This study aims to analyze the influence of the polycyclic aromatic hydrocarbon (PAH) content in diesel on the physical and chemical properties of diesel soot particles. Four diesel fuels with different PAH content were tested on a 11.6 L direct- injection diesel engine. The raw particulate matter (PM) before the after-treatment devices was collected using the thermophoresis sampling system and the filter sampling system. A transmission electron microscope and Raman spectrometer are used to analyze the physical properties of the soot particles, including morphology, primary particle size distribution, and graphitization degree. A Fourier transform infrared spectrometer and thermogravimetric analyzer are
used to characterize the surface chemical composition and oxidation reactivity of soot particles, respectively. The results show that as the PAH content in the fuel decreases, the size of the primary soot particles decreases from 29.58 to 26.70 nm. The graphitization degree of soot particles first increases and then decreases, and the relative content of the aliphatic hydrocarbon functional groups of soot particles first decreases and then increases. The T10, T50, and T90 of soot from high-PAH fuel are 505.3, 589.3, and 623.5 °C, while those from low-PAH fuel are 480.1, 557.5, and 599.2 °C, respectively. This indicates that exhaust PM generated by the low-PAH fuel has poor oxidation reactivity. However, as the PAH content in fuel is further decreased, the excessively high cetane number may cause uneven mixing and incomplete combustion, leading to enhanced oxidation reactivity.

Henry's coefficient of volatiles in the polymer system is a crucial parameter reflecting the gas-liquid equilibrium, which is very important for the devolatilization process. In this research, POE-cyclohexane and PDMS-hexane systems were taken as examples, using the gas-liquid equilibrium method, Henry's coefficient was obtained by measuring the gas phase equilibrium partial pressure when polymer solution containing different mass fractions of volatiles reached a saturated state. The effects of temperature, kinds of volatiles and polymer viscosity on the gas phase equilibrium partial pressure and Henry's coefficient of volatiles were investigated. Experimental results indicate that, with the increase of temperature and polymer viscosity, the gas phase equilibrium partial pressure and Henry's coefficient of volatile cyclohexane increase. As temperature increases, the solubility of gas in liquid decreases. In POE-cyclohexane system, the relationship between Henry's coefficient of cyclohexane and temperature can be expressed by lnH=389.39-244402.54×(1/T)+3.86×10^7×(1/T)^(2 ). While in the PDMS-cyclohexane, it can be expressed by lnH=106.57-60139.08×(1/T)+8.69×10^6×(1/T)^2 . In PDMS-hexane system, the gas phase equilibrium partial pressure and Henry's coefficient of n-hexane with straight chain structure are higher than those of cyclohexane with cyclic structure. Henry's coefficient obtained in this study can provide a reference for perfecting the devolatilization process and improving the devolatilization effect.

The FMOFs-[HeMIM]Cl/(ZnBr2)2, FMOFs-[CeMIM]Cl/(ZnBr2)2, and FMOFs-[AeMIM]Cl/(ZnBr2)2 were, respectively, immobilized in functional metal -organic framework materials (FMOFs). They were used to catalyze the cycloaddition reaction of carbon dioxide (CO2) and epoxides. The results from the investigation showed that the three metal-based ionic liquid catalysts were the target products. Under the conditions of reaction temperature 110 oC, reaction pressure 2.0 MPa, and catalyst dosage accounting for 2.0% of the mass of epoxide, the conversion of epoxide was 96.63% and the selectivity of propylene carbonate was 98.64%, thus forming the optimal catalyst FMOFs-[CeMIM]Cl/(ZnBr2)2. Moreover, the catalyst has no obvious change in catalytic performance after being recycled four times.

Solid waste-based activated carbon (AC) was utilized as a carbon source to synthesize a series of carbon-based functional material RAC-X (X= P and S). The toluene adsorption capacities of RACs samples can be significantly improved adopting the heteroatomic modification strategy. TheRACs modified by phosphoric acid and sulfuric acid have the same specific surface area (1156 m2/g) and the similar porous structure. However, their exists the different toluene adsorption capacities, RAC-P of 316.22 mg/g and RAC-S of 460.12 mg/g, respectively, which are 1.6 and 2.4 times greater than that of RAC. Through X-ray photoelectron spectroscopy measurements, it is found that the increase in the amount of π–π* chemical bond over the AC surface results in an improvement in the toluene adsorption performance. Density functional theory results show that the S-containing functional groups loaded near the defect sites of RAC-S promote the adsorption energy for the toluene. Moreover, reusability tests show that RAC-S still retains 86% of the adsorption activity after four consecutive adsorption–desorption experiments. This indicates that the heteroatomic modification method exhibits an excellent toluene adsorption performance and recycling practicability, which not only is beneficial for achieving the rational utilization of solid waste resources but also provides a practical method for the efficient elimination of VOCs.

A highly active sulfided NiPMo/MCM-41 (NiPMo-S/M41) hydrodesulfurization (HDS) catalyst was successfully synthesized using Keggin-type phosphomolybdic acid as the phosphorus and molybdenum source, and thioacetamide as the sulfur source. The supported NiPMo/M41, Ni2P-Mo/M41 and Ni2P/M41 catalysts were also prepared to investigate the effects of Mo, S, and Keggin structure on the HDS performance of the catalysts. The HDS activities of NiPMo/M41 and NiPMo/M41-S for dibenzothiophene (DBT) were much higher than that of Ni2P-Mo/M41, demonstrating that the active phases in the Keggin-structured catalysts were significantly superior than that of the Mo-modified Ni2P phase. The HDS activity of the catalysts followed the order NiPMo/M41-S (96.7%) > NiPMo/M41 (89.9%) > Ni2P-Mo/M41 (53.5%) > Ni2P/M41 (48.9%). For all the Ni2P/M41, Ni2P-Mo/M41 and NiPMo/M41 catalysts, phenyl cyclohexane (CHB) was formed in small concentrations (<21.0%), indicating that direct desulfurization (DDS) was the favored reaction route and that it did not change for Keggin-structured NiPMo/M41. What’s more, the selectivity towards CHB of NiPMo/M41-S increased to 44.6%, much higher than that of NiPMo/M41 catalyst (17.6%), showing the sulfurization deduced the improved hydrogenation ability, which was attributed to the metal-acid synergistic effect.

TiO2 is a promising photocatalyst, but the limited contact area of liquid-liquid interface and low catalytic efficiency caused by catalysts with large particle size and uneven distribution restrict the practical application. As an effective process intensification equipment, the impinging stream-rotating packed bed (IS-RPB) overcomes the mixing limitation of traditional stirred tank reactor, and provides a micro-mixing environment at the molecular scale for liquid-liquid two phase, which could reduce the particle size and distribution range. Cu/N-TiO2 nanoparticles were successfully prepared by one-step precipitation method using urea as the nitrogen source, titanyl sulfate as the titanium source, copper chloride as the copper source and ammonium hydroxide as the precipitant in an IS-RPB. The particle size of obtained photocatalyst was about 11.40 nm with narrow size-distribution via SEM and TEM. According to XPS, N replaced part of O, and was uniformly dispersed in the TiO2 lattice in the form of interstitial N and substitutional N. Cu replaced part of Ti and existed in the form of Cu2+. The synergistic effect of these two elements forms a new impurity energy level and reduces band gap energy of TiO2 nanoparticles. The specific surface areas of Cu/N-TiO2 are 152.97 m2/g. The influence of the main factors on the degradation rate was studied, the results showed that the removal efficiency could reach 100% under the optimal operating conditions after 2 hours UV light irradiation. The EPR measurement showed that the superoxide radical (O2-·) played a leading role in the degradation process, while the effect of photogenerated holes (h+) and hydroxyl radicals (OH·) were relatively weak.