Hydrodynamics,Mass Transfer and Gas Scrubbing in a Co‐current Droplet Column Operating at High Gas Velocities

The main objective of this work was to propose a new process for household fume incineration treatment: the droplet column. A feature of this upward gas‐liquid reactor which makes it original, is to use high superficial gas velocities (13 m s^–1) which allow acid gas scrubbing at low energy costs. Tests were conducted to characterize the hydrodynamics, mass transfer performances, and acid gas scrubbing under various conditions of superficial gas velocity (from 10.0 to 12.0 m s^–1) and superficial liquid velocity (from 9.4·10^–3 to 18.9·10^–3 m s^–1). The following parameters characterized the hydrodynamics: pressure drops, liquid hold‐ups, and liquid residence time distribution were identified and investigated with respect to flow conditions. To characterize mass transfer in the droplet column, three parameters were determined: the gas‐liquid interfacial area (a), the liquid‐phase volumetric mass transfer coefficient (k_La) and the gas‐phase volumetric mass transfer coefficient (k_Ga). Gas absorption with chemical reaction methods were applied to evaluate a and k_Ga, while a physical absorption method was used to estimate k_La. The influence of the gas and liquid velocities on a, k_La, and k_Ga were investigated. Furthermore, tests were conducted to examine the utility of the droplet column for the acid gas scrubbing, of gases like hydrogen chloride (HCl) and sulfur dioxide (SO₂). This is a process of high efficiency and the amount of pollutants in the cleaned air is always much lower than the regulatory European standards imposed on household waste incinerators.     

Carbon Dioxide Fixation by Algal Cultivation Using Wastewater Nutrients

Chlorella vulgaris was cultivated in wastewater discharged from a steel-making plant with the aim of developing an economically feasible system to remove ammonia from wastewater and CO₂ from flue gas simultaneously. Since no phosphorus compounds existed in wastewater, external phosphate (15·3–46·0 g m⁻³) was added to the wastewater. After adaptation to 5% (v/v) CO₂, the growth of C. vulgaris was significantly improved at a typical concentration of CO₂ in flue gas of 15% (v/v). Growth of C. vulgaris in raw wastewater was better than that in wastewater buffered with HEPES at 15% (v/v) CO₂. CO₂ fixation and ammonia removal rates were estimated as 26·0 g CO₂ m⁻³ h⁻¹ and 0·92 g NH₃ m⁻³ h⁻¹, respectively, when the alga was cultivated in wastewater supplemented with 46·0 g PO₄³ m⁻³ without pH control at 15% (v/v) CO₂. © 1997 SCI.     

A modified model and algorithm for flow‐enhanced crystallization—Application to fiber spinning

The graft copolymerization of acrylamide (AAm) monomer onto polyethylene‐coated polypropylene (PE‐co‐PP) nonwoven fabric was carried out by the mutual irradiation method. The general peculiarities of the grafting have been studied by gravimetric, scanning electron microscope (SEM), mechanical properties, and Fourier transform infrared (FTIR) methods. The influence of absorbed dose, dose rate, as well as the monomer concentration on the degree of grafting has been determined. Metal ions uptake of Cu²⁺, Co²⁺, Ni²⁺ by the grafted fabrics was evaluated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3240–3245, 2006     

Mass transfer and deodorization efficiency in a countercurrent spray tower for low superficial gas velocities

The aim of this study was to characterize mass transfer and deodorization efficiency in a countercurrent spray tower for low superficial gas velocities. The influence of operating parameters (U_G = 0.005 to 0.025 m s^?1, U_L = 6.1 × 10^?5 to 2.4 × 10^?4 m s^?1) on the liquid retention (ε_L), the drop diameter (d_g), the interfacial area (a) and the overall liquid and gas phase mass transfer coefficients (K_La, K_Ga) were estimated. The spray efficiency of some malodorous compounds was also estimated. A negative influence of the superficial gas velocity was demonstrated, during the spraying of water or chemical neutralizing scrubbing solutions. There was also an increase with the liquid flow rate. Abatements obtained were very good with respect to ammonia (>90%), and acceptable for the other compounds.     

Influence of temperature and pH on the kinetics of the Sharon nitritation process

The SHARON (Single reactor High activity Ammonia Removal Over Nitrite) process is an innovative process that improves the sustainability of wastewater treatment, especially when combined with an Anammox process. It aims at ammonium oxidation to nitrite only, while preventing further nitrate formation. In order to optimize this process by means of modelling and simulation, parameters of the biological processes have to be assessed. Batch tests with SHARON sludge clearly showed that ammonia rather than ammonium is the actual substrate and nitrous acid rather than nitrite is the actual inhibitor of the ammonium oxidation in the SHARON process. From these batch tests the ammonia affinity constant, the nitrous acid inhibition constant and the oxygen affinity constant were determined to be 0.75 mgNH₃‐N L^?1, 2.04 mgHNO₂‐N L^?1 and 0.94 mgO₂ L^?1. The influence of pH and temperature on the oxygen uptake rate of SHARON biomass was determined, indicating the existence of a pH interval between 6.5 and 8 and a temperature interval from 35 to 45 °C where the biomass activity is maximal. The kinetic parameters of the SHARON process were determined based on batch experiments. These parameters can now be implemented in a simulation model for further optimization of the SHARON process. Copyright © 2007 Society of Chemical Industry     

Color evaluation of wool fabric dyed with Rhizoma coptidis extract

Berberine is the only cationic colorant of natural plant dyes, which lies in the roots of Rhizoma coptidis and stems of phellodendron. In this study, wool fabric was dyed with the extracts of R. coptidis. Color evaluation was characterized with ΔE, L*, a*, b*, c*, H⁰, K/S. Effects of mordant, extraction concentration, pH value of dye bath, and treatment temperature on color values were studied. Results indicated that wool fabrics dyed with mordant, or at higher temperature, or in alkali solution possessed deeper shades and darker colors. And the wool fabric showed good antibacterial property after dyeing with R. coptidis extracts. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3376–3380, 2006     

Influence of an antimicrobial treatment on the strength properties of polyamide/elastane weft‐knitted fabric

Polyamide/elastane weft‐knitted fabric, as a suitable compression material, was treated with gentamicin sulfate and a natural antimicrobial preparation of the autochthonous essential oil of Picea abies. The antimicrobial bioactivity of the treated fabric in vitro was tested for different groups of bacteria and a fungus (Staphylococcus aureus, Escherichia coli, Klabsiella, and Candida albicans). The results of the experiment showed that the antimicrobial‐treated knitted fabric expressed a wide range of bactericidal, fungicidal, and bacteriostatic activity versus the various groups of microorganisms. The influence of the antimicrobial treatments on the tensile strength and elongation, tear strength and elongation, stiffness, and elasticity of the chosen test material was also examined. These properties of the fabric were changed after the antimicrobial treatments. Both the tensile strength and tear strength increased about 14% after the treatment. The scope of the experiment also included the testing of the compression distribution at the skin/knitted fabric interface on the legs of human test subjects. Pressure generated by the application of the knitted fabric on the leg surface increased in correlation with a decrease in the leg circumference. On the basis of these observations, it was concluded that the knitted fabric could be used as a compression textile before and after the treatment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4012–4019, 2007     

Relationship between the structure and mechanical properties of polypropylene: Effects of the molecular weight and shear‐induced structure

A series of homopolymer polypropylenes (PPs), within a weight‐average molecular weight (M_w) range of 100–1600 kg/mol, were manufactured as dumbbell microspecimens. The effects of the molecular weight and shear‐induced crystallization on the mechanical properties and morphology were studied to gain a better understanding of the structure–property relationship. The results showed that the crystallinity decreased from 50 to 41% and the lamellar thickness increased as M_w increased. Tensile tests demonstrated that the stiffness and especially the tensile strength rose to extremely high values (Young's modulus = 2400 N/mm², stress at 30% strain = 120 N/mm²). Furthermore, the strain hardening effect was strongly affected by the lamellar thickness and highly oriented superstructures. Dynamic mechanical analysis demonstrated that the mobility of the molecular chains depended on M_w and on the lamellar thickness. In addition, the viscoelastic properties of unannealed and annealed samples indicated further the existence of shish‐kebab structures caused by shear‐induced crystallization during injection molding. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 519–533, 2007     

Carrier‐free dyeing of radiation‐grafted polyester fabrics with disperse dyes

Carrier‐free dyeing of radiation‐grafted polyester fabrics with disperse red dye was studied in the temperature range 283–363 K. 1‐vinyl 2‐pyrrolidone (NVP), acrylic acid (AA) or their mixture was used to graft poly(ethylene terephthalate) (PET) fabric. The effects of pH of the dye solution, graft yield (GY), dyeing time (t), dye concentration (C), and dyeing temperature (T) on the colour difference (CD) of PET fabric were studied. The best dyeing condition was achieved at pH 5.5. CD increases linearly with the increase in GY, with slopes depending on the type of grafted copolymer. CD increased rapidly as the dyeing time increased; this was followed by a relatively slow dyeing rate within a few minutes. The initial dyeing rate (R) was found to increase with an increase in C and T. The dyeing rates for all grafted samples followed 0.35‐order kinetics and are temperature‐independent. Average activation energy 9.26 kJ mol^?1 is calculated for the dyeing process and is independent of the fabric treatment. Pre‐exponential rate constants 1976, 1839, and 1579 (CD/GY) s^?1 were calculated for dyeing PET samples grafted with AA/NVP mixture, NVP and AA, respectively, while 1074 CD s^?1 was evaluated for carrier dyeing of ungrafted fabric. Analysis of the kinetic parameters and the dyeing mechanism revealed that dyeing PET fabric was diffusion‐controlled. Grafting PET fabric improved significantly the dyeing affinity of the DR dye over ungrafted samples dyed in solutions containing a carrier. Copyright © 2005 Society of Chemical Industry     

Functional finishing by using atmospheric pressure plasma: Grafting of PET nonwoven fabric

Poly (ethylene terephtalate) (PET) nonwoven fabric was treated with He/O₂ plasma to produce peroxides and grafted with acrylic acid (AA) for introducing carboxyl groups onto PET surface. The graft yield increased with AA concentration from 1.5M to 2.5M, and then decreased with further increase in AA concentration. Graft yield increased with sodium pyrosulfite (SPS) concentration from 0.005M to 0.02M, and then decreased with further increase of SPS concentration. X‐ray photoelectron spectroscopy results indicated that both of plasma treatment and AA grafting increased oxygen content and decreased carbon content on the PET nonwoven fabric surface. The grafted PET nonwoven fabric showed increase in moisture regain and dye uptake. And drastic increase in wettability was observed after grafting. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3655–3659, 2007     

Gas‐Liquid Mass Transfer in Fibrous Bed Reactor with Counter‐Current Liquid Recycle

In this work, the gas‐liquid mass transfer in a lab‐scale fibrous bed reactor with liquid recycle was studied. The volumetric gas‐liquid mass transfer coefficient, k_La, is determined over a range of the superficial liquid velocity (0.0042–0.0126 m.s^–1), gas velocity (0.006–0.021 m.s^–1), surface tension (35–72 mN/m), and viscosity (1–6 mPa.s). Increasing fluid velocities and viscosity, and decreasing interfacial tension, the volumetric oxygen transfer coefficient increased. In contrast to the case of co‐current flow, the effect of gas superficial velocity was found to be more significant than the liquid superficial velocity. This behavior is explained by variation of the coalescing gas fraction and the reduction in bubble size. A correlation for k_La is proposed. The predicted values deviate within ± 15 % from the experimental values, thus, implying that the equation can be used to predict gas‐liquid mass transfer rates in fibrous bed recycle bioreactors.     

Modification of surface properties of wool fabric with linde type a nano‐zeolite

Wool is a naturally occurring composite fiber consisting of keratin and keratin‐associated proteins as the key molecular components. The outermost surface of wool comprises a lipid layer that renders the surface hydrophobic, which hinders certain fabric processing steps and moisture management properties of wool fabrics. In this study, Linde Type A (LTA) nano‐zeolite (a Na⁺‐, Ca²⁺‐, and K⁺‐exchanged type A zeolite) was integrated onto the surface of wool using 3‐mercaptopropyl trimethoxy silane as a bridging agent. The resultant surface morphology, hydrophilicity, and mechanical performance of the treated wool fabrics were evaluated. Notably, the surface hydrophilicity of wool increased dramatically. When wool was treated with a dispersion of 1 wt % zeolite and 0.2 wt % silane, the water contact angle decreased from an average value of 148° to 50° over a period of approximately 5 min. Scanning electron microscopic imaging indicated good coverage of the wool surface with zeolite particles, and infrared spectroscopic evaluation demonstrated strong bonding of the zeolite to wool keratins. The zeolite application showed no adverse effects on the tensile and other mechanical properties of the fabric. This study indicates that zeolite‐based treatment is potentially an efficient approach to increasing the surface hydrophilicity and modifying other key surface properties such as softness of wool and wool fabrics. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42392.     

A facile method to fabricate durable super‐hydrophobic cotton fabric

This article presents the fabrication of super‐hydrophobic cotton fabric using titanium dioxide nanoparticles and tetraethyl orthosilicate, alongside control samples modified by 1H,1H,2H,2H‐perfluorooctyltriethoxysilane. The samples were analyzed using scanning electron microscopy and Fourier transform infrared spectrometry, and then, the water contact angles were measured. Moreover, the durability of the hydrophobic surface was examined by measuring the abrasion resistance and laundering durability. For the tetraethyl orthosilicate‐treated fabric, the water contact angle reached 150.3°, whereas that for the 1H,1H,2H,2H‐perfluorooctyltriethoxysilane‐treated fabric was 154.1°. After 300 abrasion cycles (or 40 min of laundering), the water contact angles of cotton fabrics treated with a 20% tetraethyl orthosilicate treatment solution dropped by 6.67% (or 2.86%). Therefore, hydrophobic cotton fabrics can be obtained via treatment with tetraethyl orthosilicate solution, which is more environmentally friendly than that obtained via fluorosilanes such as 1H,1H,2H,2H‐perfluorooctyltriethoxysilane. J. VINYL ADDIT. TECHNOL., 26:3–9, 2020. © 2019 Society of Plastics Engineers     

Electrolytic removal of ammonia from brine wastewater: scale‐up,operation and pilot‐scale evaluation

Brine wastewater with a high ammonia content from an iodine processing plant (commonly called kansui in Japan) was treated by electrolysis. The system, which can be considered as an indirect electrolytic treatment process, generates chlorine at the anodes and initiates the formation of mixed oxidants like hypochlorous acid. The oxidants then act as agents for ammonia destruction. Laboratory‐scale experiments showed that high ammonia concentrations (as much as 200 mg dm^?3) could be completely removed within a few minutes, and could be considered a good alternative for efficient ammonia removal from saline wastewaters. From laboratory‐scale experiments in the batch and continuous modes, the charge dose was analyzed and used as the operating and scale‐up factor. The value of the charge dose was not severely affected by changes in operating conditions such as electrode spacing and temperature. The charge dose from batch and continuous runs was found to be in the range of 23 C (mg NH₄‐N removed)^?1 to 29 C (mg NH₄‐N removed)^?1. Using the charge dose obtained from laboratory‐scale continuous electrolysis experiments as the scale‐up factor, a pilot‐scale reactor was designed, and the operating conditions were calculated. In the pilot‐scale reactor tests at different flow rates, the effluent ammonia concentrations were reasonably close to the calculated values predicted from the charge dose equation. Copyright © 2004 Society of Chemical Industry     

High‐throughput microporous tube‐in‐tube microreactor as novel gas–liquid contactor: Mass transfer study

High‐throughput microporous tube‐in‐tube microchannel reactor (MTMCR) was first designed and developed as a novel gas–liquid contactor. Experimentally measured k_Lα in MTMCR is at least one or two orders of magnitude higher than those in the conventional gas–liquid contactors. A high throughput of 500 L/h for gas and 43.31 L/h for liquid is over 60 times higher than that of T‐type microchannel. An increase of the gas or liquid flow rate, as well as a reduction of the micropore size and annular channel width of MTMCR, could greatly intensify the gas–liquid mass transfer. The interfacial area, α, in MTMCR was measured to be as high as 2.2 × 10⁵ m²/m³, which is much higher than those of microchannels (3400–9000 m²/m³) and traditional contactors (50–2050 m²/m³). The artificial neural network model was proposed for predicting α, revealing only an average absolute relative error of <5%. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Synthesis and characterization of polystyrene‐supported glucosamine resin and its adsorption behavior for Au(III)

A novel chelating resin, crosslinking polystyrene‐supported glucosamine (PS‐GA), was prepared and its structure was confirmed by FTIR, elemental analysis, and X‐ray photoelectron spectroscopy. The adsorption properties of PS‐GA for Au(III) were investigated. PS‐GA resin possessed excellent enriching property to Au(III) ions and adsorption proportion E% could reach to about 90 shortly after 3 h. The adsorption dynamics of Au(III) showed that the adsorption was controlled by liquid film diffusion and the apparent activation energy E_a was 12.91 kJ mol^?1. Both Langmuir model and Freundlich model could describe the isothermal process of Au(III), and ΔG, ΔH, ΔS values were calculated. The mechanism of adsorption for Au(III) was confirmed by FTIR, SEM, and XPS. The results showed that redox reaction occurred and both coordination and ion‐exchange existed simultaneously in the adsorption. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4581–4586, 2006     

Emission of methane, nitrous oxide, and ammonia from dung windrows

Gaseous emissions from livestock waste composting were measured within a project aiming at the determination of the nitrogen balance in biological farming. Gas was collected from windrows of animal waste using gas flux chambers (cover boxes). The gas analysis was performed by a high resolution FT-IR spectrometer. The results showed that ammonia and methane emissions dropped down within two to three weeks, whereas nitrous oxide was emitted mainly in the middle of the composting periods. The mean values of the total emissions per composting period were 57.6 g m⁻² for ammonia, 12.8 g m⁻² for nitrous oxide, and 1346 g m⁻² for methane. The mean ratios of the total gas fluxes related to the carbon dioxide flux were 2.6 10⁻³ for NH₃, 5.9 10⁻⁴ for N₂O and 6.2 10⁻² for CH₄. Both of these factors (total gas flux and mean ratios of total gas fluxes) can serve as indicators to quantify impacts on the environment. This revised version was published online in August 2006 with corrections to the Cover Date.     

Non‐dispersive absorption of CO2 in parallel and cross‐flow membrane modules using EMISE

BACKGROUND: This paper reports an analysis of the mass transfer behaviour of CO₂ absorption in hollow fibre membrane modules in parallel and cross‐flow dispositions. The ionic liquid EMISE, 1‐ethyl‐3‐methylimidazolium ethylsulfate, is used to achieve a zero solvent emission process and the experimental results are compared with CO₂ permeation through the membrane, without solvent in the lumenside. RESULTS: Overall mass transfer coefficients K_{overall, CF} = (0.74 ± 0.02) × 10^?6 m s^?1 and K_{overall, PF} = (0.37 ± 0.018) × 10^?6 m s^?1 were obtained for cross‐flow and parallel flow, respectively. These values are one order of magnitude lower than the coefficient obtained in permeability experiments, K_{overall, PERM} = (6.16 ± 0.1) × 10^?6 m s^?1, indicating the influence of the absorption in the process. Including the specific surface and gas volume of each contactor in the analysis, a similar value of a first‐order kinetic rate constant, K_R = 2.7 × 10^?3 s^?1 is obtained, showing that the interfacial chemical reaction CO₂‐ionic liquid is the slow step in the absorption process. CONCLUSION: An interfacial chemical reaction rate constant K_R = 2.7 × 10^?3 s^?1, describes the behaviour of the CO₂ absorption in the ionic liquid EMISE using membrane contactors in parallel and cross‐flow dispositions. Copyright © 2012 Society of Chemical Industry     

Metal‐ion‐containing ionic liquid hydrogels and their application to hydrogen production

A cationic hydrogel synthesized from (3‐acrylamidopropyl) trimethyl ammonium chloride as poly[(3‐acrylamidopropyl) trimethyl ammonium chloride] [p(APTMACl)] was put into contact with the chloride salts of metals such as CoCl₂, NiCl₂, and CuCl₂ in ethanol. The metal‐loaded p(APTMACl) hydrogels were used as catalyst systems in hydrogen generation from the hydrolysis of sodium borohydride (NaBH₄) and ammonia borane. The activation energy values for the hydrolysis reaction were calculated for all of the catalyst systems and were found to be 53.43 and 26.74 kJ/mol for p(APTMACl)–[CoCl₄]^2? and p(APTMACl)–[NiCl₄]^2?, respectively. These activation parameters were better than values reported in the literature for the ionic liquid metal complexes of smaller molecules used for the same purpose. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40183.     

Studies on molecular transport of n‐alkanes through poly(tetrafluoroethylene‐co‐propylene) elastomeric membrane

Molecular transport of a series of n‐alkanes through commercial TFE elastomer (FA 150L) has been studied in the temperature range 30–50 °C using sorption‐gravimetric method. The Fickian diffusion equation was used to calculate the diffusion coefficients, which were dependent on the size of the alkanes and temperature. The diffusion coefficients at 30°C varied from 4.53 × 10^?8 cm²/s (n‐heptane) to 0.18 × 10^?8 cm²/s (n‐hexadecane). The liquid concentration profiles have also been computed using analytical solution of Fick's equation with the appropriate initial and boundary conditions and these were presented as a function of penetration depth of molecular migration and time of immersion. These results have been discussed in terms of molecular size of alkanes as well as temperature. In all the liquid penetrants, the transport phenomenon was found to follow the anomalous behavior. From the temperature dependence of diffusion and permeation coefficients, the Arrhenius activation parameters have been estimated. These parameters do not exhibit any systematic variation with the size of the penetrants. The resulting low diffusion coefficients, contribute to the superior barrier performance of the membrane, is due, in part, to the high glass transition temperature of Aflas? TFE elastomer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2228–2235, 2006