Showing papers by "Fenglin Yang published in 2006"

Electropolymerization and ion exchange properties of a polypyrrole film doped by para-toluene sulfonate

Abstract: Electropolymerization and ion exchange properties of the polypyrrole film doped by para-toluene sulfonate (PPy/pTS) were investigated in aqueous solutions. The film with a column-like surface morphology was galvanostatically synthesized at 3 mA/cm2 during 1800 s. Cyclic voltammetric measurements of the PPy/pTS film in sodium para-toluene sulfonate (NapTS), tetraethylammonium chloride ((C2H5)4NCl), and NaCl aqueous solutions showed a cation exchange property, an anion exchange property, and a combination of them, respectively. Moreover, the large ions could decrease the transport of the small ions coexisting in the same solution, and the redox processes were proved to be electrochemically irreversible and ion transport-limiting reactions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2518–2522, 2006

Comparisons of simultaneous phosphorus and nitrogen removal in sequencing batch membrane bioreactors

Abstract: Two SBMBRs run in AO and A2O mode were operated in parallel to compare their ability of simultaneous phosphorus and nitrogen removal The results showed that the removals of COD and ammonium nitrogen were averaged over 90% and 95%, respectively A2O MBR has the stronger anaerobic phosphorus release ability; its SPRR30 outdoes 475% compared to AO MBR SPUR30 of A2O MBR was lower which may attribute to the higher effluent TP content The ratio of DPAO was enhanced 57% compared to AO MBR And when nitrate as the only electron accepter, the phosphorus uptake mass with unit electron transfer was 30% higher in A2O MBR This two factors lead to the stronger denitrifying phosphorus removal ability of A2O MBR Furthermore, the membrane fouling was mitigated in A2O MBR though the aerobic time was half to that of AO MBR The membrane filter function made SBMBR's effluent free of the sludge settlement ability

[Effect of activated sludge properties on short-term membrane fouling in submerged membrane bioreactor based on statistical analysis].

Abstract: The influence of activated sludge properties on membrane fouling was investigated using statistical method The results show that extracelluler polymeric substances (EPS), soluble microbial products (SMP), suspended solids in the supernatant (SSs), dynamic viscosity (micro), relative hydrophobicity (RH) and Zeta potential all have a significant influence on membrane permeability during microfiltration of activated sludge wastewater The pearson's correlation coefficient (r(p)) for linear correlations between membrane fouling resistance and these sludge properties are 0898, 0712, 0810, 0691, 0837, -0881, respectively The statistical results also show that SMP, micro, SSs, Zeta potential, and RH are mostly determined by EPS, indicating that EPS is the main and essential factor affecting membrane fouling in activated sludge properties The pearson's correlation coefficient (r(p)) for linear correlations between total EPS and other sludge properties are 0682, 0633, 0783, -0953, 0877, respectively EPS should be controlled in the operation of membrane bioreactor to achieve a suitable permeation

Dynamic fugacity model for describing the fate of persistent organic pollutants in the river

Abstract: Dynamic model depending on temperature with fugacity approach is formulated which describes the fate of Persistent Organic Pollutants (POPs) in a river The fugacity capacity, the degradation rate and transfer coefficients of pollutants are depending on temperature in the model The model is illustrated by calculating the fate of gamma-HCH in Liao River The results show that from 273K to 298K, the fugacity capacities in air, water and sediment of gamma-HCH are respectively reduced in 84%, 897% and 897% However, in the same range of temperature, the degradation rate coefficients in air, water and sediment, and volatilization and diffusion rate coefficients of gamma-HCH are increased in 069, 220, 45, 79 and 16 times, respectively The calculated value agree well with the field observed value in the order of magnitude, which shows that the model is appropriate for simulating the fate of POPs in a long time

Experimental study on application of the boundary layer theory for determining steady aeration intensity of precoated dynamic membrane bioreactor

Abstract: The rheological behaviour of the low sludge concentration liquor in MBR was investigated and made a conclusion that this liquor approximated to the Newtonian fluid while the concentration of the sludge was less than 8000 mg x L(-1) Furthermore, when the laminar flow boundary layer thickness on the surface of flat membrane came up to the thickness of precoated dynamic membrane (PDM), the steady aeration intensity was calculated by using the boundary layer theory in the Newtonian hydrodynamics In order to ensure the stability of the pre-coated dynamic membrane bioreactor (PDMBR), oxygen supply aeration intensity was chosen to supply the best dissolved oxygen (3-5 mg x L(-1) in the initial stages and gradually increased to the steady aeration intensity The results indicated that this mode could enhance the stability of PDM In the experiment period (31 d), effluent COD was less than 1248 mg x L(-1) and its average removal rate was 9749%, NH4+ -N was less than 527 mg x L(-1) and its average removal rate was 7613%, while the operational pressure just increased to 27 kPa During the last period of the experiment, the stability of the PDMBR was studied when the aeration intensity was more than the steady aeration intensity and it was found that the precoated layer had been brushed off from the surface of common filter cloth, so this phenomenon proved that using the boundary layer theory could determine steady aeration intensity of PDMBR