Internal Mass Transfer Research Articles

Effect of structure parameters on internal mass transfer and performance of PEMFC with spider-web flow field using multi-physical simulation

Optimizing the flow field structure is an important means to enhance gas transport and improve the proton exchange membrane fuel cell (PEMFC) performance. Based on the structural features of the spider-web, a three-dimensional multiphase flow model of the PEMFC with a spider-web biomimetic flow field (SWFF) was established firstly, and the influence of inlet and outlet positions on the performance of the PEMFC was investigated, then the cathode side catalytic layer (CL) oxygen utilization as an evaluation index based on the cluster model was proposed, which is used to investigate the effect of inlet and outlet positions on internal mass transfer and performance of PEMFC. Finally, the influence of different structural parameters on the performance of PEMFC with SWFF was investigated based on the orthogonal experimental design method. The results show that a reasonable arrangement of inlet and outlet positions can effectively increase the peak current density by 2.31% and reduce the pressure drop by 96.07% compared to a serpentine flow field. The placement of baffles at the intersection of the main channel and divergent channels can significantly improve the PEMFC performance. The results of the research provide a new evaluation index and a theoretical basis for the optimal design of flow field structures.

Synergistic improvement of Seebeck coefficient and power density of an aqueous thermocell using natural convection for low-grade heat utilization

As a cutting-edge heat-to-electricity technology, thermocells possess the advantages of large Seebeck coefficient, low cost and high scalability, indicating a great prospect in low-grade heat recovery. Previous studies about thermocells focus on the electrode materials and electrolytes, but the internal heat and mass transfer mechanisms are less considered, especially the effects of natural convection on the performance of aqueous thermocells. The purpose of this study is to explore the influence of natural convection on the performance of aqueous thermocells. Firstly, a fundamental test bench for aqueous ferricyanide/ferrocyanide ([Fe(CN)6]3−/4-) thermocells using Pt as electrodes is designed and established. Based on the self-developed test bench, then the performance of thermocells related to electrode orientation θ are experimentally investigated under typical thermal boundary conditions, including the constant electrode temperature, and constant heating and cooling temperature. The experimental results under constant electrode temperature show that natural convection can significantly reduce the internal resistance of thermocells. The thermocell obtains the largest |Se| of 1.75 mV/K at θ = 90°, which is 19.9% higher than that of θ = 0°. Meanwhile, the thermocell achieves the maximum power density of 0.211 W/m2 at θ = 135°, which is 744% higher than that of θ = 0°. In addition, by combining the experimental results under constant heating and cooling temperature, it can be observed that natural convection can also sharply reduce the thermal resistance and then lead to a smaller temperature difference of two electrodes. Overall, natural convection has trade-off effects on internal resistance and thermal resistance, and the proper use of natural convection can succeed in prominent improvement of Seebeck coefficient and power density for thermocells.

Experimental study and modeling of a packed bed bioreactor for urea removal in wines

The study involved the development and modeling of a fixed-bed bioreactor for the removal of urea from wines. The reactor, based on the immobilization of acid urease enzyme, was studied under both stationary and non-stationary conditions. The developed model, including internal and external catalyst particle mass transfer, Michaelis-Menten kinetics, convection and dispersion in the liquid along the reactor axis, was able to produce urea concentration profiles in both the solid and liquid phases under various volumetric flow rates and inlet urea concentrations. The experimental results were in good agreement with the model predictions, the mean relative error between simulated and experimental outlet ammonia concentration ranging from 4.1 % to 16.4 %. Model simulations confirmed that in wines the reaction kinetics is of the pseudo-first order and that internal and external catalyst particle diffusion limitations are negligeable. Simulations of the decrease of urea concentration as a function of space velocity for the reactor under study operating in the continuous mode and for three different wines were obtained confirming that urea removal by immobilized urease in wines is more difficult than in sake. The results obtained form the basis for the designing and scaling up of bioreactors for the treatment of wines.

Mechanism modeling and application of Salvia miltiorrhiza percolation process

Percolation is a common extraction method of food processing industry. In this work, taking the percolation extraction of salvianolic acid B from Salvia miltiorrhiza (Salviae Miltiorrhizae Radix et Rhizoma) as an example, the percolation mechanism model was derived. The volume partition coefficient was calculated according to the impregnation. experiment. The bed layer voidage was measured by single-factor percolation experiment and the internal mass transfer coefficient was calculated by the parameters obtained by fitting the impregnation kinetic model. After screening, the Wilson and Geankoplis, and Koch and Brady formulas were used to calculate the external mass transfer coefficient and the axial diffusion coefficient, respectively. After substituting each parameter into the model, the process of percolation of Salvia miltiorrhiza was predicted, and the coefficient of determination R2 was all greater than 0.94. Sensitivity analysis was used to show that all the parameters studied had a significant impact on the prediction effect. Based on the model, the design space including the range of raw material properties and process parameters was established and successfully verified. At the same time, the model was applied to the quantitative extraction and endpoint prediction of the percolation process.

Influence of ultrasound-pretreated convective drying of Roselle (Hibiscus sabdariffa L) leaves on its drying kinetics and nutritional quality

The drying kinetics and the nutritional qualities of Roselle (Hibiscus sabdariffa L) leaves as affected by ultrasound pretreatment during hot air drying were investigated in this work. Ultrasound frequency and power at 20 kHz and 600 W, respectively, were used for the experiment. Roselle leaves were subjected to ultrasound pretreatment in distilled water for 0 min (untreated), 5 min (UD5), 10 min (UD10) and 15 min (UD15) before hot air drying. The result showed that UD15 samples had about 47% reduction in drying time compared with the untreated samples. The effective moisture diffusivity of the treated and untreated samples ranged from 1.21 to 3.29 × 10−1m2/s. The Page and Logarithmic models best described the drying behavior for the untreated and treated samples respectively. The values of the mass transfer Biot number (ratio of internal mass transfer resistance to external mass transfer resistance) for all the samples ranged from 0.9032 to 1.2391. The samples of UD10 and UD5 had the highest amount of carotenoid and vitamin C contents, respectively, amongst the untreated and treated samples. The total color change of the treated samples were significantly lower than the untreated samples after drying. Drying of Roselle leaves is usually done using convective drying method with its attendant's effects such as long drying time, loss of nutrients and high energy usage. But this work showed that application of ultrasound pretreatment during drying of Roselle leaves can significantly reduce the drying time and at the same time retain the nutritional quality of the dried treated samples.

Calculation of Mass Transfer Limitations for a Gas-Phase Reaction in an Isothermal Fixed Bed Reactor: Tutorial and Sensitivity Analysis

The study of the reactivity of catalysts requires one to assess chemical kinetics and mechanisms in the absence of mass transport artifacts. Despite the existence of models and criteria for assessing the presence of mass transfer limitations during catalytic tests for gas-phase reactions in isothermal fixed bed reactors, the literature does not present straightforward protocols for performing the latter calculations. In this work, we present a systematic protocol for the calculations above. Particularly, we present protocols for estimating the effectiveness factor for external and the Weisz-Prater number for the internal mass transfer limitations. Data previously published on the oxidation of propane over mixed vanadium–aluminum (hydr)oxides was taken as a case study. Based on these protocols, we did a sensitivity study of the models used for calculations. Results showed that the model for calculating the effectiveness factor was poorly sensitive to all the above modifications. Meanwhile, the Weisz-Prater number was much more sensitive to the studied modifications, even reaching deviations up to ∼200%.

Biodegradation of Phenol Using the Indigenous Rhodococcus pyridinivorans Strain PDB9T NS-1 Immobilized in Calcium Alginate Beads.

Phenolic compounds are the major contaminants identified from various industrial effluents, which pose an extreme threat to the environment. Therefore, investigating an effective technique to remove these toxic phenolic compounds from the contaminated environment is very essential. In the present investigation, batch tests were performed to assess the biodegradation of phenol using an indigenous Rhodococcus pyridinivorans strain PDB9T NS-1 encapsulated in a calcium alginate bead system. In order to improve the mechanical stability, silica was added to the cell-embedded Ca-alginate beads. The impact of experimental conditions such as contact time, pH, and initial phenol doses was investigated. The biodegradation of phenol was examined over a wide range of phenol, and the results showed that more than 99.6% degradation was achieved at an initial phenol dose of 1000 mg/L in 70 h at 30 °C. Among the various sorption isotherm tested, the Freundlich isotherm was the best fitted to the experimental data. This behavior indicated a multilayer biosorption process and was controlled by heterogeneous surface energy. Based on an intra-particle diffusion model, internal mass transfer or pore diffusion predominated over exterior mass transfer in controlling the entire phenol biosorption process. The biosorption of phenol onto the cell encapsulated in the Ca-alginate bead follows pseudo-first-order kinetics with a superior phenol biosorption capacity of 155 mg/g of Ca-alginate. Further stability study revealed that the bead could be recycled successfully without any substantial decline in phenol degradation efficiency, indicating that the immobilized microbe possesses exceptional operating stability.

Modeling and simulation of trickle bed reactors for the purification of 1-butene

Abstract In this contribution, a mathematical model of an industrial trickle-bed reactor employed in the purification of a C4 cut by selective hydrogenation of acetylenic or dienes compounds to obtain high purity 1-butene is presented. A reaction network of ten reactions is included in the model, with kinetics expressions and parameter estimation obtained from previous experimental studies on a commercial catalyst. Internal mass transfer resistances in the catalyst particles are significant; therefore the reaction-diffusion equations must be solved. External mass transfer resistances in the liquid phase were retained, while those in the vapor phase were negligible. The model was employed to analyze the reactor behavior by varying the inlet molar flow rate of hydrogen, the operating pressure, inlet temperature and the level of activity of the catalyst, taking into account its deactivation. It was demonstrated that the mass transfer resistances, inside and outside the catalyst particles, have a significant impact on the selectivity, but a careful operation of the reactor can improve the selectivity and extent the catalyst life. On the other hand, an alternative system was proposed, with two beds and a distributed input of H2, which led to a significant improvement in the selectivity.

Investigation on the catalysis performance of metal-doped zeolites on ring-opening acidolysis reaction

Metal-incorporated zeolites as heterogeneous Lewis acid were applied in the ring-opening acidolysis of ethylene oxide with acrylic acid to prepare 2-hydroxyethyl acrylate (HEA). The catalysis characteristics, including Lewis acid strength and internal mass transfer resistance, were systematically investigated to facilitate the rational design of zeolite catalysts. Through modifying the Lewis acid strength of zeolites via different metals (Sn, Zr and Ti) incorporation and the internal mass transfer resistance of zeolites from the particle size, pore diameter or pore structure, it was found that the increased Lewis acidity can accelerate both the main and side reactions, resulting in the high activity but low selectivity of zeolite catalysts; the enhanced internal diffusion was the key to limiting subsequent cascade alcoholysis side reactions as well as the decline of catalytic performance. Based on these findings, Zr-containing zeolites featured with moderate Lewis acidity and uniform intracrystalline mesoporosity were designed and prepared, presenting excellent catalysis and recycling performance. These results demonstrated the great potential of the developed zeolite catalysts for the green synthesis of HEA as well as the similar ring-opening acidolysis of epoxides.

The significance of granular activated carbon pore structure in modeling dissolved organic carbon removal in fixed-bed filters

A reliable model that describes DOC removal during biological-active granular activated carbon filtration for advanced wastewater treatment has to cover several aspects that influence biological and adsorptive removal processes. For this purpose, this work introduces a two-domain internal diffusion approach to a multicomponent adsorption model, which is combined with a traditional biofilm model for the first time. DOC was divided into fictive components according to biodegradability and adsorbability to calculate multicomponent adsorption equilibrium based on the ideal adsorbed solution theory. Adsorption kinetics included external mass transfer (diffusion through a boundary layer and a biofilm) and internal mass transfer (fast pore diffusion in the larger pores and slow surface diffusion in the micropores). Mass transfer in the micropore domain was implemented by adjusting the adsorptive driving force depending on the available internal surface area for DOC adsorption based on an empirical surface diffusion model. Simulated DOC breakthrough curves were sensitive to model parameters related to the pore structure of the granular activated carbon (GAC). The model was validated with two GAC types and empty bed contact times ranging between 6 and 33 min. The model results showed a good agreement with measured DOC breakthrough curves over the entire operation time, demonstrating the applicability and transferability of the model. In particular, the initial DOC breakthrough was well represented. However, some systematic deviations between measured and simulated DOC breakthrough curves were observed, which are probably due to the level of detail of the implemented biofilm model.

Micro-mechanism insights into the adsorption of anionic dyes using quaternary ammonium-functionalised chitosan aerogels

The development of adsorbents with outstanding adsorption capacities, wide versatility, and excellent recyclability for the removal of organic dyes remains a challenge. In this study, a quaternised chitosan-based aerogel (QCSA) was fabricated via a facile method to effectively treat concomitant anionic dyes. Porous QCSA with high hydrophilicity, nontoxicity, excellent thermal stability, and sustainability exhibits adsorption properties superior to most previously reported adsorbents. The equilibrium adsorption capacities for Congo red, Sunset yellow, and Methyl orange were 1259.6, 550.2, and 607.5 mg/g, respectively. Notably, the spent QCSA exhibits excellent cyclic performance. The multilayer adsorption, external–internal mass transfer resistance, and adsorption on the active site models were employed to enable a more accurate description of the dynamic characteristics, confirming that double-layer chemisorption was the dominant process. A quantitative analysis of the electrostatic potential and the independent gradient model further verified that electrostatic interactions, hydrogen bonding, and van der Waals forces led to the highly efficient adsorption of dye molecules. Therefore, the eco-friendly and recyclable QCSA is a promising adsorbent for trapping anionic dyes from aquatic systems.

Experimental study and kinetic modeling of methanol conversion to propylene with co-feeding of C4 and C5/C6 hydrocarbon cuts over a ZSM-5 catalyst.

Extensive experimental data were used to develop a comprehensive kinetic model for the methanol to propylene (MTP) process over a ZSM-5 catalyst. Preliminary experiments were performed to determine the reaction conditions that would ensure the absence of external (film) and internal mass transfer resistances. The kinetic experiments were subsequently carried out at 420-500 °C under conditions where mass transfer limitations were absent. A detailed reaction network was proposed for the MTP process based on the experimental product distribution and various reported kinetic models in the literature. According to the first series of experiments (without C4 and C5/C6 recycle streams) conducted at various temperatures, the best yield for propylene production was achieved at 480 °C with a water to methanol ratio of 0.7. Subsequently, kinetic experiments were performed at 480 °C and a water to methanol ratio of 0.7 using feeds with different amounts of C4 and C5/C6 hydrocarbons as recycle streams. Species material balances for the integral tubular reactor along with power-law rate functions and the Arrhenius equation for rate constants were employed in an optimization algorithm to obtain the kinetic parameters. The predictive ability of the model was checked against experimental data, and the kinetic parameters were validated by additional experiments.

Pore-size dependent catalytic activity of supported Pd catalysts for selective hydrogenation of nitrile butadiene rubber

Pore diffusion effect plays a crucial role in heterogeneous hydrogenation of unsaturated polymers. However, how large pore size can eliminate the pore diffusion limitation remains a controversial issue. Herein, we prepared a series of Pd/SiO2 catalysts with graded pore sizes and investigated the effect of pore size on hydrogenation activity of nitrile butadiene rubber (NBR). It is found that when the catalyst pore size (Dcat) is 7 times of the diameter of NBR chains (DNBR), the Weisz modulus Φ can be reduced to < 0.3 thus the internal mass transfer limitation can be eliminated, making NBR easier to approach the active sites. Consequently, the catalysts with the Dcat/DNBR > 7 exhibit excellent catalytic activity (96.7%) and selectivity (100%) to C = C. This work emphasizes that the pore size of catalysts can regulate the pore transfer limitation and the accessibility of internal active sites, providing useful guidance for the design of efficient macromolecular hydrogenation catalysts.

Cross-scale modeling and optimization analysis of the solid oxide fuel cell cogeneration system based on the heat current method

The multi-scale, multi-component, multi-process, and multi-parameter characteristics increase intermediate variables and complexity of modeling and analysis of solid oxide fuel cell cogeneration systems. This paper applied the standard thermal resistance for constructing the heat current model to analyze the overall heat transfer performance of the external heat exchangers. On this basis, the research introduced the equivalent electric circuit for presenting the internal electrochemical process and then proposed the overall cross-scale modeling of the solid oxide fuel cell cogeneration system from the internal heat and mass transfer and electrochemical processes to the various external heat exchangers. Moreover, considering the internal and external multi-processes, the system's overall constraints were derived. The simulation results show that the total energy utilization rate of the solid oxide fuel cell cogeneration system is 79.12 %. Besides, the influences of water-to-carbon ratio, excess air coefficient, thermal conductances of each heat exchanger, and ambient temperature on the system performance were developed. The optimal operation parameters are given for improving the maximum net power generation of the system. Finally, the proposed cross-scale modeling method is feasible and convenient for analyzing and improving the solid oxide fuel cell cogeneration system.

Enhancement of Fischer-Tropsch Synthesis by Periodical Draining of the Wax-Filled Pores of a Cobalt Catalyst by Hydrogenolysis

Fischer-Tropsch reactors operated in a steady state suffer from a low pore effectiveness factor and a high methane selectivity caused by internal mass transfer limitations due to the accumulation of long-chain hydrocarbons inside the catalyst pores. Therefore, an alternating process switching between Fischer-Tropsch synthesis (FTS) and drainage of the pores by hydrogenolysis is proposed. The periodical cracking of the accumulated waxes within the (partially) filled pores, realized by a switch from syngas (H&lt;sub&gt;2&lt;/sub&gt;, CO) to pure hydrogen, results in a higher overall catalyst productivity and a more favorable product distribution. The influence of temperature and time of FTS on drainage time and product distribution was experimentally investigated at typical temperatures of FT fixed bed processes in a range of 210 to 240°C. Alternating drainage of the pores by hydrogenolysis at a hydrogen partial pressure of just 1 bar leads to an improvement of the rate of CO conversion by up to 90% (240°C, 2 h FTS) and an improvement of even 120% concerning the rate of production of non-methane hydrocarbons (240°C, 2 h FTS).

Исследование гигроскопических параметров желатина из отходов переработки рыбы

We studied the hygroscopic properties of gelatin from waste-products after processing of common fresh-water fish species form the Astrakhan region (skin, scales, bones, fins, and cartilage) as an object of drying. The analysis of the thermodynamics of internal mass transfer was carried out during the interaction of the substance of the specified product with water. The objects of study were concentrates obtained by convective-radiation drying of gelatin granules, previously foamed to a constant expansion ratio and cooled to the gelatinization temperature. The studies were carried out experimentally and analytically using the tensometric method by Van Bamelen. For the thermodynamic analysis of hygroscopic characteristics, classical Gibbs–Helmholtz equation was used. On the basis of empirical data, sorption isotherms were obtained – functional dependences of the level of water activity Aw on the equilibrium moisture content and temperature of the product. The isotherms of the concentrates of the studied gelatin are S-shaped, typical for colloidal capillary-porous bodies, which is due to the foam structure of the product. The curves can be conventionally subdivided into three zones, corresponding to the moisture of monomolecular and polymolecular adsorption, structural, microcapillary, and microcapillary moisture. Based on the analysis of sorption isotherms for the product under study, the hygroscopic moisture content of gelatin was determined for its various temperatures: Wg1 = 0.280 kg/kg for T = 283 K and Wg2 = 0.301 kg/kg for T = 303 K. The specified moisture content is a threshold for the range of hygroscopic states and is important from the point of view of rationalization and modeling heat and mass transfer during material dehydration. As a result of calculations using sorption isotherms and the Gibbs–Helmholtz equation, the dependences of free, bound, and internal energy as well as the total specific thermal energy of water evaporation on moisture content and temperature of the product under study were derived. It has been established that the nature of these dependences for the studied samples of gelatin concentrates is generally consistent with the published data for a number of materials of a biopolymer nature. These dependencies can be used in the development of dehydration processes and in the design of drying equipment for the production of gelatin concentrates from fish waste.

Dimethyl ether low-temperature catalytic oxidation over Rh/Al2O3 in a stagnation-flow reactor

Dimethyl ether (DME) is a promising fuel for use in low-temperature portable hydrogen production, domestic applications, or diesel engines. It burns with less emissions than conventional fuels and has properties similar to LPG in terms of storage and transport, rendering it effective in many strategies for combating climate change. In this study we investigated the partial and total oxidation of DME over 5 wt% Rh/Al2O3 at low temperatures (215 to 320 °C), relevant to portable and domestic energy applications as well as the after-treatment systems of DME-powered engines. We captured the effects of temperature, flow rate, and inlet feed composition on the reactivity. For partial oxidation, we utilized the stagnation-flow reactor geometry to isolate the oxidation zone from the reforming zone. We discuss the reaction order with respect to DME and O2 and provide activation energy values under kinetics control. We also provide data where internal and external mass transfer limitations are present to examine the diffusive-convective transport near the catalyst surface, not easily done in three-dimensional environments such as packed beds. The experimental data we provide here pave the way for accurate kinetic modeling of DME partial and total oxidation on Rh/Al2O3, for reactor design and optimization as well as rational catalyst design.

The internal circulations on internal mass transfer rate of a single drop in nonlinear uniaxial extensional flow

The internal flow of a droplet in the nonlinear extensional flow field will exhibit more than two internal circulations with the variation of nonlinear intensity (E). In this paper, the effect of positions and sizes of internal circulations on internal mass transfer rate of a single spherical droplet in a nonlinear extensional flow field is studied and compared with that in a linear extensional flow field. The simulation results show that when E ≥ 0, there are two symmetrical internal circulations in the droplet, which is the same with that in a linear extensional flow. The limit value of mass transfer rate Sh is 15, which is equal to that in a linear extensional flow, no matter how large E is. When E ≤ –3/7, the number of internal flow circulation of a droplet increase to four and the transfer rate Sh increases. When E = –1, the maximum internal transfer rate Sh equals 30 which is twice of that in a linear extensional flow. The generation of new flow circulations in droplets and the circulation positions will enhance mass transfer when E ≤ –3/7, which provides a new idea for enhancing the internal mass transfer rate of droplets.

Separate effect of turbulent pulsation on internal mass transfer in porous biofilms

Turbulence is considered to be the result of coupled time-averaged and pulsating velocities, making it difficult to distinguish the respective effects, and the quantitative effect of turbulent pulsation alone on mass transfer within biofilms has not been discussed in the literature. In this study, we constructed a special oscillating grid biofilm reactor combining Particle Image Velocimetry (PIV) measurements and Computational Fluid Dynamics (CFD) simulations to achieve nearly isotropic turbulence in a designed ambient without time-averaged velocity and shear stress. Subsequently, velocity and contaminant concentration distributions were obtained by solving a mass transfer model with a k-ε turbulence model, combined with measurements of biofilm structure parameters. The results showed that the increase in turbulent pulsation intensity led to a significant stratification of the percolation velocity gradient in biofilms, which enhanced convective mass transfer. The changes of biofilm density and porosity under turbulent pulsation were more strongly correlated with convective mass transfer. When the turbulent intensity (q) increased to 2.50 cm s−1, the removal rate reached the highest value of 96.93%, accelerating the migration of contaminant concentration and the diffusive mass transfer effect was obvious. In addition, the trend of biofilm thickness under turbulent pulsation was consistent with the change of contaminant concentration distribution, and the correlation between them was greater. In summary, at q of 2.50 cm s−1, there was a positive effect on both convection and diffusion mechanisms in biofilms, and the contaminant removal rate and biofilm thickness reached the maximum, which was the recommended turbulent pulsation conditions.

Synthesis of Ibuprofen Monoglyceride Using Novozym®435: Biocatalyst Activation and Stabilization in Multiphasic Systems

This work was focused on the enzymatic esterification of glycerol and ibuprofen at high concentrations in two triphasic systems composed of toluene+ibuprofene (apolar) and glycerol or glycerol–water (polar) liquid phases, and a solid phase with the industrial immobilized lipase B from Candida antarctica named Novozym®435 (N435) acting as the biocatalyst. Based on a preliminary study, the concentration of the enzyme was set at 30 g·L−1 and the stirring speed at 720 r.p.m to reduce external mass transfer limitations. To obtain more information on the reaction system, it was conducted at a wide range of temperatures (50 to 80 °C) and initial concentrations of ibuprofen (20–100 g·L−1, that is, 97 to 483 mM). Under these experimental conditions, the external mass transfer, according to the Mears criterion (Me = 1.47–3.33·10−4 &lt;&lt; 0.15), was fast, presenting no limitation to the system productivity, regardless of the presence of water and from 50 to 80 °C. Considering that the enzyme is immobilized in a porous ion-exchange resin, limitations due to internal mass transfer can exist, depending on the values of the effectiveness factor (η). It varied from 0.14 to 0.23 at 50 to 80 °C and 0.32–1 mm particle diameter range in the absence of water, and in the same ranges, from 0.40 to 0.66 in the presence of 7.4% w/w water in the glycerol phase. Thus, it is evident that some limitation occurs due to mass transfer inside the pores, while the presence of water in the polar phase increases the productivity 3–4 fold. During the kinetic study, several kinetic models were proposed for both triphasic reacting systems, with and without first-order biocatalyst deactivation, and their fit to all relevant experimental data led to the observation that the best kinetic model was a reversible hyperbolic model with first-order deactivation in the anhydrous reaction system and a similar model, but without deactivation, for the system with added water at zero time. This fact is in sharp contrast to the use of N435 in a water-glycerol monophasic system, where progressive dissolution of ibuprofen in the reacting media, together with a notable enzyme deactivation, is observed.