This review focuses on the removal of emerging contaminants (ECs) by biological, chemical and hybrid technologies in effluents from wastewater treatment plants (WWTPs). Results showed that endocrine disruption chemicals (EDCs) were better removed by membrane bioreactor (MBR), activated sludge and aeration processes among different biological processes. Surfactants, EDCs and personal care products (PCPs) can be well removed by activated sludge process. Pesticides and pharmaceuticals showed good removal efficiencies by biological activated carbon. Microalgae treatment processes can remove almost all types of ECs to some extent. Other biological processes were found less effective in ECs removal from wastewater. Chemical oxidation processes such as ozonation/HO, UV photolysis/HO and photo-Fenton processes can successfully remove up to 100% of pesticides, beta blockers and pharmaceuticals, while EDCs can be better removed by ozonation and UV photocatalysis. Fenton process was found less effective in the removal of any types of ECs. A hybrid system based on ozonation followed by biological activated carbon was found highly efficient in the removal of pesticides, beta blockers and pharmaceuticals. A hybrid ozonation-ultrasound system can remove up to 100% of many pharmaceuticals. Future research directions to enhance the removal of ECs have been elaborated.

No abstract

The permeation behavior of water vapor, H2, CO2, O2, N2, and CH4 gases in a series of novel poly(aryl ether sulfone)s has been examined over a temperature range of 30-100°C. These polymers include four alkyl-substituted cardo poly(aryl ether sulfone)s and four intermolecular interaction enhanced poly(aryl ether sulfone)s. Their water vapor and gas transport properties were compared to the unmodified cardo poly(aryl ether sulfone) (PES-C). It was found that the bulky alkyl substituents on the phenylene rings were advantageous for gas permeability, while the intermolecular hydrogen bonds and ionic bonds resulted in a considerable increase in gas permselectivity. The causes of the trend were interpreted according to free volume, interchain distance, and glass transition temperature, together with the respective contribution of gas solubility and diffusivity to the overall permeability. Of interest was the observation that IMPES-L, which simultaneously bears bulky isopropyl substituent and pendant carboxylic groups, displayed 377% higher O 2 permeability and 5.3% higher O2/N2 permselectivity than PES-C. Furthermore, sodium salt form PES-Na + and potassium salt form PES-K + exhibited water vapor permeability twice as high as PES-C and H2O/N2 selectivity in 10 5 order of magnitude.

Abstract:This paper focuses on the characterization and modeling of a solid/gas thermochemical reaction between a porous reactive bed and moist air flowing through it. The aim is the optimization of both energy density and permeability of the reactive bed, in order to realize a high density thermochemical system for seasonal thermal storage for house heating application. Several samples with different implementation parameters (density, binder, diffuser, porous bed texture) have been tested. Promising results have been reached: energy densities about 430-460 kWh.m -3 and specific powers between 1.93 and 2.88 W.kg -1 of salt. A model based on the assumption of a sharp reaction front moving through the bed during the reaction was developed. It has been validated by a comparison with experimental results for several reactive bed samples and operating conditions. Keywords:Thermochemical process, seasonal thermal storage, sharp front model, high-density reactive salt, permeability.

No abstract

No abstract

SYNOPSISThe novel polyetheretherketone (PEK-C) prepared from phenolphthalein in our institute is an amorphous, rigid, tough material with good mechanical properties over a wide temperature range. To improve its water vapor permeability for the application of gas drying, PEK-C was sulfonated with concentrated sulfuric acid and transferred in sodium, cupric, and ferric salt forms. Sulfonation degree can be regulated by controlling the temperature and reaction time. Characterization of sulfonated PEK-C in sodium form was made by infrared spectroscopy. Some properties of the sulfonated PEK-C, such as solubility, glass transition temperature, thermal stability, mechanical properties, and transport properties to nitrogen and water vapor, are also discussed. 0 1996 John Wiley & Sons, Inc. INTRODUCTIONPolyetherketone with Cardo (PEK-C) synthesized from phenolphthalein in our institute is a novel polyetheretherketone (PEEK) with the structure' Although most of the PEEK compounds that exhibit partial crystallinity and thus are difficult to proceed solution processes, PEK-C is an amorphous polymer and is soluble in a few aprotic polar solvents such as N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), and some chlorohydrocarbons and thus can be solution casted into membranes. In the meantime, it is a match for PEEK in mechanical and thermal properties. Furthermore, it can be modified easily by various chemical reactions, and thus its applications in membrane separation process will be found. In fact, the permeabilities for various gases through PEK-C membranes are fairly low, but the separate factors for some gas pairs are rather high, for example, the permeability for oxygen is only about 1 barrer (1 barrer = 1 X lo-'' cm3-cm/ cm2-s-cm Hg) and the selectivity for oxygen over nitrogen is 6.2.' It has been proven that the sulfonation of polymers is an effective method to increase both the permeability of water vapor and the selectivity for water vapor over n i t r~g e n .~-~ Therefore, the sulfonated PEK-C could be used in the air drying and natural dehydration that is one of the emerging application of membranes. EXPERIMENTAL MaterialsPEK-C samples (q,/C = 0.97, M u = 300,000, Tg = 228OC) were synthesized in our laboratory. H2S04, 98%. Other solvents and reagents have been purchased and used without further purification. The changes in sulfonation degree (X,) with acid by washing, the polymer was cut up and shredded in a blender, washed thoroughly free from acid, and then filtered and dried under vacuum at 6OoC. A yellow-brown product was obtained. Polymers with higher degree of sulfonation were difficult to wash due to their swelling in water. NeutralizationThe SPEK-C samples were neutralized with enough 1N NaOH aqueous solution. The neutralized polymers were filtered, washed several times with water, and then dried under vacuum to give SPEK-C-Na polymers. The cupric and ferric salt forms of SPEK-C were transferred by immersing the SPEK-C in acid form in 1N CuC12 and FeC13 aqueous solution for a week, respectively. De...

SYNOPSISPermeability coefficients of Hz, Oz, and Nz were measured under 10 atm at the temperature from ambient temperature up to 15OoC in a series of structurally different aromatic homoand copolyimides, which were prepared from 4,4'-oxydianiline (ODA) or 4,4'-methylene dianiline (MDA) with various aromatic dianhydrides. The study shows that the molecular structure of the polyimides strongly influences gas permeability and permselectivity. As a result, the permeability coefficients of the polyimide membranes for each gas vary by over two orders of magnitude. In general, among the polyimide membranes studied, the increase in permeability of polymers is accompanied by the decrease in permselectivity, and the MDA-based polyimide membranes have higher permeability than ODA-based ones. Among the polyimides prepared from bridged dianhydrides, the permeability coefficients to Hz, 0 2 , and Nz are progressively increased in the order BPDA < BTDA < ODPA -TDPA < DSDA < SiDA < GFDA, while Hz/Nz and Oz/Nz permselectivity coefficients are progressively decreased in the same order. The copolyimide membranes, which were prepared from 3,3',4,4'biphenyltetracarboxylic dianhydride (BPDA), bis(3,4-dicarboxyphenyl)dimethylsilane dianhydride (SiDA), and ODA, have favorable gas separation properties and are useful for Hz/N2 separation applications. 0