Korean Journal of Chemical Engineering (v.30, #9)

Synthesis of metal-organic frameworks: A mini review by Yu-Ri Lee; Jun Kim; Wha-Seung Ahn (1667-1680).
Metal organic frameworks (MOFs) are porous crystalline materials of one-, two-, or three-dimensional networks constructed from metal ions/clusters and multidentate organic linkers via coordination bonding, which are emerging as an important group of materials for energy storage, CO2 adsorption, alkane/alkene separation, and catalysis. To introduce newcomers in chemical engineering discipline to the rapidly expanding MOF research works, this review presents a brief introduction to the currently available MOFs synthesis methods. Starting from the conventional solvothermal/hydrothermal synthesis, microwave-assisted, sonochemical, electrochemical, mechanochemical, ionothermal, drygel conversion, and microfluidic synthesis methods will be presented. Examples will be limited to those representative MOF structures that can be synthesized using common organic ligands of 1,4-benzenedicarboxylic acid (and its functionalized forms) and 1,3,5-benzenetricarboxylic acid, in conjunction with metal nodes of Zn2+, Cu2+, Cr3+, Al3+, Fe3+ and Zr4+. Synthesis of widely-investigated zeolitic imidazolate framework (ZIF) structure, ZIF-8 is also included.
Keywords: Metal Organic Frameworks (MOFs); Zeolitic Imidazolate Frameworks (ZIFs); Solvothermal/Hydrothermal Synthesis; Microwave; Sonochemistry; Electrochemical Synthesis; Mechanochemical Synthesis

A feed forward three-layer artificial neural network (ANN) model was developed for VLE prediction of ternary systems including ionic liquid (IL) (water+ethanol+1-butyl-3- methyl-imidazolium acetate), in a relatively wide range of IL mass fractions up to 0.8, with the mole fractions of ethanol on IL-free basis fixed separately at 0.1, 0.2, 0.4, 0.6, 0.8, and 0.98. The output results of the ANN were the mole fraction of ethanol in vapor phase and the equilibrium temperature. The validity of the model was evaluated through a test data set, which were not employed in the training case of the network. The performance of the ANN model for estimating the mole fraction and temperature in the ternary system including IL was compared with the non-random-two-liquid (NRTL) and electrolyte non-random-two-liquid (eNRTL) models. The results of this comparison show that the ANN model has a superior performance in predicting the VLE of ternary systems including ionic liquid.
Keywords: Vapor-liquid Equilibrium; Ionic Liquid; Ternary System; Artificial Neural Network

A novel triazine flame retardant (FR) has been successfully synthesized by the reaction of cyanuric chloride with sodium sulfanilate followed by diethanol amine. Its structure has been fully characterized by IR and 1H NMR spectroscopy. The effects of reaction solvent, acid-binding agent, reaction temperature, and molar ratio of starting materials on the yield of FR were investigated in detail. Experiments showed that when the molar ratio of intermediate I to diethanol amine is 1 to 1.2 in the presence of sodium carbonate as acid-binding agent in acetone-water at 45 °C, the yield of the obtained FR reaches 81.4%. Thermogravimetry (TG) test indicated that the FR has good thermostability and char-forming ability. In addition, the flame retardancy and thermal behavior of the cotton fabrics treated with FR were studied by limiting oxygen index (LOI), vertical flammability test, and thermogravimetry (TG) to evaluate the flameretardant performance of the target FR. These results demonstrated that the flame retardancy and thermal stability of the cotton fabrics treated with FR were clearly improved.
Keywords: Triazine; Flame Retardant; Synthesis; Thermal Stability; Cotton Fabrics

An explicit solution of the mathematical model for osmotic desalination process by Do Yeon Kim; Boram Gu; Dae Ryook Yang (1691-1699).
Membrane processes such as reverse osmosis and forward osmosis for seawater desalination have gained attention in recent years. Mathematical models have been used to interpret the mechanism of membrane processes. The membrane process model, consisting of flux and concentration polarization (CP) models, is coupled with balance equations and solved simultaneously. This set of model equations is, however, implicit and nonlinear; consequently, the model must be solved iteratively and numerically, which is time- and cost-intensive. We suggest a method to transform implicit equations to their explicit form, in order to avoid an iterative procedure. In addition, the performance of five solving methods, including the method that we suggest, is tested and compared for accuracy, computation time, and robustness based on input conditions. Our proposed method shows the best performance based on the robustness of various simulation conditions, accuracy, and a cost-effective computation time.
Keywords: Modeling; Desalination; Reverse Osmosis; Forward Osmosis; Membrane Process

Evaluation of solvent dearomatization effect in heavy feedstock thermal cracking to light olefin: An optimization study by Mohsen Nouri; Mehdi Sedighi; Mostafa Ghasemi; Majid Mohammadi (1700-1709).
Response surface method was used to study the effect of aromatic extraction of heavy feedstock in thermal cracking. N-methylpyrrolidone as the solvent performing dearomatization of feedstock was at different temperature and molar solvent to oil ratios. Temperature, flow rate and steam-to-hydrocarbon ratio were in the range of 1,053–1,143 K, 1–2 g/g, and 0.75–1.2 g/min, respectively. From the CCD studies, the effects of flow rate and coil outlet temperature were the key factors influencing the yield of light olefins. Ethylene and propylene yields increased more than 10% by dearomatization. C 5 + decreased by 13% on average. Finally, we obtained the single maximum yield of ethylene, propylene, and simultaneous maximum yields for untreated and raffinate.
Keywords: Thermal Cracking; Dearomatization; Response Surface; Olefin; Multi-response Optimization

The effect of trimethyl phosphate on Cu/Zn catalyst prepared by co-precipitation method for hydrogenation of methyl laurate to dodecanol in a slurry phase was studied using a stirred autoclave reactor system. The catalysts were characterized by means of XRD, EDS, XPS, SEM and BET. The results indicated that catalytic activity decreased with the increased amount of trimethyl phosphate. Correlating with the results from the above characterization, it was found that the main cause for the catalyst deactivation was the trimethyl phosphate occlusion of active sites by the physical adsorption and BET surface area decrement.
Keywords: Fatty Alcohol; Cu/Zn Catalyst; Deactivation; Phosphate

Catalytic characteristics of carbon black for methane decomposition at high temperatures were investigated. A fixed bed reactor was made of carbon steel with 28 mm I.D and 450 mm height. The reaction was carried out under atmospheric pressure at temperature of 1,293–1,443 K. The objective was to investigate the catalytic activity of carbon black at high temperature, similar to the manufacturing process of carbon black. Almost 100% methane conversion was observed at 1,443 K, and the activation energy of the catalytic reaction over carbon black was 198 kJ/mol. The specific surface area decreased as the amount of deposited carbon increased. Since a large amount of the produced carbon was deposited on the surface, the increase of aggregates size and protrusions size of deposited carbon was larger than in the results of previous work.
Keywords: Catalytic Decomposition; Methane; Hydrogen; Carbon Black; Catalyst

A chelating matrix prepared by surface grafting of polymer containing a functional monomer, poly[1-(N,N-bis-carboxymethyl)amino-3-allylglycerol-co-methylacrylamide] (poly(AGE/IDA-co-DMAA) onto a modified silica. The silica surface was modified by silylation with 3-mercaptopropyltrimethoxysilane followed by graft polymerization. Monomer of allyl glycidyl ether-iminodiacetic acid was synthesized by reaction of allyl glycidyl ether with iminodiacetic acid. The chelating sorbent can be reused for 15 cycles of sorption-desorption without any significant change in sorption capacity. The profile of cobalt uptake on the sorbent reflects good accessibility of chelating sites in poly(AGE/IDA-co-DMAA)-grafted silica gel. The equilibrium adsorption data of Co(II) on modified sorbent were analyzed by Langmuir, Freundlich, Temkin and Redlich-Peterson models. The method was applied for cobalt ions determination in human plasma and sea water sample with satisfactory results.
Keywords: Solid Phase Extraction; Polymer Grafting; Cobalt; Isotherm Study; Preconcentration

We studied the simultaneous removal of Pb(II) and chemical oxygen demand (COD) from synthetic solutions using immobilized microorganism. The immobilized microorganisms on polyurethane foam (IPUF) were successfully prepared by cultivating the microbe B350 in a mixture of culture medium and polyurethane foam (PUF). The adsorption of Pb(II) ion from aqueous solutions onto PUF and IPUF was studied by batch adsorption. IPUF exhibited high Pb(II) removal efficiency. When 0.12 g of IPUF was used to treat 50mL of 20mg/L P(II) solution at pH 7.0 and 25 °C for 120 mins, the removal ratio was 80%. The biosorption kinetics could be described by the pseudo-secondorder model, and the adsorption isotherms could be described by Langmuir and Freundlich equations. In addition, for synthetic wastewater containing Pb(II) and C6H12O6, the removal ratios of Pb(II) and COD after being treated by IPUF for 8 hours were 92.0% and 84.2%, respectively. The removal ratio of COD clearly decreased with the increase of Pb(II) concentration, meaning that Pb(II) was toxic to the mobilized microorganisms and lower Pb(II) concentration was preferred.
Keywords: Immobilization; Adsorption; Pb(II); Polyurethane Foam; Wastewater Treatment

Simultaneous removal of SO2 and NO X with ammonia absorbent in a packed column by Yong Jia; Daqian Du; Xinxi Zhang; Xilou Ding; Oin Zhong (1735-1740).
Catalytic oxidation of NO followed by simultaneous removal of SO2 and NO X with ammonia is a promising method for control of coal-fired flue gas pollutants. We investigated simultaneous absorption of SO2 and NO X in a packed column with ammonia, and found that SO2 and NO X could promote absorption with each other in the process of simultaneous removal SO2 and NO X . The removal efficiency of SO2 and NO X was, respectively, about 98% and 70.9% at pH 5.5, temperature 323.15 K, SO2 concentration 1,800×10−6, NO X concentration 400×10−6 and $${{m_{NO_2 } } mathord{left/ {vphantom {{m_{NO_2 } } {m_{NO} }}} ight. kern- ulldelimiterspace} {m_{NO} }}$$ in our experimental system. The experimental results also show that the formation of sulfite oxidized by reacting with dissolved NO2 and the molar ratio of sulfite to total sulfur is more than 0.8 in the solution. Accordingly, the energy consumption for sulfite oxidation would be greatly reduced in the process of simultaneous desulfurization and denitrification with ammonia.
Keywords: Sulfur Dioxide; Nitrogen Oxides; Ammonia; Simultaneous Absorption

Effects of surfactant contamination on oxygen mass transfer in fine bubble aeration process by Xulu Chen; Guo-hua Liu; Haitao Fan; Meidi Li; Tao Luo; Lu Qi; Hongchen Wang (1741-1746).
The effects of anionic, cationic, and non-ionic surfactants (SDS, SDBS, CTAB and Tween20) on oxygen mass transfer (OMT) in fine bubble aeration systems were investigated. The overall gas-liquid volumetric mass transfer coefficient (K L a), specific interfacial area (a), and liquid-side mass transfer coefficient (K L ) parameters were used to assess the influence of the surfactants. At the same concentration, the different surfactants were observed to influence the K L a value as follows: K L a (SDBS)>K L a (SDS)>K L a (tween20)>K L a (CTAB). For all used surfactants, the overall trends showed a significant decrease in the K L a value at low concentrations (0–5mg/L), while the K L a value recovered somewhat at high concentrations (10–20mg/L). The decrease to the KL value was found to be much larger than increase in the a value in the presence of surfactants. Furthermore, a simple model was established that provides an OMT prediction for different surfactants.
Keywords: Surfactant; Fine-bubble Aeration; Mass Transfer; Interface Coverage Rate; OMT Prediction Model

Supramolecular recognition of functional magnesium tetraphenylporphyrin (MgTPP) with pyrrolidine for SO2 capture was investigated in CH2Cl2 by steady-state fluorescence and UV-vis absorption spectroscopic techniques. The UV-vis spectra showed that the interaction of MgTPP with pyrrolidine resulted in red shift of 2 nm for MgTPP Soret absorption band. Once introduced, SO2 competes with MgTPP for pyrrolidine, which eventually leads to the release of MgTPP. The fluorescence spectra suggested that MgTPP interacted with pyrrolidine to form 1: 1 molecular adducts, and showed that the binding of MgTPP with pyrrolidine with the association constants (Kassoc) of (0.86 to 1.19) is not only exothermic but enthalpy-driven with ΔH=−15.805 kJ mol−1, ΔS=−52.727 J mol−1 K1, and ΔG=−214.444 J mol−1 at T=296.15 K.
Keywords: Magnesium Tetraphenyl Porphyrin (MgTPP); Pyrrolidine; Spectroscopy; Thermodynamic

Sulfur removal of gas oil using ultrasound-assisted catalytic oxidative process and study of its optimum conditions by Zahra Shayegan; Mohammad Razzaghi; Aligholi Niaei; Dariush Salari; Mohammad Taghi Shervani Tabar; Arash Noshad Akbari (1751-1759).
Ultrasound-assisted oxidative desulfurization process (UAOD) was applied to reduce sulfur compounds of gas oil containing various types of sulfur content. The environmental regulation requires a very deep desulfurization to eliminate the sulfur compounds. UAOD is a promising technology with lower operating cost and higher safety and environmental protection. For the first time the typical phase transfer agent (tetraoctyl-ammonium-bromide) was replaced with isobutanol because using isobutanol is much more economical than TOAB, imposing no contamination. The reaction was carried out at optimal point with various temperatures, in single-, two- and three step-procedures, investigating the effect of gradual increase of H2O2 and TOAB being used instead of isobutanol. Total sulfur concentration in oil phase was analyzed by ASTM-D3120 method. The highest removal of about 90% for gas oil containing 9,500 mg/kg of sulfur was achieved in three-steps during 17 minutes of process at 62±2 °C when 180.3 mmol of H2O2 was used and extraction carried out by methanol.
Keywords: Ultrasound-assisted Oxidative Desulfurization; Gas Oil; Oxidant; Catalyst; Isobutanol

Evaluation of recovery characteristic of acidic and alkaline solutions from NaNO3 using conventional electrodialysis and electrodialysis with bipolar membranes by Kwang-Wook Kim; Jun-Taek Hyun; Keun-Young Lee; Eil-Hee Lee; Dong-Young Chung; Jei-Kwon Moon (1760-1769).
We compared the electrodialysis performance for HNO3 and NaOH recovery from NaNO3 solution by conventional electrodialysis (ED) and electrodialysis with bipolar membranes (EDBM) at constant current and constant voltage. The individual resistances of the components of the electrodialysis systems were also evaluated. The electrodialysis extent for HNO3 and NaOH recovery from NaNO3 solution was almost proportional to the total amount of electricity supplied to the system, regardless of the operation mode and the electrodialysis systems. For the same volume of feed solution, the energy consumption and current efficiency differed depending on the operation mode and the electrodialysis system. In both the ED and EDBM systems, the conductivity of the feed solution strongly affected the overall cell resistance after approximately 50% of the ions in the feed solution had migrated.
Keywords: Electrodialysis; Acid; Base; Bipolar Membrane (BM); Cation Exchange Membrane (CEM); Anion Exchange Membrane (AEM)

Biodegradation of methylene chloride by a mixed microbial culture, isolated from a common sewage treatment plant, was investigated in a batch system. Batch experiments were performed at room temperature (27 °C) and pH value of 7. The methylene chloride concentration in growth media varied from 25 mgl−1 to 250mgl−1. A maximum observed degradation was 1 mgl−1h−1 at 100 mgl−1 of methylene chloride. The culture followed substrate inhibition kinetics and specific growth rate were fitted to different substrate inhibition models (Haldane, Aiba and Edwards models) by MATLAB 7.1@. Among all models, Haldane was found to better fit with root mean square of 0.947. The biokinetic constants estimated using these models show good potential of the mixed microbial culture in methylene Chloride degradation. Escherichia coli and Staphylococcus aureus are predominant microbes present in the mixed culture.
Keywords: Mixed Culture; Dichloromethane; Biodegradation; Kinetics; Inhibition Models

Chitosan effects on glass matrices evaluated by biomaterial. MAS-NMR and biological investigations by Hassane Oudadesse; Eric Wers; Xuang Vuong Bui; Claire Roiland; Bruno Bureau; Imane Akhiyat; Amany Mostafa; Hassan Chaair; Hicham Benhayoune; Joel Fauré; Pascal Pellen-Mussi (1775-1783).
Bioactive glass 46S6 and biodegradable therapeutic polymer (Chitosan: CH) have been elaborated to form 46S6-CH composite by freeze-drying process. The kinetics of chemical reactivity and bioactivity at the surface were investigated by using physicochemical techniques, particularly solid-state MAS-NMR. Immortalized cell line used to construct multicellular spheroids was employed as three-dimensional (3D) cell cultures for in vitro studies. Obtained results showed a novel structure of the composite; the chemical treatment (ultrasound, magnetic stirring, freeze drying process and lyophilization) led the bioactive glass particles to be loaded in the chitosan-based materials. 29Si and 31P MAS-NMR results showed the emergence of two new species, Q Si 3 (OH) and Q Si 4 , which are characteristic of the vitreous network dissolution in simulated body fluid (SBF). MAS-NMR also confirmed the formation of amorphous calcium phosphate (ACP) at the surface of the initial 46S6-CH. Three-dimensional (3D) cell cultures highlighted the effect of chitosan, where the cell viability reached up to 78% in 46S6-CH composite and up to 67% in 46S6. The association of (CH) and bioactive glass (BG) matrix promotes a highly significant bioactivity, demonstrating surface bone formation and satisfactory behavior in biological environment.
Keywords: Bioactive Glass; Chitosan; Composite; Bioactivity; Hydroxyapatite; 31P MAS NMR; 29Si MAS NMR; Immortalized Cell; 3D Cells Viability

Anti-inflammatory effects of silkworm hemolymph on lipopolysaccharide-stimulated macrophages by Mi-Ra Chang; Woong Hee Lee; Won Jong Rhee; Tai Hyun Park; Eun Jeong Kim (1784-1789).
Macrophages participate in several inflammatory pathologies such as sepsis and arthritis. We investigated the effect of silkworm hemolymph (SH) on the LPS-induced pro-inflammatory macrophages. SH inhibits LPS-induced nitric oxide (NO) production in RAW 264.7 cells and murine peritoneal macrophages. The decreased NO was reflected as a decreased amount of inducible nitric oxide synthase (iNOS) mRNA and protein. It was also found that SH inhibited pro-inflammatory cytokines, IL-1β, IL-6, and TNF-α production. To elucidate the mechanism by which SH inhibits NO production and iNOS expression, we investigated that SH suppressed IκB phosphorylation, which leads to the activation of NF-κB followed by degradation of IκB. This observation suggests that SH is a potential therapeutic modulator for inflammation-associated disorders.
Keywords: Macrophages; Silkworm Hemolymph; Nitric Oxide (NO); Inducible Nitric Oxide Synthase (iNOS); Pro-inflammatory Cytokines

Absorption kinetics of carbon dioxide into aqueous ammonia solution: Addition of hydroxyl groups for suppression of vaporization by Soo-Bin Jeon; Jong-Beom Seo; Hyung-Don Lee; Seong-Kyu Kang; Kwang-Joong Oh (1790-1796).
Aqueous ammonia can act as an alternative absorbent for CO2 removal, but it has high volatility and reduces the ammonia concentration. We analyzed the hydroxyl additives 2-amino-2-methyl-1-propanol (AMP), ethylene glycol, and glycerol to reduce the vapor pressure of ammonia solutions. In addition, absorption efficiency groups of aqueous ammonia solutions containing hydroxyl additives were investigated. The results show that the addition of AMP, ethylene glycol, or glycerol to NH3 reduced the vapor pressure of the absorbent by 14.0%, 22.7%, and 75.2%, respectively. The reaction rate constants of aqueous NH3 containing AMP, ethylene glycol, and glycerol additives at 293, 303, 313 and 323 K are given by $$k_{2,NH_3 /AMP} = 4.565 imes 10^5 exp ( - 1396.5/T)$$ , $$k_{2,NH_3 /ehylene glycol} = 1.499 imes 10^6 exp ( - 1978.7/T)$$ and $$k_{2,NH_3 /glycerol} = 7.078 imes 10^6 exp ( - 2413.3/T)$$ , respectively.
Keywords: Aqueous Ammonia; CO2 ; AMP; Ethylene Glycol; Glycerol

Co-precipitation of loperamide hydrochloride and polyethylene glycol using aerosol solvent extraction system by Edward Widjojokusumo; Bambang Veriansyah; Yong-Suk Youn; Youn-Woo Lee; Raymond Rubianto Tjandrawinata (1797-1803).
The co-precipitation of loperamide hydrochloride (LPM) and polyethylene glycol (PEG) using aerosol solvent extraction system (ASES) was examined. Scanning electron microscopy — energy dispersive X-ray spectroscopy (SEM-EDS) analysis showed that the co-precipitation was achieved in various LPM-PEG mass ratios with changes in its morphology. In 10–50% PEG mass ratios, angular-shaped particles were formed, whereas in 65–90% PEG mass ratios, irregular-shaped particles were formed. X-ray diffraction (XRD) analysis of the co-precipitates revealed that the LPM retained amorphous structure, while, on the other hand, the PEG retained crystalline structure. Fourier transform infrared (FT-IR) spectra indicated carbonyl function group of LPM and ether function group of PEG appeared in the co-precipitates. Results of a dissolution test showed that the co-precipitates of LPM-PEG had higher dissolution rate compared to that of the raw material and processed LPM with ASES. Taken together, the co-precipitation of LPMPEG was achieved using ASES and higher in its dissolution rate.
Keywords: Loperamide Hydrochloride; Polyethylene Glycol; Co-precipitation; ASES

An effective in situ recovery of acetone, butanol and ethanol (ABE) from fermentation broth is requisite to overcome the low productivity of ABE production. Pervaporation has proven to be one of the best methods for recovering ABE from fermentation broth. We fabricated an immobilized ionic liquid-polydimethylsiloxane (PDMS) membrane in which a [Tf2N] based ionic liquid covalently bound to the PDMS backbone polymer and used it to recover ABE from aqueous solution by pervaporation. Permeate flux of immobilized IL-PDMS membrane was 7.8 times higher than that of conventional supported IL-PDMS membrane (where ILs are physically absorbed on the supported membrane). Butanol enrichment factor of immobilized IL-PDMS membrane was three-times higher than that of PDMS membrane. In addition, high enrichment factor both to acetone and ethanol as well as high operational stability of immobilized IL-PDMS membrane can enhance the efficacy of ABE recovery by employing this membrane.
Keywords: Liquid Membrane; Ionic Liquid; Butanol; Pervaporation

Adsorption thermodynamic and kinetic studies of C. I. disperse dye 60 on PBO fiber pretreated with polyphosphoric acid (PPA) were carried out under the conditions of pH 6.0±0.2, initial dye concentration 0.05–1.0 g/L and liquor ratio 2,000: 1. The results showed that the equilibrium adsorption isotherm of the disperse dye on the pretreated PBO fiber was a Langmuir-Nernst mixed Model and the saturated adsorption capacity of the turning point was 1.046 mg/g. The thermodynamic parameters were calculated by the equilibrium adsorption isotherm, such as standard affinity, enthalpy change and entropy change, which indicated that the adsorption of disperse dye on the pretreated PBO fiber was an exothermic process. Based on the thermodynamic and kinetic data, the adsorption of the dye on the pretreated PBO fiber was a kinetics controlled process, and the disperse dye could only diffuse into the surface layer of pretreated PBO fiber. Meanwhile, the adsorption kinetics of disperse dye on pretreated PBO fiber well agreed with a pseudo-first-order kinetic model.
Keywords: PBO Fiber; Adsorption; Diffusion; Thermodynamics; Kinetics; Disperse Dye

Cellulose acetate butyrate membrane containing TiO2 nanoparticle: Preparation, characterization and permeation study by Mohammad Ali Haj Asgarkhani; Seyed Mahmoud Mousavi; Ehsan Saljoughi (1819-1824).
Cellulose acetate butyrate/TiO2 hybrid membranes were prepared via phase inversion by dispersing the TiO2 nanoparticles in casting solutions. The influence of TiO2 nanoparticles on the morphology and performance of membranes was investigated. The scanning electron microscope images and experiments of membrane performance showed that the membrane thickness and pure water flux were first increased by adding the TiO2 nanoparticles to the casting solution up to 4 wt% and then decreased with the addition of further nanoparticles to it. The obtained results indicated that the addition of TiO2 in the casting solution enhanced the rejection and permeate flux in filtration of bovine serum albumin solution. Furthermore, increasing the TiO2 nanoparticle concentration in the casting solution increased the flux recovery and consequently decreased the fouling of membrane.
Keywords: Cellulose Acetate Butyrate; Membrane; TiO2 Nanoparticle; Blending