Short Residence Time Research Articles

Thermochemical energy storage using calcium magnesium acetates under low CO2 pressure conditions

The calcium looping multicycle performance of CaO-based materials, derived from calcium magnesium acetates with different Mg content were tested under experimental conditions compatible with thermochemical energy storage. In order to reduce the sintering-induced decay in performance, calcination at an absolute CO2 pressure of 0.1 bar and 0.01 bar is implemented. CaO carbonation is performed at standard 1 bar CO2 conditions. The samples can be fully calcined in short residence times. Samples with MgO present high cycling stability, even when the MgO content is as low as 5 mol%. The effective conversion values lie within the range 0.88–0.84 over ten calcination/carbonation cycles, which provides an accumulated energy storage density of 90.9 GJ/m3. This outstanding reactivity is related with the microstructure of the sample after calcination composed of CaO nanoparticles that are highly reactive for carbonation.

PK-PD Evaluation of Inhaled Microparticles loaded with Ciprofloxacin-Copper complex in a Rat Model of Chronic Pseudomonas aeruginosa Lung Infection.

The potential gain in efficacy of pulmonary administration over IV administration of some antibiotics such as ciprofloxacin (CIP) may be limited by the short residence time of the drug at the site of infection after nebulization. Complexation of CIP with copper reduced its apparent permeability in vitro through a Calu-3 cell monolayer and greatly increased its pulmonary residence time after aerosolisation in healthy rats. Chronic P. aeruginosa lung infections in cystic fibrosis patients result in airway and alveolar inflammation that may increase the permeability of inhaled antibiotics and alter their fate in the lung after inhalation compared to what was seen in healthy conditions. The objective of this study was to compare the pharmacokinetics and efficacy of CIP-Cu2+ complex-loaded microparticles administered by pulmonary route with a CIP solution administered by IV to model rats with chronic lung infection. After a single pulmonary administration of microparticles loaded with CIP-Cu2+ complex, pulmonary exposure to CIP was increased 2077-fold compared to IV administration of CIP solution. This single lung administration significantly reduced the lung burden of P. aeruginosa expressed as CFU/lung measured 24 h after administration by 10-fold while IV administration of the same dose of CIP was ineffective compared to the untreated control. This better efficacy of inhaled microparticles loaded with CIP-Cu2+ complex compared with CIP solution can be attributed to the higher pulmonary exposure to CIP obtained with inhaled CIP-Cu2+ complex-loaded microparticles than that obtained with IV solution.

How do urban public health services affect rural migrant women's fertility intentions? A study based on the Mobile Population Dynamics Monitoring Survey in China

Public health service is an important guarantee by the government to safeguard the health rights of rural migrant women. This not only concerns the health status of rural migrant women and their willingness to stay in the urban area but can also affect their fertility intention. This study systematically examined the impact of public health services on the fertility intentions of rural migrant women as well as the mechanisms, underlying these intentions based on the data from the 2018 China Migration Dynamics Monitoring Survey. Urban public health services, including health records management and health education, could effectively enhance the fertility intentions of rural migrant women. Furthermore, their health status and willingness to stay in urban areas were important mechanisms, by which, the public health services could influence the fertility intentions of rural migrant women. Additionally, urban public health services have a better effect on improving the fertility desire of rural migrant women who have no pregnancy experience, a low income level, and a short residence time in the inflow area. This study contributed to the examination and clarification of the policy effects of public health services on the fertility intentions of rural migrant women. Additionally, it also provided important evidence to support the government policies related to the optimization of the public health service system, improvement of the health status, citizenship, and fertility intentions of the rural migrant women, as well as the development of the uniform public health services.

Kinetic study of uranium (VI) extraction with tributyl-phosphate in a stratified flow microchannel

Solvent extraction kinetics are of considerable importance in process and apparatus design, especially when the mass transfer is coupled with a chemical reaction. In such circumstances, the mass transfer can either be diffusion limited, reaction limited, or both in a mixed regime. Conventional extraction techniques lead to acquire an overall mass transfer coefficient for fast chemical systems. The latter brings together diffusional and reactional parts that are difficult to distinguish independently. This problem is addressed using a high velocity parallel flow microfluidic setup for the investigation of the extraction kinetics of the fast chemical system U(VI):HNO3/TBP:TPH. Experimental data were analyzed using a combination of overall mass transfer resistance calculations and advection–diffusion-reaction models. Results indicate that a chemically limited regime was obtained at a high initial concentration (119 g.l−1) of uranium (VI) due to Marangoni convections. Whereas, for low initial concentrations (10–30 g.l−1) and short residence times in the microchannel (≤13 ms), both diffusion and reaction impact the transfer rate. The obtained value of the apparent rate constant under current operating conditions ([HNO3] = 3 M, % TBP = 30 % (v/v)) was of (6.5 ± 1.7) × 10−4 m.s−1. This value is much higher than what conventional extraction techniques predicted, indicating the better mass transfer efficiency in the microfluidic setup due to the decrease of the diffusional limitation.

Nano-Encapsulation Of Neem Based Pesticide Formulations

Neem based pesticide formulations are reported to control plant parasitic fungi, bacteria, virus, nematodes, insects and mites. Despite its many promising properties, low stability under field conditions, mainly due to a high rate of photo-degradation, as well as a short residence time and slow killing rates, compared to conventional pesticides hinder effective large-scale use of Neem. Although when two lines of Myzus persicae Were exposed to pure azadirachtin and refined Neem seed extract at the same concentration, it was found that after forty generations, the line treated with azadirachtin had developed ninefold greater resistance compared to a control line, whereas the line treated with the extract did not show resistance. To overcome these limitations, nanotechnology has emerged as a novel tool for agricultural sustainability. Many studies have shown that the encapsulation of agrochemicals in nanoparticulate systems can enhance the efficacy of the active ingredient, decrease toxicity toward the environment and humans, and reduce losses due to volatilization, leaching, and photobleaching. Thus, the use of nanoparticles provides an effective means of protecting neem oil against premature degradation, resulting in prolongation of its effect on the target pest. Due to nano encapsulation sustained release of the active component is achieved. Furthermore, the number of applications of neem oil can be reduced, bringing substantial economic benefits. Therefore, nano-encapsulation of neem oil may enable the production of more stable formulations for control of diseases and pests. Further, the use of nanotechnology is an excellent way to combat development of resistance in insects and pathogens due to indiscriminate use of neem oil.

Molecular imaging of HER2 receptor: Targeting HER2 for imaging and therapy in nuclear medicine.

Targeting HER 2 for imaging and therapy in nuclear medicine has been used with a special emphasis on developing more powerful radiopharmaceuticals. Zirconium-89 plays an essential role in immune PET imaging so was used labeled with anti-HER2 antibody (Trastuzumab and Pertuzumab). Also there were attempts with other PET tracers as Cuprum-64 and Galium-68, as well as SPECT radiopharmaceuticals Indium-111 and Technetium- 99m. Regarding antibody pharmacokinetic that is not quite appropriate for imaging acquisition, several smaller molecules with shorter residence times have been developed. These molecules called nanobody, affibody, minibody do not compromize HER2 receptor affinity and specificity. Excess of Trastuzumab do not block the affinity of labeled affibodies. Silica nanoparticles have been conjugated to anti-HER2 antibodies to enable targeting of HER2 expressing cells with potential of drug delivery carry for antitumor agents and b(beta) or a(alfa) emitting radioisotopes commonly used for radionuclide therapy, as Iodine-131, Lutetium-177, Yttrium-90, Rhenium-188 and Thorium-277.

Nanocarrier-Based Drug Delivery to Brain: Interventions of Surface Modification.

Brain disorders are a prevalent and rapidly growing problem in the medical field as they adversely affect the quality of life of a human. With an increase in life expectancy, it has been reported that diseases like Alzheimer's, Parkinson's, stroke and brain tumors, along with neuropsychological disorders, are also being reported at an alarmingly high rate. Despite various therapeutic methods for treating brain disorders, drug delivery to the brain has been challenging because of a very complex Blood Brain Barrier, which precludes most drugs from entering the brain in effective concentrations. Nano-carrier-based drug delivery systems have been reported widely by researchers to overcome this barrier layer. These systems due to their small size, offer numerous advantages; however, their short residence time in the body owing to opsonization hinders their success in vivo. This review article focuses on the various aspects of modifying the surfaces of these nano-carriers with polymers, surfactants, protein, antibodies, cell-penetrating peptides, integrin binding peptides and glycoproteins such as transferrin & lactoferrin leading to enhanced residence time, desirable characteristics such as the ability to cross the blood-brain barrier (BBB), increased bioavailability in regions of the brain and targeted drug delivery.

Cost-Effectiveness Of Tailings Dewatering And Stacking

Over the last one hundred years, tailings dams have failed globally at a rate of 2 to 5 per annum. This failure rate is considered unacceptable by the community and by the mining industry. The conventional transport of slurry or thickened tailings and their storage in a tailings dam, requires low capital and operational expenditure, as slurry tailings can be transported by pipeline using relatively inexpensive and robust centrifugal pumps. Recently, the filtration of tailings, their transport by conveyor or truck, and “dry” stacking have been seen as an alternate method of tailings management. However, filtration and dry stacking are considered expensive. Over the full life cycle, including post-closure, of filtration and a dry stack facility, the potential to increase water recovery for recycling and increased options post-closure can lead to a reduction in the total expense of a dry stack facility. This study aimed to contribute to understanding of the cost-effectiveness of tailings dewatering and dry stacking as a tailings management method. Various tailings samples from different locations and with different characteristics were tested for their filtration potential. The potential for monetary savings through the reuse/recycling of the water recovered from the tailings through filtration was a particular focus. While tailings with higher clay mineral contents had more potential for water recovery than coarser-grained tailings, they were also more difficult to dewater. Tailings with lower clay mineral contents were relatively easy to dewater, requiring a short residence time, leading to increased water recovery and volume reduction potential. The results identified that there is significant potential for water recovery, leading to monetary savings through the reuse/recycling of water, potential for storage volume reduction, and potential for higher value post-closure uses.

The effects of supported Pd, Pt, Re, Rh, Ru, Ir, Au, and Ni catalysts on renewable hydrocarbon production from alternative feedstock

Screening tests of supported commercial and prepared Pd, Pt, Re, Rh, Ru, Ir, Au (5%), and Ni (5–65%) metal catalysts were conducted under one-pot solvent-free hydrotreating (HT) conditions to evaluate their activity, selectivity, and potential for renewable hydrocarbon (RH) production from rapeseed oil (RO). Catalysts were characterized by XRF, XRD, FE-SEM, TEM, and N2 sorption analysis. Composition of RO, liquid, and gaseous products were analyzed by GC-FID, GC-MS, C, H, N, S elemental analysis, FT-IR, and GC-TCD. Full conversion of RO with RH yield up to 85% were achieved over most active supported commercial Ni (65%) and Re, Rh, Ru (5%) catalysts in short residence time (up to 10 min) under relatively mild reaction temperature 340 °C and initial H2 pressure 10 MPa. Noticeable effect of Ru catalysts on cleavage of -C-C- bond reactions make them promising for practical application in RH synthesis. Multi-function SiO2–Al2O3 supported Ru (5%) catalyst (Ru5SAp) prepared by developed simple method is perspective for wide molecular weight hydrocarbon production by –CC- hydrogenation, oxygen removal and cleavage of -C-C- bonds including ring opening reactions for structure modification of different raw materials – fats, oils, phenols, and fossil based feedstocks. Benzene, toluene, tetralin, guaiacol, and n-nonadecane were used as model compounds for investigation of catalytic effects. Ru5SAp possesses similar performance as most active supported commercial noble metal catalysts in HT process of RO. It is reusable up to three HT reaction cycles although deactivation of catalyst causes significant changes in obtained hydrocarbon composition.

Novel Hot Vapor Filter Design for Biomass Pyrolysis.

Fast pyrolysis is a mature technology for the conversion of solid biomass into a liquid intermediate, fast pyrolysis bio-oil (FPBO). FPBO has so far been used mainly as heating fuel, but the target is to use it for the production of sustainable fuels and chemicals in the future. In the pyrolysis process, inorganic materials (ash) from the biomass are mostly sequestered in char particles, which can be separated with cyclones. Small particles (<10 μm) escape the cyclones and condense with vapors. In bio-oils, these solid materials are unfavorable because they can cause erosion, corrosion, and blockages at injection nozzles in power generation systems and deactivate the catalyst in bio-oil upgrading. Hot vapor filtration using either moving bed or barrier filters has been tested on a small scale for the removal of fine particles from the pyrolysis vapors. The challenges with these filter types have been the increased pressure drop across the filter with time, inefficient solid removal, and loss in organics. A new hot vapor filter combining both a barrier filter and a moving bed filter was constructed and tested to overcome these problems. In this filter system, the filter elements are inserted in a vessel, where hot sand flows through to continuously remove the cake over filter candles. The filter was successfully tested with stem chips, contaminated wood, and forest residue for 6-8 h without any pressure increase. The organic liquid yield decreased in the best case only by 3 wt % using the lowest filtration temperature and shortest residence time. The oil properties were slightly affected by cracking of the sugar fraction, which decreased the oxygen content, microcarbon residue, and carbonyl content but increased the acidity. Only minor improvements in metal removal were seen due to the high detection limits of metal analysis.

Intracellular Delivery of Itaconate by Metal–Organic Framework-Anchored Hydrogel Microspheres for Osteoarthritis Therapy

Treatment of osteoarthritis (OA) remains a significant clinical challenge. Itaconate (IA), an emerging regulator of intracellular inflammation and oxidative stress, may potentially be harnessed to treat OA. However, the short joint residence time, inefficient drug delivery, and cell-impermeable property of IA can seriously hamper the clinical translation. Herein, IA-encapsulated zeolitic imidazolate framework-8 (IA-ZIF-8) nanoparticles were self-assembled by zinc ions, 2-methylimidazole, and IA to render them pH-responsive. Subsequently, IA-ZIF-8 nanoparticles were firmly immobilized in hydrogel microspheres via one-step microfluidic technology. It was demonstrated in vitro experiments that IA-ZIF-8-loaded hydrogel microspheres (IA-ZIF-8@HMs) exhibited good anti-inflammatory and anti-oxidative stress effects by releasing pH-responsive nanoparticles into chondrocytes. Importantly, compared with IA-ZIF-8, IA-ZIF-8@HMs showed better performance in the treatment of OA due to their superior performance in sustained release. Thus, such hydrogel microspheres not only hold enormous potential for OA therapy, but also provide a novel avenue for cell-impermeable drugs by constructing appropriate drug delivery systems.

Wiped film evaporator with a roller wiper and an internally mounted condenser for the recovery of TBP and n-DD from degraded PUREX solvent

Wiped Film Evaporator (WFE) is a promising choice for processing viscous and thermally labile compounds due to its short residence time, enhanced heat transfer rates, and a high fraction of distillate yield in a single pass. This article evaluates the viability of a WFE with a roller wiper and an internally mounted condenser to recover tri-butyl phosphate (TBP) and n-dodecane (n-DD) from degraded PUREX solvent by vacuum distillation. Degraded solvents derived from different sources were purified using a combination of primary cleanup by sodium carbonate scrubbing and secondary cleanup by vacuum distillation using the WFE. Primary cleanup could efficiently remove the acidic degradation products of TBP. However, the scrubbed solvents were not of acceptable quality due to their poor physical properties. Secondary cleanup by vacuum distillation notably improved the physical properties of the solvent. A detailed quality assessment of the recovered solvents in terms of density, viscosity, interfacial tension (IFT), and phase separation time (PST) ratio showed that all the solvents recovered were of acceptable quality. The highest PST ratio and lowest IFT of the recovered solvents were 1.36 and 8.6 mN m−1, respectively. The maximum solvent recovery, TBP recovery, and n-DD recovery obtained were 93.8%, 83.8%, and 99.8%, respectively.

Self-seeded coprecipitation flow synthesis of iron oxide nanoparticles via triphasic reactor platform: Optimising heating performance under alternating magnetic fields

Liquid-liquid segmentation is a common method to prevent reactor fouling when synthesising nanoparticles in flow, despite limiting synthetic protocols to single reagent addition steps before segmentation. This work demonstrates how a modular triphasic (gas–liquid–liquid) flow reactor platform overcomes this limitation, facilitating a continuous and fouling-free four-step co-precipitation flow synthesis of iron oxide nanoparticles (IONPs) for magnetically induced hyperthermia cancer treatment (MHCT). For this and other biomedical applications water-based IONP syntheses such as co-precipitation are favoured, but producing IONPs > 10 nm as needed for MHCT remains challenging. To overcome this size barrier for co-precipitation syntheses, a seeded growth co-precipitation strategy was employed here for the first time. After demonstrating the synthesis in batch, a triphasic flow reactor was developed to translate the multistep batch protocol into flow. Nitrogen gas was used to space the liquid–liquid segmented slugs evenly, enabling self-synchronised solution addition into the aqueous slugs dispersed in heptane. Three additions of the iron precursor solution followed by citric acid solution addition formed the seeds, grew them to larger IONPs and stabilised them. The flow platform was used for screening of the synthetic parameters to optimise the IONP heating performance in an alternating magnetic field, hence investigating their potential as MHCT heating agents. The optimal reactor settings identified made it possible to continuously synthesise 0.46 gIONPs/h colloidally stable IONPs in the aqueous phase of size ∼15 nm. The fouling-free flow reactor operated at short overall residence times (<5 min) using just ferric and ferrous salts, sodium carbonate and citric acid. The IONPs exhibited high heating performance, with an intrinsic loss power up to 3.76 nH m2 kgFe-1.

Mollusk Response Under Ocean Acidification in Shallow Marine Settings of Sicily (Central Mediterranean)

Anthropogenic CO2 is a major driver of change in most marine ecosystems, as the consequent ocean acidification is threatening marine calcifying organisms. In this respect, long-term analyses on ocean acidification effects on marine ecosystems acclimated to high pCO2, as found around CO2 vents, are needed. Here we tackle mollusk assemblages from acidified shallow marine settings off the Aeolian archipelago (Central Mediterranean). The detected gradient manifests along a 34 m long transect (9.6 m and 11.4 m water depth), mostly in a Posidonia oceanica matte from normal (site 1) to high levels (site 3) of pCO2 (405 μatm, pH 8.1 and 715 μatm, pH 7.8; respectively). The strongest acidified condition at the vent crater (site 4, pCO2 1110 μatm, pH 7.7). At the vent site gaseous emissions are characterized by ~99% in volume of CO2 and ~0.6% of H2S. However, water dissolved H2S was below detection limit and the sulphate content along the transect does not show significant variations with respect to normal seawater values. Preliminary paleoecologic surveys on diversity structure (diversity profiles) and taphonomic degradation (NMDS, z scored % values) were conducted on mollusk remains collected along the natural pH gradient (sites 1-4). Along the P. oceanica matte (sites 1-3), overall mollusk taxon diversity (alpha and beta) decreased, mollusk in site 3 were mostly juveniles and had higher overall taphonomic damages than those retrieved at normal pH conditions. Within the vent crater only fewer and highly taphonomically altered gastropod specimens were retrieved on the pebbly seafloor, suggesting a very short residence time of shell material and rapid dissolution. Even if vents are not exact predictors of the anthropogenic-designed future of marine settings, due to their limited spatial and temporal extent, they can act as natural laboratories where to evaluate the output of ecosystem processes under rising pCO2 and the effects on the creation of the future fossil record.

Using Kriging surrogate model to analyze hydrogen generation with dimethyl ether in partial oxidation catalytic fluidized bed reactor

The study aimed to present a fluidized bed reactor filled with 50% platinum catalytic beads and 50% quartz sand for syngas generation via the partial oxidation of dimethyl ether (DME). For obtaining useful information, experiments were carried out using Taguchi orthogonal array method, which cut test run by 75.3%, with the results being used for constructing the Kriging surrogate model. The model was then modified to reduce the mean square error. It is validated that the model can predict the results reasonably well. The outcome shows that the proposed reactor can self-sustain the syngas reforming reaction without incurring extra heat for reactants preheating. In the operation region, the results show that the start-up temperature is most negligible in hydrogen generation. The yield rate of hydrogen increases in sync with the increase of oxygen's molar ratio and DME, thanks to higher reaction temperature. The results also suggest that the higher the molar ratio of oxygen and DME, the more significant the reverse water shift reaction. Playing a key role in the fluidized bed in the proposed reactor for hydrogen generation, the normalized velocity must be at a proper level, in order to induce bubbling fluidization without causing a lower hydrogen yield, the latter due to the short residence time of reaction caused by excessive velocity. The sensitive analysis of independent variables also proved the inference from the measured results. By comparing with the literature, the performance of the proposed reactor in the present study shows a reasonably well performance. Given focused hydrogen generation, the study's findings can be used as a basis for evaluating DME as a hydrogen carrier and the proposed fluidized bed reaction.

Impact of CO2 atmosphere on coal pyrolysis in indirectly heated fixed bed with internals

To clarify how CO2 affects pyrolysis characteristics in reactor with internals, pyrolysis of Yulin coal under N2 (inert) and CO2 (active) atmospheres is performed in fixed-bed reactors for two kinds of pyrolysis, i.e., with and without internals.CO2 exhibits different impact on tar yield for two types of pyrolysis, i.e., raising tar yield for pyrolysis in reactor without internals but lowering tar yield for that with internals. Tar yield pyrolysis under CO2 atmosphere is 6.31 wt% with internals, which is still higher 15.97% than that without internals at 1000 °C. In addition, CO2 atmosphere can produce more CO, high BET surface area char and high-quality of tar with more light tar (<C10), but less char, H2 and CH4 for both types of pyrolysis. The different impact of CO2 may be ascribed to the various flow routes for two kinds of reactors, and the extent of CO2-inclusive reactions, such as CO2-char gasification and reverse water gas shift (RWGS), is weakened by the adoption of internals due to occurring at lower temperatures and shorter residence time.

Timescales of Magma Mixing Beneath the Iheya Ridge, Okinawa Trough: Implications for the Stability of Sub-Seafloor Magmatic Systems

Submarine volcanic eruptions can be destructive for marine environments and resources. Magma mixing is considered to be an important trigger for volcanic eruptions. Determining the magma residence time from mixing to eruption is conducive to assessing the stability of magmatic systems, especially beneath the seafloor where in situ volcano monitoring is inaccessible. Here, we estimated the timescale of magma mixing beneath the Iheya Ridge, Okinawa Trough, which is characterized by pervasive magma mixing. We focused on andesitic and rhyolitic magma generated by basalt–rhyolite mixing and rhyolite–rhyolite mixing, respectively. By taking advantage of the Mg diffusion chronometry, we showed that the andesitic magma resided in the magma chamber for very short time (~0.1–0.3 years), whereas the residence time of the rhyolitic magma was much longer (~80–120 years). The different times might be in part related to the different rheology of the mixed magmas. The short residence time of the andesitic magma suggested efficient magma mixing that allowed the andesites to be erupted, which may explain the appearance of scarce andesites in basalt–rhyolite dominant settings. However, the rapid mixing and eruption of magma is a disadvantage for the development and preservation of seafloor hydrothermal resources. Therefore, we suggest that the stability of sub-seafloor magma systems must be evaluated during the assessment of seafloor sulfide resources and mining prospects.

Structural Evolution and Durability of Ultrafine NiFe Phosphide Nanoparticle/Carbon Composite Films in Water Oxidation at High Current Densities

NiFe phosphide (NiFe-P) is a highly active precatalyst for the oxygen evolution reaction (OER), but its compositional and structural changes during sustained electrolysis have not been thoroughly understood. Moreover, the size control of NiFe-P particles remains challenging yet desirable without multistep synthesis or surface capping agents. To realize this, flame aerosol synthesis (FAS) is a promising method due to its short particle residence time, tunable redox environment, and good scalability. Herein, the one-step FAS of NiFe-P is reported for the first time. With the controlled coformation of carbon, interlaced NiFe-P nanoplates and <5 nm NiFe-P nanoparticles are selectively synthesized on nickel foam in 10 min. At the anodic potential of OER, NiFe-P transforms into highly active (oxy)hydroxides in situ by surface oxidation and dephosphorylation. The overpotential of the optimal film at 500 mA cm–2 increases at only 0.28 mV h–1 over 100 h, making it among the most durable NiFe-based catalysts reported. Post-OER cyclic voltammetry, double-layer capacitance, and inductively coupled plasma mass spectrometry (ICP-MS) measurements indicate performance degradation to be mainly caused by the selective leaching of Fe from the (oxy)hydroxides. Counterintuitively, slight structural instability of the films induced by the electrochemical removal of carbon enhances durability by keeping a relatively stable surface Fe content through a self-refreshing mechanism.

Study on removing marine multiple pollutants in raw exhaust gas with a novel composited method combined with pre-agglomeration and wet scrubbing technology.

Most of the existing oxidation denitrification methods need longer residence time to obtain higher NOx removal efficiency. In this study, urea peroxide (CO(NH2)2·H2O2) was first used for removing SO2 and NOx on diesel engine bench. The addition of ferrous sulfate can enhance the oxidant capacity of the solution. The better removal efficiency and lower nitrate content in liquid can be achieved in short exhaust gas residence time. The raw gas flow and residence time contained the actual application situation in ships and have high reference value. The removal efficiency decreased with the increase of gas flow, and the reaction temperature, urea peroxide concentration, liquid-gas ratio were the main factors. The optimal Fe2+ concentration of 50mmol/L and pH value of 4 were determined. The urea peroxide concentration, reaction temperature, and liquid-gas ratio were 9%, 70℃, and 10L/m3 respectively. The maximum gas treatment capacity was about 100L/min, and residence time was close to 10s for the scrubber. The pre-agglomerating method were used to improve the particle capturing efficiency combined with spray technology. The composited method can realize the synchronous and efficient removal of multiple pollutants in a single scrubber. The possibility of application on ship was further increased.

Microflow precipitation of barium sulfate nanoparticles from mineral barium sulfide black ash

Microflow precipitation reaction is an effectively method for preparing high quality nanoparticles. In this study, BaSO4 nanoparticles were successfully prepared from BaS black ash in a simple capillary microreactor. Two important microflow parameters, feed flow velocity and residence time, on morphology, structure, component, average particle size (dav) and coefficient of variation (CV) of the as-synthesized product are investigated. The results show that well-dispersed ellipsoidal nanoparticles of BaSO4 with purity >99 wt% can be prepared using this novel method. High flow velocity is beneficial for producing small particles with low CV, and short residence time is also good for slightly small particles but with high CV. The dav and CV values are in the range of 33.8∼53.5 nm and 0.32∼0.39, respectively. In addition, the preparation of the BaSO4 product by this new method is compared with those by precipitation in other typical reactors. Combined with the simplicity of the microchannel structure, continuity of process operation and atomic economy of the raw materials, this proposed method is effective for preparing high quality BaSO4 nanoparticles with narrow particle size distribution.