Journal of Environmental Chemical Engineering
·
2021
·
IF 5.909
Wanying Xie,Ji Li,Feiyun Sun,Wenyi Dong,Zijun Dong
Aiming at the fouling problem of PVDF membrane, one novel integrated strategy was used for the first time, including hydrophilic membrane modification and low-pressure operation. Permeability and anti-fouling ability of PVDF were simultaneously improved by nano-TiO 2 embedment. From perspective of operating condition optimization, the concepts of critical flux (J C ) and threshold flux (J TH ) were recommended as fouling-control tools. The J C and J TH of PVDF-TiO 2 membrane were tested by two constant pressure-steps methods, i.e. Constant pressure-step method and Alternating constant pressure-step method. Three indicators, consisting of instant FTTT curves, dFlux/dt condition and TMP-Flux ave curve, were employed to evaluate the J C and J TH of PVDF-TiO 2 membrane. In brief, the J C and J TH of PVDF-TiO 2 were 10.62 and 23.91 L/(m 2 ·h), respectively, which were nearly 3 times of PVDF membrane. Fouling resistance results displayed that protein irreversible fouling of two PVDF membranes were effectively reduced by J C mode and J TH mode. Besides, reversible fouling of PVDF-TiO 2 membrane was controlled well by J C mode meanwhile. The pure water filtration line (PWF line) and the normalized resistance were both used to judge the form of J C of two membranes. As compared with PVDF, it was speculated the enhancement of J C and J TH mainly related to the better hydrophilicity and local hydraulic condition of PVDF-TiO 2 modified membrane.
研究领域:
环境科学
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材料科学
·
生物工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2021
·
IF 7.033
Jianan Chen,Jun Zhu,Wentao Xu,Yi Chen,Jicheng Zhou
Highly efficient H 2 and S production from copious waste H 2 S is beneficial from both environmental and energy. Whereas, the highly effective direct decomposition of H 2 S reaction faces a gigantic obstacle, that is, there is the severe thermal equilibrium limitation. Herein, a family of TiO 2 modified Mo x C as novel microwave catalysts have been developed. This work demonstrates that Mo 2 C, Mo 2 C-TiO 2 and MoC@TiO 2 microwave catalysts display excellent catalytic performance to recover both valuable H 2 and elemental S from the direct decomposition of H 2 S under microwave irradiation . The optimal H 2 S conversion of MoC@TiO 2 can be as high as 99.9% (almost complete conversion) at 700 °C, which greatly outpaces the corresponding H 2 S equilibrium conversion under microwave irradiation . This result of the chemical equilibrium limitation being broken shows an interesting phenomenon, namely a significant microwave selective catalytic effect by microwave catalysis in H 2 S decomposition reaction . In addition, the apparent activation energy of the Mo 2 C, Mo 2 C-TiO 2 and MoC@TiO 2 microwave catalysts reduced to 18.2 kJ/mol, 16.8 kJ/mol and 15.6 kJ/mol under microwave irradiation. The work supplies a strategy for highly effective valuable H 2 and S production from H 2 S decomposition reaction , and paves a path to high-value utilization of hazardous waste H 2 S resources with energy-saving heating method.
研究领域:
化学工程
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环境科学
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能源科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
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2018
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IF 3.525
Pengwei Wang,Xin Zhang,Guofeng Zhao,Ye Liu,Yong Lu
Mn 2 O 3 -Na 2 WO 4 /SiO 2 is considered as the most promising catalyst for the oxidative coupling of methane (OCM) process; however, it only has a better catalytic performance over 800 °C. To improve its low-temperature performance, an attempt has been made to modify the Mn 2 O 3 -Na 2 WO 4 /SiO 2 catalyst using TiO 2 , MgO, Ga 2 O 3 , and ZrO 2 . Among the synthesized catalysts, the TiO 2 -modified Mn 2 O 3 -Na 2 WO 4 /SiO 2 catalyst shows markedly improved low-temperature OCM performance, achieving a high CH 4 conversion of ~23% and a good C 2 -C 3 selectivity of ~73% at 700 °C (the catalyst bed temperature), along with promising stability for at least 300 h without signs of deactivation. In comparison with the unmodified Mn 2 O 3 -Na 2 WO 4 /SiO 2 catalyst, the TiO 2 modification results in significant improvement in the low-temperature activity/selectivity, whereas the MgO modification has almost no impact and the Ga 2 O 3 and ZrO 2 modifications have a negative effect. The X-ray diffraction (XRD) and Raman results reveal that the formation of a MnTiO 3 phase and a MnTiO 3 -dominated catalyst surface is crucial for the improvement of the low-temperature activity/selectivity in the OCM process.
研究领域:
化学工程
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催化科学
✓ 已验证
DOI
高影响因子
Sustainable Energy & Fuels
·
2019
·Vol. 3
·期 11
·3234-3243
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IF 4.912
Shiyi Deng,Yunjiao Li,Qiongyu Dai,Jiamin Fu,Yongxiang Chen,Junchao Zheng,Tongxing Lei,Jia Guo,Jing Gao,Wei Li
The elevation of energy density is the constant pursuit of the lithium-ion battery industry. LiNiO2 has reacquired recognition because it exhibits high capacity without an increase in the cut-off voltages. To address the flaws of this kind of cathodes, herein, trace nano-TiO2-modified LiNiO2 was synthesized via a simple solid-state method. Via combined characterization, the Ti element was verified to be doped into the bulk lattice and located at the transition-metal sites; after Ti doping, the Ni2+ content was clearly increased due to charge balance, followed by an increase in the Li/Ni disorder. The doped Ti and the as-generated Ni pillar mutually facilitated the stabilization of the material structure and benefitted the Li+ de/insertion. Nanosized TiO2 participating in the calcination process could effectively homogenize the size of the primary particles, adjust the surface morphology and reduce the specific surface area of the material. This morphological regulation may be favorable for reducing the contact area of the cathode with the electrolyte and establishing a stable electrode/electrolyte interface, where some detrimental side-reactions take place. With respect to electrochemical properties, Ti doping could decrease the electrode polarization, lower the impedance and promote the Li+ transfer. As a result, the Ti-modified LiNiO2 cathodes, especially the 0.2% Ti-doped (Ti-2) material, presented enhanced electrochemical performances.
研究领域:
材料科学
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能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
Coatings
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2020
·Vol. 10
·期 2
·179
·
IF 2.436
Hui Shu,Ming Yang,Qiang Liu,Maobin Luo
Coating materials can effectively protect stone-built cultural heritage and, as such, research into coating materials has gained comprehensive attention from researchers. The aim of this work is to prepare a TiO2-modified sol coating material (TSCM) and study its protective effects on stone-built cultural heritage. TSCM and pure TiO2sol (p-sol, unmodified; for comparison) were applied evenly over the entire surface of stone samples. The prepared stone samples included untreated stone, stone treated with pure sol, and stone treated with TSCM. The protective effects of TSCM were evaluated by water absorption, water vapor permeability, acid resistance, and weather resistance experiments. The results show that stone treated with TSCM has excellent water absorption and water vapor permeability, strong acid resistance, and good weather resistance, compared with untreated stone or stone treated with p-sol. The acid resistance of stone treated by TSCM was 1.75 times higher than that treated with traditional coating materials. The weather resistance cycle number of stone treated by TSCM was four times higher than that treated with organic protective materials. These findings are expected to provide useful suggestions for the protection of stone-built cultural heritage.Keywords:stone-built cultural heritage protection;TiO2-modified sol;coating material;weather resistance;acid corrosion resistance
研究领域:
材料科学
·
文物保护
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Tong Zhang,Fan-xin Kong,Xi-chen Li,Qian Liu,Jin-fu Chen,Chun-mei Guo
Polysulfone ultrafiltration (UF) and polypiperazine-amide nanofiltration (NF) membranes were first fabricated by phase inversion and interfacial polymerization, and then modified by the commonly used TiO 2 on the membrane surface, respectively. Compared with the pristine UF and NF membranes, pure water flux decreased by 40.66% for modified UF membrane and 12.92% for modified NF membrane, while the contact angle of the modified membranes decreased from 66.5° to 35.3° for UF membrane and from 48.2° to37.7° for NF membrane. However, the membrane modified by TiO 2 nanoparticles for both UF and NF membranes exhibited much better anti-fouling and separation performance for two types of oil-in-water emulsions with different droplet size (i.e., prepared oil-in-water emulsion with low salinity and oil produced water in Shengli oilfield, China). It was obvious that water flux of modified UF only slightly decreased and the stable water flux was 2.2 times and 15.6% higher than that of pristine membranes for the prepared oil-in-water emulsion and produced water, respectively. According to the five fouling models for UF, the TiO 2 modified UF membrane could alleviate the fouling on membrane surface and greatly increase water flux by reducing the adsorption, deposition, blockage of membrane pores and formation of cake layer for two types of oil-in-water emulsion. For NF, water flux of the modified membrane increased by 66.1% and 22.8% for prepared oil-in-water emulsion and produced water, respectively. TiO 2 coating effectively alleviated the oil adhesion and cake layer formation on the membrane surface.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）