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One of the most important issues in the world in recent years is water pollution, which is brought about by rapid industrialization. Peroxymonosulfate (PMS) oxidation is an effective technique for wastewater treatment. Transition metals such as cobalt, manganese, iron are used to activate PMS. Therefore, in this study, a novel activated carbon and cobalt phthalocyanine catalyst (Co-AC) was synthesized by the solvothermal method.Rhodamine B (RhB) and 2,4,6-Trichlorophenol (2,4,6-TCP) were used as model pollutants in the catalytic tests. The effective catalytic activity was observed at a low concentration of Co-AC and PMS compared to the literature. XRD, TEM, Raman, SEM and XPS techniques were used for the characterization of the as-synthesized catalyst. In addition, the surface area of Co-AC was calculated by BET and QS-DFT analysis. As a result, the degradation of RhB was found to be 97.07% after 16 minutes, and 100% for 2,4,6-TCP after 6 minutes. Experimental parameters such as temperature, pH, the concentration of the catalyst and PMS were studied and optimum conditions were determined In addition, TOC removal values ​​were found to be 46% for RhB and 66% for 2,4,6-TCP, respectively. The ICP-OES technique was used for the cobalt leaching and the results were found to be 1.35 mgL−1 for the RhB solution and 1.38 mgL−1 for 2,4,6-TCP. These results ​​are in good agreement with previously published works. The synthesized activated carbon-supported cobalt-based catalyst in line with these results acts as an effective catalyst especially in the treatment of wastewater containing pollutants such as RhB and 2,4,6-TCP.

Platinum (Pt) loaded activated carbons (ACs) were synthesized by the thermal decomposition of platinum (II) acetylacetonate (Pt(acac)2) over chemically activated glucose-based biochar. The effect of Pt loading on surface area, pore characteristics, surface chemistry, chemical structure, and surface morphology were determined by various techniques. XPS studies proved the presence of metallic Pt0 on the AC surface. The graphitization degree of Pt loaded ACs were increased with the loaded Pt0 amount. The electrochemical performance of the Pt-loaded ACs (Pt@AC) was determined not only by the conventional three-electrode system but also by packaged supercapacitors in CR2032 casings. The capacitive performance of Pt@AC electrodes was investigated via cyclic voltammetry (CV), galvanostatic charge-discharge curves (GCD), and impedance spectroscopy (EIS). It was found that the Pt loading increased the specific capacitance from 51 F/g to 100 F/g. The ESR drop of the packaged cell decreased with the Pt loading due to the fast flow of charge through the conductive pathways. The results showed that the surface chemistry is more dominant than the surface area for determining the capacitive performance of Pt loaded AC-based packaged supercapacitors.

Different parts (needle and cone) of the same biomass (pine, Pinus pinaster) were used as carbon source for activated carbon production. Biomass-derived activated carbons (ACs) were produced by the chemical activation of pyrolytic char. Dependence of the surface characteristics to the biomass type and activation agent were discussed by N2 Physisorption, Raman, and X-ray photoelectron spectroscopy (XPS) techniques. Pine-cone-derived ACs exhibit higher BET surface area and mesopore volume to micropore volume ratio compared to needle-derived ACs. Regardless of the biomass type, higher BET surface area and Vmes/Vmic ratio were obtained by KOH activation. XPS results proved that the KOH dominantly reacts with the aliphatic groups while H3PO4 reacts with aromatic groups during the activation. Hence, KOH activation led to the higher relative amounts of surface aromatic groups which will contribute to the total specific capacitance by creating pseudocapacitance. The electrochemical performance of the synthesized ACs was determined in packaged supercapacitors in CR2032 casings. Galvanostatic charge-discharge and self-discharge tests proved that all packaged supercapacitors displayed a repeatable cycle behavior and were highly stable. Cone-derived AC-based supercapacitors displayed higher specific capacitance than those of needle-derived ACs at all current densities (0.25–1 A/g). However, higher ESR values were observed for cone-derived AC based electrodes. The cone-derived AC (by KOH activation) based supercapacitor displayed 99% capacitance retention over 5000 cycles at 500 mA/g current density. It is found that the biomass type primarily affects the surface and electrochemical properties of ACs.

Herein, a facile and simple method is reported for preparation of composite electrode materials based on conducting polymer/nano metal oxide combination for supercapacitor applications. The heterostructured composite redox-active electrode materials, having both p- and n-doping ability, were fabricated using poly(3,6-dithien-2-yl-9H-carbazol-9-yl acetic acid) and nano sized TiO2 particles without any binder and conducting additives. The heterostructured composite electrodes exhibited remarkable a specific capacitance (Cspec = 462.88 F g−1), specific power (SP = 266.96 kW kg−1), specific energy (SE = 89.98 W h kg−1), good cycling performance and excellent reversible capability (81.7% capacitance retention after 8000 charge/discharge cycles) at 2.5 mA cm−2 current density within a 1.2 V potential window with two-electrode symmetric cell configuration. Besides, heterostructured composite electrode materials were fabricated using different particle sized TiO2 (3–5 nm, average 21 nm and bulk), and the effect of the particle size on supercapacitor performances was investigated and compared in detail. Our symmetric pseudo-capacitor device lighted a LED for 4.7 min with 42 s charge time at 2.5 mA cm−2 even after 8000 charge/discharge cycles.

A novel highly sensitive electrochemical carboxymethylcellulose-gelatin-TiO(2)-superoxide dismutase biosensor for the determination of O(2)(•-) was developed. The biosensor exhibits high analytical performance with a wide linear range (1.5 nM to 2 mM), low detection limit (1.5 nM), high sensitivity and low response time (1.8s). The electron transfer of superoxide dismutase was first accomplished at the carboxymethylcellulose-gelatin-Pt and carboxymethylcellulose-gelatin-TiO(2)-Pt surface. The electron transfer between superoxide dismutase and the carboxymethylcellulose-gelatin-Pt wihout Fe(CN)(6)(4-/3-) and carboxymethylcellulose-gelatin-Pt, carboxymethylcellulose-gelatin-TiO(2)-Pt with Fe(CN)(6)(4-/3-) is quasireversible with a formal potential of 200 mV, 207 mV, and 200 mV vs Ag|AgCl respectively. The anodic (ks(a)) and cathodic (ks(c)) electron transfer rate constants and the anodic (α(a)) and cathodic (α(c)) transfer coefficients were evaluated: ks(a)=6.15 s(-1), α(a)=0.79, and ks(c)=1.48 s(-1) α(c)=0.19 for carboxymethylcellulose-superoxide dismutase without Fe(CN)(6)(4-/3-), ks(a)=6.77 s(-1), α(a)=0.87, and ks(c)=1 s(-1) α(c)=0.13 for carboxymethylcellulose-superoxide dismutase with Fe(CN)(6)(4-/3-), ks(a)=6.85 s(-1), α(a)=0.88, and ks(c)=0.76 s(-1) α(c)=0.1 carboxymethylcellulose-gelatin-TiO(2)-superoxide dismutase. The electron transfer rate between superoxide dismutase and the Pt electrode is remarkably enhanced due to immobilizing superoxide dismutase in carboxymethylcellulose-gelatin and TiO(2) nanoparticles tend to act like nanoscale electrodes.

Carbonaceous particles are synthesized under hydrothermal conditions using two waste biomasses (olive oil waste and hazel nutshell) and saccharides (glucose and lactose). A stainless steel autoclave with 75 mL of capacity was used to apply the hydrothermal carbonization (HTC) process to the starting materials stated above. In the experiments, 2.5 g of sample dispersed in 50 mL of deionized water is subjected to HTC at 180 °C for 4 h. H/C and O/C ratios for the chars were found to be more similar to the lignite than those of the starting materials. The heating values for the chars were found to be higher as compared to that of the feedstocks. FTIR investigations of the chars reveal that biochars of saccharides have different chemical structures compared with glucose and lactose, while biochars of waste biomasses are similar chemical nature with their starting materials. Hydroxymethylfurfural (HMF), phenol, acids, and aldehyde contents of aqueous phases were also determined. Solid-state 13C CP/MAS NMR analy...

The hydrothermal conversion of cellulose in the presence of nanometal oxide particles (SnO2 and ZnO) was investigated in this study. Both catalysts were synthesized hydrothermally and characterized using TEM, FESEM-EDX, X-ray diffraction spectroscopy and BET (Brunauer, Emmett and Teller) methods. In order to reveal the effect of nano-scale catalysts, experiments were conducted using bulk (non-nano) metal oxide and pure cellulose without any catalyst. The hydrothermal conversion experiments were carried out in a micro autoclave at 300, 400, 500, 600 degrees C and 1 h reaction time. The compositions of the gaseous products and the aqueous phase were determined with various analytical techniques (GC, ion chromatography, HPLC, UV-vis). Contribution of carbon containing products to the carbon mass balance was also represented. The results indicated both nano and bulk ZnO and SnO2 to have an effect on the water-gas shift reaction at varying temperatures. The water-gas shift reaction (WGS) proceeded fast at 300 degrees C in the presence of ZnO, while the rate of WGS was lower at 300 degrees C in the presence of SnO2. Nano ZnO led to improved hydrogen yield, while ethane and propane were formed as a result of side reactions in the presence of nano and bulk SnO2. (C) 2011 Elsevier B.V. All rights reserved.

Tin oxide nanoparticles about 4 nm in size were successfully synthesized using hydrothermal method. The photocatalytic activity of the particles was determined by the decolorization of malachite green (MG) and titanium yellow (TY) under UV light. 12 ppm of MG and TY were used for the solution with an initial volume of 100 mL. The amounts of catalysts were 10, 30 and 50 mg. The effect of the catalyst loading on the reaction kinetic parameters and the decolorization rate constants (k) were determined. In order to reveal the photocatalytic efficiency of the nano particles, further experiments were conducted with bulk SnO(2). The oxygen species registered no observable effect on the reaction mechanism as nitrogen bubbling leads to no change in decolorization rates. Results showed that the synthesized nano tin oxide particles represent excellent photocatalytic activity for the decolorization of 12 ppm MG under UV light with 150 min of irradiation time. The energies of the highest occupied molecular orbital (HOMO) E(HOMO) of the dyes were also calculated by using the quantum chemical software in order to discuss the differences for the decolorization of two dyes. Electrical energy efficiency values for the decolorization of two dyes were also calculated.

In order to compare the catalytic activity of hydrothermally synthesized nano tin oxide particles with that of red mud (byproduct of Aluminum factory), HZSM5, K2CO3, the hazelnut shell was subjected to pyrolysis in the presence of these catalysts. The nano SnO2 particles were characterized by X-ray diffraction and transmission electron microscope. The characterization results indicate that nano SnO2 particles with 3-4 nm were successfully synthesized by hydrothermal method. Effect of all catalysts on the yields of pyrolytic oil, gas and char was discussed in detail. The pyrolytic oils were further analyzed by GC-MS and FTIR techniques in order to reveal the different activity of catalysts used. The results indicate that the synthetic nano SnO2 particles make a more positive influence compared to the other catalysts. GC-MS and FTIR analysis of pyrolytic oils prove that product distribution and structure of the pyrolytic oil vary with the catalyst type. (C) 2009 Elsevier Ltd. All rights reserved.

3-4 nm of SnO2 nanoparticles having uniform spherical shape were successfully synthesized using a hydrothermal method. The hydrothermal method has many advantages over other methods of preparing nanoparticles (such as sol-gel, solid state, and chemical precipitation), because there is no need for calcination and milling steps. The particles were characterized by X-ray diffraction, pore size diamater analysis, transmission electron microscope, scanning electron microscope analysis, Raman spectroscopy, and thermogravimetric analysis/differential thermogravimetric analysis. The results confirm that SnO2 nano powders are homogeneous, nano scale, and of high crystalline quality.

The use of metal oxide nanoparticles (NPs) in industrial applications has been expanding, as a consequence, risk of human exposure increases. In this study, the potential toxic effects of zinc oxide (ZnO) NPs on human periodontal ligament fibroblast cells (hPDLFs) and on mouse dermal fibroblast cells (mDFs) were evaluated in vitro. We synthesized ZnO NPs (particle size; 7-8 nm) by the hydrothermal method. Characterization assays were performed with atomic force microscopy, Braun-Emmet-Teller analysis, and dynamic light scattering. The hPDLFs and mDFs were incubated with the NPs with concentrations of 0.1, 1, 10, 50 and 100 μg/mL for 6, 24 and 48h. Under the control and NP-exposed conditions, we have made different types of measurements for cell viability and morphology, membrane leakage and intracellular reactive oxygen species generation. Also, we monitored cell responses to ZnO NPs using an impedance measurement system in real-time. While the morphological changes were visualized using scanning electron microscopy, the subcellular localization of NPs was investigated by transmission electron microscopy. Results indicated that ZnO NPs have significant toxic effects on both of the primary fibroblastic cells at concentrations of ∼50-100 μg/mL. The cytotoxicity of ZnO NPs on fibroblasts depended on concentration and duration of exposure.

A novel highly sensitive electrochemical impedimetric Protein A immunosensor for the determination of immunoglobulin G (IgG) was developed by immobilization of Protein A within a newly synthesized, and characterized polymer, poly(maleicanhydride-alt-decene-1). TiO2 nanoparticles (10-30 nm) were synthesized, characterized with X-ray diffraction, transmission electron microscopy and Brunauer-Emmett-Teller surface analysis. The electron transfer between IgG and the poly(maleicanhydride-alt-decene-1)-TiO2-Protein A is quasireversible with a formal potential of 225 mV vs Ag|AgCl. The response of the poly(maleicanhydride-alt-decene-1)-TiO2-Protein A immunosensor was proportional to IgG concentration with a correlation coefficient of 0.9963. The detection limit and linear range was 0.57 ng mL(-1) and 0.0062-500 μg mL(-1), respectively. Impedance measurments showed that synthesized TiO2 nanoparticles have better conducting properties compared with commercial degussa P25 TiO2 nanoparticles. The nonspecific binding of anti-MBP was 10 %. The label-free impedimetric immunosensor provided a simple and sensitive detection method for the specific determination of IgG in human serum.

3-4 nm of SnO2 nanoparticles having uniform spherical shape were successfully synthesized using a hydrothermal method. The hydrothermal method has many advantages over other methods of preparing nanoparticles (such as sol-gel, solid state, and chemical precipitation), because there is no need for calcination and milling steps. The particles were characterized by X-ray diffraction, pore size diamater analysis, transmission electron microscope, scanning electron microscope analysis, Raman spectroscopy, and thermogravimetric analysis/differential thermogravimetric analysis. The results confirm that SnO2 nano powders are homogeneous, nano scale, and of high crystalline quality.

The effect of the SnO2 nanoparticles (SNPs) on the behaviour of voltammetric carbon paste electrodes were studied for possible use of this material in biosensor development. The electrochemical behaviour of SNP modified carbon paste electrodes (CPE) was first investigated by using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques. The performance of the SNP modified electrodes were compared to those of unmodified ones and the parameters affecting the response of the modified electrode were optimized. The SNP modified electrodes were then tested for the electrochemical sensing of DNA purine base adenine to explore their further development in biosensor applications.

In this study, ZnO nanoparticles (ZNP) of approximately 30 nm in size were synthesized by the hydrothermal method and characterized by X-ray diffraction (XRD), Braun–Emmet–Teller (BET) N 2 adsorption analysis and transmission electron microscopy (TEM). ZnO nanoparticles enriched with poly(vinylferrocenium) (PVF + ) modified single-use graphite electrodes were then developed for the electrochemical monitoring of nucleic acid hybridization related to the Hepatitis B Virus (HBV). Firstly, the surfaces of polymer modified and polymer–ZnO nanoparticle modified single-use pencil graphite electrodes (PGEs) were characterized using scanning electron microscopy (SEM). The electrochemical behavior of these electrodes was also investigated using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Subsequently, the polymer–ZnO nanoparticle modified PGEs were evaluated for the electrochemical detection of DNA based on the changes at the guanine oxidation signals. Various modifications in DNA oligonucleotides and probe concentrations were examined in order to optimize the electrochemical signals that were generated by means of nucleic acid hybridization. After the optimization studies, the sequence-selective DNA hybridization was investigated in the case of a complementary amino linked probe (target), or noncomplementary (NC) sequences, or target and mismatch (MM) mixture in the ratio of (1:1).

In the present study, thermal degradation of polyolefins (PP and LDPE) and PET in a tubular reactor in an inert atmosphere was conducted. Each polymer was subjected to pyrolysis at the temperatures of 673, 773, 873, and 973 K. Yields of tar, residual coke and gas, and conversion degrees were calculated. Tars which include valuable chemicals were characterized by GC-MS, H-1-NMR, FTIR, and GPC. Pyrolysis gases (C1 + C2, C3, C4, C5, and C6 + C7) were also analyzed by GC analysis. From the comparison of data, it can be said that pyrolysis of PP and LDPE leads to the formation of tar containing mainly paraffinic structures, while aromatic structures were produced by the pyrolysis of PET.

In this study, SnO2 nanoparticles (SNPs)-poly(vinylferrocenium) (PVF+) modified single-use graphite electrodes were developed for electrochemical monitoring of DNA hybridization. The surfaces of polymer modified and polymer–SNP modified pencil graphite electrodes (PGEs) were firstly characterized by using SEM analysis. The electrochemical behaviours of these electrodes were also investigated using the differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques. The polymer–SNP modified PGEs were then tested for the electrochemical sensing of DNA based on the changes at the guanine oxidation signals. Experimental parameters, such as; different modifications in DNA oligonucleotides, DNA probe concentrations were examined to obtain more sensitive and selective electrochemical signals for nucleic acid hybridization. After optimization studies, DNA hybridization was investigated in the case of complementary of hepatitis B virus (HBV) probe, mismatch (MM), and noncomplementary (NC) sequences.