Sharif Digital Repository

Chlorinated benzenes are a group of cyclic aromatic compounds which are used mainly as intermediates in the synthesis of pesticides and other chemicals. These compounds have harmful effects on human health, as on blood, kidneys, skin and eyes, and cause biological disorders and cancers. Chlorobenzenes have been ranked as priority pollutants by the US Environmental Protection Agency (EPA). The permissible level of these compounds for drinking water ranges between 2 μg/L and 1 mg/L. Hence determination of these compounds is of a significant importance. Solid Phase Dynamic Extraction (SPDE) of 5 types of chlorobenzenes (monochlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene,... 

In this study, the SPME nanocomposite coating of metal organic framework/polyaniline (MOF/PANI) was fabricated by the electrochemical polymerization process. Its application was investigated via extraction of chlrobenzenes from head-space aqueous solution. The power supply voltage, time of deposition and the percent of added MOF to main polymer solution was investigated and optimized in the electrochemical polymerization process. Also extraction parameters influencing the extraction efficiency including ionic strength, extraction temperature, extraction time, as well as desorption temperature and time were investigated and optimized. The detection limits of the developed method under... 

Superhydrophobic surfaces have attracted much attention in recent years due to their unique properties. Artificial superhydrophobic surfaces can be fabricated by employing chemical modifying a hierarchical structured surface (micro- and nanostructures) with a low surface free energy material. In this report, we used a simple one-step coating process to prepare superhydrophobic sorbents with a large surface area. Surface chemistry and porosity are fundamental parameters for an efficient sorbent capable of extracting low levels of analytes. Considering physical and chemical peroperties of chlorobenzenes, superhydrophobic materials make to be good sorbents. So in this project melamine... 

In the past decades, electrospinning has been widely used for the production of micro/nanofibers. In spite of the simplicity and effectivity of the conventional electrospinning for fabricating nanofibers, compact structure and small pores of the nanofibers hinder the efficient penetration of analytes during the extraction process. In order to overcome this issue, an applicable strategy called wet electrospinnig has been employed to enlarge the pore size of the electrospun scaffolds. By applying this technique, a collector was placed at the bottom of a solvent bath and highly porous foam from polyamide nanofibers was produced immediately after freeze-drying (3D electrospinning).... 

In this study, a three dimensional molybdenum oxide based coordination polymer of{(M¬o2O6)(4,4'–bpy)}n was synthesized by solvothermal process. Excellent properties of the fabricated metal–organic framework such as crystallinity, porosity, sufficient thermal stability and possession of different interactions encouraged us to employ it as a novel extraction phase in sample preparation. Extraction efficiency of the MOF–based sorbent was evaluated in needle trap extraction of some chlorobenzenes as volatile aromatic organic compounds in conjugation with gas chromatography–mass spectrometry. To achieve maximum efficiency and sensitivity, influential parameters including desorption time and...