Pure Methanol Research Articles

Study on the mechanism of influence of cetane improver on methanol ignition

Methanol has attracted much attention because it can realize carbon neutral cycle. Methanol is difficult to use in compression ignition engines because of its low cetane number and high latent heat of vaporization. 2-ethylhexyl nitrate (EHN) is a widely used cetane number improver, which can effectively promote the ignition of methanol. Therefore, a reduced mechanism of methanol and EHN containing 61 species and 479 reactions is proposed in this paper, and it has been verified to fit well with the original mechanism and experimental date. Then, chemical kinetic analysis is carried out using CHEMKIN PRO. Results show that after adding EHN, the ignition delay is significantly shortened. As the EHN ratio increases, the effect of EHN on shortening the ignition delay period does not increase nonlinearly, but shows a slowing trend. The reaction with higher positive temperature sensitivity changes from R133 (CH3OH + HO2 = CH2OH + H2O2) to R307 (CH2O + NO2 = HONO + HCO), and the reaction with higher negative temperature sensitivity changes from R18 (2HO2 = H2O2 + O2) to R305 (HCO + NO2 = HONO + CO). The reaction time of H, OH and HO2 is advanced and the peak values decrease. In the methanol dehydrogenation pathway, the proportions of reactions involving HO2 decrease significantly and the proportions of reactions involving NO2 and OH increase. The methanol consumption rate increases significantly after adding EHN. With the addition of 3% EHN, the reaction time of methanol was reduced by 99.8% compared to pure methanol.

Performance of solid-oxide fuel cells fed with pure hydrogen and methanol steam reforming products – experimental study

A solid-oxide fuel cell (SOFC) can be fed by fuels other than pure hydrogen, making it suitable for methanol-based economy power cycles. In the reported article, we carried out for the first-time experiments on different types of SOFCs fueled with methanol steam reforming (MSR) products to evaluate and compare the SOFC performance with pure hydrogen. Through this novel comparison, the study provides new insights into the potential of using methanol as a fuel source for SOFCs. Experimental investigation was conducted to evaluate a button SOFC performance operating with MSR products and pure hydrogen under 700, 750, 800, and 850 °C. Two types of SOFC were tested: 1) NiO-YSZ anode-supported cell and 2) the Next-Cell-HP Hionic™ electrolyte-supported cell. The results indicate that the fuel cell fed with MSR products exhibits slight reduction (less than 5%) in power density compared to pure hydrogen. The results were compared with the theoretical values using zero-dimensional simulations. It was found that the change in effective diffusivity causes the main disparity in the SOFC performance when fed with MSR products and hydrogen. Based on the obtained results, we suggest that the SOFC has the potential to be successfully integrated into methanol-based power generating cycles with thermochemical recovery of a waste heat.

The intermolecular interactions of methanol diluted in protic and aprotic solvent probed by polarized Raman spectroscopy and HNMR

Polarized Raman spectra of the VV component (R∥) and the VH component (R⊥), 2D-COS synchronous and asynchronous spectra, and HNMR of CH3OH/CH3CN and CH3OH/H2O binary mixture were collected at different volume fractions. The intermolecular interactions of methanol diluted in protic (H2O) and aprotic solvent (CH3CN) were compared and discussed. The experiments showed that the frequency difference ΔνAIS = ν⊥-ν∥ of C-O stretching was −4 for pure methanol and 0 at very dilute concentrations. During the dilution process, the ν∥ of C-O stretching downshifted by approximately 17 cm−1 for CH3OH/H2O binary mixture, while down shifted 5 cm−1 for the CH3OH/CH3CN mixture and 12 cm−1 for the CH3OH/CHCl3 mixture. The dilution process was identified as a cyclic cluster depolymerization process. The difference in amplitude of frequency downshift could be explained by the different properties of the hydrogen bond. Different H-bond cyclic clusters were proposed for different volume fractions of the CH3OH/H2O mixture. Additionally, the chemical shift movement of δOH with concentration also supports the cluster depolymerization process, which is consistent with the results of polarization Raman spectroscopy. The establishment of the coupling-induced spectral splitting theory will play an important role in determining the aggregation behavior of biomolecules and the structure of supramolecular self-assembly.

Bioactive Compounds and Antioxidant Capacity from Different Fruit Extracts of Aonla (Emblica officinalis Gaertn.)

Aonla (Emblica officinalis Geartn.) possess significant nutraceutical properties which is distributed throughout the semi-arid region of northern Madhya Pradesh, Rajasthan, plains of Uttar Pradesh, valley of Himalayas and tropical southern part of India. Aonla is also called as Indian Gooseberry which is nutraceutical rich and also utilized in ayurvedic preparations. The study has been done to access the nutraceutical potential of Aonla from different extracts of fruit pulp powder of a local cultivar. Different extracts of fruit pulp powder i.e., in pure methanol, 80 % ethanol and Ethanol: Ethyl Acetate: Water (4:3:3) were prepared and analyzed for their bioactive compounds and antioxidant capacities. The local cultivar contains a good amount of bioactive compounds and exhibit better antioxidant capacities. Results show that the solvent of Ethanol: Ethyl Acetate: Water in ratio of 4:3:3 showed highest quantity of bioactive compounds extraction and antioxidant activity followed by 80% Ethanol in aonla. While pure methanol was found best for extraction yield and tannin content.

Removal, Adsorption, and Cleaning of Pharmaceutical on Polyamide RO and NF Membranes.

Pharmaceuticals are present in various waters and can be almost completely rejected by membrane separation processes, i.e., nanofiltration (NF) and reverse osmosis (RO). Nevertheless, the adsorption of pharmaceuticals can decrease their rejection, so adsorption can be considered a very important removal mechanism. In order to increase the lifetime of the membranes, the adsorbed pharmaceuticals must be cleaned from the membrane. The used pharmaceutical (albendazole), the most common anthelmintic for threatening worms, has been shown to adsorb to the membrane (solute-membrane adsorption). In this paper, which is a novelty, commercially available cleaning reagents, NaOH/EDTA solution, and methanol (20%, 50%, and ≥99.6%) were used for pharmaceutical cleaning (desorption) of the NF/RO membranes used. The effectiveness of the cleaning was verified by Fourier-transform infrared spectra of the membranes. Of all the chemical cleaning reagents used, pure methanol was the only cleaning reagent that removed albendazole from the membranes.

Optimisation of methanol distillation using GA and neural network hybrid

ABSTRACT Distillation is an energy-intensive non-stationary process represented using non-linear model equations and involves multiple objectives. For such processes, data-based multi-objective optimization methods are more suitable compared to conventional non-linear optimization methods. Therefore, a surrogate-assisted multi-objective optimization (SAMOO) approach is developed by hybridizing an artificial neural network (ANN) and genetic algorithm (GA) to simultaneously minimize the annualized capital expenditure cost (ACAPEX) and annualized operational expenditure cost (AOC) for the methanol separation process. The approach is then extended for operational optimization to maximize methanol purity and minimize heat duty. The Pareto optimal fronts obtained using the data-based SAMOO approach are found to be very close to the optimization results obtained using the actual physics-based Aspen Plus model. The coupling of the genetic algorithm and ANN modeling in SAMOO approach reduces the computing time of optimization by ∽ 50% with nearly the same results as that of the physics-based model.

The Business Prospect of Biomass to Methanol Development in Namibia: A Review

In Indonesia, the demand for methanol as renewable alternatives or chemical feedstock has been rising significantly to address the shortage of its domestic fossil fuels need. In the future, Indonesia expects to increase their methanol production using gasification process to balance its domestic demand. This paper presents the business prospect of methanol production from overseas, i.e., Namibia using biomass (encroacher bush types) feedstocks. It is concluded that biomass is available as an alternative feedstock to generate pure methanol. In Namibia, biomass is one of the most abundant and easily accessed resources for energy uses. However, without appropriate business endorsement by the government, such as a well-designed policies and incentives, the project’s prospect is still limited and very costly to be implemented. The financial planning of investment, particularly in how to find the best technological design of methanol processing, is highly essential to gain the maximum net business profit.

Spray and explosion characteristics of methanol and methanol-benzene blends near azeotrope formation: Effects of temperature, concentration, and benzene content

The explosion hazard of flammable liquids leaking to form spray in storage and transportation at ambient temperature has not been systematically investigated. This work presents new results from experimental investigations of the atomization and explosion characteristics of methanol, and methanol-benzene blends forming near the azeotrope under different initial conditions (initial temperature (298.15–318.15 K), methanol concentration (198–514.8 g/m3) and benzene content (41–81%)) in a 20-L spherical vessel. The empirical formulas for Sauter Mean Diameter (SMD) of the droplets and the maximum explosion pressure with respect to the initial temperature and methanol concentration were obtained from the quantitative analysis. Compared to the explosion hazard of pure methanol and methanol-benzene blends spray, the results showed that the maximum rate of pressure rise and maximum explosion temperature of methanol-benzene blends were relatively low. Furthermore, the effect of carbon soot formation on the explosion hazard during explosion development was analyzed.

Hydrogen Production from Supercritical Water Gasification of Model Compounds of Crude Glycerol from Biodiesel Industries

Biodiesel production through transesterification results in a large quantity of crude glycerol as a byproduct, the utilization of which is technically and economically challenging. Because of the ability to efficiently process wet feedstocks, supercritical water gasification (SCWG) is utilized in this study to convert crude glycerol into hydrogen-rich syngas. A significant challenge addressed through this study is the decomposition routes of different heterogeneous components of crude glycerol during SCWG. Pure glycerol, methanol and oleic acid were investigated for SCWG as the model compounds of crude glycerol. SCWG of model compounds at temperature, pressure, feedstock concentration and reaction time of 500 °C, 23–25 MPa, 10 wt% and 1 h, respectively, revealed methanol to exhibit the highest H2 yield of 7.7 mmol/g, followed by pure glycerol (4.4 mmol/g) and oleic acid (1.1 mmol/g). The effects of feedstock concentration from 30 wt% to 10 wt% increased H2 yield from all model compounds. Response surface methodology (RSM) was used to develop a response curve to visualize the interactive behavior and develop model equations for the prediction of H2-rich gas yields as a function of the composition of model compounds in the crude glycerol mixture. Predictive models showed a good agreement with experimental results, demonstrating high accuracy and robustness of the model. These findings demonstrated a strong potential of crude glycerol for SCWG to generate H2-rich syngas.

New perspectives to enhance the electro-oxidation of atrazine in methanol medium: Photo assistance using UV irradiation

There has been a considerable increase in the use of herbicides worldwide, and this has resulted in the contamination of soil and water bodies. The presence of large volumes of water limits the direct application of electrochemical treatment when the pollutants are present in low concentrations; this limitation can be circumvented by using pre-concentration techniques via adsorption and desorption with organic solvent. Taking this into account, the present study sought to investigate atrazine (ATZ) degradation through the application of photocatalysis (PC) and photo-assisted electrocatalysis (PAEC) in methanol medium using mixed metal oxide anode. The application of PC and PAEC in pure methanol led to nearly 92 % and 98 % of ATZ removal, respectively. The addition of water in the methanol medium under the PAEC technique led to better pollutant removal, where an increase was observed in ATZ removal from 97.2 % in pure methanol and 99.2 % in methanol containing 10 % of water (methanol/10 % H2O). Furthermore, the application of PAEC yielded higher kinetic constants (k), where an increase of up to 74.7 % and 49.4 % in k was obtained for pure methanol and methanol/10 % H2O, respectively. Variations in energy consumption (EC) were observed when PAEC was applied for ATZ degradation via the media investigated; the use of pure methanol and methanol/10 % H2O led to EC of 0.219 and 0.183 kW h m−3 %−1, respectively, in one hour of experiment. Finally, changes in the analytical technique and reaction medium led to variations in the by-products formed, where the formation of some by-products was favored over others due to differences in the oxidizing species generated in the process. The results obtained show that the application of PAEC in methanol is a highly promising technique for the treatment of effluents.

Performance and ANN-based optimization of an advanced process for wet CO2-to-Methanol using a catalytic fluidized bed reactor integrated with separators

Large-scale green processes to produce methanol from massive industrial sources of CO2 with a certain amount of water are increasingly attractive for carbon neutralization. In this study, an advanced CO2-to-Methanol (CTM) process, consisting of a turbulent fluidized bed (TFB) reactor, separators, and other units, was developed, analyzed from start-up to steady state, and optimized for high-purity methanol production (98.5–99.9 wt%) from a wet CO2 source (1.3 MtCO2/year with 1.35 mol% H2O). A two-stage flash drum with direct feeding of wet CO2 into a flash drum was applied to the developed CTM process to remove water and enhance unconverted gas recovery. At a methanol purity of 99.9 wt%, the advanced CTM process increased the methanol yield (0.15–0.31%), production capacity (5700–10100 tMeOH/year), and net CO2 reduction (0.0009–0.0033 kgCO2/kgMeOH) but decreased production cost (3.7–7.4 $/tMeOH) compared to the conventional CTM process under various of reactor temperatures (478–538 K) and pressures (40–90 bar). During the start-up process, the CTM process indicated the peaks in the methanol molar fraction and flow rate as the TFB reactor performed the stable profile of solid temperature (548–553.75 K) and volume fraction (∼0.249). In the performance assessment, the main units (compressor, TFB reactor, and distillation column) accounted for 96, 95, and 82.5% of capital expenditure (CAPEX), operating expenditure (OPEX), and energy consumption, respectively. Meanwhile, lowering the price of the annual CO2 and H2 increased CAPEX and OPEX contributions from 10.92 (present) to 28.64% (in 2050). To optimize the process using an artificial neural network (ANN) model, three main objectives and four main operating variables were selected as features through data analysis. The ANN model precisely predicted process performances (>99% accuracy) could reduce the computational cost by 900-fold compared to the process simulation. For methanol purity of 98.5–99.9 wt%, the CTM process should be operated in the optimum domain with a reactor pressure of 57.18–75.74 bar, reactor temperature of 493.62–506.32 K, reflux ratio of 1.02–1.08, and reboiler ratio of 1.32–1.38. The results are useful for designing, operating, and decision-making processes for producing various grades of green methanol from wet CO2 sources.

Techno-economic analysis of methanol synthesis from syngas derived from steam reforming of crude glycerol

AbstractDue to the large amount of crude glycerol produced as a by-product by the biodiesel industry, alternative technologies for converting glycerol to value-added fuels such as syngas have been proposed. By employing four main processes, the syngas could further be used to produce methanol. The first process is steam reforming (STR) where the crude glycerol is converted into syngas. The next step is a three-unit pressure swing adsorption (PSA) system which is employed to condition the syngas into the required stoichiometric ratio. The final two process are the methanol synthesis and methanol purification processes. The effects of STR temperature, steam-to-glycerol ratio (SGR), methanol synthesis temperature and pressure were all investigated. The results obtained shows that 0.29 kgMeOH/kgCG can be obtained through this process at STR of 650 ℃, SGR of 9, and methanol synthesis temperature and pressure of 250 ℃ and 80 bar respectively. In addition, a methanol production plant capacity of 6.8 tonnes/hr of crude glycerol feed for a 20-year plant life was investigated. The result from the economic analysis carried out shows that production of methanol from glycerol is economically feasible with net present value (NPV), return on investment, (ROI), discounted payback period (DPBP) and net production cost (NPC) of $74.2 million, 17%, 4.59 years, and 85₵/kgMeOH respectively. The sensitivity analysis results show that the revenue from sales of methanol and byproducts (hydrogen and methane), the manufacturing cost, the cost of raw materials, as well as fixed capital investment (FCI) were the most sensitive economic parameters.

The Effect of Types of Biogas and Methanol Purification and Loading as Fuel for Four-Stroke Generators on Exhaust Emissions

Biogas is a type of new renewable energy that is formed through the fermentation process of organic waste materials, such as livestock manure, organic waste, and other materials by methanogenic bacteria in anaerobic (without oxygen) conditions. Methanol is a very light, volatile, colorless, tasteless, flammable, toxic liquid with a very faint odour. In addition, methanol can be used as a solvent and also as an alternative fuel. This study aimed to determine the effect of the type of biogas and methanol purification and loading as fuel for a 4-stroke generator on exhaust emissions. An experimental study to test the efficacy of biogas and methanol fuels with or without loading with RON-90 gasoline (Pertalite®). The percentage of carbon monoxide (CO) and hydrocarbon (HC) emissions is used as a reference in assessing the efficacy of fuels in reducing emissions. The results of exhaust emission test studies using biogas purified from H2S, H2O, CO2, and methanol produce exhaust emission values of HC and CO with a lower value compared to the maximum value of the threshold according to the standards of the Minister of Environment Number 05 of 2006 so that biogas purified from H2S, H2O, CO2, and methanol is more environmentally friendly than RON-90 gasoline on the market.

Is Direct DME Synthesis Superior to Methanol Production in Carbon Dioxide Valorization? From Thermodynamic Predictions to Experimental Confirmation

CO2 valorization is a key measure to reach climate neutrality. Thermodynamics suggest direct conversion of CO2 into dimethyl ether (DME) to have greater potential than the indirect route via methanol synthesis, followed by purification of methanol and then a separate dehydration into DME. In this work, we introduce heteropoly acids as a capable class of dehydration catalysts for direct DME synthesis from CO2 and H2. To clarify if direct DME synthesis is in fact superior to sole MeOH synthesis, accurate thermodynamic equilibrium calculations are performed and pose as the base of our argumentation. An efficient Cu/ZnO/ZrO2 (CZZ) methanol catalyst is used to compare the methanol synthesis using a feedstock with stoichiometric CO2/3H2 mixture against bifunctional catalysts, containing CZZ and a dehydration component. The dehydration components include a commercial ferrierite (FER) and heteropoly acid (HPA) coated alumina and zirconia. For direct DME synthesis, the CO2 feed gas at gas hourly space velocities (GHSVs) between 1,250 and 158,400 NL kgcat–1 h–1, at temperatures of 210–270 °C and 40 bar pressure, was investigated. Based on the wide parameter window investigated, the following can be concluded at 250 °C: under a thermodynamic regime, CO2 conversion is close to the theoretical limit (30%exp/32%theo) and the direct DME synthesis is superior to sole methanol synthesis (+20%exp/+33%theo). The amount of valuable products (methanol, DME) profits significantly more (+70%exp/+88%theo) from the direct DME synthesis than CO2 conversion indicates. Under a kinetic regime, HPA-coated catalysts show superior apparent activation energies for DME production than the widely used ferrierite (HPA: 45 kJ mol–1/FER: 80 kJ mol–1), making HPA coatings a great option for highly capable dehydration catalysts under CO2- and water-rich conditions.

Development of an efficient method for separation and purification of cordycepin from liquid fermentation of Cordyceps militaris and analysis of cordycepin antitumor activity

Cordycepin (3 ′-deoxyadenosine) is the main active component of Cordyceps militaris, which is a chemical marker for quality detection of Cordyceps militaris and has important medicinal development value. Existing methods for obtaining cordycepin are complex and costly. In this study, an economical and simple method for separation and purification of cordycepin from Cordyceps militaris fermentation liquid through physical crystallization was explored. First, lyophilized powdered fermentation liquid (LPFL) and pure methanol (1 g/100 mL, w/v) were mixed, and then repeatedly dissolved and crystallized until the precipitation was white. Purified product was obtained by freeze-drying the precipitate. The substance was determined to be cordycepin by high performance liquid chromatography, mass spectrometry and infrared spectroscopy, and the purity was 94.26%. Compared with the existing methods, this method is simple and low cost. In addition, the functional activity of cordycepin was determined by in vitro test. The results exhibited that cordycepin caused death and morphological changes in human colon cancer Caco-2 cells, and significantly inhibited the proliferation of Caco-2 cells, with a half-maximal inhibitory concentration (IC50) of 107.2 μg/mL. Cordycepin could induce early apoptosis of Caco-2 and caused cell cycle arrest in the G2 phase. Caco-2 cell apoptosis and cell cycle arrest showed dose dependence to cordycepin over a certain range. These results improved cordycepin purification method, provided insights into the mechanism of cordycepin in cancer inhibition, and would provide important reference for further development and clinical application of cordycepin.

Cryogenic Chemistry and Quantitative Non-Thermal Desorption from Pure Methanol Ices: High-Energy Electron versus X-Ray Induced Processes.

X-Ray irradiation of interstellar ice analogues has recently been proven to induce desorption of molecules, thus being a potential source for the still-unexplained presence of gaseous organics in the coldest regions of the interstellar medium, especially in protoplanetary disks. The proposed desorption mechanism involves the Auger decay of excited molecules following soft X-ray absorption, known as X-ray induced electron-stimulated desorption (XESD). Aiming to quantify electron induced desorption in XESD, we irradiated pure methanol (CH3 OH) ices at 23 K with 505 eV electrons, to simulate the Auger electrons originating from the O 1s core absorption. Desorption yields of neutral fragments and the effective methanol depletion cross-section were quantitatively determined by mass spectrometry. We derived desorption yields in molecules per incident electron for CO, CO2 , CH3 OH, CH4 /O, H2 O, H2 CO, C2 H6 and other less abundant but more complex organic products. We obtained desorption yields remarkably similar to XESD values.

Recovery of Pure Methanol from Humid Gas Using Mn-Co Prussian Blue Analogue.

Conventional methanol recovery and purification processes are highly energy-intensive; processes using selective adsorbents that consume low energy are preferable. However, conventional adsorbents have low methanol selectivity under humid conditions. In this study, we develop a selective methanol adsorbent, manganese hexacyanocobaltate (MnHCC), which enables the efficient removal of methanol from waste gas and its subsequent reuse. MnHCC adsorbs 4.8 mmol-methanol/g-adsorbent at 25 °C in a humid gas containing 5000 ppmv of methanol, which is five times higher than the adsorption capacity of activated carbon (0.86 mmol/g). Although MnHCC exhibits the simultaneous adsorption of methanol and water, it has a higher adsorption enthalpy for methanol. Thus, pure methanol (95%) was recovered via thermal desorption at 150 °C after dehydration. The estimated energy of this recovery was 18.9 MJ/kg-methanol, approximately half that of existing mass production methods. MnHCC is reusable and stable even after 10 cyclic experiments. Consequently, MnHCC has the potential to contribute to both the recycling of methanol from waste gas and its low-cost purification.

Effects of 2-ethylhexyl nitrate (EHN) on combustion and emissions on a compression ignition engine fueling high-pressure direct-injection pure methanol fuel

Green methanol is a good carbon–neutral fuel, but the cetane number of methanol is so low that it is unsuitable for use in conventional compression ignition engines. Stable combustion of methanol is a great challenge at low load. Cetane improver such as 2-ethylhexyl nitrate (EHN), can improve the combustion stability of low cetane number fuel. In the current work, the effects of EHN on combustion and emissions were studied on a compression ignition engine at low load by using pure methanol fuel. Four methanol fuels with different EHN addition ratios were used, namely 0 % EHN (pure methanol), 0.1 % EHN, 1 % EHN and 3 % EHN, and diesel was used as the baseline. Results show that compared with diesel, the shortened combustion duration of pure methanol is mainly caused by the shortening of premixed combustion phase. The brake thermal efficiency (BTE) of pure methanol is relatively higher than that of diesel at 120 °C intake temperature. But the BTE of diesel at 50 °C intake temperature is slightly higher than that of pure methanol. As the ENH increases, the ignition delay decreases gradually, and the BTE decreases first and then increases. The NOx emissions of methanol are lower than those of diesel, but NOx emissions increase with the increase of EHN. NOx emissions of 3 % EHN are 31 % more than those of pure methanol and 77 % less than those of diesel. The soot emissions are close to zero for all test methanol fuels. The BTE of all fuels increases initially and decreases subsequently with the delay of start of injection. The higher EGR rate, lower intake temperature and injection pressure improve the BTE of all fuel. For 3 % EHN, the lowest intake temperature is not higher than 40 °C for stable operation, and the optimal operating strategy for the highest BTE (30.5 %) is single injection, 25 MPa injection pressure, 15 % EGR rate and 40 °C intake temperature. Methanol shows 0.6 % higher optimal BTE than diesel at the operating condition.

Relationships of Enantioselective Retention of Chiral Oxazolopyrroloquinolones on a Stationary Phase with Grafted Ristocetin А Antibiotic from Aqueous Methanol Solutions

The mechanisms of retention and separation of the enantiomers of chiral oxazolopyrroloquinolones on a stationary phase with graftеd macrocyclic antibiotic ristocetin A under conditions of high-performance liquid chromatography with aqueous methanol mobile phases have been studied. The retention factor was found to decrease monotonically when the CH3OH concentration in the mobile phase increased to 90 vol %; then it slightly increased as the composition of the mobile phase approached pure methanol. The thermodynamics of adsorption of oxazolopyrroloquinolones in different regions of this dependence was studied. A mathematical model has been proposed; it describes well the experimental data and allows for analyte solvation in the mobile phase and competitive adsorption (with mobile phase components) on a chiral selector. The results were compared with previously obtained data for water–acetonitrile mobile phases. The reasons for the observed differences were discussed.

CO2 capture enhancement by encapsulation of nanoparticles in metal–organic frameworks suspended in physical absorbents

In this study, CO2 nanoabsorbents composed of encapsulated Fe3O4 nanoparticles in metal-organic frameworks (MOFs) and methanol, are developed to overcome the limitations of conventional CO2 sorbents. The polyvinylpyrrolidone-functionalized Fe3O4 nanoparticles encapsulated in (Zn)MOF-74 [Zn2(DOBDC), DOBDC = 2, 5-dihydroxyterephthalic acid] are dispersed in the methanol. Compared with pure methanol, CO2 absorption and regeneration performances of Fe3O4 @ (Zn)MOF-74/methanol are improved by 13.07% and 16.25% (Abs.: 0.84 g-CO2/L-solvent and reg.: 0.77 g-CO2/L-solvent), respectively, at optimum conditions of 0.01 wt%. Cyclic stability experiments exhibit that the performance of Fe3O4 @ (Zn)MOF-74/methanol can preserve 93.76% of their initial capacities. It is finally concluded that the absorption performance is improved by hydrodynamic and shuttle effects while the CO2 sorbent regeneration performance is enhanced by metal-organic heat carriers (MOHCs) and nucleation from the surface of nanoparticles by introducing Fe3O4 @ (Zn)MOF-74 nanoparticles.