Sharif Digital Repository

In this study, a newly designed needle trap device (NTE) containing modified nanosilica as sorbent is used for sampling and preconcentration of some polycyclic aromatic hydrocarbons (PAHs) from headspace of aqueous solutions. An inexpensive modifier, cis-9-octadecenoic acid (oleic acid), which contains a long chain, was used to modify the surface of the nano-scaled silica particles. The hydrophobic interaction between oleic acid and aromatic compounds was the preliminary evidence for extraction of these compounds. After adsorption of selected compounds, thermal desorption was, subsequently, employed to transfer the extracted analytes into a GC–FID. Extraction time and temperature, flow rate... 

Sustainable development requires the development and promotion of environmental management and a constant search for green technologies to treat a wide range of aquatic and terrestrial habitats contaminated by increasing anthropogenic activities. In this work we investigated the ability of four previously isolated fungi, BBRC 9057, BBRC 20020, BBRC 9058 and BBRC 9002, in degradation of polycyclic (PAHs) and the effect of UV irritation on fungi cell growth and degradation of PAHs. Also we studied the degradation of anthracene by thermophilic filamentous fungi in liquid and soil slurry bioreactor. Cell growth and anthracene degradation ability of BBRC 9057 increased 6.51 and 1.82 times rather... 

Commercial solid phase microextraction fibers posses a few drawbacks such as relatively low recommended operating temperature, instability and swelling in organic solvents, breakage of the fiber, stripping of coatings, and bending of the needle. Some of these problems have been obviated by covalent bonding of the polymer phase to the fused-silica substrate by sol-gel technology, but the easy breakage of the fiber remains a problem. In this study a new technique for preparation of unbreakable, thin and very porous fiber coatings for solid phase microextraction was proposed. In this technique firstly an intermediate film consisting ... 

Polyaromatic hydrocarbons are toxic compounds generally produced by combustion of explosives and petroleum materials. They cause soil and ground water contamination. PAHs are carcinogenic and lead to serious health problems for human and other living things; hence they should be removed from the environment. Soil washing technique has been one of methods applied for soil treatment during the years and surface active compounds like emulsifiers and surfactants have been introduced into washing process to improve the removal efficiency. On the other hand, synthetic surfactants made of chemicals and petroleum materials are not degradable and remain in the environment. To void this secondary... 

In this study, a multivariate-based strategy was developed for simultaneous determination of thirteen carcinogenic polycyclic aromatic hydrocarbons (PAHs) in water samples using gold nanoparticles (AuNPs) as solid-phase extraction (SPE) sorbent combined with gas chromatography-flame ionization detector (GC-FID). The extraction technique is based on the strong affinity between citrate capped AuNPs and PAHs. Furthermore, characterization of AuNPs was performed by UV-Vis and TEM techniques. A rotatable central composite design (CCD) combined with multiple linear regression (MLR) was used for designing the extraction procedure and developing models using the GC peak areas of 13 PAHs. Also,... 

Attentions to nano materials due to their vast applications in different branches of science and technology have been remarkably increased in recent years. Nanofibers are an important class of nano materials which could be used as novel sorbents because of their high surface to volume ratio as a result of long lengths and nano-to-micro-scale diameters. Electrospinning is a broadly used technology which utilizes high electrostatic forces for producing nanofibers. In this study a novel high temperature resistant solid phase microextraction (SPME) fiber was prepared besed on Polyetherimide (PEI) by this method. The porosity of the PEI fiber was investigated by scanning electron microscopy... 

Porous materials using polymers have been developed for a variety of industrial applications. These structures mostly contain well-aligned microchannels and exhibit good mechanical properties and high porosity.There are several ways to prepare porous polymeric structures, such as sintering, stretching, track etching and phase separation processes. In this work Phase separation method using anti-solvent of selected polymer in liquid nitrogen was used to fabricate the porous structures. Considering physical and chemical peroperties of polycyclic aromatic hydrocarbons, porous polystyrene make to be good sorbents. Solvent supported microextraction technique was applied to extract polycyclic... 

TPPB are characterized by a cell-containing aqueous phase, and an immiscible and biocompatible organic phase that partitions toxic/insoluble substrates to the cells base on their metabolic demand and the thermodynamic equilibrium of the system. Surface areas, Mass transfer coefficient, Hydrophobicity of polycyclic aromatic hydrocarbons (PAH) are considered as limitation in two phase partition bioreactors (TPPB). For solving of this challenge, in this project used solid particle for increment of mss transfer and surface area, and also solid particles can eliminate limitation of initial concentration of polycyclic aromatic hydrocarbon and ratio of aqueous/organic phases. Naphthalene is used as... 

Polyhedral oligomeric silsesquioxanes (POSSs) are 3D nanoscale structures with fascinating potential to be used as extractive phases in solid phase microextraction (SPME). Here, as a case study, the octaglycidyldimethylsilyl polyhedral oligomeric silsesquioxane (POSS–epoxy) network was fabricated on a stainless steel wire via sol–gel methodology and used as a SPME fiber coating. The uniform pore structure, high surface area, and hydrophobicity of POSS–epoxy, make it susceptible toward isolation of non– to semi–polar compounds. Performance of the POSS–epoxy fiber coating was examined considering three classes of typical environmental pollutants including chlorobenzenes (CBs), benzene... 

Coordination polymers are a wide range of metal-organic polymers that have good potential for use as extraction phase in solid phase extraction and solid phase microextraction. Also, these polymers can be synthesized in various morphologies such as nanorods, microspheres, nanofibers, etc. to demonstrate the effect of morphology on extraction efficiency.In this study, the extraction efficiency of a coordination polymer with two morphologies (nanorods and microspheres) and different nitrogen percentages was investigated in needle trap device using gas chromatography-mass spectrometry to measure polycyclic aromatic hydrocarbons as model analytes.PAHs were measured in conventional cigarette... 

To date, the plasmonic properties of many metallic and semi-conducting materials have been investigated and used in various industries. One of the plasmonic material categories that have always been considered is polycyclic aromatic hydrocarbon or PAH, whose plasmonic resonance energy depends on the charge state of the molecule. In this regard, it is easy to change the plasmonic resonance energy via changing the induced charge, which is a unique feature of the mentioned materials. In addition, plasmonic structures with excitations in the infrared region are able to enhance the vibration intensity of absorbed molecules by increasing the electric field around themselves. Therefore, they have... 

In recent years, comprehensive two-dimensional gas chromatography (GC×GC) has been widely used, especially in the separation and measurement of complex mixtures, due to its features such as higher peak capacity and better resolution in separation than usual chromatography methods, which the mixture analysis of polycyclic aromatic hydroarbons (PAHs) compounds have been targeted in this study. One of the main challenges in this field is the large amount of data and the qualitative and quantitative interpretation of the resulting data. Therefore, the identification, separation and quantitative measurement of species in this field is important, especially in the presence of interference in the...