Reaction Apparatus Research Articles

Sublimation‐Induced Vapor Deposition of Cyanuric Acid‐Melamine Supramolecular Single Crystals on Surfaces

AbstractHerein, a low‐temperature sublimation‐based vapor deposition (SVD) method is developed to synthesize hexagonal crystal plates of cyanuric acid‐melamine (CAM) with outstanding crystallinity. Through meticulous design of the reaction apparatus and careful selection of source materials, substrate‐confined SVD in a tube furnace is explored to grow single crystals of CAM in hexagonal shapes. Additionally, the orientation preference of the (202) facet is revealed, corresponding to the 2D arrangement of the H‐bonded network, of single‐crystalline plates on surfaces using selected area electron diffraction and X‐ray diffraction techniques. By employing atomic force microscopy and scanning electron microscopy for topography characterization, a mechanism of three‐stage step‐growth crystallization is proposed, including nucleation, in‐plane expansion, and out‐of‐plane growth. Furthermore, it is found that the interactions among melamine molecules in CAM synthesized via SVD are more intense compared to those in CAM synthesized via water‐based methods, as evidenced by infrared and photoluminescent spectra studies. Subsequent nanoindentation tests on the (202) facet of CAM single‐crystalline plates reveals a reduced modulus and hardness of 12.8 and 0.82 GPa, respectively. This methodology addresses the longstanding challenge of synthesizing hexagonal CAM single crystals and provides valuable insights for the fabrication of functional organic crystalline materials.

Novel synthesis of CuFe2O4/g-C3N4 based on microwave ferromagnetic resonance effect for the thorough removal of TC in mariculture wastewater under natural sunlight

Superior separation of photogenerated carriers holds the key to intensive degradation of tetracycline (TC) in mariculture wastewater under natural sunlight. CuFe2O4/g-C3N4 (CFO/g) was synthesized by secondary microwave co-precipitation (SMCP) based on the ferromagnetic resonance absorption effect. Under the reaction conditions of pH = 6.5, CFO/g = 0.2 g/L, [H2O2] = 1 mM, 99.0 % TC removal was realized in 40 min. Enhanced performance for TC removal in high-salinity environments heavily relied on elevated ionic strength and rapid electron transfer of CFO/g in conjunction with high-salinity interactions. To ecologically remediate mariculture wastewater under natural sunlight, we immobilized powdered CFO/g to a ferrite magnet and devised a continuous flow reaction apparatus, incorporating the controlled injection of hydrogen peroxide (H2O2), to achieve the 100 % TC removal and simultaneously undertake the pretreatment of other contaminants (∼70 %). Ultimately, a safety assessment demonstrated that the degradation of mariculture wastewater by the CFO/g photo-Fenton system is a reliable and efficient technology, and the growth of clownfish remained unimpaired. SMCP successfully accelerated the conversion of high-valent metal ions to low-valent ones and eased the activation barriers of H2O2, enabling various active species to execute their respective roles productively. Innovative application of microwave resonance to enhance the magnetic properties of CFO/g and to support the equilibrium conversion of elemental valence states in high-salinity environments from real wastewater.

Continuous ultrasonic ozone coupling technology-assisted control of ceramic membrane fouling coupled enhanced multiphase mixing to treat dye wastewater and CFD flow field simulation

In this study, ozone catalysts (hydrogenation-modified red mud, HM-RM) successfully prepared by hydrogenation-modification of industrial hazardous solid waste red mud (RM) as a raw material in accordance with the viewpoint of treating waste with waste and using waste. Meanwhile, as for the common phenomenon of membrane fouling, uneven distribution of multiphase solid catalysts and ozone in liquids, the addition of ultrasound can not only disperse materials, but also play a role in online cleaning of ceramic membranes and catalysts. The optimum treatment conditions for Rhodamine B (RhB) solution with volume of 2 L and concentration of 40 mg/L were catalyst concentration of 0.4 mg/L, reaction temperature of 45 °C, ultrasonic time of 1 h, ultrasonic intensity of 600 W, removal rate of RhB was up to 90 %. In addition, the computational fluid dynamics (CFD) simulation method was used to investigate the fluid flow between the two gas-liquid phases and the effect of the negative pressure of the membrane pump on the fluid by the analysis of flow, pressure and ozone flux of the ceramic membrane(CM) reaction apparatus. The CFD simulation results showed that at the inlet gas-liquid flow rate of 3 m/s and the negative pressure of 20,000 Pa, the maximum flow rates of CM-1 were 3 m/s, 0.752 m/s for CM-2, and 0.228 m/s for CM-3, respectively. Vortices, which are beneficial to solid-liquid mixing and gas-liquid mass transfer, formed between the suction port CM-1 of CM-1 and the inlets of CM-2 and CM-3. This discovery is consistent with relevant experimental research results. Significantly higher concentrations of both •OH and dissolved ozone were observed in the US/HM-RM/O3 system compared to other systems, indicating the significant improvement in ozone utilization rate through the application of ultrasound. The superiority of the US/HM-RM/O3 device was demonstrated. The real dye effluent was tested under optimum operating conditions and the results showed that COD and TOC were reduced by 81.34 % and 60.23 % respectively after 180 min of treatment. The above research can provide technical support for the treatment of dye wastewater using Ultrasound-enhanced ozone oxidation ceramic membranes.

Comparing in vitro nitric oxide blood uptake to its pulmonary diffusing capacity

Whether endothelium derived Nitric Oxide (NO) uptake by the blood is limited by a boundary layer, the red cell membrane or its interior is the subject of continued debate. Whether lung uptake of NO in the single-breath DLNO test is limited by blood or not is also debated. To understand which processes are limiting blood NO uptake we have modelled NO chemical kinetics and we have derived a shrinking core model, Thiele Modulus and FTCS (Euler) numerical solution. In a rapid reaction apparatus, NO uptake appears limited by a boundary layer, and throughout the red cell, by diffusion. In the single breath situation, and arguably with endogenous NO in vivo, NO uptake appears limited by a boundary layer and a pseudo first order chemical reaction in the outer molecular layers of the red cell. We have not found evidence to support red cell membrane limitation.

Clinically Translatable Hyperpolarized 13C Bicarbonate pH Imaging Method for Use in Prostate Cancer.

Solid tumors such as prostate cancer (PCa) commonly develop an acidic microenvironment with pH 6.5-7.2, owing to heterogeneous perfusion, high metabolic activity, and rapid cell proliferation. In preclinical prostate cancer models, disease progression is associated with a decrease in tumor extracellular pH, suggesting that pH imaging may reflect an imaging biomarker to detect aggressive and high-risk disease. Therefore, we developed a hyperpolarized carbon-13 MRI method to image the tumor extracellular pH (pHe) and prepared it for clinical translation for detection and risk stratification of PCa. This method relies on the rapid breakdown of hyperpolarized (HP) 1,2-glycerol carbonate (carbonyl-13C) via base-catalyzed hydrolysis to produce HP 13CO32-, which is neutralized and converted to HP H13CO3-. After injection, HP H13CO3- equilibrates with HP 13CO2 in vivo and enables the imaging of pHe. Using insights gleaned from mechanistic studies performed in the hyperpolarized state, we solved issues of polarization loss during preparation in a clinical polarizer system. We successfully customized a reaction apparatus suitable for clinical application, developed clinical standard operating procedures, and validated the radiofrequency pulse sequence and imaging data acquisition with a wide range of animal models. The results demonstrated that we can routinely produce a highly polarized and safe HP H13CO3- contrast agent suitable for human injection. Preclinical imaging studies validated the reliability and accuracy of measuring acidification in healthy kidney and prostate tumor tissue. These methods were used to support an Investigational New Drug application to the U.S. Food and Drug Administration. This methodology is now ready to be implemented in human trials, with the ultimate goal of improving the management of PCa.

Continuous Flow Synthesis of N-Doped Carbon Quantum Dots for Total Phenol Content Detection

The carbon quantum dot (CQD) paper-based analytical device (PAD) has drawn great attention and is being intensively explored. However, the construction of a continuous flow CQD synthesis device remains challenging. In this work, a continuous flow reaction apparatus was constructed to synthesize nitrogen-doped CQDs using a mixed-solvent system of tetraethylene glycol and water. The optical properties of the CQDs were characterized. The CQDs were found to be quenched by phenolics such as chlorogenic acid, salvianolic acid B, and rutin. The CQD PAD was prepared for the determination of the total phenolic content of honeysuckle extracts. A smartphone was used to test the analytical performance of the CQD PAD. The results demonstrated that the degree of fluorescence quenching of the CQDs showed a linear relationship with the concentration of the added chlorogenic acid solution. This method was compared with the total phenolic assay in the Chinese Pharmacopoeia, and the statistical test showed no significant difference between their results. With aqueous tetraethylene glycol as the solvent for the synthesis, the continuous flow reactor for CQD preparation could be easily set up. The CQD PAD is convenient, cheap, and expected to be used for the rapid quality detection of traditional Chinese medicines.

The influence of gas purification and addition of macro amounts of metal-carbonyl complexes on the formation of single-atom metal-carbonyl-complexes

Abstract Using the Fast On-line Reaction Apparatus (FORA), the influence of various gas-purification columns onto the formation of metal carbonyl complexes (MCCs) under single-atom chemistry conditions was investigated. MCCs were synthesized from single atoms of Mo, Tc, Ru and Rh being produced by the spontaneous fission of 252Cf and recoiling into a CO-gas containing carrier gas atmosphere. The in-situ synthesized MCCs were volatile enough to be transported by the carrier gas to a charcoal trap where they were adsorbed and their subsequent decay was registered by γ-spectrometry. It was found that the type and combination of purification columns used to clean the applied CO-gas strongly influences the obtained formation and transport yields for all MCCs. With the exception of Rh-carbonyl, intense gas-purification strategies resulted in reduced formation and transport yields for MCCs in comparison with less efficient or even completely missing purification setups. It was postulated that the observed reduction in yield might depend on the content of Fe(CO)5 and Ni(CO)4, as well as potentially other MCCs, in the CO-gas, being formed by the interaction between CO and the steel-surfaces of FORA as well as from impurities in the used charcoal traps. Subsequently, it was shown that macro amounts of Fe(CO)5, Ni(CO)4, Mo(CO)6 and Re2(CO)10 added to the used process gas indeed increase significantly the overall yields for MCCs produced by 252Cf fission products. Ni(CO)4 appeared the most potent to increase the yield. Therefore, it was used in more detailed investigations. Using isothermal chromatography, it was shown that Ni(CO)4 does not affect the speciation of carbonyl species produced by the 252Cf fission product 104Mo. For 107Tc, 110Ru and 111Rh a speciation change cannot be excluded. For 111Rh a speciation change cannot be excluded. An inter-carbonyl transfer mechanism is suggested boosting the formation of MCCs. The current discovery might allow for new opportunities in various research fields, which are currently restricted by the low overall yields for MCCs produced under single-atom chemistry conditions. Examples are the chemical investigation of transactinides or the generation of radioactive ion beams from refractory metals at accelerators.

The use of induction heating in reaction apparatus small tonnage production

Currently, in the planning and further implementation of technological processes that require heating of products to operating temperatures of about 1300 C, the issue of selecting energy-efficient environmentally friendly reactors using various heating methods is an acute issue. This scientific article discusses the effective use of electric and non-electric heating methods. Recommendations on the practical application of these methods are given, based on the final product and the specific features of the technological cycle of a particular enterprise. The question of the compliance of both methods with modern international requirements for the small-tonnage chemistry devices under consideration is considered. On the example of the Scientific Production Association «Lakokraspokrytiye» the main advantages in the application of induction heating in reactors used in technological lines for the production of paints and varnishes and coatings are shown. Examples are given of devices that are currently being developed and implemented in the Scientific Production Association «Lakokraspokrytiye», their basic characteristics are described. The described small-tonnage chemistry devices are widely used in the Russian Federation, CIS countries and Eastern Europe.

Prospects for Creating H+- or OH–-Conducting and Hydrogen- or Oxygen-Producing Surfaces in a Reaction Apparatus from Polyvinyl Chloride Materials

Prospects for Creating H+- or OH–-Conducting and Hydrogen- or Oxygen-Producing Surfaces in a Reaction Apparatus from Polyvinyl Chloride Materials

The influence of physical parameters on the in-situ metal carbonyl complex formation studied with the Fast On-line Reaction Apparatus (FORA)

Abstract The Fast On-line Reaction Apparatus (FORA) was used to investigate the influence of various reaction parameters onto the formation and transport of metal carbonyl complexes (MCCs) under single-atom chemistry conditions. FORA is based on a 252Cf-source producing short-lived Mo, Tc, Ru and Rh isotopes. Those are recoiling from the spontaneous fission source into a reaction chamber flushed with a gas-mixture containing CO. Upon contact with CO, fission products form volatile MCCs which are further transported by the gas stream to the detection setup, consisting of a charcoal trap mounted in front of a HPGe γ-detector. Depending on the reaction conditions, MCCs are formed and transported with different efficiencies. Using this setup, the impact of varying physical parameters like gas flow, gas pressure, kinetic energy of fission products upon entering the reaction chamber and temperature of the reaction chamber on the formation and transport yields of MCCs was investigated. Using a setup similar to FORA called Miss Piggy, various gas mixtures of CO with a selection of noble gases, as well as N2 and H2, were investigated with respect to their effect onto MCC formation and transport. Based on this measurements, optimized reaction conditions to maximize the synthesis and transport of MCCs are suggested. Explanations for the observed results supported by simulations are suggested as well.

The influence of chemical parameters on the in-situ metal carbonyl complex formation studied with the fast on-line reaction apparatus (FORA)

Abstract A new setup named Fast On-line Reaction Apparatus (FORA) is presented which allows for the efficient investigation and optimization of metal carbonyl complex (MCC) formation reactions under various reaction conditions. The setup contains a 252Cf-source producing short-lived Mo, Tc, Ru and Rh isotopes at a rate of a few atoms per second by its 3% spontaneous fission decay branch. Those atoms are transformed within FORA in-situ into volatile metal carbonyl complexes (MCCs) by using CO-containing carrier gases. Here, the design, operation and performance of FORA is discussed, revealing it as a suitable setup for performing single-atom chemistry studies. The influence of various gas-additives, such as CO2, CH4, H2, Ar, O2, H2O and ambient air, on the formation and transport of MCCs was investigated. O2, H2O and air were found to harm the formation and transport of MCCs in FORA, with H2O being the most severe. An exception is Tc, for which about 130 ppmv of H2O caused an increased production and transport of volatile compounds. The other gas-additives were not influencing the formation and transport efficiency of MCCs. Using an older setup called Miss Piggy based on a similar working principle as FORA, it was additionally investigated if gas-additives are mostly affecting the formation or only the transport stability of MCCs. It was found that mostly formation is impacted, as MCCs appear to be much less sensitive to reacting with gas-additives in comparison to the bare Mo, Tc, Ru and Rh atoms.

Quantum electronic control on chemical activation of methane by collision with spin-orbit state selected vanadium cation.

By coupling a newly developed quantum-electronic-state-selected supersonically cooled vanadium cation (V+) beam source with a double quadrupole-double octopole (DQDO) ion-molecule reaction apparatus, we have investigated detailed absolute integral cross sections (σ's) for the reactions, V+[a5DJ (J = 0, 2), a5FJ (J = 1, 2), and a3FJ (J = 2, 3)] + CH4, covering the center-of-mass collision energy range of Ecm = 0.1-10.0 eV. Three product channels, VH+ + CH3, VCH2+ + H2, and VCH3+ + H, are unambiguously identified based on Ecm-threshold measurements. No J-dependences for the σ curves (σ versus Ecm plots) of individual electronic states are discernible, which may indicate that the spin-orbit coupling is weak and has little effect on chemical reactivity. For all three product channels, the maximum σ values for the triplet a3FJ state [σ(a3FJ)] are found to be more than ten times larger than those for the quintet σ(a5DJ) and σ(a5FJ) states, showing that a reaction mechanism favoring the conservation of total electron spin. Without performing a detailed theoretical study, we have tentatively interpreted that a weak quintet-to-triplet spin crossing is operative for the activation reaction. The σ(a5D0, a5F1, and a3F2) measurements for the VH+, VCH2+, and VCH3+ product ion channels along with accounting of the kinetic energy distribution due to the thermal broadening effect for CH4 have allowed the determination of the 0 K bond dissociation energies: D0(V+-H) = 2.02 (0.05) eV, D0(V+-CH2) = 3.40 (0.07) eV, and D0(V+-CH3) = 2.07 (0.09) eV. Detailed branching ratios of product ion channels for the titled reaction have also been reported. Excellent simulations of the σ curves obtained previously for V+ generated by surface ionization at 1800-2200 K can be achieved by the linear combination of the σ(a5DJ, a5FJ, and a3FJ) curves weighted by the corresponding Boltzmann populations of the electronic states. In addition to serving as a strong validation of the thermal equilibrium assumption for the populations of the V+ electronic states in the hot filament ionization source, the agreement between these results also confirmed that the V+(a5DJ, a5FJ, and a3FJ) states prepared in this experiment are in single spin-orbit states with 100% purity.

Molecular Rotors with Aggregation-Induced Emission (AIE) as Fluorescent Probes for the Control of Polyurethane Synthesis

In this work, the use of fluorescent molecular rotors such as 9-(2,2-dicyanovinyl)julolidine (DCVJ) and 2,3-bis(4-(phenyl(4-(1,2,2-triphenylvinyl) phenyl)amino)phenyl)fumaronitrile (TPETPAFN) was proposed for the real-time monitoring of polyurethane (PU) formation in a solution of dimethylacetamide starting with 4,4′-methylenediphenyl diisocyanate (MDI) and different polyethylene glycols (PEG400 and PEG600) as diols. Notably, relative viscosity variations were compared with fluorescence changes, recorded as a function of the polymerization progress. The agreement between these two parameters suggested the innovative use of a low-cost fluorescence detection system based on a LED/photodiode assembly directly mountable on the reaction apparatus. The general validity of the proposed experiments enabled the monitoring of polyurethane polymerization and suggested its effective applications to a variety of industrial polymers, showing viscosity enhancement during polymerization.

Study on the catalytic pyrolysis of coal volatiles over hematite for the production of light tar

In this paper, to investigate the catalytic pyrolysis behavior of coal (XJ) volatiles over two hematite (HA and HB), a double-layered fixed-bed reaction apparatus, which was easy to separate coal and catalysts was employed to measure the pyrolysis tar yield, and the composition of pyrolysis tar and gas was investigated by GC-MS and GC. The results indicated that both hematite A and hematite B reduced the tar yield and caused an increase in CH4, CO2 and H2 output. Analysis of the chemical composition of tar indicated that XJ had a high content of pitch (46.39 %). At the same time, the addition of HA and HB decreased the pitch content by 7.59 and 8.88 %, respectively. Then, the change in the hematite chemical composition and physical structure after catalytic pyrolysis was characterized by XRD, TEM, XPS, SEM and N2 adsorption-desorption. Furthermore, a catalytic mechanism was proposed to illustrate the transformation of pyrolysis tar over hematite. Fe atoms and lattice oxygen are the decisive factors in the bond cleavage of pyrolysis tar. Fe atoms can break the CC and CH bonds of aliphatic hydrocarbons, while lattice oxygen can promote CO bond cleavage and produce CO2.

Micro-Polluted Surface Water Treated by Yeast-Chitosan Bio-Microcapsules.

Ammonia nitrogen and natural organic matter (NOM) seriously degrade the quality of surface waters. In this study, the optimum preparation conditions of a yeast-chitosan bio-microcapsule of the Candida tropicalis strain, used to treat micro-polluted surface water, were investigated. Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize the bio-microcapsules. A continuous laboratory-scale reaction apparatus was built to evaluate the engineering applications of the bio-microcapsules and their treatment efficiency for major pollutants in micro-polluted raw water. The yeast-chitosan bio-microcapsules were found to rapidly and effectively remove suspended solids and ammonia nitrogen. Moreover, the bio-microcapsule pre-treatment process was capable of resisting impact loads and fluctuations in water quality. Even at low temperatures (12 °C), the removal rate of ammonia nitrogen still reached 79%. The treatment did not lead to a temporary increase in nitrite concentration, nor to the excessive accumulation of nitrogen. The application of bio-microcapsules is simple; it only requires aeration and certain nutrient substrates, and can be adapted to treat raw drinking water with a poor nutrient substrate, therefore showing promise for future use in engineering applications.

RF-ICP Thermal Plasma for Thermoplastic Waste Pyrolysis Process with High Conversion Yield and Tar Elimination

This paper demonstrates an RF thermal plasma pyrolysis reaction apparatus that achieves 89 wt.% reaction conversion yield with no tar content. The demonstrated experimental apparatus consists of a 1100 W RFVII Inc. (104 Church St, Newfield, NJ 08344, United States) @ 13.56 MHz RF thermal plasma generator, a Navio matching network, intelligent feedback controller, and an 8-turn copper RF-ICP torch embedded in a 12 L thermochemical reactor. The intelligent feedback controller optimizes the thermal performance based on feedback signals from three online gas analyzers: CO, CO2 and NOx. The feedback controller output signal controls the RF thermal plasma torch current that provides real-time temperature control. The proposed reaction system achieves precise temperature profiles for both pyrolysis and gasification as well as increases end-product yield and eliminates undesired products such as tar and char. The identified hydrocarbon liquid mixture is 90 wt.% gasoline and 10 wt.%. diesel. The 8-turn RF-ICP thermal plasma torch has an average heating rate of +35 °C/min and a maximum operating temperature of 2000 °C and is able to sustain stable flame for more than 30 min. The reaction operating parameters are (550–990 °C τ = 30 min for pyrolysis and (1300 °C τ = 1 sec) for the gasification process. The identified hydrocarbon liquid products are 90 wt.% of a n-butyl-benzene (C6H5C4H9) and oluene (C7H8) mixture with less than 10 wt.% decane diesel fuel (C10 H22). Comsol simulation is used to assess the RF-ICP thermal plasma torch’s thermal performance.

Application of green analytical chemistry to a green chemistry process: Magnetic resonance and Raman spectroscopic process monitoring of continuous ethanolic fermentation.

Compact 1 H NMR and Raman spectrometers were used for real-time process monitoring of alcoholic fermentation in a continuous flow reactor. Yeast cells catalyzing the sucrose conversion were immobilized in alginate beads floating in the reactor. The spectrometers proved to be robust and could be easily attached to the reaction apparatus. As environmentally friendly analysis methods, 1 H NMR and Raman spectroscopy were selected to match the resource- and energy-saving process. Analyses took only a few seconds to minutes compared to chromatographic procedures and were, therefore, suitable for real-time control realized as a feedback loop. Both compact spectrometers were successfully implemented online. Raman spectroscopy allowed for faster spectral acquisition and higher quantitative precision, NMR yielded more resolved signals thus higher specificity. By using the software Matlab for automated data loading and processing, relevant parameters such as the ethanol, glycerol, and sugar content could be easily obtained. The subsequent multivariate data analysis using partial linear least-squares regression type 2 enabled the quantitative monitoring of all reactants within a single model in real time.

Design of a chemical reactor under microwave irradiation in resonance conditions

Reaction processes often show to be improved by microwave application, but the enhancing effect is not always due solely to the temperature increasing in the medium, which is produced by the radiation exposure. Thus, to study the evolution of such kind of processes needs a strict control of the irradiation conditions and the use of a proper reaction apparatus in which the interaction between radiation and irradiated materials can be precisely defined. The present work is made necessary by the need of operating with controlled and reproducible experimental conditions, and the aim was to design a multi-tube reactor, to work in resonance conditions, inside which the tubes with the fluid to be processed are positioned. In fact, working in resonance conditions allows the irradiated fluid to be exposed to constant microwave power, and the field intensity and power absorption can be accurately calculated and mapped. The cavity was designed by the authors using a proper commercial software for 3-D electromagnetic simulation, then the reactor operation was tested by another commercial multiphysic simulation software. The results here presented show the proper geometrical characteristics of the cavity and of the internal tubes to work at 2.45 GHz of frequency while the irradiation power can be varied depending on the needs of the process. The reactor can work with different homogeneous systems, both chemical and biological (enzyme reactions). The future development will be the construction and the real operation of the designed apparatus in order to confirm the simulation results.

Removal of non-aqueous phase liquids (NAPLs) from TPH-saturated sandy aquifer sediments using in situ air sparging combined with soil vapor extraction

Contamination in coastal aquifer plains is of great concern in many countries given that non-aqueous phase liquids (NAPLs) have polluted numerous sites through accidental oil spills or improper disposal. We have developed a method to remove pollutants such as NAPLs from sandy sediment samples collected from the Mandol area of Gomso Bay in western South Korea. The sediments were collected from around the diffuser in a two-dimensional (2D) acrylic reaction apparatus, and these contained a total petroleum hydrocarbon (TPH) concentration of 89.3 ppm (mg/kg media). The maximum perchloroethylene (PCE) concentration was 398.51 ppm in the unsaturated zone and 0.77 ppm in the saturated zone. Volatile organic compounds (VOCs) were detected between 20 and 44 hour. However, non-volatile contaminants remained in the sediments after treatment. In situ air sparging (IAS) combined with soil vapor extraction (SVE), transformation from sorbed and nonaqueous phases to the vapor phase, is incomplete when treatment is performed using a pervasive air flow for sediments such as the sand of Mandol. During air transformation, the groundwater flow conditions increased the rate of contaminant removal. Although pilot-scale testing in the field site was fluctuated due to the heterogeneous of sediments condition, this 2D study found that the proposed method can alter the measurable geophysical properties of NAPLs. These findings demonstrate that IAS combined with SVE in the saturated zone is an effective technology for aquifer remediation high applicability of sandy coastal sediments contaminated by NAPLs.

Effect of CO2 and H2O on gasification dissolution and deep reaction of coke

To more comprehensively analyze the effect of CO2 and H2O on the gasification dissolution reaction and deep reaction of coke, the reactions of coke with CO2 and H2O using high temperature gas–solid reaction apparatus over the range of 950–1250°C were studied, and the thermodynamic and kinetic analyses were also performed. The results show that the average reaction rate of coke with H2O is about 1.3–6.5 times that with CO2 in the experimental temperature range. At the same temperature, the endothermic effect of coke with H2O is less than that with CO2. As the pressure increases, the gasification dissolution reaction of coke shifts to the high-temperature zone. The use of hydrogen- rich fuels is conducive to decreasing the energy consumed inside the blast furnace, and a corresponding high-pressure operation will help to suppress the gasification dissolution reaction of coke and reduce its deterioration. The interfacial chemical reaction is the main rate-limiting step over the experimental temperature range. The activation energies of the reaction of coke with CO2 and H2O are 169.23 kJ·mol−1 and 87.13 kJ·mol−1, respectively. Additionally, water vapor is more likely to diffuse into the coke interior at a lower temperature and thus aggravates the deterioration of coke in the middle upper part of blast furnace.