEDOT (poly(3,4-ethylenedioxythiophene)) were carried out by the four-probe technique

Synthesis and Characterization of Conducting Copolymers of Bisphenol A-Diglycidyl Ether with Thiophene Side-Groups and Pyrrole

Copolymers of bisphenol A-diglycidyl ether with thiophene side-groups and pyrrole were synthesized by electrochemical polymerization. Bisphenol A-diglycidyl ether with thiophene side-groups (DGEBATh) was obtained from the reaction between bisphenol A-diglycidyl ether (DGEBA) and thiophene-3-acetic acid. The syntheses of copolymers of DGEBATh and pyrrole were achieved electrochemically using three different supporting electrolytes, p-toluene sulfonic acid (PTSA), sodium dodecyl sulfate (SDS) and tetrabutylammonium tetrafluoroborate (TBAFB). Characterizations of DGEBATh and copolymers were performed by combination of techniques including cyclic voltammetry, scanning electron microscopy, gel permeation chromatography, differential scanning calorimetry, 1H-NMR and FT-IR. The conductivities were measured by the four-probe technique

Sustainable polysiloxanes via siloxane metathesis

WOS: 000432475704163