With the acceleration of industrialization,a large amount of refractory organic contaminants were discharged into water, bringing new challenges to the traditional water treatment technologies.As an advanced oxidation process (AOPs),the heterogeneous catalytic ozonation shows great potential for water treatment due to its high efficiency and environmental friendliness.The surface hydroxyl groups,Lewis acid sites,redox cycling, and structural defects could act as active sites on heterogeneous catalysts,which could effectively promote the ozonolysis reaction and generate reactive oxygen species (ROS) for enhancing the degradation of organic pollutants.By active site engineering,both the metal?based catalysts and non?metal catalysts could significantly improve the efficiency of ozonation reactions.This paper provides a comprehensive review of the use of heterogeneous catalytic ozonation in industrial wastewater treatment.The working mechanism of this technology,the active sites of catalysts,the typical catalysts and their applications in wastewater treatment were fundamentally discussed.Finally,this paper provides insights into the future research direction of heterogeneous catalytic ozonation,emphasizing the importance of establishing a unified catalyst evaluation standard and improving the catalyst stability for the practical application of the heterogeneous ozonation catalysts.
The long-distance natural gas pipeline is characterized by large diameter and fast flow,and the uneven mixing of hydrogen gas will increase the risks of metal hydrogen embrittlement,seal leakage and unstable operation of equipment in the pipeline transportation system.According to the operating conditions of a long?distance natural gas pipeline in China,numerical simulation was used to study the flow field characteristics and mixing effect of four types of static mixers (SK,SX,SL,HEV) when hydrogen doping is transported(the ratio of hydrogen doping is 3%).The results show that all four types of static mixers have disturbing mixing effects on natural gas with hydrogen addition,and the value of the mixed non?uniformity COV decreases with the increase of flow rate,while the pressure loss increases with the increase of flow rate.The mixing characteristics and effects of SK, SX,SL and HEV type mixers vary significantly under the operating conditions of 3% hydrogen doping ratio,4.22 MPa hydrogen doping pressure,and flow rates ranging from 13×108 Nm3/a to 36×108 Nm3/a.The COV value should be reduced to less than 5% at different mixing distances.It can be optimally or innovatively designed with a relatively simple structure, short mixing distance, low non?uniformity, excellent turbulence characteristics,good shear characteristics, and moderate pressure drop as a large-caliber long-distance natural gas main pipeline hydrogen mixer.
According to the requirements of constructing a fair and open large?scale platform by the National Pipeline Network Group,the surplus transportation capacity of crude oil pipelines will be opened to the whole society.This article investigates the changes in energy consumption costs in the batch transportation of blended crude oil in pipelines using a simulation and modeling approach.Based on the simulation results,an optimization model for the batch transportation of blended crude oil in the pipeline system is established.The relationship between energy consumption costs and viscosity,as well as throughput index variations,is analyzed.This optimization model enables the cost?effective batch transportation of blended crude oil with different viscosities, thereby providing technical support for the safe and economically efficient transporting of new crude oil with different properties in the pipeline.
During the development of the Fuyu oil reservoir in the Longxi block of Daqing,hydrogen sulfide (H2S) was discovered and exceeded the threshold value (15.0 mg/m3), but its generation mechanism is still unclear. To investigate this, the mechanism of H?S generation in the Longxi block formation was investigated through laboratory experiments on H?S generation,combined with numerical simulations using PHREEQC and CMG software.The results show that the mechanism of H2S generation in high?temperature reservoirs (100~125 ℃) is sulfate thermochemical reduction reaction, with viscosity of H2S generated ranges from 3.20 mg/m3 to 6.10 mg/m3.In low?temperature reservoirs (≤60 ℃),the mechanism of H2S generation is sulfate?reducing bacteria reduction reaction,with a maximum H2S viscosity of up to 29.70 mg/m3.Fracturing fluid reduces the temperature in the near?wellbore zone, promoting SRB proliferation, and the viscosity of H2S generated in a short time increases by 7.5 times compared to the sulfate?reducing bacteria reduction reaction in produced water. The mass concentrations of H2S generated by the reaction of 1 m3 acid with the core and plug containing 0.80 mol FeS are 3 330.69 mg/m3 and 11 466.75 mg/m3,respectively. Therefore, fracturing and acidification are the main mechanisms for the generation of H2S during the development of the Fuyu oil reservoir in the Longxi block.
The hydrogen transfer properties of HY zeolite and lanthanum ion modified Y(LaHY) zeolite were investigated using in situ FTIR technology. Combined with characterization data of zeolite crystal structure, texture properties, and acidity, the regulatory mechanism of rare earth modification and hydrothermal treatment on the hydrogen transfer reaction performance of Y zeolite was explored. The results show that the Brønsted (B) acid density and strong acid strength of Y zeolite decreased, while rare earth species located in the supercage formed weak Lewis (L) acid sites. The synergistic effect of B acid and L acid sites in the supercage promoted the occurrence of hydrogen transfer reaction. After hydrothermal treatment, the total acidity of HY-LH and LaHY-LH zeolites significantly decreased, and the L acid centers related to rare earth species in the supercages completely disappeared, which significantly reduced the hydrogen transfer reaction performance of HY zeolites. The research results can provide important theoretical guidance for a deeper understanding of the laws of hydrogen transfer reactions in catalytic cracking reactions, as well as achieving the goals of regulating olefin product selectivity and inhibiting coking deactivation.
The selectivity and stability of Pt?based catalysts can be improved by adjusting the active phase by adding additives. The active phase of Pt?based catalyst was regulated by changing n(Ga)/n(Pt) with Ga as an additive and characterized by BET, FT-IR, TG, H2-TPR, etc. The n(Ga)/n(Pt) of the active phase was optimized under the reaction temperature of 580 ℃, volume space velocity of 2 000 h-1 and hydrogen?hydrocarbon ratio (volume ratio of hydrogen to propane) of 1. The results show that the Pt in the Pt7Ga/Al2O3 catalyst has the smallest particle size and the best dispersion.The Pt7Ga/Al2O3 catalyst has the best dehydrogenation performance, and the propylene selectivity of the reaction for 3 h was 90.98%, which was 3.01% higher than that with the PtSn/Al2O3 catalyst. The regulation of Ga can enhance the interaction force between Pt and Al2O3 support, lower the acidity of catalyst and the degree of graphitization of catalyst carbon deposition.
The use of solar photocatalytic degradation of pollutants is one of the most promising technologies to solve water pollution problems and achieve solar energy conversion. By changing the amount of g-C3N4 added, g-C3N4/Co3O4 catalysts with different g-C3N4 mass fractions are prepared based on the calcination method with cobalt nitrate hexahydrate (Co（NO3)2-6H2O) and urea (NH4CNO) as raw materials. The samples are analyzed and characterized using X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and ultraviolet visible absorption spectroscopy （UV-vis DRS）. To speculate on the active species of the catalyst, capture agent experiments are conducted on it. The results indicate that the synergistic effect between g-C3N4 and Co3O4 can improve the transfer and separation efficiency of charge carriers at the interface between the two phases. Under visible light, the degradation effect of 10% g-C3N4/Co3O4 is the best, with a degradation rate of 66.50%, which is higher than the degradation effect of single Co3O4 （degradation rate of 35.90%）. The active species of the catalyst are mainly superoxide radicals（·O2-） and holes（h+）. After compounding with g-C3N4, the drawbacks of Co3O4 electron hole pair, such as too fast recombination and a deficient energy level structure, are improved, providing ideas for the degradation of organic pollutants in the future.
With the significant increase in the price of lithium?ion batteries,low-cost,energy-efficient sodium-ion batteries have attracted widespread attention.As a bridge connecting the positive and negative materials of sodium ion batteries,the electrolyte plays a crucial role.The first coulomb efficiency,cycle stability and rate performance of sodium?ion batteries can be effectively improved by constructing suitable electrolytic liquid system for different electrode materials.In this paper,the research progress of various electrolyte additives in sodium?ion battery systems,the formation mechanism of interface film and the future research direction of electrolyte additives have been discussed.
Blending poly(propylene carbonate) (PPC) with poly(adipate?butylene terephthalate) (PBAT) was involved in the preparation of PPC/PBAT composites. However, the limited compatibility between the two materials hinders the potential performance enhancement of PPC/PBAT composites. To improve the compatibility between PPC and PBAT, maleic anhydride (MA) as a polar monomer and 2,5-dimethyl-2,5-bis(tert-butyl peroxy) hexane (DHBP) as an initiator were chosen for grafting onto PBAT to produce copolymer grafted Maleic anhydride (PBAT-g-MA).The interplay between PPC and PBAT-g-MA, as well as its impact on the properties of the blend, was thoroughly examined. The elongation at break of the blend was found to gradually increase with higher mass fraction of PBAT-g-MA. The elongation at break of PPC/PBAT-g-MA blends increased from 21.2% to 68.1%（60 and 40 are the quality scores of PPC and PBAT-g-MA, respectively）. Studies have shown that when the PBAT-g-MA content is lower than that of PPC, PBAT-g-MA functions as a uniformly dispersed phase within the PPC matrix. The anhydride group present in the material can effectively react with the end groups of PPC, thereby significantly enhancing compatibility between both phases and promoting stress transfer at interface layers to improve the mechanical properties of blends.
