ENVIRONMENTAL POLLUTION
·
2017
·
IF 5.099
Guoyang Zhang,Bingdang Wu,Shujuan Zhang
Acetylacetone (AcAc) has proven to be a potent photo-activator in the degradation of color compounds. The effects of AcAc on the photochemical conversion of five colorless pharmaceuticals were for the first time investigated in both pure and natural waters with the UV/H 2 O 2 process as a reference. In most cases, AcAc played a similar role to H 2 O 2 . For example, AcAc accelerated the photodecomposition of carbamazepine, oxytetracycline , and tetracycline in pure water. Meanwhile, the toxicity of tetracyclines and carbamazepine were reduced to a similar extent to that in the UV/H 2 O 2 process. However, AcAc worked in a way different from that of H 2 O 2 . Based on the degradation kinetics, solvent kinetic isotope effect , and the inhibiting effect of O 2 , the underlying mechanisms for the degradation of pharmaceuticals in the UV/AcAc process were believed mainly to be direct energy transfer from excited AcAc to pharmaceuticals rather than reactive oxygen species-mediated reactions. In natural waters, dissolved organic matter (DOM) played a crucial role in the photoconversion of pharmaceuticals. The role of H 2 O 2 became negligible due to the scavenging effects of DOM and inorganic ions. Interestingly, in natural waters, AcAc first accelerated the photodecomposition of pharmaceuticals and then led to a dramatic reduction with the depletion of dissolved oxygen. Considering the natural occurrence of diketones, the results here point out a possible pathway in the fate and transport of pharmaceuticals in aquatic ecosystems .
研究领域:
环境科学
·
药理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Ke Xiang,Zhen-Liang Xu,Yong-Jian Tang
Recent studies have shown that the temperature and time of the heat curing process have important effects on the nanofiltration (NF) membrane structure and properties. However, the mechanism of the relative humidity (RH), as one of the important factors in the heat curing of NF membranes, is still unclear. To analyze the specific effect of RH, we compared the heat curing results of the NF polyamide (PA) membranes fabricated with different monomer concentrations at various RH. The nanofiltration performance of the membranes appeared to be non-uniform when the RH was in the range of 40 %–60 %. Within the appropriate RH range , the rejection of Na 2 SO 4 was preserved at about 98.5 % for the manufactured NF membranes. At high concentrations, the increasing RH created a discontinuous condensate layer on the PA layer surface, which affected the morphology and physicochemical properties of the NF membrane causing a doubling of pure water permeability (PWP) to 8.33 L m −2 h −1 ·bar −1 . At low concentrations, the PA layer was not significantly changed with the increase of RH, but the evaporation of water from the smaller capillary pores in its PES substrate was slowed down, which reduced the capillary stress on the substrate and prevented the collapse of the substrate pore size, resulting in a nearly 20 times increase in its PWP to 39.7 L m −2 h −1 ·bar −1 . This work reveals the effect of RH during heat curing and gives significant guidance to the design and synthesis of high-performance NF membranes.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 89
·48317-48321
·
IF 3.708
Yun Yu,Weimin Hou,Xuebing Hu,Yang Yu,Le Mi,Lixin Song
A novel superhydrophobic Al2O3 microfiltration membrane was prepared by the layer-by-layer assembly of TiO2 coating with subsequent fluorination grafting surface treatment by 1H,1H,2H,2H-perfluorodecyltriethoxysilane. The influence of surface morphology on membrane superhydrophobicity, pore size diameter distributions and pure water permeability of the different membranes were studied. By optimizing the grafting parameters, a needle-like surface of grafted TiO2-coated Al2O3 membrane with a water contact angle of 169.5° was obtained. The pure water permeability of different membranes varied from 100 l m−2 h−1 bar−1 before grafting to 3–5 l m−2 h−1 bar−1 after grafting, and the grafted superhydrophobic membrane showed excellent water repellence. The novel superhydrophobic membrane is shown to be promising for liquid–liquid and gas–liquid separation.
研究领域:
材料科学
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 67
·62186-62192
·
IF 3.289
Jianjian Cai,Shouyong Zhou,Yijiang Zhao,Ailian Xue,Yan Zhang,Meisheng Li,Weihong Xing
The hydrophilicity of a thermo-responsive PVDF/palygorskite-g-PNIPAAM hybrid ultrafiltration membrane was enhanced via surface segregation induced by coagulation bath temperature (CBT). The N1s content of the hybrid ultrafiltration membranes prepared at 5 and 20 °C is 1.77% and 1.02%, respectively while that of the membrane prepared at 40 °C is just 0.73%. This indicated that the PNIPAAM chains could be dragged to the membrane surfaces or pores via surface segregation induced by temperature. This resulted in higher hydrophilicity and permeability as well as thermo-responsiveness for membranes prepared at lower temperatures. The initial water contact angle of the PVDF/palygorskite-g-PNIPAAM hybrid ultrafiltration membrane prepared at 5 and 20 °C is 75.2° and 75°, respectively, which is about 6° lower than the one prepared at 40 °C. A higher pure water flux (PWF) of about 366 L m−2 h−1 at 40 °C was obtained for the hybrid membrane prepared at 5 °C while the one prepared at 40 °C only reached 274 L m−2 h−1. Meanwhile, membranes prepared at low temperature exhibited fewer macrovoids, lower membrane thickness and larger elongation.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Chemistry
·
2025
·
IF 14.9
Rui Xue,Shu Yuan,Rongyi Wang,Tianzi Bi,Guiru Zhang,Huiyuan Li,Jiewei Yin,Liuxuan Luo,Shuiyun Shen,Xiaohui Yan,Junliang Zhang
With the development of renewable energy, electrochemical carbon dioxide reduction reaction (CO 2 RR) has become a potential solution for achieving carbon neutrality. However, until now, due to issues with salt precipitate and regeneration of the electrolyte, this technology faces challenges such as difficulty in maintaining long-term stable operation and excessive costs. The pure water CO 2 electrolyzers are believed to be the ultimate solution to eliminate the salt depreciation and electrolyte issues. This study develops an in-situ method tailored for CO 2 reduction in pure water. By employing distribution of relaxation times (DRT) analysis and in-situ electrochemical active surface area (ECSA) measurements, we carried out a comprehensive investigation into the mass transport and electrochemical active surface area of gas diffusion electrodes (GDE) under pure water conditions. The maximum 89% CO selectivity and high selectivity (>80%) in the range of 0–300 mA/cm 2 were achieved using commercial Ag nanoparticles by rational design of catalyst layer. We found that ionomers influence the CO 2 electrolyzers performance via affecting local pH, GDE-membrane interface, and CO 2 transport, while catalyst loading mainly influences the active area and CO 2 transport. This work provides benchmark and insights for future pure water CO 2 electrolyzers development.
研究领域:
能源科学
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2024
·Vol. 12
·期 29
·18204-18213
·
IF 10.7
Qingsheng Zhang,Shuya Yuan,Huabing Yin,Jianjun Yang,Zhongjie Guan
The photocatalytic pure water splitting performance of photocatalysts is still restricted by the low utilization efficiency of photogenerated holes. Recent studies suggest that metal oxide clusters can efficiently abstract holes from a bulk photocatalyst via discrete energy bands. However, the decay dynamics of excited states in such a heterostructure have not been explored. Herein, ultra-small CoOx clusters decorated on ZnIn2S4 (ZIS) are prepared for pure water splitting. Experimental characterization studies confirm that CoOx clusters efficiently capture holes from ZnIn2S4, thus inhibiting charge recombination. Femtosecond transient absorption spectroscopy (fs-TAS) reveals that the lifetime of holes trapped by CoOx clusters is prolonged to 911.6 ps, enabling more opportunities to participate in the surface reaction. Moreover, density functional theory calculation suggests that the CoOx cluster is the preferential adsorption site for H2O to boost surface water oxidation. Benefiting from the above factors, the optimized CoOx/ZIS shows improved H2 and H2O2 evolution rates of 404.1 μmol g−1 h−1 and 371.9 μmol g−1 h−1 under visible light irradiation, respectively, which are about ten times higher than that of pure ZIS. The study highlights the significance of efficient hole extraction for improving photocatalytic pure water splitting performance.
研究领域:
材料科学
·
光催化
·
能源转换
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2020
·Vol. 27
·期 4
·1241-1251
·
IF 2.183
Huang Siqi,Wu Xiaoxu,Li Zhi,Shi Long,Zhang Yan,Liu Qiong
In this work, monolithic silica aerogels were prepared in pure water within 4 h by using MTMS as the precursor under ambient pressure drying (APD). The effects of the volume ratio of H 2 O/MTMS, CTAB content and NH 3 ·H 2 O concentration on the properties of MTMS-based aerogels (MSA) were investigated experimentally. The realization of the rapid synthesis of MSA under APD is attributed to getting rid of the aging process, solvent exchange and surface modification. It demonstrates that the microstructure of MSA is comprised of coralloid branches. Furthermore, the greater volume ratio of H 2 O /MTMS, larger CTAB content and smaller NH 3 ·H 2 O concentration cause relatively slimmer coralloid branches, smaller pores and weakened connectivity of skeletons. It also finds that the MSA with a greater volume ratio of H 2 O/MTMS presents larger Young’s modulus and smaller compressive stress, which is because of the correspondingly different microstructures. The as-prepared MSA shows a low density of 0.064 g/cm 3 and a contact angle as high as 143.4°, which provides their potentials for some engineering applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2016
·
IF 5.557
Dong Zou,Minghui Qiu,Xianfu Chen,Yiqun Fan
Compared to the traditional separation technology, membrane separation is particular beneficial for the treatment of contaminated fresh water such as agricultural runoff, and hydraulic fracturing wastewater. However, the development of cost-effective membranes with both high permeability and high rejection performance is still a challenge. In this study, we design one-step preparation of high-performance bi-layer α-alumina ultrafiltration (UF) membranes supported on coarse tubular substrates via co-sintering process. In this approach, boehmite sol and alumina nanoparticles were mixed in different ratios for the fabrication of microfiltration (MF) layer and UF layer, respectively. The effects of dip-coating dispersion formulation, coating time and thermal treatment process on the membrane microstructure and performance were comprehensively investigated. It was found that the presence of boehmite sol in the MF layer could accelerate its sintering process, while the addition of alumina nanoparticles into UF layer could promote the phase transition from γ phase to α phase at low temperature and retard the shrinkage. The optimized doping content of boehmite and alumina nanoparticles were 2 wt% and 4 wt% to achieve a good match of thermal expansion properties between the two co-sintering layers. For MF layer and UF layer, the membrane thickness were controlled to be 40–50 µm and about 1 µm, respectively. After co-sintering at 1000 °C for 2 h with a heating rate and cooling rate of 0.5 °C/min, tubular α-alumina UF membranes were found to display a high pure water permeability of 70 L m -2 h -1 bar -1 and a small pore size of ~5 nm, which also exhibited good dye removal capabilities in the process of treating dye waste water.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
·
2022
·
IF 5.431
Zhen Yang,Yuanpeng Yao,Huiying Wu
Surfactants are often used as additives to stabilize the dispersed phase of the water-based multicomponent fluids (such as non-azeotropic emulsion) for enhancing the boiling process, but their effects on the boiling heat transfer of water are still not clear. In this paper, a pool boiling experiment is designed to investigate the specific effects of surfactants (Tween20 (Polysorbate 20), Span20 (Arlasel 20), and Tween20-Span20 mixture) on the subcooled boiling heat transfer characteristics of pure water. The experimental results are analyzed by considering the influences of addition type and concentration of surfactant as well as the applied heat loads. It is found that: (1) Tween20 can achieve excellent boiling enhancing performance (decreasing the wall superheat by up to 10.4 °C and raising the boiling heat transfer coefficient by up to 13.4%) by increasing the number of nucleation sites. And the enhancement is improved with the increase of concentration when the heat flux is below a certain level, while it is weakened at high heat flux for Tween20 with a high concentration (1 mL L -1 ). The reason is that high concentration Tween20 results in an excessive increase of nucleation sites which prevents the return of working fluid and weakens the enhancement of heat transfer. (2) Span20 shows a boiling enhancement only when its concentration is 0.05 mL L -1 (lower than the CMC) among the test ones. Further increment in Span20 concentration (exceeding the CMC) leads to a large increase of wall superheat because it increases the viscosity of working fluid and deteriorates the heat transfer performance. (3) Tween20-Span20 mixture significantly aggravates the aforementioned boiling deterioration effect of Span20 (due to the reduced CMC for the mixture of Tween20 and Span20, weakening the heat transfer), and thus is not suitable for preparing boiling-heat-transfer-enhancing fluids. These results can provide a better understanding of surfactants and guide the practical preparation of multicomponent fluids for boiling heat transfer enhancement.
研究领域:
热力学
·
传热学
✓ 已验证
产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2023
·
IF 9.8
Yuhua Chen,Chengqi Feng,Chenkai Jin,Yuxin Zhu,Juncheng Huang,Haining Na,Jin Zhu
Pyruvaldehyde as a carbon source is synthesized together with boric acid to produce a carbon-based solid catalyst with in situ bifunctional groups of adsorptive boron hydroxyls and carboxyls in a single-step hydrothermal carbonization process, which is mainly utilized to induce the hydrolysis of cellulose to sugar in pure water. The obtained catalyst exhibits a strong adsorption capacity of 532 mg g−1 with cotton cellulose and possesses good water dispersibility. It can effectively break the aggregated structure of cellulose through the strong interfacial adsorption interaction to induce the hydrolysis of cellulose to sugar with high efficiency in the pure aqueous system. The cellulose conversion and the glucose yield reach 97.3% and 40.0%, respectively. Additionally, the catalyst demonstrates excellent hydrothermal stability and reusability. As a result, a high-yield, acid-free, green, and environmentally friendly hydrolytic process of cellulose to sugar in pure water is successfully established.
研究领域:
化学工程
·
可再生资源利用
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Mingjie Liu,Peipei He,Hantao Gong,Zhenghua Zhao,Yueming Li,Kai Zhou,Yuemin Lin,Jing Li,Zongbi Bao,Qiwei Yang,Yiwen Yang,Qilong Ren,Zhiguo Zhang
Direct synthesis of hydrogen peroxide (H 2 O 2 ) using oxygen and water through the photocatalytic route is a prospective approach for the on-site production of H 2 O 2 . However, the limited varieties of photocatalytic sites and ambiguous structure-active relationship impede the development of environmentally friendly technology. Herein, we report a active compound (benzotrithiophene, BTT) for the photosynthesis of H 2 O 2 using oxygen and water, and design four benzotrithiophene-based 2D covalent organic frameworks (BTT-COFs) linked with aromatic amines linkers. Significant enhancement in photocatalytic activity has been observed via the introduction of BTT struct into 2D COFs. The high crystallinity of COFs increases the visible light absorption ability and photostability of BTT. The suitable distance of BTT struct in COFs and the construction of donor–acceptor (D-A) structure further promote the carrier generation and transfer. The COF-BTT-TAPT exhibited the highest H 2 O 2 production rate of 620 μmol g −1 h −1 . Mechanism investigation experiments have given the validation that BTT-COFs efficiently reduce oxygen in pure water to form H 2 O 2 under visible-light irradiation. This work paves a revolutionary way for designing and fabricating high-performance metal-free photocatalysts for visible-light-driven H 2 O 2 production.
研究领域:
材料科学
·
环境科学
·
化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING RESEARCH & DESIGN
·
2024
·
IF 3.7
Yunwu Yu,Yan Wu,Yong Yuan,Yan Wang,Changwei Xu,Yanfeng Fang,Yaxin Gu,Peng Liu,Ye Wan,Lihua Wang,Xiaowei Sun
Based on the previous study, the properties, separation efficiencies, and anti-fouling performances of TiO 2 nanoparticle embedded PEEKWC/PEI cross-linked ultrafiltration membrane made via non-solvent-induced phase separation were investigated. SEM, contact angle measurement , ATR-FTIR, and other methods were used to characterize the membranes, and then the pure water flux (PWF) and dye rejection were measured. The TiO 2 nanoparticle embedded PEEKWC/PEI cross-linked ultrafiltration membranes were prepared by stepwise solution blending method. Compared to the pristine PEEKWC/PEI cross-linked ultrafiltration membrane, the anti-fouling and pure water flux performances were enhanced as the addition of TiO2 nanoparticles. The pure water flux of TiO 2 nanoparticle embedded membranes was significantly increased and could even reach 3368.2 LMH at 5 bar much greater than that of the pristine PEEKWC/PEI ultrafiltration membrane (1423.8 LMH), remaining a retention rate for BBR higher than 98.5%. And the TiO 2 nanoparticle embedded PEEKWC/PEI cross-linked ultrafiltration membranes exhibited a certain degree of increase of FRR (higher than 80%) after UV illumination. After a series of characterisation, the dye wastewater treatment property of membranes was assessed through filtration of Coomassie brilliant blue and Congo red solutions and researches were conducted on the anti-fouling capabilities of membranes. The TiO 2 nanoparticle embedded PEEKWC/PEI cross-linked ultrafiltration membranes exhibited self-cleaning efficiency with lower irreversible fouling ratio. The pure water flux recovery ratio following dye fouling was higher after being exposed to UV irradiation, which could be attributed to the TiO 2 nanoparticles' photocatalytic destruction of organic pollutants .
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）