Simulation of Carbon Dioxide Removal by Three Amine Mixture of Diethanolamine, Methyldiethanolamine, and 2-Amino- 2-Methyl-1-Propanol in a Hollow Fiber Membrane Contactor Using Computational Fluid Dynamics

The present paper investigates the simulation of carbon dioxide removal from natural gas stream by a mixture of three amines of diethanolamine (DEA), methyldiethanolamine (MDEA), and 2-amino- 2-methyl-1-propanol (AMP) in a hollow fiber membrane contactor made from polypropylene using finite volume method (FVM). The effect of structural parameters of length and thickness of membrane and diameter of shell on the removal efficiency was studied and the optimized values were calculated. The calculations were made with the assumption of two-dimensional symmetric geometry and compared with those of three-dimensional one. The effect of number and size of the meshes on the simulation results was also studied. The simulation results were validated against the experimental values from the literature. The results imply that the increase in the length and decrease in the thickness of membrane enhances the removal efficiency. As a result, higher quantities of carbon dioxide are transferred from the shell to the membrane and amine solution inside the tube which decreases the effluent CO2 of shell and increases the average concentration of CO2 in the membrane and tube sides. The changes in effluent CO2 of shell with respect to amine solution concentration and influent CO2 indicate the insignificant influence of influent CO2 concentration on the removal efficiency

Investigation of mass transfer coefficients in irregular packed liquid-liquid extraction columns in the presence of various nanoparticles

In the present study, the effect of various nanofluids on mass transfer coefficients in an irregular packed liquid-liquid extraction column was investigated. The chemical system of toluene–acetic acid–water was used. 10 nm SiO2, TiO2 and ZrO2 nanoparticles with various concentrations were dispersed in toluene-acid acetic to provide nanofluids. The influence of concentration and hydrophobicity/hydrophilicity of nanoparticle on mass transfer coefficient was discussed. The experimental results show that the mass transfer coefficient enhancement depends on the kind and the concentration of nanoparticles. The maximum enhancement of 35%, 245% and 207% was achieved for 0.05 vol% of SiO2, TiO2 and ZrO2 nanofluids, respectively. A new conceptual model was proposed for prediction of the effective diffusivity as a function of nanoparticle concentration, drop size and drop Reynolds number

Poly (Vinylidene Fluride) Membrane Preparation and Characterization: Effects of Mixed Solvents and PEG Molecular Weight

In this study, polyvinylidene fluoride (PVDF) ultrafiltration membranes were prepared via immersion precipitation method using a mixture of two solvents triethyl phosphate (TEP) and dimethylacetamide (DMAc), which had different affinities with the nonsolvent (water). Properties of the prepared membranes were characterized using scanning electron microscope (SEM) and contact angle and membrane porosity measurements. The prepared membranes were further investigated in terms of pure water flux and BSA rejection in cross flow filtration experiments. The results showed that by using a mixture of DMAc and TEP as solvent and changing the mixed solvent composition, membranes with different morphologies from sponge-like to macrovoid containing were obtained. Maximum flux of the prepared membranes with different solvent mixing ratios was obtained for the one with 60%wt TEP in the casting solution of PVDF/TEP-DMAc/ PEG which equals to 76.8 lm-2h-1. The effect of addition of polyethylene glycol with different molecular weight on morphology and performance of the membranes has also been discussed. </span

High Loaded Synthetic Hazardous Wastewater Treatment Using Lab-Scale Submerged Ceramic Membrane Bioreactor

Submerged ceramic membrane bioreactors (SCMBRs) are more efficient combinations of traditional activated hazardous sludge and new membrane separation processes in wastewater treatment. Suspended solids are separated from hazardous effluent using microfilter ceramic membranes in SCMBRs. A&nbsp;high loaded wastewater was treated using an SCMBR employing a homemade tubular ceramic membrane in laboratory scale. Hydraulic Retention Time (HRT) was 32 h and COD range was varied from 2000 to 5000 mg/l. COD removal was evaluated to be more than 90% after a week and the lab scale SCMBR showed desired performance for the wastewater treatment. Mixed Liquor Suspended Solid (MLSS) was increased from 2000 to 4000 mg/L during the SCMBR operation time

Gas transport properties of reverse-selective poly(ether-b-amide6)/[Emim][BF4] gel membranes for CO2/light gases separation

The present research investigates deeply the effect of 1-ethyl-3 methylimidazolium tetrafluoroborate ([Emim][BF]) ionic liquid on separation performance and transport properties of poly(ether-b-amide6) (Pebax1657) at different operating pressures from 2 to 20bar and temperatures from 25 to 65°C. [Emim][BF] showed interesting separation factor for CO/light gases as a solvent and it was expected that its addition to Pebax1657 leads to more amorphous structure, thereby increasing diffusion and permeability of gases. [Emim][BF] was added to the polymer solution up to 100wt% of Pebax1657 weight and permeation coefficients of CO, H, CH and N through the prepared membranes were measured. The results showed remarkable increment in permeation of all the tested gases, particularly CO and ideal selectivity of CO/H enhanced significantly due to high solubility selectivity of the added compound. Effect of operating conditions on solubility coefficients was also investigated; thus sorption isotherms and activation energies of permeability, solubility and diffusion were calculated. In addition, the membranes were characterized by SEM, DSC, FT-IR spectroscopy and Tensile analysis to inspect changes in their physical and thermal properties, precisely

Wastewaters treatment containing phenol and ammonium using aerobic submerged membrane bioreactor

Abstract Phenolic wastewater was treated using anaerobic submerged membrane bioreactor (ASMBR). Effect of different solids retention times on MBR performance was studied. Various ratios of carbon to nitrogen were used in the synthetic wastewaters. During the operation, phenol concentration of feed was changed from 100 to 1000 mg L−1. Phenol concentration was increased stepwise over the first 30 days and kept constant at 1000 mg L−1, thereafter. For the first 100 days, a chemical oxygen demand (COD) to N ratio of 100:5.0 was used and this resulted in phenol and COD removal more than 99 and 95%, respectively. However, the ammonium removal decreased from 95 to 40% by increasing the phenol concentration of feed, from 100 to 1000 mg L−1. For the last 25 days, a COD to N ratio of 100:2.1 was used due to the ammonium accumulation in the ASMBR. This led to the complete ammonium removal and no ammonium was detected in the ASMBR permeate. These results suggest that in the ASMBR at high phenol loading of 1000 mg L−1, COD to N ratio of the phenolic wastewater must be 100:2.1 for ammonium removal, while at low phenol loading, COD to N ratio of 100:5.0 can be used

Synthesis of Nanostructured Anatase Mesoporous Membranes with Photocatalytic and Separation Capabilities for Water Ultrafiltration Process

In this work, the nanostructured anatase mesoporous membranes were prepared for water ultrafiltration (UF) process with photocatalytic and physical separation capabilities. A macroporous substrate was synthesized from α-Al2O3, then a colloidal titania sol was used for the preparation of the intermediate layer. Also, the membrane top layer was synthesized by deposition and calcination of titania polymeric sol on the intermediate layer. The characterization was performed by DLS, TG-DTA, XRD, BET, FESEM, TEM, and AFM techniques. Also, the filtration experiments were carried out based on separation of methyl orange from aqueous solution by a membrane setup with a dead-end filtration cell. Photocatalytic activity of the membranes was evaluated by methyl orange photodegradation using UV-visible spectrophotometer. The mean particle size of the colloidal and polymeric sols was 14 and 1.5 nm, respectively. The anatase membranes exhibited homogeneity, with the surface area of 32.8 m2/g, the mean pore size of 8.17 nm, and the crystallite size of 9.6 nm. The methyl orange removal efficiency by the mesoporous membrane based on physical separation was determined to be 52% that was improved up to 83% by a coupling photocatalytic technique. Thus, the UF membrane showed a high potential due to its multifunctional capability for water purification applications