The anaerobic simultaneous denitrification and methanogenesis (SMD)process has attracted considerable attention recently for the integrated removal of carbon and nitrogen.This review elucidated the mechanism of anaerobic SMD process and the involved materials and electron flow, and summarized the current research status on microbial communities and main influencing factors. Then the problems in current researches were discussed and direction for further study was proposed. More studies should be conducted to optimize the electron flow to both denitrification and methanogenesis, explore more suitable ratios of COD/NO^-_x-N and distribute the electron flow properly to produce energy-rich biogas. Additionally, the SMD process could be affected by sludge morphology, and anaerobic granular sludges or biofilms were found to be more suitable for SMD because it could relieve the inhibition of nitrogen oxides to methanogenesis.However, effects of mass transfer resistance and high suspended solids in the influent on this sludge system should be taken into consideration.

The thermodynamics of poisoning on F-T synthesis catalyst with hydrogen sulfide was determined according to some thermodynamic data and related software.Poisoning of Ru, Fe and Co may occur spontaneously under the condition of F-T synthesis reaction because of the low negative value of ΔG. Metal ruthenium in Ru-based F-T synthesis catalyst may be poisoned by H₂S even to 10^-8 level.There are many types of Fe and Co sulfides generated in the poisoning reactions.Their equilibrium constants are different for different reactions, and their concentrations of hydrogen sulfide required are also different.The concentration limitation of hydrogen sulfide is obtained.The results provide useful data and theoretical guidance to the development of sulfur tolerant F-T synthesis catalyst.

Some liquid alkanes bearing 5—24 carbon atoms were optimized in structure and the topological distance matrix was built with the space topological distance among atoms calculated by using density functional theory (DFT)at the B3LYP/6-31+G(d)level. A new group of topological index PX_m(m=1, 2, 3)was introduced based on the topological distance matrix, and branch vertex of atoms in a molecule was put forward by coloring atoms in the molecular graph with equilibrium electro-negativity. The topological model of quantitative relationship between thermal conductivity λ and PX_m of liquid alkanes was proposed by the multivariate linear regression (MLR).The results from the formula indicated that the deviation between calculated values and experimental data and that between predicted values and experimental data were small and within the experimental errors. To validate the estimation stability for internal samples and the predictive ability for external samples of the models, the method of leave-one-out (LOO)cross validation (CV)and external validation were performed. Compared with other results reported, the number of parameters in this model is much fewer and the calculation is much easier. It provides a new method for predicting the thermal conductivity of liquid alkanes.

The solubilities of taurine in different solvents, such as water and water + sodium sulfate solution, were measured by using laser monitoring technique at atmospheric pressure in the temperature range of 294.07—339.72 K. The equation for solubility of ideal solution, Apelblat equation, and λh equation were used to correlate the solubility of taurine in the aqueous solutions of inorganic salts. The models are in good agreement with experimental data. The correlation results of Apelblat equation are better than those of λh equation and the ideal solution equation. The result provides thermodynamic data for new synthesis method, engineering design and industry production of taurine.

In order to simulate the mold filling process of non-Newtonian fluid and calculate the velocity of free surface without Ghost method, a three dimensional mathematical model for incompressible gas-liquid two-phase flow coupled with Navier-Stokes equations is established.The governing equations are solved by the finite volume method on a non-staggered grid and the interpolation technique on the collocated grid is used for solving pressure-velocity decoupling problem.The melt interface evolution versus time is captured by the Level Set method and the physical quantities of the flow field, such as velocity, pressure, shear rate and temperature at each time step, are obtained with corresponding analysis.The effect of injection parameters, such as injection rate and inlet temperature, on the filling process and thickness of solidified layer are studied.The simulation result is in good agreement with the experimental data.Numerical results show that the three dimensional mathematical model for the gas-liquid two-phase flow can describe the filling process of polymer melt more precisely, and larger injection rate and higher inlet temperature lead to thinner solidified layer.

Flow field in a stirred tank was divided into chaotic and isolated mixing zones.To enhance mixing efficiency and reduce energy consumption of fluid mixing, it was an alternative way to control the flow field structure.With the aid of image processing software, fractal dimension of air-water mixing system was investigated in the eccentric air-jet stirred tank with double mechanical impeller.The results showed that the fractal dimension of flow structure was affected by the mechanical agitation speed and air flow rate, and it could be controlled by eccentric jet and the chaotic mixing performance could be enhanced.Fluid mixing performance could be improved by controlling coherent structure with increased agitation speed.

In order to investigate the structure parameters effect on wet gas performance of throttling device, a long slot internal Venturi throttling device with the fluid restricted to the periphery of the pipe which is relative to the traditional Venturi is designed, and the wet gas metering characteristic is studied based on experiment, the hydraulic diameter and the liquid dispersion effects on the over-reading are analyzed relatively.The experimental study and theoretical analysis show that the friction pressure loss due to the acceleration effect of gas to liquid is a major reason behind the over-reading, under the same flow conditions, the over-reading tends to increase with smaller hydraulic diameter of the throttling device and more homogeneous mixed gas and liquid.The result analyze the geometry structure parameters effect on wet gas performance of throttling device in detail and supply important design values for optimizing the structure of the wet gas flow meter based on the throttling devices that restrict the fluid to the periphery of the pipe.

This paper aims at investigating the effect of the rough gas diffusion layer (GDL)on liquid water transport behaviors in gas channels (GCs)employing the volume of fluid (VOF)in the commercial CFD package, FLUENT 6.3.26.It is found that the liquid water on the hydrophilic rough GDL tends to spread along the corner and presents as a water film with the concave surface, with many holes in the GDL covered by the liquid water, whereas the liquid water on hydrophobic rough GDL presents as the water droplet which covers less holes and can be easily drained out of the GC, indicating that a hydrophobic GDL surface is desirable in PEMFCs.Simulations then focus on investigating the effects of the rough hydrophobic GDL on the liquid water transport behaviors in GCs.The simulation results show that the droplet is inclined to form the Cassie droplet on the rough GDL surface.The water droplet is easier to be drained out of the GC with the rough GDL surface.The water coverage ratio for the cases with the rough GDL surfaces is lower than that with the smooth GDL surface.The higher the roughness is, the less the GDL surface is covered by water.The pressure drop in the GCs increases with the increase of GDL surface roughness.

The conventional pulsating heat pipe (PHP）does not work or work at low efficiency at the inclination angle of 0° (horizontal PHP), which limits its application greatly.In this study, 4 PHPs with turn number of 3 are fabricated and tested.They are filled with deionized water with a filling factor of 50%. Three PHPs are inserted with nickel-chrome wires in the tubes, among which one PHP has a wire with a diameter of 0.7 mm, another with 0.5 mm, and the third has two wires of 0.35 mm.The length of wires is the same as that of PHPs.It is found that PHPs with wires are less sensitive to the inclination angle, easier to start at horizontal position, and operate more stably.Thus the heat transfer performance of horizontal PHP is improved greatly.The position of wire in the copper tube is also investigated, which may influence the mode of heat transfer.

Numerical simulation of micromixing in Beckmann rearrangement of cyclohexanone oxime was carried out with engulfment-deformation-diffusion model by taking into account the reaction kinetics.The effects of key industrial parameters on the reaction and mass transfer were investigated.The results showed that Beckmann rearrangement was micromixing controlled and the local molar ratio of acid to oxime was lower than the value in macro-scale process, which deviated from the normal reaction condition and explained the difference between the theoretical minimum acid amount and industrial value.Higher temperature leaded to poor quality of product though it was in favor of molecular diffusion.Decrease in the diameter of mixer resulted in better micromixing to some extent, which may improve mass transfer and the quality of caprolactam.

The flow field, pressure filed and friction characteristics of laminar flow in in-line arranged micro-cylinder groups were numerically investigated using de-ionized water as working fluid at low Reynolds numbers.The friction factors in the micro-cylinder group (cylinder diameter D =0.5 mm, cylinder height H =1.00, 0.75, 0.50 and 0.25mm)were measured.It was found that the friction factor decreased with the increase of micro-cylinder height due to the end-wall effect, and the correlations available could not predict the friction characteristics very well.A 3-D model was employed to simulate the vortex distribution in the in-line micro-cylinder groups with different geometrical parameters, including the diameter (0.5 mm)and height (0.25, 0.50, 0.75, and 1.00 mm)of micro-cylinder, pitch (0.75, 1.00, and 1.25 mm), and number of rows (3, 5, 7, 9)and columns (5, 10, 15, 20)of micro-cylinder.It was found that the vortex number increased with the pitch ratio, so that the friction factor increased.The friction factor for the in-line arranged micro-cylinder group decreased with the increase of the cylinder height and the decrease of the column number, but the influence of the row number on the friction factor was negligible.A new correlation was obtained to predict the friction factor of laminar flow in the in-line arranged micro-cylinder group and the deviation of predictions from experimental results is 10%—25% at 40<Re<150.

The thermal resistances of micro/mini circular shaped pin-fin heat sinks are from the heat conduction through the sink bottom layer and the pin fins, the heat convection of cooling liquid between the sink layer and the pin fins, and the enthalpy change of the cooling liquid.The heat transfer characteristics through the bank of circular shaped micro/mini pin-fin heat sinks are investigated experimentally with deionized water as cooling fluid and by heating at constant heat flux over Reynolds numbers ranging from 100 to 1000, with the heating power in the range of 50—300 W.It is found that the convective heat transfer coefficient increases with the volume flow rate of cooling fluid and the Nusselt number increases with the increase of the Reynolds number and the heating power.As the volume flow rate of fluid increases, the total thermal resistance of the heat sinks decreases exponentially and gradually reaches a constant value.The experimental results show that the height of micro/mini pin fins of the heat sinks has little effect on the convective heat transfer and there is no difference in the total thermal resistance and different heights of micro/mini pin fins as the volume flow rate changes.The experimental results are compared with some relations in literature, and the Zukauskas relation is appropriate to predict the Nusselt number.

The bubble dynamics and temperature response curve of a microheater in Al₂O₃-H₂O nanofluids were experimentally investigated.The bubble dynamics and temperature variation in water and nanofluids with different concentrations of Al₂O₃-H₂O ［0.1% and 0.2%（mass）］are compared.Under pulse heating, the temperature response curves are different in nanofluids with different concentrations, and the bubble dynamics on the microheater are also different.Results show that the heat transfer coefficient of the microheater is significantly higher in Al₂O₃-H₂O nanofluids than in pure water.The nanoparticle concentration has important effects on the bubble dynamics on the microheater and the heat transfer coefficient.According to the experimental results and the influence of nanoparticles on the gas-liquid-solid contact line, the phenomenon that bubbles detach from the microheater more easily in nanofluids than in pure water is analyzed and the heat transfer enhancement in the nanofluids in terms of a model considering the effect of nanoparticle on bubbles is explained.

The instantaneous flow behaviors, i.e., the average velocity, turbulent kinetic energy and turbulent dissipation of diluted pulp at different planes, were simulated using the granular Eulerian multiphase model that combines the standard k-εturbulence model with sliding-grid algorithm (SG)technique in FLUENT.The characteristics of pulp flow in the dilution-zone and S-type dischargers with different structures, type-Ⅰ,Ⅱ and Ⅲ, at the bottom of high consistency bleaching tower were analyzed.To validate the model, the image separation and filtration for fiber and water tracer were performed in the particle image velocity (PIV)system and the velocities of fiber and water were measured.The comparison between the experimental data measured by PIV system and the CFD (computational fluid dynamics)simulations indicated that the Eulerian and standard k-ε turbulence models gave a better description for the flow patterns in the dilution-zone of the tower, which provide a good guidance for further study on the discharger.Among the dischargers, the one with type-Ⅰ structure (the ellipse section of 38 mm×50 mm)provides uniform falling of high consistency pulp and rapid discharging for diluted pulp in the dilution zone, in which the turbulent kinetic energy and turbulent dissipation of diluted pulp are greater than those in type-Ⅱ and Ⅲ dischargers, so it is more appropriate for pulp discharging at the bottom of the tower.

Understanding the combustion process of a single droplet is helpful to improve the design for internal combustion engine.The volume of fluid (VOF)formulation is applied to model the combustion process of an n-decane droplet in room and high temperature (300 K, 633 K, and 1000 K)convective air streams.The flow fields for both phases are obtained with the axisymmetrical model.The chemical reaction is modeled with the one-step finite-rate mechanism and the physical properties of gas mixture are species and temperature dependent except for surface tension.A mass transfer model applicable to the VOF calculations due to vaporization of the liquid phase is developed in consideration with the fluctuation of the liquid surface.The model is validated by checking the burning rate constants, which accord well with the experimental data in literature.The Stefan flow is also clearly captured by the calculations.The results verify the feasibility of the VOF CFD formulation as well as the mass transfer model due to vaporization.

 Mixed oxides TiO₂-M_xO_y(M=Fe, Si, Al, Zr）prepared by co-precipitation method were impregnated in aqueous solutions of sulfuric acid to form doped solid acid samples.These catalysts were characterized by XRD, FTIR, NH₃-TPD and H₂-TPR.Their catalytic activity was tested in the transesterification reaction between soybean and methanol.The results showed that the addition of second oxide into TiO₂/SO₄^{2 -} could improve the catalytic activity and inhibit the formation of TiOSO₄ in impregnation process except Al.The restraint effect was the strongest for silica.The doping of Si, Zr and Fe oxides could enhance surface acidity of catalysts while the addition of Al even made the acidity lower.The decrease of reduction temperature by H₂ was larger for Fe-involving sample than for Si-involving one.The Fe doped catalyst was found to be readily reusable in activity upon reuse for three times with subtle decrease conversion.

Due to the large difference of pyrolysis performance of n-paraffin,i-paraffin, 5-cyclanes and 6-cyclanes in Daqing heavy naphtha, it may be necessary to modify the 8 lumped component kinetic model. A 10 lumped component kinetic model with 4 stock lumped component is proposed for the pyrolysis of Daqing heavy naphtha.The kinetic parameters in the new model can be determined as follows: using the conception of shallow pyrolysis, the reaction rate constants are estimated by combining lay-method and stepwise-method, including their activation energy and pre-exponential factors.The better agreement between experimental and calculated data shows that this model is of predicting ability with better accuracy in wider range of feedstocks.

The non-isothermal crystallization behavior of pure low-density polyethylene（LDPE） coating and LDPE/n-SiO₂ composite coating prepared by flame spraying was investigated by differential scanning calorimetry (DSC)at various cooling rates.The Avrami analysis modified by Jeziorny and Mo models could describe the non-isothermal crystallization process of LDPE and LDPE/n-SiO₂ composite coating successfully.The values of Z_c and n increased with increasing cooling rate.The values of Z_c and n of composite coatings containing nano-SiO₂ were higher than those of pure LDPE coating.The half-time values of crystallization showed that the crystallization rate of LDPE/n-SiO₂ composite coating was faster than that of pure LDPE coating at a given cooling rate.Furthermore, it was found that nano-SiO₂ in LDPE coating acted as an effective nucleation agent.

The CFD method was employed to simulate the back mixing of particles in a guide vane separator based on the Reynolds stress model (RSM)and the discrete particle model (DPM).The results show that the back mixing of particles is serious at the bottom of the dust discharge, which contains 38% of the total mass of particles.The mass flow rate of back mixing of particles in the dust discharge is 47% of the total mass flow rate.The back mixing of particles decreases sharply at 1.1D above the dust discharge, where D is the diameter of cyclone.The particle back mixing that affects cyclone efficiency is only 2.5% of total inlet mass flow rate of particles.The particles smaller than 13 μm affect the total efficiency.Smaller particles result in more significant influence.

Amino acid ionic liquid adsorbs CO₂ rapidly and N-methyldiethanolamine (MDEA)has high CO₂ absorption load.Therefore, tetramethylammonium glycinate (［N₁₁₁₁］［Gly］)was synthesized and mixed with N-methyldiethanolamine (MDEA)aqueous solutions to form complex absorbents.The CO₂ absorption capabilities of the complex absorbents were measured with the constant volume method.The results indicated that the absorption capacity per volume increased with CO₂ pressure and concentration of ［N₁₁₁₁］［Gly］, while the mole absorptivity at absorption equilibrium was independent of ［N₁₁₁₁］［Gly］ concentration under different CO₂ pressures.The absorption of CO₂ was also performed in a countercurrent falling film column, showing that the concentration of ［N₁₁₁₁］［Gly］

The process of adiabatic evaporation in a free falling liquid column was investigated theoretically and experimentally.A model for the vacuum evaporation on the surface of vapor-liquid flow was built with an adiabatic evaporation experiment at temperature of 20—55℃, evaporation pressure of 2—15 kPa, and Reynolds number 1500—5000.A criterion equation for the heat transfer in the system was obtained.The analysis result showed that excessive superheat (ΔT_sup>11℃)would cause entrainment to decrease the separation efficiency.The evaporation efficiency could reach 63.2%—6.5% with the length-diameter ratio from 43.5 to 87.Higher length-diameter ratio caused a breakup of the liquid column, and the enhancement of the evaporation efficiency was not significant.Based on the evaporation model, the evaporation process of free falling liquid column could be analyzed effectively with process simulation, which provides a reference for its industrial design.

Hyperbranched solid amine was prepared with KIT-6 type mesoporous silica, which was modified by tetraethylenepentamine (TEPA)using post-synthetic impregnation.The adsorption behavior of CO₂ on KIT-6(TEPA)was investigated using an adsorption column.The adsorption capacity of KIT-6(TEPA)for CO₂ increased with temperature at 303—343 K, but decreased as temperature increased at 343—353 K.The maximum adsorption capacity is 3.1 mmol·g^-1 at 343 K. The mechanism of CO₂ adsorption on KIT-6(TEPA)is mainly chemical adsorption.The adsorption capacity is improved by moisture.It reaches 3.5 mmol·g^-1 in the presence of 12% water.The adsorption capacity is maintained after 20 cycles of adsorption and regeneration, indicating that the KIT-6(TEPA)is stable in a prolonged cyclic operation.Experimental breakthrough curves are fitted with a deactivation model, giving good agreement with experimental data.

Traditional multivariate statistical fault detection methods are designed for single operating conditions and may produce erroneous conclusions if used for multi-mode process monitoring.A novel multi-mode process monitoring approach based on PCA mixture model is proposed in this paper.First, the PCA technique is used to reduce the dimension of original variables and to guarantee the nonsingular covariance matrix.In order to overcome the limitations of EM (expectation-maximization), the BYY(Bayes Ying-Yang)scale-incremental EM algorithm is then adopted to automatically optimize the number of mixture components.With the obtained PCA mixture model, a novel process monitoring scheme is derived for fault detection of multi-mode processes.The validity and effectiveness of the proposed monitoring approach are illustrated by numerical example and the TE process.The results show that the proposed algorithm can achieve good parameter estimation of the mixture model with correct model selection.Therefore, it can achieve accurate and early detection of various types of faults in multi-mode processes.

Based on periodical change of generation, storage and consumption of byproduct gases, the features of supply-demand change of steam and electricity for each period, aimed at minimizing energy consumption and optimal benefit of cost-effective, a multi-period coupling model of surplus byproduct gas, steam and electricity in iron and steel works was formulated.The model is implemented by ILOG Cplex and the optimal distribution scheme of byproduct gases, MP steam, LP steam and electricity is obtained.The results indicate: the model can distribute the energy medium reasonably, safely and efficiently, such as surplus byproduct gases, steam and electricity, for improving energy utilization efficiency and decreasing the product cost.

Aiming at the real-time fault diagnosis and optimized monitoring requirements of the polymerizer of PVC production process, a real-time polymerizer fault diagnosis strategy was proposed based on rough set (RS)theory with improved discernibility matrix and back propagation (BP)neural network.The improved discernibility matrix was adopted to reduce the attributes of rough set in order to reduce the input dimensionality of fault characteristics effectively.Fuzzy C-means clustering algorithm was used to discrete the continuous variables of the decision table.Then Levenberg-Marquardt BP neural network was trained according to the reduced decision table in order to decide the configuration parameters of the proposed polymerizer fault diagnosis model.Thus the classification of the fault patterns was to realize the nonlinear mapping from fault symptom set to polymerizer fault set according to a set of symptoms.Polymerizer fault diagnosis simulation experiments were performed by combining with industry history data.Simulation results showed the effectiveness of the proposed fault diagnosis method based on rough set and BP neural network.

The behavior of the start up process of dry gas seal (DGS), which has great significance in engineering was studied based on the steady state analysis.With the hypothesis of critical gas film thickness, a criterion for expressing the opening behavior of DGS, namely the critical opening rotational speed (CORS), was proposed.Changes of the sealing parameters in the opening process, such as gas film thickness, opening force, film stiffness, leakage rate, frictional torque and frictional power consumption were investigated.Influences of operating and structural parameters on the opening behavior of DGS were analyzed.The results indicated that the sealing parameters changed remarkably near the opening critical film thickness in the start up process.CORS was greatly affected by sealing operating pressure, but it could be changed through structural parameter adjustment.By providing a method for analyzing the opening behavior of DGS, this work is helpful for the structural design of seal end faces and the guidance of the opening or closing operation.

The electrochemical corrosion behavior of X80 pipeline steel was investigated in northern Shaanxi saline soil saturated with water by using electrochemical measurement, scanning electron microscopy (SEM) and energy dispersive spectrum (EDS)analysis.The results showed that the corrosion tendency and corrosion rate of X80 steel significantly increased，pitting depth and area increased continuously, which was induced by change of corrosion morphology from uniform corrosion to localized corrosion. Corrosion mechanism was oxygen-concentration corrosion cell and localized corrosion autocatalysis effect, and corrosion rate was controlled by oxygen diffusion process.The characteristics of double capacitive reactance arcs and Warburg impedance could be found in electrochemical impedance spectra, the resistance of charge transfer and diffusion mass transfer in pitting became bigger and bigger, and binding layer resistance significantly decreased.It was dependent on the integrity and compactness of corrosion product films.The corrosion product was basically a mixture of iron oxides, iron sulfides and salts in soil.

A comprehensive evaluation method of thermal, environmental and economic (TEE)performance for an energy system with multi-products was proposed.In this approach, environmental impact of the energy system was quantified in form of exergy cost of the virtual emission treatment unit, which was a virtual unit and had no effect on energy system itself.Then, exergy cost of virtual emission treatment unit was distributed to each unit of energy system to reflect the difference of influences of environmental concern on different products, according to the proportion of emission produced by each unit in the total emission of energy system.And then, in order to introduce application of this comprehensive evaluation approach, a coal gasification Fischer-Tropsch synthesis and electricity co-production system was analyzed.Compared with that by the conventional technical and economic approach based on the first law of thermodynamics, the proposed approach could be used to calculate the energy consumptions and costs of different products, and analyze the benefit sources of comprehensive TEE performance of the co-production system.Compared with that by the conventional exergy-economic analysis method, the proposed approach could reflect the difference of influences of environmental concern on different products, and the comprehensive TEE performance potential of the co-production system.

Based on the reservoir fluid analysis for Zhongyi block of Shengli Oilfield, the effect of different carbon sources, including glucose, corn starch hydrolysates, wheat starch and sodium carboxymethyl cellulose, on activating indigenous microorganisms in the water from District 7N11 Wells was studied at high temperature (65℃)and high pressure (10 MPa)of reservoir conditions.The results showed that the carbon source could influence significantly growth cycle, community structures and metabolic activities, and the overall effect of corn starch hydrolyzates was better than others.The physical simulation experiments were carried out using the corn starch hydrolysates activator.The results indicated that oil production increased significantly, and the raise of oil recovery rate could reach 4.8% after 30 days’ activation.

Study on simultaneous biological removal of iron, manganese and ammonia in a simulated groundwater involving iron and manganese and pollutant ammonia-nitrogen was carried out in biological aerated filter with dual layer ceramic material.The influence of the flow rate on the removal of iron, manganese and ammonia and the change of their concentrations along the depth of the filter were measured.The results show that if flow rates increase suddenly only after 2—3 d culture for the filter, the concentrations of iron, manganese and ammonia at exit of the filter can be lower than that of the National Drinking Water Standard.It is found that when flow rates of the simulated contaminated groundwater increase from 0.74 m·h^-1 to 3.0 m·h^-1，the filter depth to meet the National Drinking Water Standard is only 0.75 m for concentrations of iron and ammonia in water, but it increases from 0.75 m to 1.60 m for the concentration of manganese.

Removal behaviors of biological phosphorus (P)and nitrogen (N)in real domestic sewage with low C/N ratio were studied in a laboratory-scaled anaerobic/anoxic/oxic (A²/O)-biological aerated filter（BAF） combined system.In order to improve removal efficiency of the combined system, short sludge retention time （SRT）was applied in A²/O, which was favorable for P removal and denitrification, while longer SRT used in biological aerated filter (BAF), which was favorable for polyphosphate-accumulating organisms（PAOs）and for nitrification to remove the ammonium nitrogen.The recycled liquid involving nitrate from BAF provided electron acceptor enough for the anoxic-zones of A²/O and necessary condition for de-phosphorus by denitrifying.Experimental results showed that with these operations in this combined system COD, N and P could be removed simultaneously.At conditions of HRT 7.5 h, SRT 15 d, the recycling ratio of liquid 400%, the concentrations of COD, ammonium nitrogen, total nitrogen (TN)and total phosphorus（TP）could be reduced from at average values of 376,67.9,72.9 and 6.1 mg·L^-1 in the raw waste water to 42,0.86,9.6 and 0.1 mg·L^-1 in the effluent, respectively.The rate of phosphorus removal by denitrifying were 1.49 and 1.64 g TP·（

Recently, water source pollution has become serious.Many kinds of organics have been detected in drinking water with higher concentration, and the water quality safety reduced greatly.In order to enhance the removal rate of dissolved organics in water sources, the pilot experiment containing the conventional treatment as well as the ozone and biological activated carbon filter (BACF)was reported in this paper.Taking the raw water from the Huangpu River as the sample, the characteristics and constituents of dissolved organics in the process were investigated.Results showed that the majority of organics were those with low molecular weight (MW)in the raw water, the percentage of low MW (<3000)organics reached 55.9%.In the combined treatment process, the conventional unit removed the organics with high MW (>10000)effectively, and the removal rate was up to 61.1%, while only 7.9% removal rate for low MW(<3000).The function of ozone oxidation was to modify the refractory organics into low MW organics to enhance the performance of BACF, and the removal rate of organics with MW<3000 reached 28.9% via BACF. The majority of trace organics were removed by the coordination of ozone and BACF, the types of trace organics reduced from 77 to 30, and the concentration decreased 67.4%.The trihalomethane formation potential(THMFP)was removed effectively, and the removal rate reached 73.7%.

In order to eliminate the bacteria in inoculating sludge, which consume hydrogen, and to speed start-up as well as to rise efficiency of hydrogen production, effect of pretreatment temperatures of 65, 80, 95, 110 and 121℃ for 30 min on hydrogen production from glucose was investigated in a batch cultures, with anaerobic granular sludge come from workshop treating wastewater of beer factory.The results come from fermentation showed that the amount of hydrogen produced, at conditions of initial pH=7.0, glucose concentration 10000 mg·L^-1 and amount of inoculating sludge 2 g MLVSS·L^-1, was less for untreated sludge than pretreated one.For anaerobic granular sludge treated at 95℃, the maximum accumulative hydrogen production in 120 h, 133.47 ml, was obtained, and equal to hydrogen yields of 1.40 mol·mol^-1 glucose, and specific hydrogen production of 15.93 mmol H₂·(g MLVSS)^-1. Although hydrogen production was varied for different pretreatment temperature, butyrate and acetate were dominated in soluble liquid products for all glucose fermentation tests, and their account was about 80% of the total volatile fatty acids and ethanol.

The arsenic contained reagent was added to the cement raw meal to produce clinkers.Leaching test, sequential extraction procedures and SEM-EDS analysis were employed to evaluate the migration characteristics and the mineralogy change of arsenic during the sintering and hydration process.The results show the retention rate of arsenic during the sintering process is higher than 60%, while the content of arsenic in C₃S, the major mineral phase in clinker was only 0.4%—0.6%.The SEM-EDS analysis of clinkers show arsenic has a strong dependent relationship with Fe.XRD analysis of clinkers showed the complex compounds with the chemical form of AsCr_xFe_y or AsCr_xV_y were generated during the clinkerisation process, which were more stable under the high pH environment during the hydration process.Leaching test shows that the leaching concentration of arsenic has no considered increase compared to the blank samples.The BCR sequential extraction procedure analysis of the clinkers showed that the exchangeable water and acid-soluble phase of arsenic was only account for 0.01% of the total, while the easily reduced phase of arsenic had the biggest ratio, up to 39.35%.Finally, the residue fraction of arsenic accounts for 25.41% of the total, which show that the co-processing of high arsenic contained waste in the cement kiln has the potential environmental impact.

Pyrolysis of printed circuit boards （PCB）made with anti-Br type epoxy resin were investigated in nitrogen.The effect of temperature(300—900℃), heating rate(10—40℃·min^-1)and holding time（30—60 min）on the yield of pyrolysis products was studied.Pyrolysis oil and residue were analyzed by infrared spectra, gas chromatography-mass spectroscopy（GC/MS）, elementary analysis and scanning electron microscope.Results show that solid residues account for about 61.74%—71.08%

Kinetics of perfluorooctane sulfonate and perfluorooctanoate degradation by ultrasound irradiation

2011, 62(3):  829-835. 

Abstract ( 1181 )   PDF (435KB) ( 772 )  

Related Articles | Metrics

The feasibility of perfluorooctane sulfonate (PFOS)and perfluorooctanoate (PFOA)degradation by ultrasound irradiation was studied, and the effects of ultrasonic frequency, initial PFOS and PFOA concentration, initial pH, sorts of saturated gas, various organic and inorganic compounds coexisting with PFOS and PFOA, on the sonochemical decomposition rates were evaluated.The experimental results showed that PFOS and PFOA degradation followed the pseudo-first order kinetics in range of initial concentration 10—3650 μg·L^-1.Complete sonolysis could be reached over a range of frequencies from 200 to 610 kHz and at 100 μg·L^-1 of initial concentration.However, the degradation rate constants has an apparent maximum at 358 kHz, and at this frequency, the influences of initial concentration, initial pH and sorts of saturated gas on PFOS and PFOA degradation are great.Volatile aliphatic and aromatic organic components have effect on the degradation, while inorganic compound NaClO₄ could accelerate the degradation rates.