A ‘‘micro-explosion” strategy for preparing membranes with high porosity, permeability, and dye/salt separation efficiency

Xinyang Li,Ligang Lin,Zitian Li,Jing Yang,Wensong Ma,Xu Yang,Xiaopeng Li,Chunhong Wang,Qingping Xin,Kongyin Zhao 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.119 No.-

In this study, inspired by ‘‘micro-explosion” strategies, a separation membrane with high porosity andpermeability, and highly efficient separation performance was prepared. With the use of polyvinylidenefluoride (Solvay6015) as membrane material, azodicarbonamide (AC) as an ‘‘explosion center point” tothe casting membrane solution, and NaOH as an ‘‘external stimulus” in the coagulation bath, the twochemicals undergo in-situ foaming reaction to form a loose nanofiltration membrane. FTIR, XPS, andTGA results demonstrated that the decomposition of AC was complete, which produced gases thatincreased the porosity of the membrane. The optimized membrane has a higher flux(101.72 L m2 h1 at 0.3 Mpa), higher negative surface charge, and better mechanical properties underthe premise of separating CR/NaCl. In the separation of pollutants with different molecular weights,the permeation flux of the optimized membrane increased by more than double. This foaming technologywas also applied to another membrane material, ethylene vinyl alcohol, from which we found that themembrane also had higher porosity and better permeability. Together, this paper presents an in-situfoaming method for preparing separation membranes and lays the foundation for solving the trade-offbetween membrane permeability and rejection in dye/salt separation.

The effect of aeration mode on the operational effectiveness and membrane bioreactors for greywater treatment and membrane fouling

Chunhong Shi,Bo Yan,Xiangmeng Zuo,Cheng Wang,Zifu Li,Lixin Zhu 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.2

This study aims to investigated the effect of aeration mode on membrane bioreactors (MBRs) using a self-designed integrated hollow fiber MBR and flat sheet organic MBR for rural greywater treatment. The pollutant removal efficiency, characteristics of activated sludge and mixed liquor, and mechanisms of membrane fouling were systematically analyzed under intermittent aeration and continuous modes. The results indicate that the permeability of MBRs in intermittent aeration mode is higher than that in the continuous aeration mode when operating at the same aeration rate. Due to the higher extracellular polymeric substance (EPS) and soluble microbial product (SMP) concentrations. The removal rates of TN and TP by both MBRs at the intermittent aeration mode were higher than those in the continuous aeration mode due to the difference in the aeration environment. Compared to the flat-sheet organic membrane, the hollow-fiber membrane surface was more likely to form biofilms, which cause biological fouling.The relative abundance of Thermomonas showed a positive correlation with the EPS concentration, indicating that Thermomonas participates in EPS synthesis. This study provides a theoretical basis for evaluating the influence of aeration modes on MBRs,and would be a useful guide for the better control of membrane fouling and treatment of rural greywater.

Influence of Hemp Fiber Softening Treatment & Blend Ratio on Quality Characteristics of Hemp-Based Ternary Blended YARNS

Chuanhe Li,Ruiqi Shao,Chunhong Wang,Guangwei Fu,Bingjie Yang 한국섬유공학회 2023 Fibers and polymers Vol.24 No.10

Quality characteristics of blended yarns, which play an important role in textile quality, are continually assessed by softness, breaking strength, breaking elongation, hairiness, irregularity, etc. In this study, hemp was softened and blended with other cellulose fibers with better softness to produce yarns. The softness of hemp is obviously lower than that of the other two fibers. With the increase of hemp fiber percentage content, the yarn properties deteriorated. Therefore, the softening treatment of hemp fiber is very necessary. Moreover, the blending hemp, cotton, and viscose in the yarn structure provided synergies, improving the weak properties of ternary fibers. Results show that softening treatment and lower percentage content of the hemp fiber will result in better yarn quality, which is consistent with the derivation result of the bending theoretical model. When the percentage content of treated hemp is 40 wt%, the overall performance of blended yarn is the best. Compared with the untreated hemp-based ternary blended yarns, the hairiness of blended yarn is significantly less (3.65 ends/m, compared to 12.23 ends/m), and the irregularity of yarn is lower (27.33% and 27.70%, respectively), yarn quality improved considerably. In addition, the resulting hemp yarn showed antibacterial activity against Escherichia coli and Staphylococcus aureus.

Efficient Removal of the Organochlorine Pesticide and Heavy-Metal Residues in Epimedium brevicornum Maxim by Supercritical Fluid Extraction

Zhao, Chunjie,Bai, Lu,Li, Huanxin,Li, Fei,Xin, Chunhong 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.12

A method involving depuration of 12 organochlorine pesticides (OCPs) and 7 heavy metals from Epimedium brevicornum Maxim was developed using supercritical fluid extraction (SPE). The pesticides in the study consisted of ${\alpha},\;{\beta}-,\;{\gamma}-,\;and\;{\delta}-Benzene$ hexachloride, Pentachloronitrobenzene (PCNB), Pentachloroaniline (PCA), Heptachlor (HEPT), Methyl -pentachlorophenyl sulfide (MPCPS), pp'-DDE[1,1-dichloro-2, 2-bis (p-chlorophenyl) ethylene], op'-DDT [1,1,1-trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane], pp'-DDD [1,1-dichloro-2-2-bis(p-chlorophenyl)]ethane, pp'-DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane]. A series of experiments was conducted to optimize the final extraction conditions as following: pure $CO_2$, extraction pressure of 15 Mpa, extration temperature of $60^{\circ}C$, extraction time of 10 min, flow rate at 55 kg/h. A GC method with electron capture detection was employed to determination of the OCPs, and an atomic absorption spectrometry (AAS) was designed for the determination of 7 heavy metals including of Pb, Cd, Cu, Fe, Zn, As, Hg in Epimedium brevicornum Maxim. A HPLC method was developed for the quantitative determination of active constituents. The SFE was used to remove the organochlorine pesticide and heavy metals from Epimedium brevicornum Maxim, receiving high decontamination rate of pesticide residue and low loss of active constituents.

Modelling and Prediction of Stress Relaxation for Thermal Bonded Nonwoven Geotextiles

Shiyuan Sun,Xiaoping Gao,Chunhong Fu,Yudong Zhou,Xiaoying Wei,Jiaxin Li,Yiping Qiu 한국섬유공학회 2020 Fibers and polymers Vol.21 No.7

Stress relaxation experiments were performed on three types of thermal bonded nonwoven geotextiles in this studyto model and predict their stress relaxation behaviors. Four mechanical models, including the standard linear solid mechanicsmodel, Eyring’s model, the modified two-Maxwell-unit model and the modified three-Maxwell-unit model were used topredict stress values for 600 h based on 3 and 90 h experimental relaxation data. Results indicated that Eyring’s model and themodified three-Maxwell-unit model fitted the experimental results better than the other two. Estimation using modified three-Maxwell-unit model seemed to construct an upper bound while that using Eyring’s model form a lower bound for thecorresponding experimental data. In addition, predicted curves were much closer to the experimental curve when equationsof the two models were built with the 90 h experimental data than those data of 3 h. Thus, the prediction capability of the twomodels can be substantially improved by employing the data with longer time. In summary, the combination of the modifiedthree-Maxwell-unit model and Eyring’s model can well forcast the range of actual stress during stress relaxation experimentswith the longer term experimental data.

Design of Novel Reactive Dyes Containing Cationic Groups: Mechanism and Application for Environmentally Friendly Cotton Dyeing

Meihui Wang,Chong Guo,Chunhong Li,Tao Zhao 한국섬유공학회 2020 Fibers and polymers Vol.21 No.12

In this work, four novel, high fixation reactive dyes containing cationic groups were synthesized using maminophenyltrimethylammoniumsalt or 4-(ethylsulfurate sulfonyl) aniline as the diazo component, 3-(N,N-diethylamino)acetanilide or 3’-aminoacetanilide as the coupling component and m-aminophenyltrimethylammonium salt or N-(2-aminoethyl)pyridinium chloride as the cationic group. The synthesized dyes containing multiple cationic groups were characterized by FTIRand 1H-NMR spectroscopy. The spectral properties were measured by UV-Vis absorption spectroscopy. Compared withconventional reactive dyes containing cationic groups, the synthesized dyes exhibited good water solubility uponintroduction of a quaternary ammonium into the chromophore. The structural design of synthetic azo dyes allows enhancedthe water solubility due to the introduction of a cationic group. The dyeing properties of the synthesized dyes to cotton fabricwere explored at various temperatures and salt and alkaline concentrations. The results showed that the synthesized dyespossessed good dyeing properties with nearly 80% fixation and good color fastness on cotton (3-5) in the absence of salt. Thesuccess of the salt-free dyeing of cotton fabric with these dyes is an excellent example of environmentally friendly cottondyeing. This study provides an important platform for the design of novel reactive dyes for cotton dyeing to reduce effluentpollution.

Efficient Removal of the Organochlorine Pesticide and Heavy-Metal Residues in Epimedium brevicornum Maxim by Supercritical Fluid Extraction

Chunjie Zhao,Lu Bai,Huanxin Li,Fei Li,Chunhong Xin 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.12

A method involving depuration of 12 organochlorine pesticides (OCPs) and 7 heavy metals from Epimedium brevicornum Maxim was developed using supercritical fluid extraction (SPE). The pesticides in the study consisted of α, β-, γ-, and δ-Benzene hexachloride, Pentachloronitrobenzene (PCNB ), Pentachloroaniline (PCA), Heptachlor (HEPT), Methyl -pentachlorophenyl sulfide (MPCPS), pp'-DDE[1,1-dichloro-2, 2-bis (p-chlorophenyl) ethylene], op'-DDT [1,1,1- trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane], pp'-DDD [1,1-dichloro-2-2-bis(p-chlorophenyl)] ethane, pp'-DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane]. A series of experiments was conducted to optimize the final extraction conditions as following: pure CO2, extraction pressure of 15 Mpa, extration temperature of 60oC, extraction time of 10 min, flow rate at 55 kg/h. A GC method with electron capture detection was employed to determination of the OCPs, and an atomic absorption spectrometry (AAS) was designed for the determination of 7 heavy metals including of Pb, Cd, Cu, Fe, Zn, As, Hg in Epimedium brevicornum Maxim. A HPLC method was developed for the quantitative determination of active constituents. The SFE was used to remove the organochlorine pesticide and heavy metals from Epimedium brevicornum Maxim, receiving high decontamination rate of pesticide residue and low loss of active constituents.

An improved unified description of charge-carrier mobilities in disordered organic semiconductors

Liguo Wang,Huaiwu Zhang,Xiaoli Tang,Chunhong Mu,Jun Li 한국물리학회 2010 Current Applied Physics Vol.10 No.4

An improved unified description of the dependence of the charge-carrier mobility on temperature, carrier density, and electric field in disordered organic semiconductors is proposed based on the Arrhenius temperature dependence ln(μ) ∝ / 1=T and non-Arrhenius temperature dependence ln(μ) ∝ / 1=T2. The improved description of the mobility can quite well fit the numerical solution of the master equation at both the low densities and high densities, the latter of which cannot be accurately described using the model introduced by Pasveer et al. [6]. Experimental current–voltage characteristics in devices based on organic semiconductors are also excellently reproduced with this improved description. Finally, we calculate and analyze the distribution of the charge-carrier density and electric field with position in polymer layer for two organic semiconductors in detail by using the improved description.

Photocatalytic Degradation Mechanism of Tetracycline by Ag@ZnO/C Core–Shell Plasmonic Photocatalyst Under Visible Light

Longbao Yu,Zhefei Ye,Jinze Li,Chunhong Ma,CHANGCHANG MA,XINLIN LIU,Huiqin Wang,Lili Tang,Pengwei Huo,Yongsheng Yan 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.6

A series of hamburger-like Ag@ZnO/C core–shell plasmonic photocatalysts have been synthesized via a simple solvothermal method for degradation of tetracycline (TC) under visible light irradiation, possessing high photocatalytic activity and good stability. The presence of localized surface plasmon resonance (LSPR) in the Ag core has increased the photocatalytic activity over an extended wavelength range. The plasmon-induced resonant energy transfer (PIRET) and direct electron transfer (DET) have facilitated the excitation and separation of photogenerated e-/h+pairs, which has been further confirmed by electrochemical investigations. The presences of hydroxyl radicals ( ·OH), superoxide radicals ( · O-2) and singlet oxygen (1O2) in the photocatalytic reaction system of Ag@ZnO/C photocatalyst have been demonstrated by electron spin resonance (ESR) measurements. All of the experiment results indicate that the ternary structure of Ag@ZnO/C can effectively enhance the photocatalytic activity. Furthermore, the effects of introduced Ag contents and carbon source dosage were researched by comparative photocatalytic experiments, and the potential structures of photodegradation products were studied by HPLC-MS.

Effect of curing mechanism on sulfuric acid corrosion resistance of geopolymer recycled aggregate concrete

Zhenmeng Chen,Hui Liu,Pinghua Zhu,Haichao Li,Tianze Ge,Lei Yang,Chunhong Chen,Yanlong Dong 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.4

To explore the effect of curing mechanism on the mechanical properties and sulfuric acid corrosion resistance of the geopolymer recycled aggregate concrete (GRAC), the specimens were cured at high temperature (60oC, 80oC) for 6 h, 24 h and 48 h respectively, and then lasted up to 7 d at room temperature. After the curing period was over, the laboratory accelerated simulation test of specimens was carried out by the periodic immersion method: the GRAC specimens (φ 50 × 100 mm) were immersed in the sulfuric acid solution with pH = 1 for 5 d and then dried at room temperature for 24 h, with a total circulation of 90 d. The results showed that after being eroded by sulfuric acid solution, the GRAC specimens cured at 60oC for 48 h had higher compressive strength with 19.9 MPa, lower mass loss rate (only 0.23%) and neutralization depth (5.71 mm) than those under other curing time. The GRAC specimens cured 80oC for 24 h also had a good performance: compressive strength achieved 16.9 MPa and had lower neutralization depth (5.99 mm), which was less affected by sulfuric acid corrosion. However, the GRAC specimens cured at 60oC for 48 h had the better mechanical properties than that cured at 80oC for 24 h. Excessive high temperature curing (80oC) would lead to more voids and microcracks inside GRAC, and destroy the dense structure, thereby reducing mechanical property of concrete. These voids and pores provided more erosion channels for sulfuric acid solution, which accelerated the corrosion rate. From the point of view of energy saving and concrete performance, no more than 60°C of curing temperature is recommended for industrial use.