CO Peak Research Articles

Low-energy argon ion beam irradiation for the surface modification and reduction of graphene oxide: Insights from XPS

Developing environmentally friendly methods for reducing graphene oxide (GO) is essential. This study investigates the surface modification and reduction of GO films using 200 eV argon ion (Ar+) beam irradiation. X-ray Photoelectron Spectroscopy (XPS) analysis reveals significant chemical changes on the GO surface. GO was irradiated with a 200 eV Ar+beam for varying times (0–80 s). XPS survey spectra showed the presence of carbon and oxygen, with an increasing carbon atomic percentage over time. High-resolution XPS spectra of C 1s revealed peaks corresponding to sp2, C–OH, O–C–O, CO, and O–CO bonds. In the O 1s spectra, CO, O–C–O, and C–OH groups were observed. Upon irradiation, the CO peak consistently decreased, the O–C–O peak fluctuated, and the C–OH peak increased, indicating effective reduction of CO groups, dynamic changes in O–C–O functionalities, and the formation of additional C–OH groups. The C/O ratio increased from ∼2.4 to 2.7, underscoring the reduction process and enhanced carbon content. This method proves to be an efficient approach for producing reduced graphene oxide (rGO) with improved properties for advanced applications.

2D mesh-knots metal organic frameworks functionalized with phytic acid for improving flame retardancy

Metal ions and organic compounds were adopted to form a two-dimensional mesh-knots metal organic frameworks (TMMOFs), which could functionalize with Phytic Acid (PA) for fireproof. The results of the functional group test show that two-dimensional mesh-knots metal organic frameworks (TM), TM with -NH2 (TMN) and TMN with PA (TMNP) have been successfully prepared by coordination bond. The samples appeared irregular ellipsoid with size of particles below 100 nm. The values of limiting oxygen index (LOI) test depicted the flame resistance have been enhanced from 22.7 % to 30 % due to the addition of -NH2 and PA. The peak heat release rate (pHRR) and total heat release (THR) value of TM-PA@wood declined noticeably by 55.9 % and 68.6 % compared to pure wood. CO2 emissions intensity of TMNP@wood declined from about 0.40 to 0.12 compared with samples without PA. The CO2 and CO maximum production of TMNP@wood were significantly lower 246% and 64% than TMN@wood, respectively. PA and ZrO2 after combustion could catalyze wood to form carbon residue as condense phase, delay and minimize the peak of CO2 and CO to reduce toxicity. This work provides an effective strategy for synthesis and application of two-dimensional materials in flame retardant field.

Molecular clouds as hubs in spiral galaxies: gas inflow and evolutionary sequence

ABSTRACT We decomposed the molecular gas in the spiral galaxy NGC 628 (M74) into multiscale hub-filament structures using the CO (2$-$1) line by the dendrogram algorithm. All leaf structures as potential hubs were classified into three categories, i.e. leaf-HFs-A, leaf-HFs-B and leaf-HFs-C. Leaf-HFs-A exhibit the best hub-filament morphology, which also have the highest density contrast, the largest mass and the lowest virial ratio. We employed the filfinder algorithm to identify and characterize filaments within 185 leaf-HFs-A structures, and fitted the velocity gradients around the intensity peaks. Measurements of velocity gradients provide evidence for gas inflow within these structures, which can serve as a kinematic evidence that these structures are hub-filament structures. The numbers of the associated 21 μm and H α structures and the peak intensities of 7.7 μm, 21 μm, and H α emissions decrease from leaf-HFs-A to leaf-HFs-C. The spatial separations between the intensity peaks of CO and 21 μm structures of leaf-HFs-A are larger than those of leaf-HFs-C. These evidence indicate that leaf-HFs-A are more evolved than leaf-HFs-C. There may be an evolutionary sequence from leaf-HFs-C to leaf-HFs-A. Currently, leaf-HFs-C lack a distinct gravitational collapse process that would result in a significant density contrast. The density contrast can effectively measure the extent of the gravitational collapse and the depth of the gravitational potential of the structure which, in turn, shapes the hub-filament morphology. Combined with the kinematic analysis presented in previous studies, a picture emerges that molecular gas in spiral galaxies is organized into network structures through the gravitational coupling of multiscale hub-filament structures. Molecular clouds, acting as knots within these networks, serve as hubs, which are local gravitational centres and the main sites of star formation.

Assessment of Air Pollution Levels from a Building Construction Site on Lagos Island

The introduction highlights the challenges of air pollution from construction activities on a site in Lagos Island, Nigeria, emphasizing the need for comprehensive studies to assess air pollution levels and evaluate its implications for public health and environmental quality. The methodology outlines the monthly data collection process, using the Earth Sense Zephyr (equipped with electrochemical detectors for gases) to measure CO, NO, NO₂, O₃, and Optical light scattering for particles) to measure PM₂.₅, and PM₁₀, and the ARA n-FRM Sampler for additional data collection on PM₂.₅, and PM₁₀. The study found that CO, NO, and NO₂ levels were influenced by construction activities, vehicle emissions and industrial sources, with notable peaks in CO and NO concentrations during specific months. Ozone levels remained consistently low, likely due to the "titration effect," while particulate matter (PM₂.₅ and PM₁₀) showed significant seasonal variation, peaking during the dry season due to construction dust and dry weather conditions. The findings underscore the need for stringent regulatory measures and effective dust control practices, particularly during periods of increased construction activity and dry weather, to mitigate air pollution and protect public health. In conclusion, the study provides valuable insights into the dynamics of air pollution from a typical construction site in Lagos Island, emphasizing the urgency of sustainable interventions to safeguard public health and environmental integrity. The study proposes enhanced monitoring and surveillance, stringent regulatory measures, promotion of sustainable construction practices, and public awareness and education, to address the challenges associated with construction-related air pollution on Lagos Island.

Vibrational heavy atom effect on relaxation and solvent shell dynamics in group VIII trimetallic carbonyls.

Infrared pump-probe and two-dimensional infrared (2D-IR) spectroscopies were used to study the vibrational dynamics of a homologous set of trimetallic dodecacarbonyls with increasingly heavy atomic masses in tetrahydrofuran solution. The vibrational lifetimes showed some evidence of the vibrational heavy atom effect (VHAE) but were not consistent across the sample set. Spectral diffusion was measured by 2D-IR spectroscopy to investigate whether the changes produced by the VHAE had influenced other aspects of vibrational dynamics. The triiron species was found to be more dynamic on very fast timescales and may exhibit evidence of a transient bridging CO structure. Centerline slope analysis of the high-frequency CO peak for each complex revealed that the vibrational dynamics were subtly but consistently slowed for the compounds with heavier metal atoms.

Investigation of emission characteristics of a marine cargo ship in real-world conditions

Pollution caused by ship emissions will considerably impact coastal areas. A test system that matched the actual conditions of a ship was designed based on a portable emission measurement system (PEMS), and the emission characteristic of gaseous and particle emissions and the particle size distribution of the ship's main engine were investigated under real-world operating conditions. The results showed that the emission concentrations of the main pollutants fluctuated greatly under the departure, anchoring, and docking conditions, and the peaks of CO, CO2, and NOx emissions appeared under these transient conditions. The emission concentrations of CO2, hydrocarbons, particle number (PN), and particulate mass increased with the increase in speed. The PN-based particle size distribution of the engine presented a unimodal distribution under daily operating conditions. The maximum emission factor of NOx based on the engine power was 29.53 g/kWh at the engine speed of 66 r/min. The results of the study may contribute to supplementing the emission factors of this type of ship, and provide data support for monitoring and assessment of the marine environment.

Construction of sustainable and highly efficient fire-protective nanocoatings based on polydopamine and phosphorylated cellulose for flexible polyurethane foam

Layer-by-layer (LBL) self-assembly is an effective strategy for constructing fire-resistant coatings on flexible polyurethane foam (FPUF), while the efficiency of fire-resistant coatings remains limited. Therefore, this study proposes an in situ flame retardancy modification combined with LBL self-assembly technology to enhance the efficiency of flame retardant coatings for FPUF. Initially, polydopamine (PDA) and polyethyleneimine (PEI) were employed to modify the FPUF skeleton, thereby augmenting the adhesion on the surface of the skeleton network. Then, the self-assembly of MXene and phosphorylated cellulose nanofibers (PCNFs) via the LBL technique on the foam skeleton network formed a novel, sustainable, and efficient flame retardant system. The final fire-protective coatings comprising PDA/PEI and MXenes/PCNF effectively prevented the collapse of the foam structure and suppressed the melt dripping of the FPUF during combustion. The peak heat release rate, the peak CO production rate and peak CO2 production rate were reduced by 68.6 %, 61.1 %, and 68.4 % only by applying a 10-bilayer coating. In addition, the smoke release rate and total smoke production were reduced by 83.3 % and 57.7 %, respectively. This work offers a surface modification approach for constructing highly efficient flame retardant coatings for flammable polymeric materials.

Effect of hornification on the isolation of anionic cellulose nanofibrils from Kraft pulp via maleic anhydride esterification

Cellulose nanofibrils (CNF) isolation based on a catalyst-free maleic anhydride esterification has proven to be effective, however, the effects of pulp hornification on CNF isolation by this strategy have yet to be explored, which could present significant impacts for CNF isolation. Herein, dried northern bleached softwood Kraft pulp (D-NBSK) and never-dried northern bleached softwood Kraft pulp (ND-NBSK) were selected as the substrates. After esterification with maleic anhydride (MA), the esterified ND-NBSK pulp (E-ND) shows a significantly smaller size and more fragmented structure than the esterified D-NBSK pulp (E-D). Meanwhile, higher degree of esterification can be realized for the never dried pulp as compared to the dried pulp, which is corroborated by the significantly stronger characteristic peaks of CO (1720 cm−1) and -COO− (1575 cm−1) from the FTIR spectra and the higher surface charge content (0.86 ± 0.04 mmol/g vs. 0.55 ± 0.05 mmol/g). A comparison of the characteristics of the resulting CNF similarly demonstrated the negative impact of hornification. Overall, this work indicates that hornification tends to reduce the accessibility of chemical reagents to the pulp, leading to insufficient deconstruction. Such negative impact of hornification should be considered when performing nanocellulose isolation, especially when using pulp as feedstock.

A survey of molecular line emission towards Herbig Be star V645 Cyg

ABSTRACT We present a survey of molecular line emission towards the molecular cloud surrounding Herbig Be star V645 Cyg. The survey was performed with the 20-m Onsala space telescope at 3 and 4 mm. We detected emission lines of 33 molecules and their isotopologues from diatomic molecules to four COMs up to seven atoms. Using detected lines, we estimated molecular column densities and abundances relative to molecular hydrogen in local thermodynamic equilibrium (LTE) approximation for all molecules except for methanol, for which we obtained physical parameters using a non-LTE model. Moreover, in the basement of the non-LTE model of methanol line emission, we consider that there is a weak maser effect in the additional spectral component of 51–40 E methanol line at 84.521 GHz. We compared the molecular abundances with values found in several astrochemical templates: molecular clouds, hot cores, and photodissociation regions, and found that signatures of these different types can be found towards V645 Cyg. We also obtained maps of the cloud in several molecular emission lines. The peaks of CO and CH3OH emission are shifted from the direction of the star, but the CS, HCO+, HNC, HCN, and N2H+ emission peaks are observed directly towards the star. Exploring the gas kinematics around V645 Cyg, we found that velocity structure in the ambient molecular cloud on the scale ≈1.6–2.0 pc is not the same as within ≈0.5 pc found previously by other authors.

Development and characterization of an active starch-based film as a chlorogenic acid delivery system

Given its health benefits for the human body, chlorogenic acid (CA) offers promising applications in the food industry. However, the instability and low bioavailability of CA remain to be solved. In this paper, a starch-based film prepared by the homogenization and solution-casting method was used as an effective carrier to alleviate these problems. Homogenization (10–50 MPa) reduced the starch paste viscosity and its particle sizes from 21.64 to 7.68 μm, which promoted the starch recrystallization and induced chemical cross-links between starch-CA, as confirmed by the FTIR result with an appearance of a new CO peak at about 1716 cm−1. Accordingly, the rapidly digestible starch content of the film was reduced to 27.83 % and the CA encapsulation efficiency was increased to 99.08 % (from 65.88 %). As a result, the film system extended CA's release time beyond 4 h and significantly increased the heat-treated CA's antioxidant activity. Besides, the tensile strength and elastic modulus of the film were also improved to 6.29 MPa (from 1.63 MPa) and 160.98 MPa (from 12.02 MPa), respectively, by homogenization. In conclusion, the developed active starch-based film could be used as an edible film for the production of functional food or active food packaging.

Hollow Superstructure In Situ Assembled by Single-Layer Janus Nanospheres toward Electromagnetic Shielding Flame-Retardant Polyurea Composites.

A dodecahedral superstructure consisting of a single layer of Janus spheres containing ZIF-67 nanodots is prepared by in situ polymerization, with ZIF-67 and bio-based phytic acid (PA) as templates and dopants. It is used to improve the flame retardant, electromagnetic (EMI) shielding, and thermal conductivity properties of polyurea (PUA). By adding 5wt% polyaniline@cobalt phytate-2.0 (PANI@Co-PA-2.0), the peak of heat release rate and the peak of smoke production rate are reduced by 54.9 and 59.9%, respectively. The peak of CO and CO2 production also decreased by 46.2 and 53.1%, respectively. A decrease in the absorption intensity of aliphatic and aromatic volatiles is also observed. The fire safety of PUA is greatly improved. In addition, PUA/PANI@Co-PA-2.0 exhibits an EMI shielding capability of 22.4dB with the help of reduced graphene oxide, which confirms the possibility of PUA material application in the field of electromagnetic shielding. The 5wt% filler increases the tensile strength of the PUA matrix to 6.3MPa, and the composite material obtains good thermal conductivity. This work provides a viable method for the preparation of a flame-retardant, conductive, and electromagnetic refractory PUA substrate.

Molybdenum‐based Nanocatalysts for CO Oxidation Reactions in Direct Alcohol Fuel Cells: A Critical Review

AbstractCarbon monoxide (CO) oxidation is crucial in fuel cell anodes. Recent research has focused on electrocatalysts that synergistically enhance CO oxidation alongside alcohol/hydrogen oxidation. High sensitivity and selectivity for CO oxidation at lower onset potentials are the key objectives. Molybdenum (Mo) has emerged as a promising non‐noble transition metal co‐catalyst for CO oxidation. Mo versatility arises from its ability to alloy with Pt and mix with other non‐noble transition metals in various forms (MoOx, MoS2, MoC). Carbon‐supported Mo nanoparticles have shown potential in reducing Pt loading and improving CO tolerance due to Mo oxyphilic properties, effectively oxidizing weakly adsorbed CO and lowering onset and peak potentials. However, challenges persist, such as a limited potential window for CO oxidation and decreased CO adsorption affinity at higher potentials. Addressing these issues requires understanding factors affecting Mo‐based electrocatalysts (Mo‐ECs) activity, including PtMo alloy composition, Mo′s chemical state, cell temperature, and the role of carbon support. This article provides a comprehensive review of Mo‐ECs role in CO electrooxidation in direct alcohol fuel cells (DAFCs) over the past two decades.

The impact of H II regions on giant molecular cloud properties in nearby galaxies sampled by PHANGS ALMA and MUSE

Context. The final stages of molecular cloud evolution involve cloud disruption due to feedback by massive stars, with recent literature suggesting the importance of early (i.e., pre-supernova) feedback mechanisms. Aims. We aim to determine whether feedback from massive stars in H II regions has a measurable impact on the physical properties of molecular clouds at a characteristic scale of ~ 100 pc, and whether the imprint of feedback on the molecular gas depends on the local galactic environment. Methods. We identified giant molecular clouds (GMCs) associated with H II regions for a sample of 19 nearby galaxies from catalogs of GMCs and H II regions released by the PHANGS-ALMA and PHANGS-MUSE surveys, using the overlap of the CO and Hα emission as the key criterion for physical association. We compared the distributions of GMC and H II region properties for paired and non-paired objects. We investigated correlations between GMC and H II region properties among galaxies and across different galactic environments to determine whether GMCs that are associated with H II regions have significantly distinct physical properties compared to the parent GMC population. Results. We identify trends between the Hα luminosity of an H II region and the CO peak brightness and molecular mass of GMCs that we tentatively attribute to a direct physical connection between the matched objects, and which arise independently of the underlying environmental variations of GMC and H II region properties within galaxies. The study of the full sample nevertheless hides a large galaxy-to-galaxy variability. Conclusions. At the ~100 pc scales accessed by the PHANGS-ALMA and PHANGS-MUSE data, pre-supernova feedback mechanisms in H II regions have a subtle but measurable impact on the properties of the surrounding molecular gas, as inferred from CO observations.

Multi-objective optimization study of hydrothermal aging on NOx-assisted soot catalytic combustion and secondary pollution emission in regeneration of CeO2 catalytic diesel particulate filter

The present study aimed to explore the effect of hydrothermal aging on the heterogeneous catalytic combustion process of soot in CeO2 catalytic diesel particular filter and the formation of secondary pollutants (N2O and CO).The present study was based on a fixed-bed experimental bench for NOx-assisted soot catalytic oxidation in CeO2-CDPF with different soot loading and catalyst coating amounts. A non-linear regression surrogate model and a multi-objective optimization decision approach were used to analyze the trade-off relationship between the design variables and the optimization objectives. The results showed that lower levels of soot loading (2.5 g/L), CeO2 catalyst coating amount (2.5 g/L) and higher NOx concentration (1000 ppm) in fresh catalysts were favorable for improving the performance of soot-assisted catalytic combustion and minimizing the formation of N2O and CO. However, it was observed that higher levels of catalyst coating amount (10 g/L) resulted in better soot catalytic combustion performance with lower N2O and CO emissions. Global sensitivity analysis showed a positive correlation between N2O and CO peak concentrations and peak temperatures with soot loading, but a negative correlation with catalyst loading. Over time, hydrothermal aging of CDPF caused the inhibitory effect of CeO2 catalyst on N2O to shift from negative to positive correlation, while also decreasing the synergistic performance of NOx in soot catalytic combustion.

Boosted N2 Activation through 4f–2p–3d Orbital Hybridization for Efficient Nitrate Electrosynthesis

AbstractThe electrochemical N2 oxidation reaction (NOR) has emerged as a promising approach for achieving high selectivity in nitric acid (HNO3) production. However, the sluggish N2 activation process in NOR due to the high cleavage energy barrier of the N≡N bond remains a challenge. Herein, a novel orbital hybridization strategy for tuning the NOR performance through the construction of cerium (Ce) 4f–O 2p–Co 3d network in Ce‐doped Co3O4 (Ce–Co3O4) is proposed. The Ce–Co3O4 catalyst exhibits an enhanced HNO3 yield of 24.76 µg h−1 mgcat−1 and a promoted Faradaic efficiency of 31.93% in 0.1 m Na2SO4 electrolyte under ambient conditions compared to those of the pure Co3O4 (13.75 µg h−1 mgcat−1 and 23.43%). Density functional theory caculations demonstrate the strong 4f–2p–3d orbital hybridization and electron transfer in Ce–Co3O4. Moreover, a series of in situ techniques provide direct evidence of stronger adsorption peaks for Co─N bond and the key intermediate *NO formed after N2 activation on the surface of Ce–Co3O4. This work provides a promising route for the preparation of efficient NOR catalysts and sheds light on the mechanism of N2 activation through orbital hybridization.

Enhancement of iron‐based oxygen carriers through alloying with tungsten oxide for chemical looping applications including water splitting

AbstractChemical looping applications offer a variety of options to decarbonise different industrial sectors, such as iron and steel and hydrogen production. Chemical looping with water splitting (CLWS) is a chemical looping technology, which produces H2 while simultaneously capturing CO2. The selection of oxygen carriers (OCs) available to be used in CLWS is finite, due to the thermodynamic limitations of the oxidation with steam for different materials at the relevant process temperatures. Iron‐based materials are one of the most widely studied options for chemical looping combustion (CLC), touted for their relative abundance and low cost; likewise, for CLWS, iron is the most promising option. However, when the reduction of iron oxide (Fe2O3) is extended to wüstite (FeO) and iron (Fe), agglomeration and sintering problems are the main challenge for fluidisation.This work presents iron and tungsten mixed oxides as the OCs for a family of chemical looping applications. The OCs were produced via co‐precipitation; performance assessment was conducted in a thermogravimetric analyser and a lab‐scale fluidised bed reactor over continuous redox cycles. The use of tungsten combined with iron results in a solid solution of tungsten within the Fe2O3 matrix that produced a more mechanically stable material during operation, which performed well during multiple redox cycles with no apparent decrease in the oxygen transport capacity and showed no apparent agglomeration. Furthermore, materials containing tungsten showed a resistance to carbon deposition, whereas the reference Fe2O3 showed peaks of CO and CO2 during the oxidation period, thus indicating carbon deposition. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.

Sulfoaluminate cement-modified straw biochar as a soil amendment to inhibit Pb-Cd mobility in the soil-romaine lettuce system

Biochar is widely used to remediate soil polluted by potentially toxic elements (PTEs), while the effect of a new type of biochar, obtained from modified cement material, on the mobility of Pb and Cd in the soil-plant system is still unknown. In this study, soils doped with sulfoaluminate cement modified biochar (SBC) were characterized using a series of approaches including FTIR, XRD, and XPS, and combined with pot experiments to explore its synergistic effects on the speciation transformation, accumulation, and mobility of both Pb and Cd in a soil-romaine lettuce system in heavily contaminated soils containing 500 mg·kg−1-Pb and 3 mg·kg−1-Cd. The results showed that SBC effectively immobilized Pb and Cd in the soil and that this was achieved through cation exchange, complexation, and gel encapsulation. Moreover, SBC also changed the soil physicochemical properties and indirectly affected the speciation transformation of Pb and Cd. FTIR and XRD analyses revealed that the groups such as –OH, –COOH, SO42−, and SiO32−introduced by SBC stimulated the conversion from the soluble to the residual state of Pb. XPS analysis indicated that, the deviation of the C–O–C, C–OOH, and O–CO peak and the increased in area suggested that organic groups in the SBC were engaged in the immobilization mechanism of Pb and Cd. The transformation of residual Cd in other extractable fractions might be due to either enhanced soil reducibility or competitive adsorption with Pb. In 5% SBC soil, Pb was reduced by 27.69% and 64.84%, and Cd was reduced by 20.45% and 35.87% for shoots and roots of romaine lettuce, respectively. SBC showed a significantly positive correlation with SOM, while SOM showed a highly significantly negative correlation with both Pb and Cd in the roots. In summary, SBC can be strongly recommended as a green amendment to remediate Pb–Cd contaminated soil and to inhibit the mobility to plant.

Electrocatalytic performance of Ni-promoted Co nanoclusters supported by N-doped carbon foams for rechargeable Zn-air batteries

Ni/Co diatomic clusters supported on nitrogen-doped carbon foams are prepared via molten salt method to improve the density of surface active sites of zinc-air battery catalysts and further explore metal-modified carbon-based catalysts. The influence of Co and Ni atoms on the carbon foam structure is investigated by X-ray diffraction and high-resolution electron microscopy, and the presence of metal atoms in N-doped carbon foams is confirmed by X-ray spectroscopy. The left shift of the diffraction peak of Co doped graphitic carbon indicates an increase in the interlayer spacing and a reduced graphitization degree, while the introducton of Ni atoms promotes graphitization. For Ni–Co/NFC-2, Ni inhibits the insertion of Co in carbon layer by increasing graphitization, thus exposing more Co-active substances on the surface, which is important for improving the catalytic process of ORR and OER. According to electrochemical tests, Ni–Co co-doped carbons exhibited superior bi-functional electrocatalytic performance with oxygen reduction reaction (ORR) Eonset = 0.97 V and a Tafel slope of 49.5 mV dec−1, accompanied by oxygen evolution reaction (OER) Ej = 10 mA cm−2 = 1.46 V. Zinc-air battery (ZAB) cell, utilizing the developed material as a catalyst, exhibited a high discharge power density of 138 mW cm−2 with stable performance for up to 200 h.

The Characteristics of Gas and Particulate Emissions from Smouldering Combustion in the Pinus pumila Forest of Huzhong National Nature Reserve of the Daxing’an Mountains

Smouldering combustion can emit a large amount of CO2, CO and particulate matter (PM). Moisture content is an important factor of the emission characteristics. As the hot spot of forest smouldering combustion, the gas and particulate emissions of the Huzhong National Nature Reserve with different moisture contents are discussed herein. The emission factors (EF) of CO2 and CO were 100.71 ± 39.14 g/kg and 11.76 ± 3.89 g/kg, respectively. The EF of PM2.5, PM4 and PM10 were 87.11 ± 19.47 g/kg, 353.37 ±159.25 g/kg and 602.59 ± 276.80 g/kg, respectively. PM2.5 accounted for 16.59 ± 5.25% of the PM, and PM4 and PM10 were 54.03 ± 13.46% and 91.00 ± 10.81%, respectively. There was no significant difference in the EF of CO2 and CO with different moisture contents, nor in the EF of PM2.5, but there was a significant difference in the EF of PM4 and PM10 with different moisture contents. In addition, the peak of CO2 and CO appeared at 2~3 h; the peak of PM2.5 lagged behind that of PM4 and PM10. According to the regression analysis, experimental expressions were obtained for the modified combustion efficiency (MCE) and the EF of PM.

Investigation of ZnCoP coating electrodeposited on Q235B steel and its corrosion resistance in simulated acid rain solution

In order to further improve the corrosion resistance of Q235B steel used for sports equipment, the Zn coating, ZnCo coating, and ZnCoP coating are electrodeposited respectively on the Q235B steel. The relationship between corrosion resistance, surface morphology, structure, and surface roughness of different coatings is studied. All the electrodeposited coatings are crystalline with typical diffraction peaks. Three diffraction peaks of Co(111),Co(200), and Co(220) can be observed on the XRD pattern of ZnCoP that indicate that the addition of sodium hypophosphite in the plating solution is conducive to the electrodeposition of cobalt. The Zn coating shows strip-like surface morphology with the roughest surface (1.431 µm) while the ZnCo coating and ZnCoP coating are both composed of granular structures with compact surfaces. Compared with all the coatings, the corrosion current density of Zn coating is about 345.78 μA/cm2 which is the largest indicating poor corrosion resistance. The corrosion current density of ZnCo coating and ZnCoP coating is 47.83 μA/cm2 and 15.63 μA/cm2 respectively which are both lower than that of Q235B. The ZnCoP coating has the best corrosion resistance due to phosphorus and cobalt doped in the coating that refine the grain size and improve the surface compactness.