Transport of Phenol in BS-12 Modified Lou Soil in the Column Experiment: Effect of Concentrations, pH and Ionic Strength

Lou soil was modified by amphoteric surfactant in column experiment which was conducted. This study attempts to explore the transport of phenol to unmodified and modified soil and inquire into the effect of concentrations, pH, and ionic strength on phenol migration in the soil column. The parameters and breakthrough curves (BTCs) of transport were fitted by using the CXTFIT (version 2.1) model. The result of Cl?’s BTCs for non-reactive by determining the equilibrium model (EM) showed the retardation factor which was smaller than 1. The result of phenol’s BTCs by determining non-equilibrium model (NEM) was shown that the R-value increased while modification ratio increased, and the R was in order of CK (1.337) < 50BS-12 (4.085) < 100BS-12 (7.048). The lower to higher concentration of phenol didn’t affect to CK and 100BS-12 was able to block higher concentration. The effect of pH on transport to CK and 100BS-12 didn’t react and the average pore water velocity was decreased at pH = 4. The decreasing ionic strength of phenol migration on CK and 100BS-12 had effect and the average pore water velocity and retardation factor also decreased. The residual retention in soil was in order of CK < 50BS-12 < 100BS-12, and 100BS-12 could hold the amount of phenol than CK 7.21 times. Thus, amphoteric modified lou soil definitely blocks phenol migration and controls groundwater pollution.

Laboratory simulation of CO_(2) immiscible gas flooding and characterization of seepage resistance

CO_(2) flooding can significantly improve the recovery rate, effectively recover crude oil, and has the advantages of energy saving and emission reduction. At present, most domestic researches on CO_(2) flooding seepage experiments are field tests in actual reservoirs or simulations with reservoir numerical simulators. Although targeted, the promotion is poor. For the characterization of seepage resistance, there are few studies on the variation law of seepage resistance caused by the combined action in the reservoir. To solve this problem, based on the mechanism of CO_(2), a physical simulation experiment device for CO_(2) non-miscible flooding production manner is designed. The device adopts two displacement schemes, gas-displacing water and gas-displacing oil, it mainly studies the immiscible gas flooding mechanism and oil displacement characteristics based on factors such as formation dip angle, gas injection position, and gas injection rate. It can provide a more accurate development simulation for the actual field application. By studying the variation law of crude oil viscosity and start-up pressure gradient, the characterization method of seepage resistance gradient affected by these two factors in the seepage process is proposed. The field test is carried out for the natural core of the S oilfield, and the seepage resistance is described more accurately. The results show that the advancing front of the gas drive is an arc, and the advancing speed of the gas drive oil front is slower than that of gas drive water;the greater the dip angle, the higher the displacement efficiency;the higher the gas injection rate is, the higher the early recovery rate is, and the lower the later recovery rate is;oil displacement efficiency is lower than water displacement efficiency;taking the actual core of S oilfield as an example, the mathematical representation method of core start-up pressure gradient in low permeability reservoir is established.

A novel numerical simulation of CO_(2) immiscible flooding coupled with viscosity and starting pressure gradient modeling in ultra-low permeability reservoir

CO_(2) immiscible flooding is an environmentally-friendly and effective method to enhance oil recovery in ultra-low permeability reservoirs.A mathematical model of CO_(2) immiscible flooding was developed,considering the variation in crude oil viscosity and starting pressure gradient in ultra-low permeability reservoirs based on the non-Darcy percolation theory.The mathematical model and numerical simulator were developed in the C++language to simulate the effects of fluid viscosity,starting pressure gradient,and other physical parameters on the distribution of the oil pressure field,oil saturation field,gas saturation field,oil viscosity field,and oil production.The results showed that the formation pressure and pressure propagation velocity in CO_(2) immiscible flooding were lower than the findings without considering the starting pressure gradient.The formation oil content saturation and the crude oil formation viscosity were higher after the consideration of the starting pressure gradient.The viscosity of crude oil considering the initiation pressure gradient during the formation was higher than that without this gradient,but the yield was lower than that condition.Our novel mathematical models helped the characterization of seepage resistance,revealed the influence of fluid property changes on seepage,improved the mathematical model of oil seepage in immiscible flooding processes,and guided the improvement of crude oil recovery in immiscible flooding processes.

Direct electrospinned La2O3 nanowires decorated with metal particles: Novel 1 D adsorbents for rapid removal of dyes in wastewater

Inorganic nanocomposites have attracted continuous attention as low cost and eco-friendly adsorbents.However,low adsorption rate and poor cycle performance limit their further application.Herein,lanthanum oxide(LO)ceramic nanowires decorated with nickel nanoparticles(NiNPs)have been synthesized by a facile electrospinning method.The decomposition of polymer precursor left high pore volume in the resultant ceramic nanowires,giving the nanowires a high surface area.The NiNPs-LO nanowires can remove various dye contaminants with adsorption rate constant higher than most adsorbents.More importantly,the NiNPs-LO nanowires can be separated and reused conveniently with stable cyclic performance,avoiding not only energy consumption but also secondary pollution.The adsorption performance fits well with pseudo-second-order and Langmuir isothermal model,indicating a monolayer adsorption process.Combined with structural and FT-IR analysis,the excellent adsorption ability is mainly ascribed to the electron interaction between the composite interfaces and contaminates under the assistance of high surface area and porosity.This work provides an ideal recyclable adsorbent for the ultra-fast water purification.

Self-assembled Ag_(4)V_(2)O_(7)/Ag_(3)VO_(4) Z-scheme heterojunction by pH adjustment with efficient photocatalytic performance

Semiconductor heterojunction plays a pivotal role in photocatalysis.However,the construction of a heterojunction with a fine microstructure usually requires complex synthetic procedures.Herein,a pH-adjusted one-step method was employed to controllably synthesize Ag_(4)V_(2)O_(7)/Ag_(3)VO_(4) heterojunction with a well-tuned 0D/1D hierarchical structure for the first time.It is noteworthy that the ordered stacking of vanadium oxide tetrahedron(VO_(3)-)guided by the pH value wisely realizes the in-situ growth of Ag_(4)V_(2)O_(7) nanoparticles on the surface of Ag_(3)VO_(4) nanorods.Furthermore,comprehensive characterization and calculation decipher the electronic structures of Ag_(4)V_(2)O_(7) and Ag_(3)VO_(4) and the formation of Z-scheme heterojunction,benefiting the visible light harvesting and carrier utilization.Such a new Ag_(4)V_(2)O_(7)/Ag_(3)VO_(4) heterojunction exhibits remarkable photocatalytic activity and excellent stability.Complete degradation of Rhodamine B(RhB)can be achieved in 10 min by the Ag_(4)V_(2)O_(7)/Ag_(3)VO_(4) heterojunction under visible light irradiation,demonstrating an outstanding reaction rate of 0.35 min^(−1) that is up to 84-fold higher than those of other silver vanadates.More importantly,this integration of synthesis technology and heterojunction design,based on the intrinsic crystal and electronic structures,could be inspiring for developing novel heterostructured materials with advanced performance.