چكيده به لاتين
Membrane technology is the most promising process for contaminations separation operation if the hydrophilicity, fouling and reusability properties could be improved. Superhydrophobicity property of the membrane surface diminishes interaction between the contaminations and membrane surface. This causes a reduction in the fouling tendency and self-cleaning characteristic. There are many methods to produce superhydrophobic properties such as radiation-induced copolymerization, layer-by-layer assembly, anodic oxidation grafting fluoroalkylsilane (FAS) on the membrane surface and electrospinning. electrospun nanofibrous membranes are well-established materials because of their low cost, simplicity, ease of scale-up and wide range of applications.
Electromembrane extraction (EME) has gained a lot of popularity among the researchers because of their aforementioned unique potentials such as high selectivity and high preconcentrations. The most membranes used in electromembrane extraction (EME) are commercial polypropylene hollow fiber. We are focusing on fabricating a flat polymeric membrane that can be used in EME setup.
In this study, for the first time, good reusable porous poly acrylonitrile (PAN)/poly dimethylsiloxane (PDMS)/TiO_2composite nanofibrous flat membranes to 10 cycles were fabricated by using an electrospinning process. Subsequently, the membranes were grafted with using a low surface energy material (CH_3 )_2SiCl_2/CH_3SiCl_(3 )to form nano-clusters, which were decorated on the microreliefs of electrospun PAN/ PDMS nanofibrous membranes, and their performance in an electromembrane extraction of some phthalate was investigated from water samples.
Phthalates were determined by gas chromatography with the flame ionization detector. The applied voltage, extraction time, agitation rate, volumes donor and acceptor phases were found to be important factors for obtaining exhaustive extraction. These parameters were optimized using response surface methodology (RSM) based on a central composite design (CCD). The optimum conditions were 200 V, 20 min, 1100 rpm, 10 ml and 1 ml for voltage, time, agitation rate, volumes donor and acceptor phases, respectively. Under these conditions, calibration curves in the range of 1-200 ng/ml and 100-4000 ng/ml for diethylhexyl phthalate (DEHP) and dibuthyl phthalate (DBP) are linear with R2>0.990. The repeatability at two concentration levels (20 and 100 ng/ml) for DEHP and two concentration levels (15 and 2000 ng/ml) for DBP and at concentration of 200 ng/ml for the membrane-to-membrane were calculated. Relative standard deviation were less than 7%, 9% and 12% for interday, intraday and membrane-to-membrane, respectively. The limits of detection were found (0.08 and 7.4 ng/ml) and limits of quantification were (0.25 and 21.06) for DEHP and DBP, respectively. Three kinds of waters were used as real samples and the recoveries of those compounds in spiked water samples at a concentration of 20-2000 ng,/ml were obtained from 86-107%.
Keywords: Reusablity; Electromembrane extraction; Flat membrane; Superhydrophobic; Phthalates; Gas chromatography; Central composite designe
