Organic polymer membranes have been widely used for wastewater treatment.Due to occurrence of irreversible membrane contamination,the replacement of the membrane after the performance decay leads to the generation of a large number of discarded membranes.How to realize the reuse of these waste polymer films has important economic and environmental value.In this study,a carbonaceous material with both ultramicroporous,mesoporous,and macroporous structures was prepared by a simple pyrolysis remodeling reaction using waste hollow fiber membranes as a template.The differences in the adsorption performance of the waste membrane?derived activated carbon and commercial activated carbon were investigated based on the structural characterizations of the carbonaceous materials.The kinetic and thermodynamic processes for the adsorption removal of typical aromatic hydrocarbon organic contaminants and antibiotics from water were investigated.It was found that the the waste membrane carbon with hierarchical pore structure had a higher removal capacity for aromatic hydrocarbon organic pollutants than commercial carbon,while the adsorption performance for antibiotics such as ciprofloxacin,carbamazepine and sulfadiazine was lower than that of commercial carbon.
This article conducts research on the injection production well patterns under different injection production conditions through two methods: physical simulation and numerical simulation. On the core scale, a reservoir physical simulation model was prepared based on similarity criteria. It was found that the higher the permeability of the physical model was, the lower the overall pressure value was and the smaller the average pressure drop after shutdown. As the viscosity of crude oil increases, the overall pressure of the model increases, and the reduction in pressure during adjustment becomes more pronounced. As the decrease in flow rate increases, the decrease in pressure regulation significantly increases. According to the numerical simulation results, due to the obstruction of the fault, there is no connectivity on both sides, resulting in different energy replenishment on both sides. As the mining progresses, the pressure difference decreases from 0.35 MPa in the initial stage to around 0.15 MPa.When both sides of the fault of the adjustment well are one injection and two extractions, the pressure difference between the two sides of the fault exists with the extension of the development time, but converges again in the late production period.While both sides of the fault of the adjustment well are one injection and two extractions and one injection and four extractions, the difference between the two sides of the fault pressure system increases with the extension of the development time. The research of this paper is of great significance to drilling of adjustment wells in the "Double High" oilfield.
Rising levels of nitrate and nitrogen in water bodies pose a potential threat to aquatic ecosystems and human health. Therefore, it is urgent to solve the problem of excessive nitrate in water bodies. Fe(NO3)3·9H2O, Co(NO3)2·6H2O, reed biochar, NH3·H2O was used as raw material, and co-precipitation method was used to load cobalt-iron layered bimetals onto reed biochar to prepare Co/Fe-LDH@BC for adsorption of excess nitrate nitrogen in water. The experimental results showed that Co/Fe-LDH@BC could effectively adsorb nitrate nitrogen in water, and its adsorption capacity was 88.52 mg/g. The adsorption kinetic model conforms to the pseudo-second-order kinetic model, and the isotherm conforms to the Langmuir isotherm model, indicating that the adsorption reaction is spontaneous and endothermic, which mainly involves four reaction mechanisms: ion exchange, ligand exchange, electrostatic attraction and hydrogen bonding. In addition, Co/Fe-LDH@BC has a strong affinity for nitrate nitrogen in most water bodies where coexisting anions are present, making it suitable for practical applications.
Aromaticity is one of the important chemical properties of aromatic compounds. Clarifying the aromaticity of a clearly ring?conjugated system is crucial for understanding the chemical reactivity and stability of the system. A detailed study of the aromaticity, one?photon absorption (OPA), two?photon absorption (TPA) spectra, and electron transfer properties of Kekulene was carried out through quantum chemical calculations and wave function analysis. The aromaticity of different benzene rings in the molecule was quantitatively analyzed through multicenter bond indices and AV1245 indices. The aromaticity of Kekulene was studied through various methods such as electron localization function (ELF), localized orbital locator (LOL), magnetic susceptibility current, and isotropic chemical shielding surface (ICSS). The electron transfer processes of OPA and TPA transitions were visualized through charge difference density (CDD) analysis. The results showed that the aromaticity of rings 1 and 2 was significantly stronger than that of rings 3 and 4. The π electrons of ELF and LOL can be highly delocalized on both sides of the first ring and form a loop. The OPA spectrum has excited states with higher transition dipole moments, which are more likely to become intermediate states in the TPA process. The research results can provide effective theoretical methods and application approaches for the aromaticity of different systems.
γ-Al2O3 is commonly used as a carrier for catalysts, and the physicochemical properties of its surface greatly influence the catalytic reaction. The exposed Al coordination environment can be regulated by adjusting the morphology of γ-Al2O3 carriers by changing the synthesis method and synthesis conditions. The energy of the exposed crystal lattice of carriers with different morphologies is different, which will directly affect the acidity of the carrier and the interaction between active metals, and active metals and carriers, thus creating different loading sites of active metals. Carrier morphology control is an effective way to regulate the structure of the active components. The regulation of the support morphology of the propane dehydrogenation catalyst will affect the catalytic performance. The research progress of γ-Al2O3 support was reviewed from the aspects of preparation method, morphology control, and its influence on propane dehydrogenation catalyst.
For the deep removal of CO from hydrogen-rich gas,the preparation of catalysts with better CO-Prox catalytic performance is a current research hotspot.CuO/NiO-CeO2 catalysts were prepared by stepwise impregnation method,and the catalysts were characterized by XRD,BET,H2-TPR and HR-TEM to investigate the effects of molar loading of metal Cu+Ni (metal loading) on the catalysts' structure,reduction properties and their CO-Prox performance.The results showed that Cu/Ni-O-Ce solid solutions were all formed in CuO/NiO-CeO2 catalysts.The catalytic activity is mainly related to the content of Cu species highly dispersed on the carrier surface as well as to the content of the solid solution.Among them,the catalyst with a metal loading of 8% had a higher content of Cu species highly dispersed on the carrier surface and a higher content of solid solutions,and the catalyst exhibited better catalytic activity.Under the CO/H2/CO2/O2/Ar atmosphere,a reaction temperature of 130 °C,an oxygen excess coefficient of 1.2,and a mass-air velocity of 20 266 mL/（g·h）,the CO conversion was 95.9%,and the CO oxidation selectivity was 86.3%.
Cu0.7Mn0.3Al2.5 ternary solid solution spinel catalysts were prepared by ball milling method using copper nitrate as the copper source, proposed thin alumina as the aluminium source, citric acid as the additive, and manganese acetate as the third component to partially replace copper. With the help of characterisation techniques such as XRD, BET, H2-TPR and XPS, the crystalline phase structure, weaving properties, reducing properties and surface cation states and distributions of Cu0.7Mn0.3Al2.5 were investigated. The catalytic performance of Cu0.7Mn0.3Al2.5 in methanol steam reforming (MSR) for hydrogen production with a sustained release feature was scrutinized, and a comparison was made with CuAl2.5 binary spinel and Cu0.7Zn0.3Al2.5 ternary spinel catalysts. The results showed that compared with CuAl2.5 and Cu0.7Zn0.3Al2.5, the Cu0.7Mn0.3Al2.5 exhibited the maximum contraction of the unit cell, resulting in a smaller unit cell constant. The catalyst had smaller crystalline size and higher specific surface area. The catalyst showed an aluminium-rich state, but with a higher percentage of Cu in the surface spinel phase, which made the reduction under H2 atmosphere more difficult, and exhibited a better slow-release catalytic performance in MSR hydrogen production. Under the conditions of a reaction temperature of 265 °C, n（H2O）/n（CH3OH） =2, and mass flow rate of 2.25 h-1, a stable conversion rate of 84% was achieved for 40 hours. The study provided valuable data reference for the development of efficient copper-based sustained-release catalysts.
Solving the sensitivity of concrete to admixture dosage and concrete shrinkage has always been a technical challenge eagerly awaited in the construction industry.A new type of ester polycarboxylate superplasticizer monomer (ACPEG) was synthesizeduses by 3-methyl-3-butenoxyacetic acid (MBA) as the priming agent.The relative molecular mass (Mw) of ACPEG was determined to be 2 389 by an multi?angle laser dispersion spectrumeig scattering instrument,indicating the formation of a polyether monomer structure.The results showed that ACPEG has a unique advantage of low polymerization activity,allowing for the one-step synthesis of superplasticizers at 40 ℃ without risk of explosion.The superplasticizer synthesized from ACPEG exhibited a water-reducing rate of 37.4%,segregation rate of 10.8%,bleeding rate of 6.2% at 1 hour,and surface tension of 35.67 mN/m. Although slightly inferior to superplasticizers synthesized from ester-type monomers (MAPEG) in terms of workability,ACPEG outperformed superplasticizers synthesized from methallyl polyethylene glycol ethers (IPEG) and isoprene polyethylene glycol ethers (TPEG) in concrete slump,bleeding distance,segregation rate,workability,and shrinkage reduction effects.
Under alkaline conditions,the aldehyde group is introduced into dibenzo-18-crown-6 (DB18C6) with the help of chloroform (CHCl3) to prepare dimethyl dibenzo-18-crown-6 (DDB18C6).Then,using DDB18C6 and soluble deacetylated chitin (CTS) as raw materials,Schiff reaction was used to synthesize a grafted crown ether CTS membrane with an increasing mass fraction of small molecule crown ethers,which was named C a-CTS membrane (a=m(DDB18C6)/m(C a -CTS membrane）).The C a -CTS membrane is ion exchanged in alkali solution.The C a -CTS membrane absorbs K+ through the oxygen hole structure,and then the C a -CTSK membrane is prepared.Eeach stage the sample membrane was subjected to structural characterization and performance testing.The results show that with the increase of the crown ether grafting degree,the thermal stability of CTS can be improved;when a=0.20,the grafting degree of C0.20-CTSK membrane can reach 43.91%,the water absorption rate can reach 168.6%,the IEC value is 1.38 mmol/g. At a temperature of 70 ℃,the conductivity of C0.20-CTSK membrane can reach 46.8 mS/cm; the introduction of grafting of crown ether improves the alkali resistance stability of this series of membranes. After the C a -CTSK series membranes are soaked in 6 mol/L KOH solution for 480 hours, the conductivity decreases only 4.0%.
The Biological seepage studies the seepage of biofluids in living organisms and fluids containing microorganisms in non-biological porous media.The mass transfer diffusion osmosis phenomenon of a porous bioelastomer material,poly(glycidyl sebacate) (PGS),implanted into human soft tissues was simulated.The pore structure of the PGS material was characterised by N2 adsorption-desorption and the scaffold model with different pore numbers and pore diameters was designed using the multi-physics field simulation software-COMSOL to investigate the effects of pore and pore diameter parameters on blood osmosis when the pore size was constant.COMSOL was used to design the adapted PGS stent models,numerically simulate the characteristics of the blood flow when blood flowed through the PGS stent,and analyse the kinetic viscosity and the shear rate of the blood field with the theory of fluid dynamics.Comparative analyses of seepage pressure and diffusion at different blood inlet velocities were carried out. The results show that the PGS material is a material that tends to be mesoporous.When the blood flows inside the porous scaffold, the kinetic viscosity varies with the shear rate,indicating that the blood seepage inside the scaffold is a kind of non-Newtonian fluid seepage.The diffusion speed of the blood inside the porous scaffold is different under different inlet velocities and the larger the inlet velocity is,the higher the pressure,and the faster the mass transfer diffusion speed will be.
