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A two-year field experiment was carried out in a Cu-Zn-Cd-Pb-contaminated field with

An aqueous blend of 1-butyl-3-methylimidazolium tetrafluoroburate ([Bmim][BF4]) + piperazine (PZ) was proposed in this work. Density and viscosity of the aqueous blend were measured and correlated at (293.15–333.15) K and atmospheric pressure. Performance of CO2 absorption into the aqueous blend was evaluated. It turned out that PZ mass fraction slightly influenced on the density and viscosity, being linear with them. Temperature significantly affected the viscosity. The calculated values are in good agreement with the experimental values. The main factors affecting the CO2 loading of the aqueous blend were PZ mass fraction, gas CO2 mole fraction and temperature. The average absorption rate of the aqueous blend was the biggest in the aqueous [Bmim][BF4], PZ and [Bmim][BF4]/PZ, and much higher than that of the former two. The performance of the aqueous [Bmim][BF4]/PZ with low PZ mass fraction was better than that with high PZ mass fraction. It demonstrated that the aqueous blend of [Bmim][BF4]/PZ is a good absorbent of CO2.

Aqueous amines are the most commonly used CO2 absorbents. But they have many shortcomings such as volatile loss, thermal degradation, corrosivity and wetting on polymer membranes. Ionic liquids can avoid the shortcomings and show unique performances. Diethanolamine glycinate, a ionic liquid made of hydroxyl ammonium amino acid salt, was developed to capture CO2 for greenhouse gas emission reduction. In order to evaluate the ionic liquid performance, membrane flux, gas outlet CO2 concentration, appropriate ionic liquid concentration and operational parameters were investigated by membrane gas absorption. Membrane liquid desorption was tested for regeneration of diethanolamine glycinate. Performance of diethanolamine glycinate ionic liquid was also compared with that of glycinate and diethanolamine. Results show that diethanolamine glycinate ionic liquid had a higher membrane flux, e.g., 6.6 × 10−4 mol m−2 s−1, and a lower gas outlet CO2 concentration (yout/yin, e.g., 0.07) in membrane gas absorption. Changes in operational conditions, e.g., gas and liquid flowrates increase, changed the membrane flux of membrane gas absorption, which increased only by 23.9%. Dominant factors affecting the membrane flux were the gas CO2 mole fraction, increasing the flux by 80.0%, and the ionic liquid concentration, increasing the flux more than 2 times. The ionic liquid was much more easily regenerated and possessed large regeneration efficiency and average regeneration velocity. Diethanolamine glycinate ionic liquid is thus an efficient and promising CO2 absorbent.

A differential probe-fed liquid crystal (LC)-based frequency tunable circular-ring patch antenna is presented. Besides, cavity model is extended to analyze the LC-based antenna for the differential operation. According to the cavity model, the permittivity and loss tangent of the LC are extracted from the measured differential reflection coefficients. Acceptable agreements among the measurement, simulation, and calculation for differential impedances, reflection coefficients, and radiation patterns are obtained and also validate the extraction method and model. More importantly, the extended cavity model can provide a deep physical insight into the LC-based antenna.

An amino acid-functionalized protic ionic liquid (IL), monoethanolamine glycinate ([MEA][GLY]), was used as a CO2 absorbent. Its performance was evaluated by a membrane gas absorption (MGA) process. Various effect factors including both absorbent aspect and operational parameters were investigated in MGA for CO2 capture. Performance of [MEA][GLY] IL was also compared with that of an amino acid salt and an amine. Liquid CO2 loading of the functional protic IL was the largest in three absorbents, presenting an order of [MEA][GLY]>PGLY>MEA. [MEA][GLY] IL obtained a high membrane flux and a low gas outlet CO2 concentration in MGA process. It could reach 3.25 × 10−4 mol m−2 s−1 of membrane flux. The IL could achieve higher initial and instantaneous membrane fluxes and the maximal membrane flux with a range of optimum concentration of 3.5–4.5 mol L−1. Change of operational parameters, especially gas CO2 mole fraction, can significantly affect and enhance the membrane flux of MGA on a limited scale. [MEA][GLY] IL is a more environmentally-friendly and efficient CO2 absorbent.

The oxidation of cyclohexane to cyclohexanone, cyclohexanol, and adipic acid, which are important raw materials in nylon industry, is still being challenged in conventional processes. Microreactors and gold catalysts are both widely researched areas at present, so an effort was made to make use of collaborative properties of both. In this study, stainless steel microcapillary coated with a supported nano-gold catalyst was prepared, characterized, and employed for the oxidation of cyclohexane. Under the temperature of 180 °C, residence time of 4 min, reaction pressure of 3 MPa and molar ratio of oxygen to cyclohexane of 0.3:1, the conversion of cyclohexane was 2.09%, with the selectivity of cyclohexanol, 29.37%; cyclohexanone, 39.89%; cyclohexyl hydroperoxide, 2.46%; and adipic acid, 18.87%. Experiments showed that stainless steel microcapillary coated with a supported nano-gold catalyst in cyclohexane oxidation is a feasible process; the reaction time is very short, and the process operation runs safely.

Extreme learning machine (ELM) has been applied in near infrared spectral analysis as a novel chemometric method which attracted the attentions of various researchers. However, the dimension of spectral data is usually very high while more hidden nodes should be incorporated in original ELM model for spectral data. Thus the problems of high dimension and high colinearity in the output matrix of hidden layer of ELM model are inevitable. The solutions obtained with the existing Moore-Penrose generalized inverse can be ill-conditional due to the high dimension and high colinearity in the hidden layer output matrix. This study aims to propose an improved ELM to build spectral regression model. The proposed method firstly uses extreme learning machine (ELM) to relate spectral variables to response variable; then the output of each hidden node are treated as new variables; VIP-SPLS ( improved stacked PLS based on variable importance in the projection) proposed by our group recently is used to build the regression model between those new variables and the response variable. In this paper, this method is called as improved ELM (iELM). VIP-SPLS model can fully utilize the output information of each hidden node and can effectively solve the problems of high dimension and high colineariy. At the same time, VIP-SPLS also has the advantage of model ensemble. Therefore, the performance of ELM model used for spectral data can be improved if the VIP-SPLS is incorporated to relate the hidden layer output matrix and response variable. The proposed method is applied to a commonly used benchmark NIR spectral data for evaluation. The results demonstrate that the precision improvement of iELM model is 29.06% to PLS model and 27.47% to original ELM model, respectively.

The size distribution of particulate was analyzed by the FA-3 9 stage sampler in Northern-suburb of Nanjing from January to November in 2014. First, the monitoring result from FA-3 was compared with the results of the same period obtained from a medium flow size grading sampler (KC-120H) and online monitoring instrument of the Environmental Protection Agency. The data correlation coefficients were all greater than 0.95. The fine particle concentration from FA-3 was lower by 13.9% and 16.6%, while PM

A blended solution as a CO 2 capture agent was composed of potassium citrate (PC) and 2-amino-2-methyl-1-propanol (AMP). Density, viscosity and surface tension of the blended solution were determined in the range of (293.15–323.15) K, respectively. Physical characteristics of the blended solution were discussed and compared with that of single component and other blended systems. Correlations were developed to predict the three physical properties of the blended solution. Results indicate that when overall concentration of the blended solution increases, quality of the solution increases to result in the increase of values of the three physical properties. The three physical properties decrease as both temperature and AMP molar ratio in the blended solution increase. Prediction values from the correlations and experimental values fit reasonably well. The correlations for the three physical properties can give extra data of the system of (PC + AMP) solution.

A protic ionic liquid (IL), diethanolamine glycinate ([DEA][GLY]), was synthesized and characterized. Its physical properties, including density, viscosity, surface tension, conductivity and refractive index, were determined. CO2 solubility in [DEA][GLY] IL was also measured. Performances of [DEA][GLY] IL in absorbing CO2 in a bubble column were evaluated. The synthesized [DEA][GLY] is an amino acid-functionalized IL with dual groups of ammonium and amino. There was a good CO2 solubility in the IL at room temperature and atmospheric pressure, much better than the traditional ILs. Pure and aqueous [DEA][GLY] ILs are good CO2 absorbents. CO2 partial pressure and IL concentration have a significant impact on their absorption performance. [DEA][GLY] had an obvious advantage over the conventional ILs for CO2 absorption.

A new amino acid-functionalized ionic liquid (IL), monoethanolamine glycinate ([MEA][GLY]), was synthesized and characterized. Its physical properties were measured, including density, viscosity, surface tension, conductivity, and refractive index. The solubility of CO2 in [MEA][GLY] was determined. The ability of [MEA][GLY] to absorb CO2 was evaluated. [MEA][GLY] with an active amino group exhibits representative physical properties of a functionalized IL. The solubility of CO2 in the IL is more than 0.5 mol CO2/mol IL at room temperature and atmospheric pressure. The [MEA][GLY] and aqueous [MEA][GLY] ILs are thus good absorbents of CO2. The CO2 partial pressure and [MEA][GLY] concentration have a significant impact on their absorption.

A new ionic liquid, tris(monoethanolamine) citrate (TMEAC), was synthesized and characterized by FT-IR spectrometry and 1H NMR. Densities and viscosities of aqueous TMEAC mixtures were determined at 293.15–323.15 K and atmospheric pressure. The thermal expansion coefficient α, excess molar volume $$ V_{\text{m}}^{\text{E}} $$ , and excess logarithm of viscosity (ln η)E were calculated to evaluate the properties of the aqueous TMEAC ionic liquid. Correlation equations were fitted using these data for the calculation of density and viscosity. The results show that the density increases almost linearly as the mass fraction of TMEAC increases. The mass fraction of TMEAC has little influence on the density at low mass fraction. The viscosity changes significantly and sharply increases at mass fractions larger than 60 %. Both density and viscosity decrease as the temperature increases. The thermal expansion coefficient initially decreases and then increases with increase of the mass fraction of TMEAC. The change of the excess molar volume presents a W-shape. The excess logarithm of viscosity shows a variation where the value initially rises but subsequently drops. Values calculated from the correlation equations are in good agreement with the experimental values. The correlation equations can offer additional results for the aqueous TMEAC ionic liquid.

An experiment system made up of a membrane absorption unit and a membrane vacuum regeneration unit was set up. Ionic liquids (ILs), 1-butyl-3-methyl-imidazolium tetrafluoroborate ([bmim][BF4]) and 1-(3-aminopropyl)-3-methyl-imidazolium tetrafluoroborate ([apmim][BF4]) as two absorbents for CO2 capture, were applied to the experiment system. Coupling processes of membrane contactor-IL absorbents and membrane vacuum-IL regenerations were evaluated by both the membrane absorption unit and the membrane vacuum regeneration unit. Water content in the ILs, CO2 loading capacity, operation conditions and modes, and regeneration factors were investigated. Results show that lower water content in [apmim][BF4] and higher water content in [bmim][BF4] were favorable for the coupling process. The aqueous [apmim][BF4] could give a high CO2 loading capacity at almost atmospheric pressure and its absorption capability was much larger than that of [bmim][BF4] in the coupling process. CO2 partial pressure had a certain influence on the membrane fluxes of both the ILs. The liquid flowrate evidently affected the membrane flux of the coupling process with aqueous [apmim][BF4]. The aqueous [apmim][BF4] could maintain a higher initial membrane flux and give a much larger instantaneous membrane flux compared with the aqueous [bmim][BF4]. The aqueous [bmim][BF4] could be completely regenerated even at low vacuum degree, while the aqueous [apmim][BF4] was difficult to be regenerated comparatively even at high vacuum degree.

In a multi-state network (MSN), data can be transmitted through different paths. The previous literatures focus on the cases with arc-disjoint paths, but not the cases in which the paths have a common arc. In this work, we consider the case that two source nodes are sending data to the sink node through their own minimal paths (MP), where these two MPs possess a common arc in the computer network. Each source node generates a data sequence. The time intervals of the generated data are randomly distributed. Also, the amount of the data generated in different time instants are randomly distributed. These two variables can be obtained by the Monte-Carlo simulation method. As all the data are transmitted through a common arc, the data need to compete for the priority using the arc and conflictions may be caused. We consider the case that the two MPs are in connection and calculate the reliabilities of the data under their transmission time constraints. Simulation results reveal that the conflictions could prolong their transmission time and thus affect their reliabilities. This work may provide a cross-reference for managers to decide the amount of the data and the time intervals to get the ideal network reliabilities.

The oxidation of cyclohexane in the microchannels not only improves the safety of the reaction, but also the performance of the oxidation reaction. Different gas-liquid micro mixers were used for the mixing of gas and liquid before entering into microchannels, and SIMM-V2 performed best of all. Excellent slug/plug flow can be formed in the microchannels after mixing in the gas-liquid micro mixer when the molar ratio of oxygen to cyclohexane is less than 0.5:1. The conversion of cyclohexane increased as the residence time increased, but the selectivity of cyclohexanol and cyclohexanone increased first and then decreased. At the reaction temperature of 200 °C, with the flow rate of the solvent isopropanol being 1 mL/min and the molar ratio of oxygen to cyclohexane being 0.15:1, both the conversion of cyclohexane and selectivity of cyclohexanol and cyclohexanone increased with the increase of pressure. The conversion of cyclohexane and selectivity of cyclohexanol and cyclohexanone reached 10.10% and 66.93% respectively at the pressure of 8 MPa. It is indicated that the new process by use of uncatalyzed cyclohexane oxidation in the microchannels will have very attractive prospects in the improvement of the safety, intensification of the gas-liquid mass transfer and obtaining good reactive performance. Therefore, the technology shows good potential in industrial applications.

An experiment system composed of a membrane absorption unit and three regeneration units was set up. The membrane absorption unit could be equipped with single and multiple modules in single cycle absorption mode. The three regeneration units included a hot regeneration, a vacuum desorption and an inert gas sweep. An efficient blended absorbent comprised of potassium glycinate (PG) and 2-amino-2-methyl-1-propanol (AMP) was developed in this work. Coupling process of membrane module-blended absorbent was evaluated by various operation modes such as single and multiple modules, single cycle absorption and regeneration, and continuous circulation of absorption and regeneration. Results show that performance of the blended absorbent (PG+AMP) was better than that of single ones (PG or AMP). The hot regeneration could give a high circular absorption capacity and a high regeneration efficiency while the vacuum desorption and the inert gas sweep gave a poor circular absorption capacity and a poor regeneration efficiency. Membrane flux of the coupling process increased as the gas and liquid flowrates increased. The absorption and regeneration time would greatly reduce by the assembly of multiple modules in consecutive and parallel modes. The circular absorption capacity and the regeneration efficiency by the hot regeneration were far larger than that by the membrane regeneration in the continuous circulation of absorption and regeneration. The membrane absorption process by coupling membrane and absorbent could be scale-up linearly. The parallel assembly mode of multiple modules was more effective than the consecutive assembly mode for CO2 capture.

Oil spill occurs frequently on the ocean. The amount of oil spill is 900 million tons from 2001 to 2010 in total, which resulted in enormous environment pollution and economic loss. The disadvantages of conventional methods such as pipe pumping method are high-energy-consuming, inefficient and high-cost. In this paper, a new method was proposed and a novel efficient oil spill cleaner was developed, which can recover 25kg oil per hour despite only 4kg weight of the cleaner itself. By using image recognition, advanced control algorithm, and roller extrusion, oil spill is detected and recovered automatically and effectively. The new method can decrease 60% energy consumption and triple the oil recovering rate. It can be concluded that this oil spill cleaner is an ideal prototype of the large novel marine oil spill recovery vessels.

Model reference adaptive control (MRAC) is widely used in linear system control areas, and Neural Networks (NN) is often used to extend MRAC to nonlinear areas. However, this kind of solution inherits some drawbacks of NN, including slow learning speed, weak generalization ability, local minima tendency, etc. Given these drawbacks, this paper attempts to use support vector regression (SVR) as a substitute of NN. In this approach, SVR is employed to compensate the nonlinear part of the plant. A stable controller-parameter adjustment mechanism is constructed by using the practical stability theory. Simulation results show that the proposed approach could reach desired performance.

Densities and viscosities of aqueous potassium citrate (PC) solutions have been determined at 293.15, 303.15, 313.15 and 323.15 K. Surface tensions of aqueous PC solutions have been measured at 293.15 K. Physical properties of aqueous PC solutions were correlated with the measured data in this work. The densities, viscosities and surface tensions of the PC solutions increase as the PC concentration increases. Densities, viscosities, and surface tensions of aqueous PC solutions have been correlated with molality and temperature. The correlation equations for each physical property can offer additional data for aqueous solutions of PC.

In this paper, a novel control system is introduced for a micro process system for the manufacturing of nanoparticles. An impinging-jet micromixer is used as the microreactor for mixing two fluid phases. In order to increase the scalability of the manufacturing system, a high speed image acquisition and processing subsystem is utilized to provide real-time visual feedback. Jet slope and shape are calculated automatically to evaluate the outcome of the mixing. A control algorithm consisting of a feedforward and feedback components is then implemented to control the pump’s flowrate to deliver guaranteed performance even with the presence of external disturbance and system uncertainty. Experimental results show the feasibility of the proposed solution.

This work proposes a generalized predictive control (GPC) based controller for the temperature of HVAC chilled water supply. In this paper, several models of evaporator are firstly introduced, wherein an identified black-box model is selected for the purpose of controller design. Based on this model, a GPC based controller is employed to obtain a satisfactory performance even with the presence of disturbance. The theoretical results show the stability of the closed-loop system and the performance of this scheme is compared with that of traditional PID controller under simulation environment.

Autothermal reforming of methanol is considered to be a promising choice for hydrogen production. However, due to the fact that a series of complex chemical reactions are involved, an exact mathematical model is extremely hard to be established, which makes the control of the process a recognized difficulty. Therefore, an adaptive feedback control method is proposed in this work for the control of hydrogen production through autothermal reforming of methanol without the requirement of an accurate model. Theoretical analysis proves that this control strategy can achieve very good performance even when the system’s parameters change significantly. Moreover, simulation results demonstrate the feasibility of this approach.

In a steel plant, fuel gas caloricity of ignition oven always changes rapidly and largely. Consequently, the temperature of ignition oven can’t keep steady. To overcome this problem we employ intelligent control of ignition oven based on PIDNN (Proportional-Integral-Derivative Neural Network). As we know, ignition oven is a nonlinear, large delay and slow time-varying process, so traditional PID control usually doesn’t work well. Artificial neural networks can perform adaptive control by learning, so we adopt Proportional-Integral-Derivative neural network to tackle the problem taking the advantages of both PID control and neural structure. In order to satisfy the restrictions of industrial instruments, we combine PIDNN control algorithm with expert system mechanism to fulfill the final intelligent control strategy. At a sintering plant in Hangzhou, we deploy the intelligent control strategy turning out a satisfactory result that the ignition oven temperature can be controlled steadily within a much smaller range with significant saving of labor costs and improving of energy efficiency.

Piperazine (PZ) and phosphates as additives were added into an aqueous N -methylmonoethanolamine (MMEA) to form complex absorbents, respectively. Performances of CO 2 capture by the complex absorbents were evaluated in a bubble column reactor. Reaction mechanisms and activations of the additives were presented theoretically. Effects of type and concentration of additives, and gas flowrates on volumetric mass transfer coefficient were investigated, and effects of orifice size of the gas sparger and stirring rates on average absorption velocity were also discussed. Results show that CO 2 loadings of MMEA–PZ and MMEA–K 3 PO 4 complex absorbents were larger than that of single MMEA and MEA absorbents. The MMEA–PZ complex absorbent gave a highest CO 2 loading in all complex absorbents. The overall mass transfer coefficient increased, subsequently reached a maximum and then decreased with the increase of K 3 PO 4 concentration in the complex absorbent. The overall mass transfer coefficient increased with the increase of the gas flow rates. Average absorption velocities increased with the decrease of the orifice size and with the increase of the orifice numbers. The average absorption velocities in moderate intensity of stirring rates were higher than that in the high intensity of stirring rates.

Densities and viscosities of aqueous solutions of potassium glycinate (PG) + piperazine (PZ) composed of xPG/xPZ (mol/mol) = 1.0/0, 0.9/0.1, 0.8/0.2, 0.7/0.3, and 0.6/0.4 have been measured at (288.15, 303.15, 313.15, and 323.15) K. Surface tensions of aqueous solutions of (PG + PZ) have been determined at 288.15 K. Correlations by means of mathematical fitting were developed for the predictions of density, viscosity, and surface tension of the aqueous solutions of (PG + PZ) using the experimental data of this work. Results show that the densities and viscosities decrease as the temperature increases. The densities of the studied solutions decrease with the increase of PZ mole fraction in the solutions, while viscosities of the solutions increase. The surface tensions of the solutions almost decrease linearly as the PZ mole fraction in the solution increases from 0 to 0.4. The prediction values from correlation equations for density, viscosity, and surface tension are in good agreement with the experiment...

An empirical dynamic model of burn-through point (BTP) in sintering process was developed. The K-means clustering was used to feed distribution according to the cold bed permeability, which was estimated by the superficial gas velocity in the cold stage. For each clustering, a novel genetic programming (NGP) was proposed to construct the empirical model of the waste gas temperature and the bed pressure drop in the sintering stage. The least square method (LSM) and M-estimator were adopted in NGP to improve the ability to compute and resist disturbance. Simulation results show the superiority of the proposed method.

Phosphate or borate as an activating agent was added into the aqueous glycinate to form amino acid salt-based complex absorbents. Capture of CO2 by the complex absorbents was studied theoretically and experimentally using a hollow fiber membrane contactor. Reaction mechanism concerning the activation effect of phosphate and borate was presented theoretically. A mathematical model was developed to simulate mass transfer of the membrane contactor. The effects of absorbent and gas CO2 concentrations on mass transfer flux and CO2 capture efficiency were investigated. Surface tension of the complex absorbents and operational stability of the membrane contactor were also discussed in this work. Results show that the activation follows the sequence B4O72− > PO43− > HPO42− > H2PO4−. The mathematical model was validated by comparing theoretical with experimental data. The mass transfer flux increased almost linearly with the increase of gas CO2 concentration. Surface tension data revealed that the complex absorben...

An activated solution based on amino acid salt was proposed as a CO2 absorbent. Piperazine (PZ) was selected as an activating agent and added into the aqueous glycine salt to form the activated solution. A coupling process, which associated the activated solution with a PP hollow fiber membrane contactor, was set up. An experimental and theoretical analysis for CO2 capture was performed. The performances of CO2 capture by the coupling process were evaluated using the PZ activated solution and the non-activated glycine salt solution. A numerical model for the simulation of the hollow fiber membrane gas–liquid mass transfer was developed. Typical parameters such as outlet gas phase CO2 concentration, capture efficiency, and mass transfer coefficient for the activated solution were determined experimentally. The effects of operation temperature and liquid CO2-loading on mass transfer coefficient and capture efficiency were discussed in this work. Axial and radial concentration profiles of CO2 in the fiber lu...

A blended solution based on amino acid salt was presented as a CO2 absorbent. Coupling process of a membrane contactor and the blended solution was investigated. The performances of the blended solution were experimentally compared with the single amino acid salt solution. Effects of various factors such as gas and liquid flow rates on CO2 concentration at gas and liquid outlets, capture efficiency, and overall mass transfer coefficient were discussed. A resistance in series model was developed to predict the overall mass transfer coefficients. Results show that performance of the blended solution is evidently better than that of the single solution. The blended solution can give lower CO2 concentration at gas outlet and higher CO2 concentration at liquid outlet as well as higher capture efficiency when compared with the single solution. The overall mass transfer coefficient with the blended solution is much higher than that with the single solution. The blended solution is confirmed to be an efficient absorbent for CO2 capture in membrane gas absorption. Model values are in good agreement with the experimental values.

A novel composite solution based on amino-acid salt as a CO 2 absorbent was proposed. Coupling process of membrane contactor and the composite solution was investigated. The performance of the coupling was experimentally compared between the single and composite solution. Overall mass transfer coefficients were determined. Effects of various factors such as flow rates and operation temperatures on mass transfer of membrane contactor were studied. Comparison of prediction for overall mass transfer coefficients using a resistance in series model with experimental values was performed. Results show that, performance of the composite solution is evidently better than that of the single solution. The overall mass transfer coefficient with the composite solution is much higher than that with the single solution. Higher operation temperature can enhance mass transfer of membrane contactor. Operation parameters such as flow rates can promote mass transfer, but the promotion is limited. Enhancement of mass transfer relies essentially on chemical reaction. Model values are in good agreement with experimental ones.

K3PO4, K2HPO4, and KH2PO4 as activating agents were added into the aqueous solution of amino acid salts glycine (GLY) to form activated absorbents (AAb) for CO2 capture. The performances of GLY and AAb for CO2 capture were evaluated using a membrane contactor-regeneration cycled setup. The effects of activating agent concentration and flow rate on overall voluminal mass transfer coefficient, mass transfer flux, and capture efficiency were studied. The phosphates exhibited remarkable activating effects on CO2 capture in the membrane contactor; the activation extents of the phosphates were in the order of PO43− > HPO42− > H2PO4−. A small amount of activating agent is sufficient to promote the CO2 capture. The changes of hydrodynamics in the membrane contactor can improve mass transfer performance and enhance mass transfer flux to a certain extent; the essential factor for enhancing the mass transfer efficiency in membrane gas absorption is the performance of absorbents used.

A wetting mechanism was presented for the system of hydrophobic hollow fiber membrane-alkanolamine absorbents for CO2 capture. A mathematical model was developed by means of correlating the resistance-in-series equation, the Laplace equation and the pore size distribution function of membrane based on the wetting mechanism. Effects of operation pressure, membrane configuration and operation temperature on membrane pore wetting were investigated experimentally and theoretically. Both experimental and model results show that, the wetting of membrane pores significantly affected the mass transfer coefficients of the membrane module, and resulted in the mass transfer stability of membrane phase and operation performance declining rapidly. Aqueous organic solutions easier wetted the hydrophobic membrane pores than water. The effects of membrane with high porosity for pore wetting on mass transfer are significantly greater than that of membrane with low porosity, and the performances of mass transfer of the higher porosity modules would deteriorate more easily. Liquid side operation pressures in the module significantly influence the pore wetting and the resistance to mass transfer of membrane phase. The overall mass transfer coefficients decreased rapidly with the increase of the liquid side operation pressures. The parameter of temperature is a sensitive factor for pore wetting of hydrophobic membrane. The wetting mechanism was validated experimentally and the model was in agreement with experiments.

In this work, CO2 capture from a CO2/N2 mixture was investigated in a membrane gas absorption (MGA) process experimentally and theoretically. 2-Amino-2-methyl-1-propanol (AMP) and piperazine (PZ) as activators were added into methyldiethanolamine (MDEA) solution, respectively, to form two aqueous solutions of activated MDEA. The experiments of CO2 absorption into the activated MDEA aqueous solutions were carried out in a hollow fiber module. The activated mechanisms which combined chemical reaction mechanisms and a shuttle mechanism were presented to explain the activation phenomena in the course of gas–liquid mass transfer. A mathematical model was developed to simulate the mass-transfer behavior of the MGA. Both experimental and simulation results show that, the activated MDEA solutions can maintain lower CO2 concentration of gas outlet of the module with an increase of liquid CO2-loading of liquid inlet as compared with the non-activated MDEA solution. The mass transfer can be effectively enhanced in MGA for CO2 capture when a little amount activators are added into the MDEA solution. Activator PZ has an advantage over activator AMP in mass-transfer enhancement of MGA. The mass-transfer fluxes of the activated MDEA solutions are significantly higher than that of MDEA solution. Effects of operation conditions such as gas and liquid flow rates on mass-transfer enhancement are limited. The model simulation is validated with experimental data.

In this work, an experimental investigation for selective absorption of H 2 S from gas-mixed streams into an aqueous blend of methyldiethanolamine (MDEA) and 2-tertiarybutylamino-2-ethoxyethanol (TBEE) in a packed column at atmospheric pressure and a constant liquid flowrate was performed. TBEE, a severe sterically hindered amine, was added into MDEA to form the blended amines. The effect of H 2 S loading of lean-solution, temperature of lean solution, the mole ratio of CO 2 /H 2 S in gas mixtures, and the gas flowrate on absorption performance were investigated by means of the evaluation of removal efficiency and selectivity factor. Based on the mass balance, overall volumetric mass-transfer coefficient ( K G a ) of H 2 S was determinated. The performance of simultaneous absorption of CO 2 and H 2 S into the aqueous blend of MDEA and TBEE is compared with that of the single aqueous solution of MDEA. The effect of gas flowrate, H 2 S and CO 2 concentration of gas-phase on K G a of H 2 S were studied also. The aqueous blend of MDEA and TBEE has been found to be an efficient mixed solvent for selective H 2 S removal. The experimental results also testified the advantages of severe sterically hindered amines (e.g., TBEE) over traditional amines in selective H 2 S absorption. This work provides the useful results for the aqueous blended amines containing sterically hindered amines to be extensively applied in the field of selective H 2 S removal.

In this paper, a novel discriminant methodology based on near infrared spectroscopic analysis technique and least square support vector machine was proposed for rapid and nondestructive discrimination of different types of Polyacrylamide. The diffuse reflectance spectra of samples of Non-ionic Polyacrylamide, Anionic Polyacrylamide and Cationic Polyacrylamide were measured. Then principal component analysis method was applied to reduce the dimension of the spectral data and extract of the principal compnents. The first three principal components were used for cluster analysis of the three different types of Polyacrylamide. Then those principal components were also used as inputs of least square support vector machine model. The optimization of the parameters and the number of principal components used as inputs of least square support vector machine model was performed through cross validation based on grid search. 60 samples of each type of Polyacrylamide were collected. Thus a total of 180 samples were obtained. 135 samples, 45 samples for each type of Polyacrylamide, were randomly split into a training set to build calibration model and the rest 45 samples were used as test set to evaluate the performance of the developed model. In addition, 5 Cationic Polyacrylamide samples and 5 Anionic Polyacrylamide samples adulterated with different proportion of Non-ionic Polyacrylamide were also prepared to show the feasibilty of the proposed method to discriminate the adulterated Polyacrylamide samples. The prediction error threshold for each type of Polyacrylamide was determined by F statistical significance test method based on the prediction error of the training set of corresponding type of Polyacrylamide in cross validation. The discrimination accuracy of the built model was 100% for prediction of the test set. The prediction of the model for the 10 mixing samples was also presented, and all mixing samples were accurately discriminated as adulterated samples. The overall results demonstrate that the discrimination method proposed in the present paper can rapidly and nondestructively discriminate the different types of Polyacrylamide and the adulterated Polyacrylamide samples, and offered a new approach to discriminate the types of Polyacrylamide.

SFE-CO2 is a novel, promising, environmentally benign and inexpensive extracting method developed over the past few years to overcome environmental problems encountered due to the use of conventional solvents. One component (the extractant) is separated from another (the matrix) using SCF-CO2 as the extracting solvents. This method is widely used for extracting heavy metals from environmental contaminant, bioactive compounds like antioxidants, plant medicine and natural products or remediating heavy metal contaminated soil by using good binding activity of SCF-CO2 to heavy metal ions. The major advantages of the use of SCF-CO2 as a solvent are its superior mass transfer properties, easy recycling and lack of secondary waste formation. We try to focus on the recent advances in SCF-CO2 extraction technology for heavy metal extraction. In this review, the mechanism, procedure, and application of heavy metal extraction by SCF-CO2 are summarized in a comprehensive manner and the factors affecting the extractio...

The single component fuel cell (SCFC) is a novel physical-electrochemical device for energy conversion which is recently discovered. The functional composite materials of Li0.15Ni0.25Cu0.3Zn0.3O2-delta (LNCZO) and Ce0.8Sm0.2O1.9 (SDC)-carbonate are proved as unique materials in SCFC (or one-layer fuel cell). In this work, the microstructure and morphology of two composite materials of LNCZO-SDC-Na2CO3 (LNCZO-NSDC) and LNCZO-SDC-(Li/ Na)(2)CO3 (LNCZO-LNSDC) are investigated by SEM-EDX and HR-TEM. Their catalytic activities for both hydrogen oxidation and oxygen reduction are studied by H-2-TPR and O-2-TPD, respectively. It is discovered for the first time that binary carbonates as ionic conductor mixing with semiconductor homogenously help to form unique semiconducting-ionic microstructure. The particle arrangement and interface conduction in the microstructure significantly influences on the SCFC performances due to different catalytic activity and polarization resistance. Even this, O-2 reduction reaction (ORR) for the single homogeneous layer still predominates in the redox reaction and binary carbonates are in favor of the oxygen conduction and desorption. These fin dings are essential to exactly understand the connections among structure, catalytic activities and performances underlying SCFC. QC 20150109

As new emerging pollutants, phthalic acid monoesters (PAMs) pose potential ecological and human health risks. In the present study, adsorption performance of monobutyl phthalate (MBP) onto two macroporous base anion-exchange resins (D-201 and D-301) was discussed. It was found that the adsorption isotherms were best fitted by the Langmuir equation while the adsorption kinetics were well described by pseudo-first-order model. Analyses of sorption isotherms and thermodynamics proved that the adsorption mechanisms for DBP onto D-201 were ion exchange. However, the obtained enthalpy values indicate that the sorption process of MBP onto D-301 is physical adsorption. The equilibrium adsorption capacities and adsorption rates of DBP on two different resins increased with the increasing temperature of the solution. D-301 exhibited a higher adsorption capacity of MBP than D-201. These results proved that D-301, as an effective sorbent, can be used to remove phthalic acid monoesters from aqueous solution.

Isobaric vapor–liquid equilibrium data of ethanol(1)-triethyl orthoformate(2), benzene(1)-triethyl orthoformate(2) and ethanol(1)-benzene(2)-triethyl orthoformate(3) were measured at 101.3 kPa and under a wide range of temperatures (349–420 K), using the Rose–Williams still modified by the authors. The experimental data of binary systems were tested for thermodynamic consistency with the method of Fredenslund and coworkers and correlated satisfactorily with SRK equation and PR equation of state. The VLE data of ethanol(1)-benzene(2)-triethyl orthoformate(3) ternary system were tested with the method of McDermont–Ellis and were predicted with the parameters of SRK and PR equation of state obtained from binary systems.

A novel composite solution consisting of N-methylmonoethanolamine (MM-EA) and 2-amino-2-methyl-1-propanol (AMP) as a CO2 absorbent was proposed. Coupling process of membrane contactor and the composite solution was investigated. The performance of the coupling was experimentally compared between the single and composite solution. Overall mass transfer coefficients were determined. Effects of various factors, such as flow rates and operation temperatures on mass transfer of membrane contactor, were studied. Comparison of prediction for overall mass transfer coefficients using a resistance in series model with experimental values was performed. Results show that performance of the composite solution is evidently better than that of the single MMEA solution. The overall mass transfer coefficient with the composite solution is much higher than that with the single MMEA solution. Higher operation temperature can enhance mass transfer of membrane contactor. Operation parameters such as flow rates can promote mass transfer, but the promotion is limited. Enhance of mass transfer relies essentially on chemical reaction. Model values are in good agreement with experimental ones.

The influence of inorganic additives (NaCl, Na2CO3 and CaCO3) on the distribution of polycyclic aromatic hydrocarbons (PAHs) in the smoke and ash from mosquito coils burning was studied, GC-MS technique was applied to analyze the contents of 16 priority-controlled PAHs recommended by US EPA. The results show that 16 priority-controlled PAHs are detected in the smoke of mosquito coil without additives, characterized by the predominance of 2- to 3-ring PAHs, which are ranked as NaP (3.109 microg x g(-1))Phe (1.230 microg x g(-1))AcP (0.495 microg x g(-1))FluA (0.311 microg x g(-1)); the emission factors in the ash are also predominated by 2- to 3-ring PAHs, but the total PAHs emission factors in the ash are only 4.7% of those in the smoke. NaCl and Na2CO3 additives can not decrease the emission of PAHs but promote total emission factors and TEQ of PAHs in the smoke of mosquito coils increase remarkably. The best additive in this study is CaCO3. With the increase of the addition of CaCO3, the proportion for 2- to 3-ring PAHs in the smoke increases remarkably than that in the ash, while the status reverse for 5- to 6-ring PAHs. CaCO3 with mole fraction of 2.0% has the most excellent property to decrease total emission factors and TEQ of PAHs in the smoke of mosquito coils, and the total emission factors and TEQ of PAHs decrease 1.8% and 86.6% respectively compared with the control.

Aromatic hydrocarbons recommended as the persistent organic pollutants distribute widely in atmospheric environment. PAHs (polycyclic aromatic hydrocarbons) and BTEX (benzene, toluene, ethyl benzene and p-xylene) are harmful to the environment and health of people, since they are the precursors of photochemical oxidants and agents of the acid rain, and have high degree of mutagenicity and carcinogenicity. Among the purifying technology for flue gas, adsorption is a relatively promising approach to remove aromatic hydrocarbons from flue gas as its advantages of high removal efficiency, low consumption and easy using. The recent studies on choice of sorbents, influence factors, parameters estimation and modeling of aromatic hydrocarbons are reviewed in this paper. By comparing the adsorption properties of different sorbents for aromatic compounds, structure and polarity of sorbents are the two main factors considered in choice of sorbents. The effects of textural properties, surface chemistry and other impact factors, such as interaction between adsorbates, physicochemical properties of adsorbates, operating conditions, on aromatic hydrocarbons adsorption behavior are analyzed.