Hydrophobic Membrane Contactor Research Articles

Life Cycle Assessment of Post-Combustion CO2 Capture and Recovery by Hydrophobic Polypropylene Cross-Flow Hollow Fiber Membrane Contactors with Activated Methyldiethanolamine

The present study evaluated the environmental impacts of post-combustion CO2 capture and recovery via membrane–gas absorption processes. We have used SimaPro v.9 packages with the Ecoinvent v3.5 database employing two different methods, ReCiPe 2016 Endpoint (H) and Midpoint (H), considering a fundamental methodological framework to determine the most environmentally friendly experimental condition. Life cycle impact categories were examined and assessed supposing a functional unit of 1 kgCO2/h recovered. Fourteen environmental impact categories including global warming, ozone depletion, eutrophication, and toxicity potentials have been evaluated within the context of a gate-to-gate approach focusing on only the process stage. Simulation results showed that the maximum liquid flow rate, sweep helium flow rate together with the minimum solvent concentration demonstrated the highest impact on human health, ecosystem, and resources. The usage of pure methyldiethanolamine (MDEA) activated by piperazine as a reactive absorbent provided the lowest environmental impact due to the elimination of the energy needed to heat and evaporate water present in aqueous absorbent solutions and the prevention of the excess water consumption depending on meeting the water needed for reactive absorption of CO2 in tertiary amine MDEA from simulated humidified flue gas stream. The study highlights the importance of LCA in the determination of an environmentally more sustainable condition during the capture and recovery of post-combustion CO2 by gas absorption and stripping using membrane contactors in tertiary amine MDEA.

CO2 Stripping from Monoethanolamine through a Polypropylene/CH3SiO2 Composite Hollow‐Fiber Membrane Contactor

AbstractTo remove CO2 through a membrane contactor system, composite polypropylene (PP) hollow‐fiber membranes were fabricated by dispersing methyl‐grafted silica nanoparticles in a PP membrane matrix. A set of characterization tests including FTIR spectroscopy, FESEM, AFM, TEM, porosity, contact angle, mechanical strength, and CO2 stripping experiments was carried out. The results showed that the porosity, hydrophobicity, roughness, and CO2 stripping flux of the composite membranes increased with increasing content of inorganic NPs. At an absorbent flow rate of 2.5 m s−1, the CO2 stripping flux of composite membranes containing 1.5 wt % NPs was higher than those of most other hydrophobic membrane contactors.

Extraction of penicillin-G from pharmaceutical wastewaters via a developed hydrophobic PVDF-HFP hollow fiber membrane contactor and process optimization

Discharge of pharmaceutical wastewaters can cause substantial environmental impacts. Since the conventional wastewater treatment processes are not efficient for comprehensive separation of pharmaceutical substances, a non-dispersive solvent extraction via a hollow fiber membrane contactor can be a promising alternative. In the present study, a structurally developed poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) hollow fiber membrane was fabricated via a non-solvent induced phase separation (NIPS) process to enhance extraction of penicillin-G (Pen-G) from the wastewater. Response surface methodology (RSM) was used for optimization of the main operating variables in the liquid–liquid membrane contactor process. From FESEM examination, the prepared membrane showed an open structure with large finger-likes, ultra-thin outer skin, and inner skinless layer. The membrane presented a narrow pore size distribution with mean pore size of 0.038μm, water contact angle of about 94°, critical water entry pressure of 350 kPa, and overall porosity of about 84 %. Extraction of Pen-G from the aqueous phase by 5 wt% organic solution of Aliquat 336 was performed. The feed concentration of 218 ppm, temperature of 41 °C, flowrate of 51 ml/min, and the organic phase flowrate of 144 ml/min were the optimum values predicted by the model. A maximum Pen-G extraction flux of 1.55×10−3 kg/m2 s was predicted at the optimum operating conditions. The value of error between the experimental and predicted fluxes was about 3.23% which confirmed accuracy of the model. Due to the developed membrane structure, the prepared PVDF-HFP hollow fiber membrane showed a considerably higher Pen-G extraction flux compared to the PP commercial membranes.

Evaluation of potassium glycinate, potassium lysinate, potassium sarcosinate and potassium threonate solutions in CO2 capture using membranes

The mitigation process of greenhouse gases emission such as CO2 into the atmosphere is known as a vital necessity in modern societies. Nowadays, amino acid salt solutions (AASSs) have been extensively applied as a promising alternative to alkanol amine absorbents to increase the CO2 sequestration efficiency from disparate gaseous flows. This article aims to computationally and theoretically evaluate the CO2 separation percentage using potassium glycinate (PG), potassium lysinate (PL), potassium sarcosinate (PS) and potassium threonate (PT) amino acid solutions from an inlet gaseous mixture inside a hydrophobic membrane contactor (HMC). To do this, the governing first principal equations inside the HMC are solved using the computational fluid dynamics procedure based on finite element technique. Acceptable agreement between the simulation results and experimental values with average deviation of approximately 3% implies the validation of developed two-dimensional (2D) simulation approach developed in this study. The analysis of obtained results demonstrated that PG is the most efficient amino acid solution for CO2 molecular sequestration with the ability of separating 90% of inlet CO2 in the system. The order of solutions is 90% sequestration using PG > 89.3% sequestration using PT > 77.4% sequestration using PL > 72.3% sequestration using PS.

Maximising resource recovery from wastewater grown microalgae and primary sludge in an anaerobic membrane co-digestion pilot plant coupled to a composting process

A pilot-scale microalgae (Chlorella spp.) and primary sludge anaerobic co-digestion (ACoD) plant was run for one year in an anaerobic membrane bioreactor (AnMBR) at 35 °C, 70 d solids retention time and 30 d hydraulic retention time, showing high stability in terms of pH and VFA concentration. The plant achieved a high degree of microalgae and primary sludge substrate degradation, resulting in a methane yield of 370 mLCH4·gVSinf−1. Nutrient-rich effluent streams (685 mgN·L−1 and 145 mgP·L−1 in digestate and 395 mgNH4-N·L−1 and 37 mgPO4-P·L−1 in permeate) were obtained, allowing posterior nutrient recovery. Ammonium was recovered from the permeate as ammonia sulphate through a hydrophobic polypropylene hollow fibre membrane contactor, achieving 99% nitrogen recovery efficiency. However, phosphorus recovery through processes such as struvite precipitation was not applied since only 26% of the phosphate was available in the effluent. Composting process of the digestate coming from the ACoD pilot plant was assessed on laboratory-scale Dewar reactors, as was the conventional sludge compost from an industrial WWTP digestion process, obtaining similar values from both. Sanitised (free of Escherichia coli and Salmonella spp.) and stable compost (respirometric index at 37 °C below 0.5 mgO 2 g organic matter−1·h−1) was obtained from both sludges.

Critical gas velocity of hydrophobic ceramic membrane contactors for SO2 absorption

Membrane gas absorption (MGA) based on ceramic membranes is considered to be an effective technology for removing SOx from ship exhaust. To develop a convenient method for designing and amplifying a membrane contactor, the critical gas velocity was defined. Two simple connection modes, series and parallel modules, were assembled and compared with a single-tube membrane contactor. The critical gas velocity is associated with the size of the membrane element and module, based on which an empirical equation can be formulated to optimize the gas velocity in different membrane contactors. In addition, another amplifying method, using multiple tubes in one shell, was also studied with computational fluid dynamics (CFD) simulations. The results imply that the addition of baffles improves the desulfurization performance of the membrane contactor at the critical gas velocity. The methods and conclusions presented herein provide a design basis for using the contactor at an industrial scale.

Resource recovery from industrial wastewaters by hydrophobic membrane contactors: A review

Abstract Hydrophobic membrane contactors (HMCs) are emerging as a promising alternative to conventional mass transfer and adsorption technologies for various wastewater treatment applications. The key advantages of this technology include large mass transfer area-to-volume ratios, no phase dispersion, ease of operation, and low energy consumption. More importantly, removed species have the potential to be concentrated in the stripping phase, allowing for recovery and recycled use. In this review, major applications of HMCs for resource recoveries from industrial wastewaters are summarized. We first start with the discussion on recoveries of ammonia nitrogen, dissolved methane, and cyanide from wastewaters via gas transfer HMCs. Next, we highlight the use of HMCs as a tool for liquid-liquid extraction for the recovery of phenol and heavy metal ions. The different process principles, mass transfer phenomena, and challenges facing each application are outlined and examined. We then focus in detail the Achilles heels of HMCs, namely membrane wetting and fouling, discussing their impacts on membrane and process performances, as well as the current mitigation methods. Last but not least, we share our insights and present the outlook for the HMCs, addressing critical gaps and recommendations for future research in areas such as fouling and wetting, long-term and scaled-up operations, economic feasibility as well as other ideas to reduce mass transfer resistance.

Computational fluid dynamics simulation of NO2 molecular sequestration from a gaseous stream using NaOH liquid absorbent through porous membrane contactors

Nitrogen dioxide (NO2) is known as a detrimental acidic contaminant, which its emission into the atmosphere can significantly endanger the human well-being. Therefore, the necessity of mitigating and controlling the NO2 molecules emission needs substantial attention. This research aims to addresses molecular sequestration of NO2 from a gaseous flow applying NaOH absorbent in a hydrophobic porous membrane contactor (HPMC). A mechanistic two dimensional (2D) model is developed based on mass transfer and fluid flow, while computational fluid dynamics (CFD) approach is used for numerical solution of the model's equations. The governing mathematical equations with their corresponding boundary conditions are solved via finite element (FE) approach. The comparison of the model's findings with the experimental data corroborated an excellent agreement with average absolute relative error (AARE) of approximately 2%. The results also demonstrated that the NaOH liquid absorbent can sequester 90% of the NO2 molecules at the inlet feed gas stream, which implies NaOH adequacy for NO2 molecular sequestration. Additionally, the results demonstrated the improvement of NO2 molecular sequestration by increasing some functional/operational parameters such as inner tube radius, module length, absorbent concentration and gas flow velocity inside the HPMC.

Mass transfer modelling of hollow fiber membrane contactor for apple juice concentration using osmotic membrane distillation

The present research study is based on theoretical and experimental investigation of hydrophobic porous hollow fiber membrane contactor (HFMC) module. The mass transfer diffusional model was developed for osmotic membrane distillation (OMD) and applied in apple juice concentration. The mathematical model was developed, taking into consideration the resistance-in-series concept for the mass transfer of water vapor molecules across the hydrophobic HFMC. The model was adapted to include the pore geometry, dimensionless numbers and concentration variation due to viscosity. The water vapor transport model was then simulated in MATLAB® and successfully validated with the experimental data. The model was applied to study the effects of driving forces for mass transfer and membrane porosity. Process parameters like juice concentration, stripping solution concentration, and Reynolds number were also studied to evaluate their effect on the overall mass transfer co-efficient and water vapor flux. The OMD experiments for the concentration of clarified apple juice were carried out in a laboratory-scale HFMC mini-module composed of two independent circuits, for stripping solution (CaCl2) and apple juice, respectively, in a total recycled mode. For the concentration of clarified apple juice, the evaporation flux ranged from 0.122 to 0.472 kgm−2h−1 resulting in a juice concentration of 30°Brix. The increase in pore diameter from 0.1 to 0.6 µm resulted in an increase in the mass transfer coefficient from 1.57 × 10−10 to 7.23 × 10−10 ms−1. Similarly, water vapor flux was increased from 0.02 to 0.50 kgm−2h−1, when the activity coefficient was changed from 0.1 to 0.5. Moreover, the results indicated that if the experimental parameters are carefully controlled, the simulation results can be used to predict the OMD process efficiency.

CH4/CO2 separation from biogas stream using porous hydrophobic ceramic hollow fiber membrane contactors

Experiments were performed to separate CO2 from biogas using a ceramic hollow fiber membrane contactor (HFMC). CH4/CO2 mixed gas (34.5% CO2, CH4 balance) and monoethanolamine (MEA) were used. The influence of operating conditions, such as the gas flow rate, liquid flow rate, L/G ratio, CO2 partial pressure, and module type, on the CO2 removal efficiency and CO2 absorption flux was evaluated. As the gas flow rate increased, the CO2 removal efficiency decreased, while the CO2 absorption flux increased. The maximum CO2 removal efficiency was 96% at a gas flow rate of 0.1Nm3 h−1 while the maximum CO2 absorption flux was 7.5×10−3 mol·m−2·s−1 at a gas flow rate of 1Nm3 h−1. Moreover, the CO2 absorption flux and CO2 removal efficiency could be increased by more than 20% using the high-flux module.

Pilot Scale Study: First Demonstration of Hydrophobic Membranes for the Removal of Ammonia Molecules from Rendering Condensate Wastewater.

Hydrophobic membrane contactors represent a promising solution to the problem of recycling ammoniacal nitrogen (N-NH4) molecules from waste, water or wastewater resources. The process has been shown to work best with wastewater streams that present high N-NH4 concentrations, low buffering capacities and low total suspended solids. The removal of N-NH4 from rendering condensate, produced during heat treatment of waste animal tissue, was assessed in this research using a hydrophobic membrane contactor. This study investigates how the molecular composition of rendering condensate wastewater undergo changes in its chemistry in order to achieve suitability to be treated using hydrophobic membranes and form a suitable product. The main objective was to test the ammonia stripping technology using two types of hydrophobic membrane materials, polypropylene (PP) and polytetrafluoroethylene (PTFE) at pilot scale and carry out: (i) Process modification for NH3 molecule removal and (ii) product characterization from the process. The results demonstrate that PP membranes are not compatible with the condensate waste as it caused wetting. The PTFE membranes showed potential and had a longer lifetime than the PP membranes and removed up to 64% of NH3 molecules from the condensate waste. The product formed contained a 30% concentrated ammonium sulphate salt which has a potential application as a fertilizer. This is the first demonstration of hydrophobic membrane contactors for treatment of condensate wastewater.

Hydrophilic membrane contactor for improving selective removal of SO2 by NaOH solution

Removal of SO2 from ship exhaust gas requires a specifically designed device due to the limitations of narrow space and inconvenient replacement of absorbent. Therefore, the scrubber should be high-efficient and the absorbent for SO2 removal should be efficiently utilized. In this work, a hydrophilic membrane (HIM) contactor was employed to selectively remove SO2 using NaOH solution from simulated ship exhaust gas. Mass transfer analysis demonstrated that the wetted membrane layer contributes to lower mass transfer of CO2 by limiting the diffusion of OH−, but it can improve the mass transfer of SO2 in the membrane phase. Experimental data showed that a SO2/CO2 selectivity factor of ~114 and a SO2 absorption flux over 0.2 mol·m−2·h−1 can be stably obtained using the HIM contactor and 0.4 mol·L−1 NaOH. These values were higher than those obtained in a hydrophobic membrane (HOM) contactor under the same conditions. The performance of selective removal of SO2 under various parameters were also investigated, including NaOH concentration, inlet SO2 concentration and packing density of membrane module.

Ammonia recovery from human urine as liquid fertilizers in hollow fiber membrane contactor: Effects of permeate chemistry

The production of the existing nitrogen fertilizer is costly and less environmental-friendly. Various green technologies are currently emerging toward providing alternative options. In this study, a liquid/liquid hydrophobic hollow-fiber membrane contactor was employed at ambient temperature and natural urine pH ~ 9.7 to recover ammonium fertilizers from human urine. Results showed that permeate side chemistry was one of the major factors affecting the ammonia mass transfer. The study on the ammonia capturing performance of diluted sulfuric acid, phosphoric acid, nitric acid, and DI water confirmed that acid type, acid concentration, and permeate side operating pH were the most important parameters affecting the ammonia capturing tendency. Sulfuric acid was slightly better in capturing more ammonia than other acid types. The study also identified increasing acid concentration didn’t necessarily increase ammonia mining tendency because there was always one optimum concentration value at which maximum ammonia extraction was possible. The best permeate side operating pH to extract ammonia for fertilizer purposes was selected based on the dissociation equilibrium of different types of acids. Accordingly, the analysis showed that the membrane process has to be operated at pH > 3 for sulfuric acid, between 3.5 to 11.5 for phosphoric acid, and above 0.5 for nitric acid so as to produce their respective high-quality liquid ammonium sulfate, ammonium monophosphate/diphosphate, and ammonium nitrate fertilizer. Therefore, permeate side acid concentration, pH, and acid type has to always be critically optimized before starting the ammonia mining experiment.

Mathematical modeling of CO2 membrane absorption system using ionic liquid solutions

This research presents a 2D mathematical modeling based on finite difference method (FDM) for absorption of CO2 into aqueous solution of ionic liquids ([bmim][BF4] and [bmim][PF6]) by means of hydrophobic polypropylene hollow fiber membrane contactor (HFMC). Governing equations with their corresponding boundary conditions were solved and the results were validated against reported experimental data and excellent agreement was found. This study has provided an opportunity to investigate the effects of various ionic liquids with different concentrations as well as liquid and gas flow rate on CO2 absorption system in membrane contactors. The results demonstrated that molar flux of carbon dioxide for 25 wt% and 50 wt% solution of [bmim][PF6] is 1.29 and 1.98 times that of pure water, respectively. Also [bmim][BF4] has a weaker performance than [bmim][PF6] due to lower carbon dioxide solubility, and the addition of 50 wt% of it to the pure water has increased the absorption rate by 32 %. Overall and liquid phase mass transfer coefficient has decreased in ionic liquid solutions. Reynolds number in tubes has been decreased by increasing of ionic liquid mass fraction and also a sharp decrease in the Reynolds number can be observed in the ionic liquids mass fractions greater than 60 wt%.

The effect of Hydrogen sulfide oxidation with ultraviolet light and aeration on sour water treatment via membrane contactors

During natural gas extraction and production, hydrogen sulfide (H2S) is often brought to the surface. In some cases, H2S could be present in water streams, referred to as “sour water”, treatment of that sour water is required before disposal or reuse. Sour water can be treated in a variety of ways including conventional stripping and chemical scavenging. Hydrophobic membrane contactors are an alternative technology for the treatment of sour water. Due to the hydrophobic nature of the membrane, dissolved gases, including H2S, can pass through while water is retained on the feed side. The sodium hydroxide receiving solution acts as a trap that captures the H2S. Once the H2S is trapped, ultraviolet (UV) light and oxygen can be applied to oxidize the sulfide to non-hazardous forms of sulfur allowing more disposal options for the receiving solution. This research focused on evaluating the feasibility and performance of a hybrid process combining a membrane contactor and a sulfide oxidation step through UV light and aeration.Oxidation experiments showed that UV light alone can oxidize the sulfide to disulfide. On the other hand, UV combined with oxygen, via aeration, was capable of further oxidizing sulfide to sulfate and thiosulfate; the two main sulfur species present in the treated water based on mass balance calculations. Both oxidation methods (UV with and without aeration) were found to follow a first order reaction rate, that of UV alone was 0.015 min−1, and when combined with aeration the rate was more than two times higher (0.035 min−1). The proposed hybrid technology can be applied in both upstream and downstream operations as a standalone process for the treatment of sour produced and process water.

Supported ionic liquid membranes (SILMs) as a contactor for selective absorption of CO2/O2 by aqueous monoethanolamine (MEA)

Application of membrane contactors in a combination of monoethanolamine as a solvent system for post-combustion CO2 capture has been extensively studied in the last decades. Due to the better performance to capture CO2 at low concentration, the potentialities of novel technology of supported ionic liquids membranes (SILMs) for absorption process in gas-liquid membrane contactor system are currently being explored to improve and compliment previous technology. In this study, a modified hydrophobic gas-liquid membrane contactor system was prepared using Liqui-Cel® parallel flow module as a membrane support and 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide [emim] [NTf2] ionic liquid as a supporting phase. Under moderate operating conditions, parallel flow mode and use of monoethanolamine (MEA) as an absorbent, the effects of absorbent temperature and gas velocity on the CO2 absorption efficiency and CO2/O2 selectivity were determined using this modified module. Further investigation to compare the performances of blank and modified membrane module was implemented at different temperatures (303–348 K) and gas velocities (4.63 × 10−6 to 3.70 × 10−5 m s−1). Results revealed that efficiency of the CO2 absorption process of the modified module is almost doubled with an average selectivity factor of CO2/O2 around 5 times compared to blank contactor system. Thus, this modified membrane contactor system had shown a great potential for further used in the real industrial CO2 capture and beneficial to bottleneck the issue of MEA oxidation that usually occurred in previous gas-liquid membrane contactor system.

Study on CO2 absorption performance of lab-scale ceramic hollow fiber membrane contactor by gas/liquid flow direction and module design

Membrane contactor has been actively studied in recent years, but it is difficult to modulate the ceramic hollow fiber membranes because they are extremely brittle and poor in flexibility. For this reason, research on ceramic hollow fiber membrane contactor modules has been rarely carried out. In this study, hydrophobic modified ceramic hollow fiber membranes were fabricated by phase inversion method. 1-in. unit module, a 3-parallel connection module, and a 2.5-in. advanced module with the ceramic hollow fiber membranes were developed. A membrane contactor CO2 capture system with the module was set up and characteristics of ceramic hollow fiber membrane contactor were analyzed. The highest CO2 absorption property was observed in the configuration in which the liquid flows on the shell side from the bottom to the top, and the gas and the liquid contacts in the counter-current. In addition, a lab-scale ceramic hollow fiber membrane contactor unit module was successfully developed to treat 0.175 Nm3/h flue gas with 90% CO2 removal efficiency. To the best of my knowledge, this is the first case of CO2 absorption experiment using hydrophobic ceramic hollow fiber membrane contactor module instead of the polymeric membrane module or single ceramic membrane. These results are expected to be very valuable as fundamental and important data for scale-up of ceramic membrane contactor process.

Dynamic modelling and experimental validation of CO2 removal using hydrophobic membrane contactor with different types of absorbent

In this study, a dynamic model was proposed to simulate and validate the profile of carbon dioxide (CO2) absorption using in-house fabricated mixed matrix membrane (MMM) from membrane gas absorption (MGA) contactors. The flat sheet MMM was fabricated by incorporating TS-530 fumed silica nanoparticles into polyvinylidene fluoride (PVDF) polymer matrix. The membrane surface was coated with low-density polyethylene (LDPE) to enhance membrane hydrophobicity and performance. The performance of the membrane on CO2 absorption was tested in the MGA contactor using different types of liquid absorbent; water, 2-amino-2-methyl-1-propanol (AMP) and dimethylamine (DEA). The mass transfer of CO2 through gas phase, membrane and liquid phase was taken into account in the proposed model. The physical and chemical absorption in liquid phase was also considered during the simulation process. Other than Henry’s constant of CO2 into the absorbent, the solubility of CO2 in the polymeric membrane was also found to have a significant effect on the CO2 absorption. The simulation results were found to be in agreement with the experimental data of CO2 absorption flux.

Continuous Ammonia Recovery from Wastewaters Using an Integrated Capacitive Flow Electrode Membrane Stripping System.

We have previously described a novel flow-electrode capacitive deionization (FCDI) unit combined with a hydrophobic gas-permeable hollow fiber membrane contactor (designated "CapAmm") and presented results showing efficient recovery of ammonia from dilute synthetic wastewaters (Zhang et al., Environ. Sci. Technol. Lett. 2018, 5, 43-49). We extend this earlier study here with description of an FCDI system with integrated flat sheet gas permeable membrane with comprehensive assessment of ammonia recovery performance from both dilute and concentrated wastewaters. The integrated CapAmm cell exhibited excellent ammonia removal and recovery efficiencies (up to ∼90% and ∼80% respectively). The energy consumptions for ammonia recovery from low-strength (i.e., domestic) and high-strength (i.e., synthetic urine) wastewaters were 20.4 kWh kg-1 N and 7.8 kWh kg-1 N, respectively, with these values comparable to those of more conventional alternatives. Stable ammonia recovery and salt removal performance was achieved over more than two days of continuous operation with ammonia concentrated by ∼80 times that of the feed stream. These results demonstrate that the integrated CapAmm system described here could be a cost-effective technology capable of treating wastewaters and realizing both nutrient recovery and water reclamation in a sustainable manner.

N2O absorption through super hydrophobic hollow fiber membrane contactor

Dinitrogen monoxide (N2O) is mainly produced in Horticulture and farming activities, industrial processes and combustion of fossil fuels. N2O is one of the harmful emissions and its global warming potential is 310 times greater than CO2 on a molecular basis. This research aims to absorb N2O from its mixture with air through super hydrophobic hollow membrane contactor using a mixture of 0.5M HNO3 and 0.5 wt % H2O2 solutions as absorbent. In the experiment, the feed gas flowed through the shell side of the contactor, while absorbent solution flowed through the lumen fibers. Experimental results show that the amount of N2O absorbed and N2O absorption efficiency increased with the absorbent flow rate and the number of fibers in the contactor resulting from the increase in the turbulence and surface area for gas–liquid contact, respectively. The overall mass transfer coefficient and the flux increased with the absorbent flow rate due to the decrease of the mass transfer resistance in the liquid phase. However, the overall mass transfer coefficient and the flux decreased with the number of fibers in the contactor due to the decrease of the absorbent flow rate in a single fiber. The amount of N2O absorbed and the flux increased but the N2O absorption efficiency decreased with increasing the feed gas cross flow rate. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 362–366, 2019