Nickel catalysts supported on zirconium oxide and modified by various amounts of lanthanum with 10, 15, and 20 wt.% were synthesized for CO2 reforming of methane. The effect of La2O3 as a promoter on the stability of the catalyst, the amount of carbon formed, and the ratio of H2 to CO were investigated. In this study, we observed that promoting the catalyst with La2O3 enhanced catalyst activities. The conversions of the feed, i.e., methane and carbon dioxide, were in the order 10La2O3 > 15La2O3 > 20La2O3 > 0La2O3, with the highest conversions being about 60% and 70% for both CH4 and CO2 respectively. Brunauer−Emmett−Teller (BET) analysis showed that the surface area of the catalysts decreased slightly with increasing La2O3 doping. We observed that 10% La2O3 doping had the highest specific surface area (21.6 m2/g) and the least for the un-promoted sample. The higher surface areas of the promoted samples relative to the reference catalyst is an indication of the concentration of the meta... [more]

This paper presents results of investigation of co-combustion process of biodiesel with gasoline, in form of mixture and using dual fuel technology. The main objective of this work was to show differences in both combustion systems of the engine powered by fuels of different reactivity. This paper presents parameters of the engine and the assessment of combustion stability. It turns out that combustion process of biodiesel was characterized by lower ignition delay compared to diesel fuel combustion. For 0.54 of gasoline energetic fraction, the ignition delay increased by 25% compared to the combustion of the pure biodiesel, but for dual fuel technology for 0.95 of gasoline fraction it was decreased by 85%. For dual fuel technology with the increase in gasoline fraction, the specific fuel consumption (SFC) was decreased for all analyzed fractions of gasoline. In the case of blend combustion, the SFC was increased in comparison to dual fuel technology. An analysis of spread of ignition d... [more]

Microscale combustion has potential application in a micro power generator. This paper studied the ignition and combustion behavior of individual graphite microparticles in a micro-combustor to explore the utilization of carbon-based fuels at the microscale system. The individual graphite microparticles inside the micro-combustor were ignited by a highly focused laser in an air flow with natural convection at atmospheric temperature and pressure. The results show that the ignition of graphite microparticles was heterogeneous. The particle diameter had a small weak effect on ignition delay time and threshold ignition energy. The micro-combustor wall heat losses had significant effects on the ignition and combustion. During combustion, flame instability, photophoresis, repetitive extinction and reignition were identified. The flame structure was asymmetric, and the fluctuation of flame front and radiation intensity showed combustion instability. Photophoretic force pushed the graphite aw... [more]

A novel carbonaceous adsorbent was prepared from sulfur-impregnated heavy oil ash via pyrolysis using potassium sulfide (K2S) solution, and its ability to remove lead (Pb2+) from aqueous solutions was examined. It was compared with an adsorbent synthesized by conventional pyrolysis using potassium hydroxide (KOH) solution. Specifically, the raw ash was immersed in 1 M K2S solution or 1 M KOH solution for 1 day and subsequently heated at 100−1000 °C in a nitrogen (N2) atmosphere. After heating for 1 h, the solid was naturally cooled in N2 atmosphere, and subsequently washed and dried to yield the product. Regardless of the pyrolysis temperature, the product generated using K2S (Product-K2S) has a higher sulfur content than that obtained using KOH (Product-KOH). Moreover, Product-K2S has a higher lead removal ability than Product-KOH, whereas the specific surface area of the former is smaller than that of the latter. Product-K2S obtained at 300 °C (Product-K2S-300) achieves the highest l... [more]

The NOx reduction in the iron ore pelletizing process becomes an important environmental concern owing to its role in the formation of photochemical smog and acid rain. Thus, it is essential to develop new technologies for reducing NOx emissions in order to contribute to the cleaner production of pellets. In this paper, NOx reduction by advanced reburning ingrate-rotary kiln for oxidized pellet production was performed on a laboratory-scale gas kiln. Temperature and NH3/NOx molar ratio (NSR) were the key factors affecting the reduction of NOx. A better denitrification effect can be obtained on flus gas with higher initial NOx concentration, at temperature = 900 °C, NSR = 1.2, and reaction time exceeds one second. NOx reduction rate had reached 55−65% when the initial NOx concentration was above 400 ppm, and exceeds 70% when the initial NOx concentration was around 680 ppm. Urea solution has the best denitrification effect compared with NH3·H2O and NH4HCO3 solution. As for additives, th... [more]

Aminoethers of boric acid (AEBA) were studied as potential extractants for the separation of aqueous−alcoholic azeotropic mixtures by extractive distillation. The conditions of vapor−liquid equilibrium in aqueous solutions of ethanol and isopropanol in the presence of AEBA were studied. The division of AEBA molecules into group components was proposed, and previously unknown geometric parameters of the boron group and the energetic pair parameters of the boron group with the alkane group, ether group, amine-3d group, and alcohol group were determined within the framework of the Universal Functional Group Activity Coefficient (UNIFAC) model. The modeling of the extractive rectification process of an ethanol−water mixture with AEBA as extractant has been carried out. The dependences of the cost function on the extractant flow rate, the residual water content in it and the number of theoretical trays were obtained. A technological scheme for ethanol dehydration has been proposed, and its... [more]

The article deals with the possibilities of using electron accelerator for controlled aging of lubricating media used in special vehicles. During use, e.g., in combustion engines, the lubricants get contaminated and thermo-oxidative degradation also occurs. The pilot project confirms the hypothesis that ionizing radiation makes it possible to simulate the operating load of lubricating media, which was repeatedly confirmed by long-term monitoring of changes in viscosity of statistically significant samples of motor oils used in special equipment. Preliminary test results also show that there are likely to be possibilities to influence other selected properties, such as the coefficient of friction depending on the radiation dose. The authors describe physicochemical processes during irradiation and, in the example of kinematic viscosity, present summary results for selected lubricating media.

This paper provides a fundamental and critical review of biomass application as renewable reductant in integrated ferroalloy reduction process. The basis for the review is based on the current process and product quality requirement that bio-based reductants must fulfill. The characteristics of different feedstocks and suitable pre-treatment and post-treatment technologies for their upgrading are evaluated. The existing literature concerning biomass application in ferroalloy industries is reviewed to fill out the research gaps related to charcoal properties provided by current production technologies and the integration of renewable reductants in the existing industrial infrastructure. This review also provides insights and recommendations to the unresolved challenges related to the charcoal process economics. Several possibilities to integrate the production of bio-based reductants with bio-refineries to lower the cost and increase the total efficiency are given. A comparison of chall... [more]

A critical issue in the design of bubbling fluidized bed reactors for biomass fast pyrolysis is to maintain the bed at a constant level to ensure stable operation. In this work, a bubbling fluidized bed reactor was investigated to deal with this issue. The reactor consists of inner and outer tubes and enables in situ control of the fluidized-bed level in the inner-tube reactor with a mechanical method during biomass fast pyrolysis. The significant fraction of biochar produced from the fast pyrolysis in the inner-tube reactor was automatically removed through the annulus between the inner and outer tubes. The effect of pyrolysis temperature (426−528 °C) and feeding rate (0.8−1.8 kg/h) on the yield and characteristics of bio-oil, biochar, and gaseous products were examined at a 15 L/min nitrogen carrier gas flow rate for wood sawdust with a 0.5−1.0 mm particle size range as a feed. The bio-oil reached a maximum yield of 62.4 wt% on a dry basis at 440 °C, and then slowly decreased with in... [more]

In this study, ZnO nanoparticles were fabricated by using the hydrothermal method for adsorption of phosphate from wastewater. The obtained ZnO nanorods were characterized by powder X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), specific surface area (BET) and energy dispersive X-ray spectroscopy (EDS). The ZnO materials were applied for adsorption of phosphate from water using batch experiments. The effects of pH (4−10), adsorption time (30−240 min), the amount of adsorbent (0.1−0.7 g/L) and initial concentration of phosphate (147.637−466.209 mg/L) on the adsorption efficiency were investigated. The optimum condition was found at pH = 5 and at an adsorption time of 150 min. The adsorption was fitted well with the Langmuir isotherm and the maximum adsorption capacity was calculated to be 769.23 mg/g. These results show that ZnO nanomaterial would highly promising for adsorbing phosphate from water. The adsorption of phosphate on ZnO nanomaterials follows the... [more]

Chemical industries rely heavily on fossil resources for the production of carbon-based chemicals. A possible transformation towards sustainability is the usage of carbon dioxide as a source of carbon. Carbon dioxide is activated for follow-up reactions by its conversion to carbon monoxide. This can be accomplished by electrochemical reduction in solid oxide cells. In this work, we investigate the process performance of the direct high-temperature CO2 electrolysis by current-voltage characteristics (iV) and Electrochemical Impedance Spectroscopy (EIS) experiments. Variations of the operation parameters temperature, load, fuel utilization, feed gas ratio and flow rate show the versatility of the procedure with maintaining high current densities of 0.75 up to 1.5 A·cm−2, therefore resulting in high conversion rates. The potential of the high-temperature carbon dioxide electrolysis as a suitable enabler for the activation of CO2 as a chemical feedstock is therefore appointed and shown.

Gaining energy independence by utilizing new and renewable energy resources has become imperative for Korea. Energy recovery from Korean municipal solid waste (MSW) could be a promising option to resolve the issue, as Korean MSW is highly recyclable due to its systematic separation, collection and volume-based waste disposal system. In this study, gasification experiments were conducted on Korean municipal waste-derived solid fuel (SRF) using a fixed bed reactor by varying the equivalence ratio (ER) to assess the viability of syngas production. Experiments were also conducted on coal and biomass under similar conditions to compare the experimental results, as the gasification applicability of coal and biomass are long-established. Experimental results showed that Korean SRF could be used to recover energy in form of syngas. In particular, 50.94% cold gas efficiency and 54.66% carbon conversion ratio with a lower heating value of 12.57 MJ/Nm3 can be achieved by gasifying the SRF at 0.4... [more]

Two kinds of tri-high coals were selected to determine the influences of ash-existing environments and coal structures on CO2 gasification characteristics. The TGA results showed that the gasification of ash-free coal (AFC) chars was more efficient than that of corresponding raw coal (RC) chars. To uncover the reasons, the structures of RCs and AFCs, and their char samples prepared at elevated temperatures were investigated with SEM, BET, XRD, Raman and FTIR. The BET, SEM and XRD results showed that the Ash/mineral matter is associated with coal, carbon forms the main structural framework and mineral matters are found embedded in the coal structure in the low-rank tri-high coal. The Raman and FTIR results show that the ash can hinder volatile matters from exposing to the coal particles. Those results indicate that the surface of AFC chars has more free active carbon sites than raw coal chars, which are favorable for mass transfer between C and CO2, thereby improving reactivity of the A... [more]

The torrefaction (mild pyrolysis) process modifies biomass chemical and physical properties and is applied as a thermochemical route to upgrade solid fuel. In this work, the catalytic effect of thermo-acoustic on oxidizing woody torrefaction is assessed. The combined effect of two acoustic frequencies (1411, 2696 Hz) and three temperatures (230, 250, and 290 °C) was evaluated through weight loss and its deviation curves, calculated torrefaction severity index (TSI), as well as proximate, calorific, and compression strength analysis of Eucalyptus grandis. A new index to account for the catalytic effects on torrefaction (TCEI) was introduced, providing the quantitative analysis of acoustic frequencies influence. A two-step consecutive reaction numerical model allowed the thermo-acoustic experiment evaluation. For instance, the thermogravimetric profiles revealed that the acoustic field has a catalytic effect on wood torrefaction and enhances the biomass oxidation process for severe treat... [more]

The thermal desorption of tritium (3H, T) and radiocarbon (14C) from spent activated carbon was investigated and three thermal desorption steps were established: the vaporization of homogeneously condensed molecules, the desorption of molecules physically binding with the carbon surface, and the decomposition of chemisorbed molecules. A model-free kinetic analysis was conducted to establish the optimum condition of vacuum thermal desorption. Physisorbed species, including tritiated water (HTO) and 14CO2, were effectively removed by vacuum thermal desorption. However, a fraction of 14C, which may take the form of carbon molecules in pyrocarbon form during the heating process, was not removed, even at a high temperature of 1000 °C under a vacuum of 0.3−0.5 Pa. Oxidative peeling of the pore surfaces by filling the evacuated pores with pure oxygen via vacuum thermal desorption and heating to 700 °C was found to be effective for reducing the level of 14C to a level below the established fre... [more]

The radical homopolymerization kinetics of 3-(methacryloylaminopropyl) trimethylammonium chloride (MAPTAC) and its batch copolymerization with nonionized acrylic acid (AA) in aqueous solution are investigated and modeled. The drift in monomer composition is measured during copolymerization by in situ NMR over a range of initial AA molar fractions and monomer weight fractions up to 0.35 at 50 °C. The copolymer becomes enriched in MAPTAC for monomer mixtures containing up to 60 mol% MAPTAC, but is enriched in AA for MAPTAC-rich mixtures; this azeotropic behavior is dependent on initial monomer content, as electrostatic interactions from the cationic charges influence the system reactivity ratios. Models for MAPTAC homopolymerization and AA-MAPTAC copolymerization are developed to represent the rates of monomer conversion and comonomer composition drifts over the complete range of experimental conditions.

5-(4-bromophenyl)-4,6-dichloropyrimidine was arylated with several aryl/heteroaryl boronic acids via the Suzuki cross-coupling reaction by using Pd(0) catalyst to yield novel pyrimidine analogs (3a-h). It was optimized so that good yields were obtained when 5 mol % Pd(PPh3)4 was used along with K3PO4 and 1,4-Dioxane. Electron-rich boronic acids were succeeded to produce good yields of products. Density functional theory (DFT) calculations were also applied on these new compounds to analyze their reactivity descriptors and electronic and structural relationship. According to DFT studies, compound 3f is the most reactive one, while 3g is the most stable one. As per DFT studies, the hyperpolarizability (β) values of these compounds do not show them as very good non-linear optical (NLO) materials. Compound 3f has the highest β value among all the compounds under study but still it is not high enough to render it a potent NLO material.

A Monte Carlo simulation algorithm is developed to visualize the impact of various initiator feeding policies on the kinetics of free radical polymerization. Three cases are studied: (1) general free radical polymerization using typical rate constants; (2) diffusion-controlled styrene free radical polymerization in a relatively small amount of solvent; and (3) methyl methacrylate free radical polymerization in solution. The number- and weight-average chain lengths, molecular weight distribution (MWD), and polymerization time were computed for each initiator feeding policy. The results show that a higher number of initiator shots throughout polymerization at a fixed amount of initiator significantly increases average molecular weight and broadens MWD. Similar results are also observed when most of the initiator is added at higher conversions. It is demonstrated that one can double the molecular weight of polystyrene and increase its dispersity by 50% through a four-shot instead of a sin... [more]

An investigation of the process of ozone combined with ultraviolet radiation has been carried out in order to establish the kinetics for photochemical oxidation of copper (Cu) from electroplating wastewater. The effects of operating parameters, including initial Cu concentration, ozone dosage, UV irradiation intensity, and pH value on the photochemical oxidation of Cu have been studied comprehensively. The Cu concentration during the reaction was identified using atomic absorption spectroscopy (AAS) method. The solid product was analyzed using X-ray diffraction (XRD) and scanning electron microscope−energy-dispersive X-ray (SEM−EDX) methods. It was found that the UV-Ozone process has high performance on Cu removal compared to UV and Ozone processes due to the high production rate of HO• radicals. It was also found that the solid product from the UV-Ozone process was CuO monoclinic crystal phase. The initial Cu concentration, ozone dosage, and pH value were significantly affected the Cu... [more]

2,5-diformylfuran (DFF) is an important downstream product obtained by selective oxidation of the biomass-based platform compound 5-hydroxymethylfurfural (HMF). In this study, a phosphorus-doped carbon (P-C) supported vanadium phosphate oxide (VPO) catalyst was successfully prepared and showed remarkably high catalytic activity in the selective oxidation of HMF to produce DFF with air as an oxidant. The effects of the reaction temperature, reaction time, solvent, catalyst amount, and VPO loading amount were investigated. The results showed that an HMF conversion rate of 100% and a DFF yield of 97.0% were obtained under suitable conditions, and DMSO was found to be the most suitable solvent under an air atmosphere.

The coal gasification wastewater figures prominently among types of industrial effluents due to its complex and phenolic composition, posing great difficulty for conventional water treatment processes. Since the coking wastewater is toxic and mutagenic to humans and animals, treatment of coal gasification wastewater is genuinely necessary. In this study, we established a lab-scale A2O (Anaerobic-Anoxic—Oxic) with moving bed biological reactor (MBBR) system and evaluated some water indicators of wastewater pretreated with internal electrolysis, of wastewater output of the established A2O-MBBR system, and of the wastewater treated by the combination thereof. The wastewater was taken from a coking plant at Thai Nguyen Iron and Steel Joint Stock Company in Vietnam. COD, BOD5, NH4+-N, phenol, and pH of the input coal gasification wastewater were 2359, 1105, 319, 172 mg/L, and 8 ± 0.1, respectively. The conditions of internal electrolysis were as follows: 720 min of reaction time, pH = 4, 25... [more]

Due to the unfavorable combination of its toxicity and high volatility, Cd is contained in most lists of potentially hazardous air pollutants with the greatest environmental and human-health concerns. The review paper evaluates the behavior of Cd during combustion (incineration) processes and its redistribution among condensed fractions (bottom ash/slag, fly ash) and volatilized fractions (that passes through most particulate control devices). The paper addresses all important effects of Cd interactions, such as presence of organic or inorganic chlorides, moisture levels, S, P and Na concentrations, flue gas composition etc. Possibilities of using various adsorbents (either within in-furnace regime or applied in post-combustion zone) are evaluated as well. Special attention is paid to mitigating its emissions factors; decreasing Cd volatility and facilitating Cd retention are discussed with the view of various combustion (incineration) conditions and the feed fuel composition.

It has been proven that vehicle emissions such as oxides of nitrogen (NOx) are negatively affecting the health of human beings as well as the environment. In addition, it was recently highlighted that air pollution may result in people being more vulnerable to the deadly COVID-19 virus. The use of biofuels such as E5 and E10 as alternatives of gasoline fuel have been recommended by different researchers. In this paper, the impacts of port injection of water to a spark ignition engine fueled by gasoline, E5 and E10 on its performance and NOx production have been investigated. The experimental work was undertaken using a KIA Cerato engine and the results were used to validate an AVL BOOST model. To develop the numerical analysis, design of experiment (DOE) method was employed. The results showed that by increasing the ethanol fraction in gasoline/ethanol blend, the brake specific fuel consumption (BSFC) improved between 2.3% and 4.5%. However, the level of NOx increased between 22% to 48... [more]

Hydrothermal carbonization (HTC) allows the conversion of organic waste into a solid product called hydrochar with improved fuel properties. Olive tree pruning biomass (OTP), a very abundant residue in Mediterranean countries, was treated by HTC to obtain a solid fuel similar to coal that could be used in co-combustion processes. Three different reaction temperatures (220, 250, and 280 °C) and reaction times (3, 6, and 9 h) were selected. The hydrochars obtained were extensively analyzed to study their behavior as fuel (i.e., ultimate, proximate, fiber and thermogravimetric analysis, Fourier-transform infrared spectroscopy (FTIR), activation energy, and combustion performance). The concentrations of cellulose, hemicellulose, and lignin in the samples depict a clear and consistent trend with the chemical reactions carried out in this treatment. Regarding O/C and H/C ratios and HHV, the hydrochars generated at more severe conditions are similar to lignite coal, reaching values of HHV up... [more]

A surfactant-free method was used to synthesize iron oxyhydroxide (akaganeite, β-FeOOH) nanorods and characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDS), and transmission electron microscopy (TEM). The synthesized nanoadsorbent was applied for the adsorptive removal of β-estradiol from aqueous solutions. The parameters affecting the adsorption were optimized using a multivariate approach based on the Box−Behnken design with the desirability function. Under the optimum conditions, the equilibrium data were investigated using two and three parameter isotherms, such as the Langmuir, Freundlich, Dubinin−Radushkevich, Redlich−Peterson, and Sips models. The adsorption data were described as Langmuir and Sips isotherm models and the maximum adsorption capacities in Langmuir and Sips of the β-FeOOH nanorods were 97.0 and 103 mg g−1, respectively. The adjusted non-l... [more]