查找使用阿拉丁产品的科研文献

Effect of different ash/organics and C/H/O ratios on characteristics and reaction mechanisms of sludge microwave pyrolysis to generate bio-fuels

Juan Luo,Junhao Lin,Rui Ma,Xing Chen,Shichang Sun,Peixin Zhang,Xiangli Liu

To study the effects of different ash/organics and C/H/O ratios on bio-fuel characteristics and energy efficiency, four kinds of sludge with different properties were used for microwave pyrolysis (800 °C). Moreover, the microwave pyrolysis reaction mechanisms of different sludge were also explored. The results showed that high-ash sludge could accelerate the frequency of polar molecule rotation in the microwave field due to the presence of oxides with dielectric properties in ash, thereby achieving faster heating rates and higher temperatures. However, compared with high-organic sludge, high-ash sludge exhibited lower bio-gas yield and higher bio-char yield. As the H/C ratio increased from 0.127 to 0.148, the bio-gas yield increased from 15.41% to 40.01%, and the content of H 2 in bio-gas and aliphatics in bio-oil increased to 36.69 vol% and 26.54 wt%, respectively. When the O/C ratio was reduced to 1.31, the content of CO and oxygenated compound in bio-oil increased to 31.25 vol% and 40.04 wt%, which lowered the quality of the bio-oil. Those consequences also determined that a mixture of sludge with different ash/organic ratios could be pyrolyzed to obtain high-quality bio-fuels and high energy efficiency. Differences in C/H/O ratios in the mixed sludge greatly affected the microwave pyrolysis heating process, which affected the pyrolysis reactions and the quality of the bio-fuels. Therefore, this study provides a theoretical basis to elevate the quality of bio-fuels and reduce microwave pyrolysis costs.

Highly Efficient Purification of Multicomponent Wastewater by Electrospinning Kidney-Bean-Skin-like Porous H-PPAN/rGO-g-PAO@Ag+/Ag Composite Nanofibrous Membranes

Na Han,Weijing Wang,Xingshuai Lv,Wenxin Zhang,Chao Yang,Menglu Wang,Xiaohui Kou,Wei Li,Ying Dai,Xingxiang Zhang

Due to the complexity of harmful wastewater components, environmental and multifunctional materials are required for sewage purification. In this paper, a novel kidney-bean-skin-like hydrophilic porous polyacrylonitrile/reduced graphene oxide-g-poly(amidoxime)-loaded Ag+ (H-PPAN/rGO-g-PAO@Ag+/Ag) composite nanofiber membrane was fabricated by combining electrospinning and hydrolysis methods. The spinning solution was pumped at a rate of 0.4 mL/h with the voltage set at a constant value of 23 kV. Then, some of the −CN groups switched to hydrophilic −COOH groups via a hydrolysis method, which acts as a linker of GO-g-PAN, Ag+, and the polyacrylonitrile (PAN) matrix. A further step of chelation and thermal treatment were used for generating Schottky junctions between rGO-g-PAO@Ag+ and Ag. After five-cycle tests, it exhibited outstanding mechanical properties ensuring the filtration and purification performance of the H-PPAN/rGO-g-PAO@Ag+/Ag composite nanofiber membrane (i.e., the tensile strength was still 7.21 MPa, and the elongation was 61.53%) for simulated wastewater. The methods of thermal treatment and high-pressure Hg lamp irradiation promoted the reduction of GO to rGO and Ag+ to Ag particles, which endows the final product H-PPAN/rGO-g-PAO@Ag+/Ag with excellent photocatalytic and bactericidal properties. Its catalytic efficiency for dyes benzoic acid (BA), Rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) was up to 99.8, 98, 95, and 91%. The antibacterial rate was 100% against Escherichia coli and 99% against Staphylococcus aureus. More importantly, the photocatalytic and antibacterial PAN-based nanofiber membrane can be simply scaled up, which provides the membrane with great potential in highly efficient wastewater treatment and augmenting water supply.

Effect of ${\rm H}_{2}$ on the Formation Mechanism and Magnetic Properties of FePt Nanocrystals

B. R. Bian,W. X. Xia,J. Du,J. Zhang,J. P. Liu,Z. H. Guo,A. R. Yan

Mixed matrix composite membranes comprising nanocage-like hollow ZIF-71(h) polyhedral nanocrystals in poly(ether-block-amide) membranes for phenol/water separation

Zhongming Zhang,Enfang Gou,Zhiying Zhao,Rui Wu,Rui Fang,Weipeng Guo,Jie Yao

Organophilic pervaporation (PV) mixed matrix membranes (MMMs) have enormous potential for organic wastewater treatment due to their environmental friendliness and high efficiency. However, developing a high-flux PV membrane remains challenging. In this work, the nanocage-like hollow ZIF-71(h) (HZIF-71(h)) polyhedral nanocrystals were synthesized by heteroepitaxial growth of a ZIF-71(h) shell and successive excavation of a ZIF-67 core. The resultant HZIF-71(h) nanocrystals were blended with poly (ether block amide) (PEBA) matrix to fabricate MMMs for phenol/water separation. Results from several characterization techniques confirmed the successful preparation and formation mechanism of HZIF-71(h). Further, a series of experiments were conducted using the composite membranes to explore the impact of filler type, filler loading, operating temperature, and feed concentration on the separation performance. The incorporation of ZIFs facilitated phenol permeation while limited water transport, thereby resulting in increased separation factor. Notably, the HZIF-71(h)/PEBA-21 MMM exhibits a higher phenol flux in comparison to ZIF-71/PEBA-21 and ZIF-67/PEBA-21 MMMs, indicating the importance of the low-resistance hollow structure. The HZIF-71(h)/PEBA-21 MMM exhibits outstanding pervaporation performance with a separation factor of 15.86 and a phenol flux of 17.32 g·m −2 ·h −1 , respectively, displaying an improvement of 41.2 % and 6.4 % compared to the PEBA/PVDF membrane. Furthermore, this composite membrane demonstrated outstanding durability during continuous testing for 84 h, implying a promising potential for phenol separation.

Mechanisms of cypermethrin degradation and remediation by Rhodococcus sp. H-3: Insights from comparative genomics, hydrolase CymE1 secretory expression, and bacterial community analysis

Guoqiang Zhao,Wenjing Chen,Rongrong Zhang,Rui Zhang,Bo Jiang,Ruyan Hou,Xing Huang

Cypermethrin, a common pyrethroid insecticide, raises significant ecological concerns due to its widespread use. In this study, a highly efficient cypermethrin-degrading strain, Rhodococcus sp. H-3, was isolated. The strain was capable of degrading 30 mg/L cypermethrin at the rate of 83.48 % within 7 days and it could hydrolyze cypermethrin into 3-phenoxybenzoic acid (3-PBA) and permethric acid (DCVA). A novel cypermethrin degradation gene, cymE1 , was identified in strain H-3 through genome analysis, and its highest level of amino acid sequence similarity observed was 33.50 % in the Swiss-Prot database. The functional strain, SCK6-E, which could secrete CymE1, was successfully constructed by using double-exchange strategies. Strain SCK6-E could be applied for the removal of cypermethrin residues from tea plant leaves with a removal rate of 57.83 % within 2 h. Furthermore, strain H-3 demonstrated the capability to remediate cypermethrin-contaminated soil, exhibiting a degradation rate of 65.80 % over 10 days. The results of the 16S rRNA high-throughput sequencing indicated that strain H-3 was conducive to the restoration of the diversity and richness of the bacterial community in the soil. This study provides novel strain and gene resources for researching the degradation mechanism of pyrethroids, and offers valuable insights for developing effective pesticide residue remediation strategies.

Novel cyclodextrin-modified h-BN@Pd(II) nanomaterial: An efficient and recoverable catalyst for ligand-free C-C cross-coupling reactions in water

Xiaojun Ma,Guanghui Lv,Xu Cheng,Weijian Li,Rui Sang,Yong Zhang,Qiantao Wang,Li Hai,Yong Wu

An environmentally friendly palladium(II) catalyst supported on cyclodextrin-modified h-BN was successfully prepared. The catalyst was characterized by FT-IR, SEM, TG, XRD and XPS, and the loading level of Pd in h-BN@β-CD@Pd(II) was measured to be 0.088 mmol g −1 by ICP. It exhibits excellent catalytic activity for the Suzuki and Heck reactions in water, and can be easily separated and consecutively reused for at least nine times. In addition, a series of pharmacologically interesting products were successfully synthesized using this catalyst to demonstrate its potential applications in pharmaceutical industries. Above all, this work opens up an interesting and attractive avenue for the use of cyclodextrin-functionalized h-BN as an efficient support for hydrophilic heterogeneous catalysts.

Injectable temperature-sensitive hydrogel system incorporating deferoxamine-loaded microspheres promotes H-type blood vessel-related bone repair of a critical size femoral defect

Yuwei Zeng,Chuang Huang,Dongming Duan,Aiju Lou,Yuan Guo,Tianhua Xiao,Jianguo Wei,Song Liu,Zhao Wang,Qihao Yang,Lei Zhou,Zenghui Wu,Le Wang

Insufficient vascularization is a major challenge in the repair of critical-sized bone defects. Deferoxamine (DFO) has been reported to play a potential role in promoting the formation of H-type blood vessels, a specialized vascular subtype with coupled angiogenesis and osteogenesis. However, whether DFO promotes the expression of H-type vessels in critical femoral defects with complete periosteal damage remains unknown. Moreover, stable drug loading systems need to be designed owing to the short half-life and high-dose toxic effects of DFO. In this study, we developed an injectable DFO-gelatin microspheres (GMs) hydrogel complex as a stable drug loading system for the treatment of critical femoral defects in rats. Our results showed that sustained release of DFO in critical femoral defects stimulated the generation of functional H-type vessels. The DFO-GMs hydrogel complex effectively promoted proliferation, formation, and migration of human umbilical vein endothelial cells in vitro. In vivo , the application of the DFO-GMs hydrogel complex expanded the distribution range and prolonged the expression time of H-type vessels in the defect area and was positively correlated with the number of osterix+ cells and new bone tissue. Topical application of the HIF-1α inhibitor PX-478 partially blocked the stimulation of H-type vessels by DFO, whereas the osteogenic potential of the latter was also weakened. Our results extended the local application of DFO and provided a theoretical basis for targeting H-type vessels to treat large femoral defects. Statement of significance Abundant functional blood vessels are essential for bone repair . The H-type blood vessel is a functional subtype with angiogenesis and osteogenesis coupling potential. A drug loading system with long-term controlled release was first used to investigate the formation of H-type blood vessels in critical femoral defects and promotion of bone repair. Our results showed that the application of DFO-GMs hydrogel complex expanded the distribution range and expression time of H-type vessels, and was positively correlated with the number of osteoblasts and volume of new bone tissue. These results expanded the local application approach of DFO and provide a theoretical basis for targeting H-type vessels to treat large femoral defects.

Nano-H-ZSM-5 with Short b-Axis Channels as a Highly Efficient Catalyst for the Synthesis of Ethyl Levulinate from Furfuryl Alcohol

Yafei Li,Shiqing Wang,Shunxin Fan,Babar Ali,Xiaocheng Lan,Tiefeng Wang

For the ethanolysis of biomass-derived furfuryl alcohol (FA) to value-added ethyl levulinate (EL), the development of an efficient solid acid catalyst is very important for industrial application with high FA concentration. Herein, a H-ZSM-5 catalyst with nano b-axis channels (NB-H-ZSM-5) was synthesized and used for the conversion of FA. Detailed catalyst characterization proved that the NB-H-ZSM-5 catalysts (Si/Al = 25∼125) with ∼70 nm b-axis channels were successfully prepared. The NB-H-ZSM-5 catalyst with Si/Al = 75 showed the highest activity. Its structural characteristics allowed for fast diffusion of reactants and products and full utilization of active sites, which endowed it with higher activity compared to commercial H-ZSM-5 (C-H-ZSM-5). Its moderate acidity effectively inhibited the polymerization of FA even at a high FA concentration of 20 wt %. The spent catalyst was easily regenerated by coke burn-off to give a good recyclability. Furthermore, based on the proposed reaction network, a method of physically mixing the NB-H-ZSM-5 (75) catalyst with a small amount of Amberlyst-15 was proposed to further increase the EL yield from 64.7 to 82.1% at an FA concentration of 6 wt %.

Electrosynthesis of Quinazolines and Quinazolinones via an Anodic Direct Oxidation C(sp3)-H Amination/C-N Cleavage of Tertiary Amine in Aqueous Medium

Zhenghong Zhou,Kangfei Hu,Jiawei Wang,Zhibin Li,Yan Zhang,Zhenggen Zha,Zhiyong Wang

An electrochemical synthesis for quinazolines and quinazolinones was developed via a C(sp3)-H amination/C-N cleavage by virtue of the anodic oxidation. The reaction can be carried out in aqueous media under mild conditions to afford the desired products with high yields. The reaction mechanism was proposed after detailed investigation.

Structural/surface characterization of transition metal element–doped H-ZSM-5 adsorbent for CH3SH removal: identification of active adsorption sites and deactivation mechanism

Xie Yuxuan,Peng Xiao,Song Xin,Ning Ping,Sun Xin,Ma Yixing,Wang Chi,Li Kai

CH 3 SH is a potential hazard to both chemical production and human health, so controlling its emissions is an urgent priority. In this work, a series of transition metal-loaded H-ZSM-5 adsorbents (Si/Al = 25) (Cu, Fe, Co, Ni, Mn, and Zn) were synthesized through the wet impregnation method and tested for CH 3 SH physicochemical adsorption at 60 °C. It was shown that the Cu-modified H-ZSM-5 adsorbent was much more active for CH 3 SH removal due to its abundant strong acid sites than other transition metal-modified H-ZSM-5 adsorbents. The detailed physicochemical properties of various modified H-ZSM-5 adsorbents were characterized by SEM, XRD, N 2 physisorption, XPS, H 2 -TPR, and NH 3 -TPD. The effects of metal loading mass ratio, calcination temperature, and acid or alkali modification on the performance of the adsorbent were also investigated, and finally 20% Cu/ZSM-5 was found to have the best adsorption capacity after calcined at 350 °C. Additionally, the Cu/ZSM-5 adsorbent modified by sodium bicarbonate could expose more active components, which improved the adsorbent’s stability. However, the consumption and reduction of the active component Cu 2+ and the accumulation of sulfate during the adsorption process are the main reasons for the deactivation of the adsorbent. In addition, the simultaneous purging of N 2  + O 2 can effectively restore the adsorption capacity of the deactivated adsorbent and can be used as a potential strategy to regenerate the adsorbent. Graphical

An innovative method for the removal of impurities and bleaching of cotton fabrics by UV/H₂O₂/pectinase: Intrinsic mechanisms and treatment effects

Ziying Guo,Yuting Zhou,Ping Wang,Qiang Wang,Bo Xu,Man Zhou,Li Cui,Ying Zhang,Yuanyuan Yu

The high energy consumption and pollution associated with traditional cotton fabric treatment have become increasingly serious concerns; thus, in this study, a synergistic cotton fabric treatment based on Novozymes pectinate lyase (NPL) scouring/ultraviolet light-mediated catalytic (UV/H 2 O 2 ) bleaching was innovatively proposed. This study investigated the degradation mechanisms of impurities in cotton fabrics, concluding that the oxidative bleaching reaction of morin follows first-order kinetics; in the UV/H 2 O 2 /NPL system, pectin degradation occurs through the β-elimination of NPL and oxidation by free radicals. Under optimized conditions—254 nm UV irradiation, 8 g⋅L −1 NPL, 30 g⋅L −1 H 2 O 2 , pH 9, and one-side irradiation for 45 min. The fabric whiteness could reach 79.04 %，but the fiber damage was severe, manifested by a 40 % decrease in polymerization and strength. After adjusting the process parameters, adjust the UV wavelength to 302 nm and add 6 g⋅L −1 of the activator (NOBS), whiteness of the fabric was about 76.7 % and strength retention rate was 96.38 %. This method overcomes the shortcomings of traditional pretreatment processes for cotton fabrics, under low temperature and alkaline conditions, low-strength damaged fabrics can be obtained, providing a new strategy for developing environmentally friendly pre-treatment processes for cotton fabrics.

An internal oxidant-directing strategy enabling transition metal-free C–S bond ligation

Yingying Zuo,Feng Xiong,Jing Zhao

Organic sulfur compounds have broad applications in biology, medicine and material sciences and intensive efforts have been devoted to developing mild and general C–S bond-forming methods. However, a mild, transition-metal-free, direct C–H bond functionalization method remains elusive. Here, we report the use of an internal oxidant-directing strategy to achieve this goal. The cascade reactions described here show excellent chemoselectivity and a wide substrate scope for both oxyamines and sulfenylation reagents. This study enlarges the synthesis toolbox for preparing structurally diverse sulfilimines under mild conditions.