Development of forward osmosis (FO) membranes with high salt selectivity is a essential issue to realize the FO technology. To improve salt selectivity of the FO membrane, a polyamide thin film composite FO membrane was fabricated by the interfacial polymerization method using aromatic hydrocarbon organic solvents on polyacrylonitrile (PAN) supports. The aromatic hydrocarbon organic solvent accelerated amine diffusion rate toward the organic phase and the subsequent reaction, which can improve membrane performance by fabricating a thin and highly dense basal PA layer. As a result, the prepared FO membrane showed ~1.7 times higher flux and ~4.5 times higher salt selectivity compared to HTI-CTA commercial membrane with 1.0 M NaCl draw solution and DI water feed solution in FO mode.
We report on the fabrication of a high performance reverse osmosis membrane based on a hydrophilic polyacrylonitrile support via an aromatic solvent-assisted interfacial polymerization process. The use of aromatic solvent (toluene or xylene) produced the membranes with unprecedentedly high NaCl rejection (~99.9%) and superior water flux, outperforming both the control membrane prepared using a conventional aliphatic solvent (n-hexane) and commercial membranes. The membranes fabricated using toluene or xylene had roof-like structures covering a thin and highly dense polyamide (PA) layer, which was induced by enhanced amine diffusion and the extended miscible layer resulting from the increased miscibility of aromatic solvent with water. The high performance of the membranes is attributed to thin and highly cross-linked basal PA layer.
Ethanol washing with distillation as a cleanup process of polycyclic aromatic hydrocarbon(PAH)-contaminated soil was investigated in this study. A multistage ethanol washing with distillation process was applied to three different types of soil, i.e., sandy soil, alluvial soil, and clay with the initial concentration of benzo(a)pyrene 10 mg/kg, benz(a)anthracene 250 mg/kg, and pyrene 100 mg/kg soil. Ethanol was selected as washing solvent because of its high PAH removal efficiency, low cost, and non-toxicity comparing to the other solvent such as isopropyl alcohol and sodium dodecyl sulfate. The satisfactory results (i.e. lower than benzo(a)pyrene 1 mg/kg, pyrene 10 mg/kg, benz(a)anthracene 25 mg/kg, which are the Canada or the Netherlands soil standard) for three types of soils were obtained by at most five-six times washing. It was suggested that organic content in soil decreased the removal efficiency by ethanol washing.
Demand for organic analysis increase as industries are growing and many products are spreaded in the daily life. One of many products is oil spill dispersant. It was used for oil accident in the ocean. When oil spill dispersant spread at the ocean, the petroleum in the ocean is dispersed. The oil spill dispersant is made of non ionic surfactant and petroleum oil. The non ionic surfactant disperse petroleum from oil accident. The other part is petroleum oil which has aromatic hydrocarbon. Because the aromatic hydrocarbon is cancerogenic material, it directly injure animals in the ocean. This cause the second pollution in the human body. Many oil accidents still are controlled by oil spill dispersant. Therefore quality control of the oil spill dispersant become important and this also demand for the exact quantitative analysis of aromatic hydrocarbon. Hereupon the first we develop separate petroleum oil from surfactant. The second standardize analytical method of aromatic hydrocarbon in the separated petroleum oil.
In order to elucidate the polycyclic aromatic hydrocarbon concentration and its origin in arctic area, four arctic brown algae (Laminaria saccharina, L. digita, Alaria esculenta, Desmarestia aculeata), one marine invertebrate (Echinoidea) and sediments were collected from Kongsfjorden in Spitsbergen from the late July to early August, 2003. In case of macroalgae, the young blade part above growth point and the old stipes and blades beneath growth point were separated and analyzed for polycyclic aromatic hydrocarbons (PAHs) in an attempt to check the mechanism of uptake in macroalgae to accumulate PAH. There was no difference in PAH concentrations between sampling sites (Stations B and C), species, and blades beneath and above growth point. PAH concentrations in all samples collected in this study were relatively higher than those reported in other areas of arctic. Especially, station C, which is known as an unpolluted area, showed 10 times higher PAH concentration (8,765 ng/g) in sediment than station A (694 ng/g) around harbor. In addition high PAH concentration, station C had very higher proportion of methylated PAH to parent PAH in sediment than station A. Source analysis using PAH isomer pair ratios as indicators showed that Kongsfjorden area seemed to be relatively contaminated with PAH derived from direct petroleum input.