JournalTOCs

Korean Journal of Chemical Engineering
Journal Prestige (SJR): 0.559

Citation Impact (citeScore): 2
Number of Followers: 5

Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1975-7220 - ISSN (Online) 0256-1115
Published by Springer-Verlag

[2469 journals]

The detection of Fe (III) and ascorbic acid by fluorescence quenching and
recovery of carbon dots prepared from coffee waste
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  Abstract: Abstract Coffee waste-derived carbon dots (C-CDs) that emit blue light were synthesized via hydrothermal process. The synthesized C-CDs have a round shape with average diameter of ∼3.7 nm. The C-CDs show PL emission centered at 450 nm with excitation wavelength at 360 nm. The C-CDs show promising applications as Fe3+ sensors in aqueous solutions by fluorescence quenching. The C-CDs exhibited strong turn-off fluorescence when trace Fe3+ was added to the solution. Furthermore, the C-CDs-Fe3+ can also be used as a turn-on sensor for the detection of ascorbic acid (AA). AA reduces Fe3+ to Fe2+, resulting in the recovery of fluorescence intensity of the quenched C-CDs. Thus, the C-CDs can be used as a rapid and effective dual mode “off-on” fluorescence sensor for Fe3+ and AA. The fluorescence response exhibits a good linear relationship with the concentration of Fe+3 and AA in the range of 0–100 and 0–1 µM, with a limit of detection (LOD) around 4.314 and 0.162 µM, respectively.
  PubDate: 2022-05-21
Experimental studies of bubble cutting in a lab-scale micro-structured
bubble column with different liquid viscosity
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  Abstract: Abstract Bubble cutting was realized by installing a wire mesh in a micro-structured bubble column (MSBC) and studied experimentally with liquid viscosity range from 1 to 39.6 mPa·s. A non-intrusive high-speed camera method was used to determine bubble size and size distribution. The changes of gas holdup, bubble size, size distribution and Sauter mean diameter before and after cutting were systematically studied with mesh openings of 3.8 mm and 5.5 mm. Three novel bubble cutting behaviors with uniform cutting, detachment cutting and indirect cutting behavior were observed. In the presence of two wire meshes, the bubble size distribution roughly shows a Gaussian curve distribution and the peak tends to shift towards lower diameters. With increasing liquid viscosity and superficial gas velocity, the dominant peak tends to move towards higher diameters, resulting in poor mesh cutting effect. After cutting, in the case of two wire meshes, the Sauter mean diameter decreased by 33.5% and 22.2% and the gas holdup increased by 3.2–12.2% and 1.2–4.4%, respectively. For the case of 3.8 mm mesh opening, the interfacial area increased by 10–26%, which is much better than 5.5 mm mesh. The mean bubble size above the mesh will grow again and its growth rate depends on the liquid viscosity.
  PubDate: 2022-05-21
Optimal strategies for supercritical gas antisolvent (GAS) coprecipitation
of pyrazinamide/PVP particles via response surface methodology
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  Abstract: Abstract This paper concerns optimization and experimental validation of coprecipitation process parameters for preparing particles of Pyrazinamide and Polyvinylpyrrolidone using gas anti-solvent supercritical method. Mixtures of organic solvents (acetone and ethanol) were selected with various combinations of the drug and the polymer. The central composite design (CCD) was adopted to explore the effect of temperature, pressure, antisolvent addition rate, polymer fraction, and ethanol fraction on particle size distribution (PSD) and solubility. The strong likelihood models were developed for all the responses using Design-Expert software. Polymer fraction was the most important (p<0.0001) factor influencing PSD, while pressure and interaction between temperature and polymer fraction significantly affected solubility. The optimal condition was specified at temperature of 50 °C, pressure of 120 bar, antisolvent rate of 16 bar/min, polymer fraction of 30%, and ethanol fraction of 50%. The model was then validated experimentally under the optimal condition and compared with pure PZA and particles obtained from the physical mixture. According to DLS, XRD, FTIR, and FESEM analyses, the crystallinity of PZA-PVP particles was reduced in optimum conditions, leading to higher solubility. Also, the results suggest that it is feasible to produce coprecipitated particles with narrower size distribution by optimized GAS process.
  PubDate: 2022-05-21
The effects of under-ribs convection on enhanced drainage parallel flow
field for proton exchange membrane fuel cell
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  Abstract: Abstract A new enhanced drainage parallel (EDP) flow field was designed that not only enhances under-rib convection but also enables a more uniform distribution of hydrogen and oxygen. Through the optimization of the model, we established the influence of the flow field size, relative humidity, and stoichiometric ratio on cell performance. When the rib width is reduced, the maximum power density is improved. Compared with the parallel flow field and serpentine flow field, the maximum power density of the EDP flow field was increased by 69.4% and 7.9%, respectively. Under optimal conditions, the net power of the EDP flow field can reach 0.56 W/cm2. In the single-cell test, the maximum power density of the EDP flow field can reach 1.19 W/cm2. This implies that the EDP flow field has potential application of proton exchange membrane fuel cells.
  PubDate: 2022-05-21
Biohydrogen production from glycerol by novel Clostridium sp. SH25 and its
application to biohydrogen car operation
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  Abstract: Abstract Biohydrogen is a clean and efficient source of energy produced easily by anaerobic systems. Therefore, the discovery of novel and efficient production methods and utilization of inexpensive starting material are crucial for economical biohydrogen production. In this study, novel hydrogen producing bacterial strain Clostridium sp. SH25 was screened from the anaerobic sludge obtained from a water treatment plant, which showed a higher hydrogen-producing activity on glycerol than other strains. The effective hydrogen production was evaluated under varying anaerobic culture conditions, and the optimum temperature, initial pH, additional NaCl concentration, and inoculum size were 37 °C, 6.0, 0%, and 10% (v/v), respectively. The cumulative hydrogen production volume from crude glycerol was 24.30±1.07 ml after 36 h. To test the practical application of biohydrogen, a 20 ml culture of Clostridium sp. SH25 was incubated for 12 h and directly applied to a small hydrogen car unit operated for 19.05±0.33 s with 8.37 ± 0.21 m displacement. Overall, identification of the efficient Clostridium sp. SH25 strain resulted in the production of a large amount of biohydrogen, which further supported the operation of a small hydrogen car. This implied a possible application of biosystems in biohydrogen production.
  PubDate: 2022-05-21
Preparation of polydopamine-coated TiO2 composites for photocatalytic
removal of gaseous ammonia under 405 nm violet-blue light
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  Abstract: Abstract Although photocatalytic reactions using the ultraviolet (UV) range (particularly UV B (280–320 nm) wavelengths) is well-established, the photocatalytic effect of longer wavelengths (especially that of UVA (≥380 nm) and visible light (≥400 nm)) have only recently been studied and utilized for environmental applications. In this work, we coated polydopamine (PDA) and TiO2 on a support and investigated the synergistic effects of the corresponding composites for the photocatalytic removal of gaseous ammonia under 405 nm violet-blue light. The PDA layer with TiO2 was covalently attached on a ceramic ball using the drop-casting method. The roughness and functional groups of the TiO2-PDA coated ball surfaces were verified using an infrared imaging microscope and field emission scanning electron microscope (FE-SEM). The photocatalytic activity of the obtained hybrid TiO2-PDA coated ball for the removal of ammonia was investigated using a UV C and 405 nm LED lamp at 24 °C. The results showed that both the TiO2 (control sample) and TiO2-PDA coated balls successfully removed ammonia under similar experimental conditions with the 254 nm UV C lamp. Notably, the TiO2-PDA coated ball exhibited an enhanced ammonia removal efficiency of 72% under 405 nm LED light irradiation. Thus, the TiO2-PDA coated ball is a promising indoor air cleaning technique under LED light irradiation.
  PubDate: 2022-05-21
Decomposition characteristics of SF6 in an electrical tube furnace and a
pilot system by combustion
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  Abstract: Abstract Sulfur hexafluoride (SF6) is widely used in a variety of industrial processes and commercial products. However, this chemically stable gas is one of the most potent greenhouse gases (GHGs) contributing significantly to global warming. Therefore, to reduce greenhouse gas such as SF6, a new eco-friendly, economic, and stable treatment technology is required. In this study, the thermal decomposition characteristics of SF6 were investigated using a laboratory scale electrical tube furnace reactor and combustion-based pilot system. Based on these results, the SF6 decomposition reaction order is around 1 and its activation energy (Ea) in the investigation temperature range is 238.04–257.18 kJ/mol. This value is used to calculate the reactor size when designing a commercial facility. Also, the experimental results of a combustion-based pilot system indicate that SF6 supply location, reaction temperature, supplied concentration, and fuel/air ratio could affect SF6 decomposition efficiency. The results demonstrate that a 99.9% decomposition efficiency could be achieved in the combustion.
  PubDate: 2022-05-21
Carbon aerogel from waste corrugated cardboard: Facile preparation,
characterization, and application to solar steam generation and adsorption
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  Abstract: Abstract Carbon aerogel (CASol-Ads) was prepared from waste corrugated cardboard (WCC) by using a green and facile strategy and it was explored as an all-in-one solar evaporator and a floatable absorbent. Thermal conversion of carbon precursor was investigated using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer. The amorphous carbon aerogel was made up of criss-crossing carbon ribbons and it had a typical micromesoporous structure and a specific surface area of 575 m2 g−1. It exhibited remarkable optical absorption over 81.8% in the UV and Vis regions and over 70% in the NIR region. The surface temperature of dry CASol-Ads can achieve 77.9 °C under 1 kW m−2 irradiation. The hydrophilic 3D network structure of CASol-Ads provides a large volume for the storage of liquids; thus, the carbon aerogel was able to store as much as 13.4 times its own weight in water. Solar-driven evaporation rate over CASol-Ads saturated with water was calculated to be 1.68 kg m−2 h−1, which was 4.5 times the value achieved with bare water under 1 kW m−2 irradiation. The adsorption behavior of CASol-Ads for methylene blue (MB) fitted the Langmuir isotherm model with the maximum monolayer adsorption capacity of 108 mg g−1. The monolithic CASol-Ads can be used as a self-floating absorbent for the adsorption of MB from water, and the adsorption kinetics followed pseudo-second-order kinetics model.
  PubDate: 2022-05-17
High potential of amine rice husk magnetic biocomposites for Cu(II) ion
adsorption and heterogeneous degradation of contaminants in aqueous
solution
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  Abstract: Abstract Rice husk (RH) cellulose as a matrix was synthesized for amine rice husk magnetic biocomposite (RB-NH2) by one-pot solvothermal method. The synergic effect of amine on magnetic nanoparticle will enhance the reactivity of material. Ethylene glycol as solvent was used for dissolved iron(III) chloride hexahydrate, Na-acetate anhydrate, and 1,6-hexanediamine, then RH was added, kept at ±200 °C for 6 h. The optimums of Fe contained and amine concentrations on biocomposite were detected at 93% and 2.9 mmol/g, respectively. The surface area of rice husk significantly increased from 1.309 m2 g−1 to 19.45 m2 g−1 when converted to biocomposite. The RB-NH2 has good capability to adsorb Cu(II) ion at 116.45 mg g−1 at pH 5 for 60 min. Surprisingly, during adsorption, the RB-NH2 also worked on reducing the chemical oxygen demand (COD) number, total suspended solid (TSS) and dye for 22%, 54.37%, and 33.74%, respectively. The reuse effectiveness for RB-NH2 showed a good result with four repetitions. The multiple effects of amine rice husk magnetic biocomposite on wastewater contaminants leads to becoming a candidate material to be developed and applied in a wide range of waste water treatment applications.
  PubDate: 2022-05-17
Effects of cobalt oxide catalyst on pyrolysis of polyester fiber
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  Abstract: Abstract Polyester fiber is a high-molecular-weight compound made from fossil fuels and is used in various synthetic fiber manufacturing processes. In this study, we performed non-catalytic and catalytic pyrolysis experiments using cobalt oxide as a catalyst to recover energy from polyester fiber. The experiment was carried out between 500–900 °C in the presence of N2. Amount of oil formation was the highest at 600 °C in non-catalytic pyrolysis and oil formation of catalytic pyrolysis was the highest at 500 °C. In both non-catalytic pyrolysis and catalytic pyrolysis, gas content was increased and char was decreased with increasing temperature. A marked difference was observed when the catalyst was used; the formation of char was suppressed and oil and gas yields increased. In the catalytic pyrolysis oil, benzoic acid compounds accounted for the largest proportion (16.15 wt%) at 900 °C, but polycyclic aromatic hydrocarbons and phenols were not observed. Benzoic acid is an important precursor material used to synthesize other organic substances, such as phenol and caprolactam. The non-condensable gas content increased from 11.55 wt% to 22.39 wt%, with increasing temperature. In particular, H2 gas yield was 4.44 wt% at 900 °C. Therefore, by using catalytic pyrolysis, high value-added chemicals such as benzoic acid compounds and H2 gas can be recovered at high yield at 900 °C from the polyester fiber. Consequently, unlike the existing treatment methods, the environmental impact of plastics can be reduced by catalytic pyrolysis.
  PubDate: 2022-05-17
Extraction and phase transformation of iron in fine-grained complex
hematite ore by suspension magnetizing roasting and magnetic separation
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  Abstract: Abstract Suspension magnetizing roasting-magnetic separation technology was used to extract iron from fine-grained complex hematite ore. The effect of roasting conditions on the magnetizing roasting-magnetic separation process was studied. In summary, a concentrate with TFe grade of 69.96% and Fe recovery of 79.02% could be obtained under conditions of a roasting temperature of 500 °C, roasting time was 12 min, reductant concentration of 30%, and total gas flow of 200 mL/min, while TFe grade of final tailings was 5.66%. The phase composition and X-ray photoelectron spectroscopy analysis showed that hematite in the sample was transformed into magnetite during suspension magnetization roasting. After roasting, the proportion of Fe content in the phase of the magnetite increased from 5.91% in roasting feed to 97.96% in the roasting product. Transmission electron microscopy results also confirmed that hematite was transformed into magnetite with spinel structure, and the newly formed magnetite had good crystallinity. Scanning electron microscopy and BET analysis showed that roasting could increase the specific surface area, total pore volume, and porosity of the roasted product, which would strengthen the internal diffusion of CO and CO2 in the particles, to improve the reduction rate of hematite. The loose internal structure of roasted particles led to the decrease of mechanical properties, which was conducive to improving the subsequent grinding efficiency.
  PubDate: 2022-05-12
Visible light photocatalytic activity of TiO2 with carbon-fluorine
heteroatoms simultaneously introduced by CF4 plasma
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  Abstract: Abstract CF4 plasma treatment is performed on commercial TiO2 to improve the photocatalytic efficiency. The CF4 plasma treatment is a facile and fast method for simultaneous introduction of carbon and fluorine atoms onto TiO2. Photodegradation of rhodamine B, methyl orange, and methylene blue is carried out under solar light irradiation to determine its CF4 plasma treatment effect. The dye removal of commercial TiO2 to rhodamine B, methyl orange, and methylene blue is 60.0, 18.9, and 49.2%, respectively, whereas TiO2 treated with CF4 plasma for 50 min is 93.5, 71.0, and 88.6% for rhodamine B, methyl orange, and methylene blue, respectively. In addition, the photodegradation rate constants of TiO2 treated with CF4 plasma for 50 min were 0.0135, 0.0083, and 0.0129 min−1 for rhodamine B, methyl orange, and methylene blue, respectively, which are up to 7.5 times higher than that of untreated TiO2 (0.0049, 0.0011, and 0.0039 min−1). This improvement is attributed to the increase in oxygen vacancies by the introduction of carbon atoms into TiO2 using CF4 plasma treatment. In addition, the F− ions physically adsorbed to the TiO2 surface promote the formation of hydroxyl free radicals, enabling effective decomposition of various dyes.
  PubDate: 2022-05-12
Deep dechlorination of hydrocarbon oil by reactive adsorption on
TiO2-based metal oxides
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  Abstract: Abstract This study reports reactive adsorptive dechlorination of hydrocarbon oil over TiO2-based metal oxides at the temperatures of 20–150 °C. TiO2 and a series of TiO2-CeO2 were prepared by precipitation method and characterized by N2 adsorption, XRD, FT-IR, pyridine-IR, NH3-TPD and CO2-TPD. The characterization results showed that both the acidity and basicity of the adsorbent had a significant impact on its dechlorination capacity. TiO2-U precipitated by urea exhibited higher dechlorination capacity than TiO2-A precipitated by ammonia due to the higher surface area, more acid and base amounts of the former. Among various Ti(1−x)CexO2 (x=0.1, 0.3, 0.5, 0.7, 0.9, 1) oxides, Ti0.7Ce0.3O2 and Ti0.3Ce0.7O2 bimetallic oxides showed higher dechlorination capacity than TiO2-U, and the chlorine removal over Ti0.7Ce0.3O2 reached 82.8% after adsorption at 150 °C for 3 h. Mixing 5 wt% of alkali earth metal oxide into Ti0.7Ce0.3O2 mechanically enhanced its dechlorination capacity, and the chlorine removal over Ti0.7Ce0.3O2-BaO reached as high as 92.1%. The chlorine removal increased with increasing the adsorption temperature. Ion chromatography and GC-MS analysis revealed that organochlorine compound was converted into Cl− and its corresponding alcohol over the adsorbent at 150 °C. Finally, the mechanism of reactive adsorption dechlorination was proposed.
  PubDate: 2022-05-12
Electroactive adsorbent composites of porous graphite carbon/carbon
nanotube for highly efficient organic dye removal
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  Abstract: Abstract The highest total organic carbon (TOC) and color removal efficiency of Acid Orange 7 (0.1 mM initial concentration) on graphite carbon/carbon nanotubes electrodes (KS44/CNT) reached more than 98% in three hours of Electro-Fenton (EF) treatment under optimal conditions (pH=3 and I=20 mA), compared to carbon graphite electrode developed without carbon nanotubes (KS44-0). The apparent kinetic constants of degradation were 0.17 and 0.12 min−1 for the KS44-(20)/CNT and KS44-0, respectively. The long-term stability and system durability were attributed to the graphite carbon/CNT electrodes due to continuous operating treatment that allowed processing efficiency and reusability without any decrease of the catalytic activity in time after five cycles of use. Regardless of the medium, superior decolorization and TOC removal efficiency were obtained for electrodes (KS44-(20)/CNT) containing 20 wt% of ferrocene powder as catalyst for CNTs’ growth and iron nanoparticle establishment. Furthermore, the presence of CNTs and iron particles as precursors enhanced drastically the electrochemical and physical properties of the electrode synthesized in a one-step process. The results confirmed that carbon electrodes behave as multifunctional materials acting both as adsorbent and active cathode in the electro-Fenton process for the destruction and total mineralization of Acid Orange 7 (AO7) as a model for organic contaminated wastewater.
  PubDate: 2022-05-12
Modeling of a methanol synthesis process to utilize CO2 in the exhaust gas
from an engine plant
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  Abstract: Abstract We investigated the conversion of CO2 in the exhaust gas of an engine plant into methanol. The process consists of CO2 purification by an acid gas removal unit (AGRU), mixed reforming, and methanol synthesis. The AGRU removes a large amount of inert gas, yielding CO2 of 98% purity at a recovery rate of 90% for use as feed to the reformer. The reformer temperature of 900 °C led to the almost total consumption of CH4. In the methanol synthesis reaction, the utility temperature had a greater influence on the conversion and methanol production rate than the inlet temperature. The optimal temperature was determined as 180 °C. Because the amount of hydrogen in the reformer effluent produced by dry reforming was insufficient, the steam available in the engine plant was used for mixed (dry and steam) reforming. The steam increased the hydrogen and methanol production rate; however, the compression cost was too high, and there exists an optimal amount of steam in the feed. The techno-economic analysis of the optimal conditions showed that utilization of CO2 in the exhaust gas along with freely available steam is economically feasible and reduces CO2 emissions by over 85%.
  PubDate: 2022-05-12
Enhancing performance of polyacrylonitrile membranes for pervaporation
dehydration of ethanol by tailoring morphology and process parameters
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  Abstract: Abstract Development of high performance membranes for ethanol (EtOH) dehydration constitutes one of the main applications of pervaporation technology. In the present study, the properties of membranes derived from PAN were examined for this purpose. Heat treatment and variation of operational parameters were explored as viable strategies for enhancing the process performance. The characteristics of the membranes including morphology, thickness and sorption behavior were investigated in detail to identify their roles. Application of heat treatment with regards to polymer Tg resulted in membranes with distinct morphological and sorption characteristics. Increase in operational temperature was found effective for optimizing the opposing trends of permeate flux and separation factor. The maximum PSI value for the pristine PAN membrane was 5,564.0 g·m−2h−1, which occurred for operation at 50 °C. Also, application of heat treatment led to drop in flux and increase in separation factor by which PSI reached 41.3 kg·m−2h−1, which was 7.5 times than that of pristine PAN membrane. This study demonstrates successful implementation of facile strategies for tuning the characteristics and performance of membranes derived from PAN for efficient dehydration of EtOH via pervaporation process.
  PubDate: 2022-05-10
A combined cycle power plant integrated with a desalination system:
Energy, exergy, economic and environmental (4E) analysis and
multi-objective optimization
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  Abstract: Abstract A cogeneration production system of power and freshwater was studied from the perspective of energy, exergy, economic, and environmental (4E). The main components of this system include a Brayton cycle (BC), dual-pressure heat recovery steam generator (HRSG), steam turbine (ST), and multi-effect evaporation with thermal vapor compression (MEE-TVC). The system was optimized with a multi-objective genetic algorithm using MATLAB software and by considering the performance of two objective functions: the total annual cost (TAC) to minimize and the thermal efficiency to maximize. The results showed that, with increasing gas turbine inlet temperature, thermal efficiency, exergy efficiency, and emission of pollutants improved, but the gain output ratio (GOR) decreased. GOR of desalination system, exergy efficiency of combined cycle power plant (CCPP), and emission of pollutants improved by increasing the compressor pressure ratio. In investigating the number of effects in desalination unit, by increasing this parameter the production of freshwater, GOR and exergy efficiency of MEE-TVC was increased. By adding a duct burner to the cogeneration system, the thermal efficiency, the exergy efficiency, and the net power output were reduced by 0.67, 3.9, and 5.91%, respectively. But the freshwater production, GOR, and TAC was improved about 7.97, 9.69, and 1.265%, respectively.
  PubDate: 2022-05-10
Box-Behnken design-based biodiesel wastewater treatment using sequential
acid cracking and electrochemical peroxidation process: Focus on COD,
oil-grease and volatile fatty acids removals
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  Abstract: Abstract The treatability of biodiesel wastewater by the electrochemical peroxidation process following acidification pretreatment was investigated. Box-Behnken design, one of the experimental designs of response surface methodology, was applied to optimize the process parameters for chemical oxygen demand (COD), oil-grease, and volatile fatty acids (VFAs) removal from biodiesel wastewater. The process parameters, i.e., applied current, H2O2/COD ratio, and reaction time, were optimized and the total cost of the process was determined. After the acidification process as a pretreatment, the COD, oil-grease, and VFAs removal efficiencies were 25.4%, 68.7%, and 50%, respectively Optimum conditions determined by the developed model for maximum oil-grease removal (98.2%) were applied: current 1.0 A, H2O2/COD ratio 0.4, and reaction time 32.8 minutes. This devised Box-Behnken model predicted removal efficiencies of 45.5%, 98.2%, and 49.5% for COD, oil-grease, and VFAs, respectively. The total cost of the process determined by the model and obtained from the validation experiments was 2.03 €/m3 and 1.97 €/m3, respectively. The results of the study showed that the applied process was efficient in pollutant removal from acidified biodiesel wastewater and the Box-Behnken design can be applied to explain the mechanism of the process and optimize the process parameters.
  PubDate: 2022-05-04
Evaluation of folic acid-conjugated chitosan grafted Fe3O4/graphene oxide
as a pH- and magnetic field-responsive system for adsorption and
controlled release of gemcitabine
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  Abstract: Abstract A pH-responsive system was prepared by using a magnetic nanocomposite, folic acid-conjugated chitosan (FA-CS) grafted Fe3O4/GO, and then used for loading and controlled release of an anti-cancer drug, gemcitabine (GEM). The successful synthesis of FA-CS/Fe3O4/GO was confirmed by various characterization techniques such as FE-SEM/EDX, TEM, FT-IR, XRD, TGA, VSM, and BET. The nanocomposite had a mesoporous structure with the specific surface area of 68.96 m2 g−1, the pore volume of 0.25 cm3 g−1, and the mean pore size of 14.78 nm. The optimum conditions for drug loading through adsorption were found to be pH=4, adsorbent dosage of 0.5 g L−1, temperature of 298 K, and contact time of 45 min. Experimental data indicated that GEM adsorption onto FA-CS/Fe3O4/GO has a satisfactory correlation with the pseudo-second-order kinetic and Freundlich isotherm equations. The maximum adsorption capacity of GEM was 221.17 mg g−1 for FA-CS/Fe3O4/GO, which was quite higher than the non-functionalized Fe3O4/GO with the value of 33.99 mg g−1. Furthermore, the in-vitro drug release profile of GEM from drug-loaded FA-CS/Fe3O4/GO was studied within 48 hours at 37 °C, and the results indicated a higher drug cumulative release amount in simulated cancer fluid (pH 5.6) compared to simulated human blood fluid (pH 7.4). Also, the Peppas-Sahlin kinetic model best fitted the release kinetics data. The result of drug release implied that FA-CS/Fe3O4/GO magnetic biocomposite could be a potential carrier for the sustained and controlled release of GEM.
  PubDate: 2022-05-04
Characteristics of Li2CO3 as sintering aid for Ce0.8Sm0.2O2−δ
electrolyte in solid oxide fuel cells
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  Abstract: Abstract Owing to its excellent ionic conductivity, 20 mol% samarium doped ceria (Ce0.8Sm0.2O2−δ, SDC) is considered a promising alternative as an electrolyte in solid oxide fuel cells (SOFCs). SDC electrolytes, however, require high sintering temperatures over 1,600 °C to attain sufficient density to be SOFC electrolytes. To lower the SDC sintering temperature, different amounts of Li2CO3 (0–12 mol% of Li) were evaluated as a sintering aid for SDC electrolytes. The SDC electrolyte samples with Li were sintered at 1,400 °C and were compared with SDC electrolytes sintered at 1,600 °C. The SDC electrolyte with 6 mol% of Li sintered at 1,400 °C (Li6SDC1400) was densified to 97.495% of theoretical density (T.D.), which is similar to that achieved by the SDC electrolyte sintered at 1,600 °C (97.433% of T.D.). The improved formation of grain boundary in the Li6SDC1400 sample increased the density of the SDC, resulting in enhancement of ionic conductivity and cell performance. At 800 °C, the maximum power density of the Li6SDC1400 electrolyte sample was 120.15 mW/cm2.
  PubDate: 2022-05-04