FUEL
·
2018
·
IF 4.908
Cheng Chen,Dongxue Jin,Xinping Ouyang,Lisha Zhao,Xueqing Qiu,Furong Wang
The structure of lignin is one of the key factors affecting its depolymerization into phenolic monomers . Four lignin fractions with different molecular weight were obtained by using ultrafiltration membrane technology , and the characteristics of lignin factions with different molecular weight were determined by gel permeation chromatography (GPC), potentiometric titration , FT-IR and NMR. It is found that wheat alkali lignin with low molecular weight contained more content of phenolic hydroxyl , methoxyl function groups, and β-O-4 linkages, which was relatively prone to depolymerize into phenolic monomers with a higher yield, although the more content of carbonyl was reported to facilitate the depolymerization of lignin. With the increase of molecular weight of lignin, the depolymerization was more difficult, and the YMC decreased. Lignin fraction with low molecular weight was favorable for depolymerization into syringyl and alkyl syringyl, while the high molecular weight lignin was prone to depolymerize into guaiacyl and alkyl guaiacyl products. Boric acid was proved effective to avoid repolymerization and improve the YMC, and the dosage of boric acid was determined by the content of hydroxyl groups in lignin.
研究领域:
生物化学
·
材料科学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2018
·
IF 2.829
Xiaomei Wang,Xiang Mao,Jianhan Huang
Herein two hierarchical porous hyper-cross-linked polymers modified with phenolic hydroxyl ( OH) groups were synthesized and their adsorption was comparatively evaluated using aniline as the adsorbate. The results reveal that the phenolic OH groups are helpful for the equilibrium adsorption due to the increased polar matching by formation of acid-base complex and hydrogen bonding , and the hierarchical porosity is favorable for the kinetic adsorption because the three dimensional continuous mesopores facilitate the rapid diffusion of aniline. The original aniline solution is optimum for the adsorption and the molecular state of aniline is preferable. The maximum equilibrium capacity is predicted to be 184.8 mg/g by the Langmuir model, and the enthalpy change, Gibbs free energy change , and entropy change are calculated to be negative. The adsorption can reach equilibrium within 60 min, the kinetic data obey the pseudo-second-order rate equation and the first step of the adsorption is mainly controlled by the intra-particle diffusion model.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2016
·
IF 3.847
Yan-Na Han,Zong-Qing Bai,Jun-Jie Liao,Jin Bai,Xin Dai,Xiao Li,Jun-Li Xu,Wen Li
Oxygen functional groups as primary adsorption site of water are one of key factors controlling water re-adsorption and drying behaviors of brown coal . The dewatering energy of brown coal because of different oxygen functional groups is still unclear. Thus, two kinds of oxidized brown coal samples carrying more phenolic hydroxyl or carboxyl groups with similar pore structures were chosen. The concentrations of different water forms of the samples were determined from the moisture holding capacity at constant humidity and temperature and from the results of dewatering experiments analyzed by thermogravimetry coupled with differential scanning calorimetry . The results showed that the concentrations of three forms of water, i.e. free water, capillary water , and molecular water, showed good correlations with concentration of carboxyl groups. Comparison of 1 H NMR analysis of dried and moisturized samples showed that the types of oxygen functional groups predominantly affected the water environment in coal. IR spectra of dried and adsorbed D 2 O samples showed that OH–π hydrogen bond due to carboxyl groups was easier broken than that due to phenolic hydroxyl groups . The water desorption energy of primary site and dewatering energy of samples with more carboxyl groups were lower than that of samples with more phenolic hydroxyl groups, because hydrogen bonding energy of water bonded to hydroxyl oxygen of carboxyl groups was lower than that of water bonded to hydroxyl oxygen of phenolic hydroxyl groups.
研究领域:
能源科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2019
·
IF 3.206
Linli Hou,Yonghai Song,Yingjie Xiao,Rong Wu,Li Wang
Fluorescent metal-organic frameworks (MOFs) have attracted wide attention in fluorescence detection. Herein, a novel sensing platform for highly selective and sensitive detection of Fe 3+ in aqueous solution was proposed based on 2,5-dihydroxyterephthalic acid (DOBDC)-Zn 2+ MOFs (ZnMOF-74). The as-prepared ZnMOF-74 exhibited uniform clavicorn nanostructures and high day-to-day stability in acidic aqueous solution (pH 4.0). Because of the special response of phenolic hydroxyl groups of DOBDC with Fe 3+ , the cation exchange between Fe 3+ and Zn 2+ occurred, which caused collapse of the skeleton and formed a blue weak-fluorescent iron(III)-phenol salt complex (Fe-DOBDC), which led to the effective fluorescence quenching of ZnMOF-74. ZnMOF-74 was used as a probe for detection of Fe 3+ under relatively acidic condition with a good linear range of 0.1–100 μM and a low detection limit of 40 nM. The fluorescence probe was also applied to determine Fe 3+ in real river water and human serum with good recovery and accuracy. This work provided a good Fe 3+ sensor based on ZnMOF-74 due to high affinity between phenolic hydroxyl group and Fe 3+ .
研究领域:
材料科学
·
分析化学
·
环境科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2013
·
IF 2.596
De zhan Ye,Li Jiang,Chao Ma,Ming-hua Zhang,Xi Zhang
The influence of lignin species on the grafting mechanism of lignosulfonate (from eucalyptus and pine, recorded as HLS and SLS, respectively) with acrylic acid (AA) was investigated. The graft polymers were confirmed by the absorption of carbonyl groups in the FTIR spectra. The decreasing phenolic group's content (Ph-OH) is not only due to its participation as grafting site but also to the negative effect of initiator. In the initial period (0–60 min), HLS and SLS both accelerate the polymerization of AA. Additionally, Ph-OH group's content is proportional to product yield ( Y %), monomer conversion ( C %) and grafting efficiency (GE%), strongly indicating that it acts as active center. Nevertheless, compared with HLS, Y % and C % in SLS grafting system are lower though it has higher Ph-OH group's content, which is due to the quinonoid structure formed by the self-conjugated of phenoxy radical in Guaiacyl unit. Finally, the lignosulfonate grafting mechanism was proposed.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 61
·38691-38698
·
IF 3.108
Bin Li,Wubin Wu,Tianyong Zhang,Shuang Jiang,Xingwei Chen,Guanghui Zhang,Xia Zhang
UiO-66 with high dispersibility and a cuboctahedron morphology was synthesized by an improved solvothermal method. The morphology of UiO-66 was adjusted using benzoic acid as a modulator. UiO-66 with a regular morphology was then used as the support to load ferrocene (Fc). A series of Fc@UiO-66 composites were prepared via a facile impregnation method. The composites were characterized by powder X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), SEM/EDX mapping, FT-IR, UV/vis, TG analysis, N2 adsorption–desorption, and X-ray photoelectron spectroscopy (XPS). The results showed that Fc was incorporated into UiO-66, thus preventing the agglomeration of Fc particles in water. The Fc@UiO-66 composites with a Fc loading of 5% (FU-5) exhibited the highest catalytic activity for hydroxylation of phenol with H2O2 at room temperature in water, which gave a phenol conversion of 38.5% and 87.4% selectivity for dihydroxybenzenes (DHB). UiO-66 played a crucial role in the enhancement of catalytic performance compared with conventional supports such as γ-Al2O3, etc. A hydroxyl radical mechanism was proposed for this catalytic hydroxylation process and the high selectivity was attributed to the interaction between Fc particles and UiO-66.
研究领域:
化学
·
催化材料科学
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2024
·
IF 3.8
Yixiong Wu,Yanqi Xu,Cunjun Li,Hai Wang,Xinyu Wang,Aimiao Qin,Haiqing Qin,Linjiang Wang
One-step selectively photocatalytic phenol hydroxylation to produce Dihydroxybenzenes (DHB) is an attractive and challenging strategy. However, the rapid recombination of photogenerated carriers existed in single component photocatalyst seriously hinders the photocatalytic efficiency. The heterojunction strategy can optimize the band structure of the photocatalyst, and effectively improve the carriers' separation and transfer during the photocatalytic process. Herein, we successfully designed and prepared a 3D TiO 2 @Ni 3 Fe 1 -LDH core-shell heterostructure photocatalyst by coupling TiO 2 nanorods with Ni 3 Fe 1 -LDH nanosheets for the photocatalytic phenol hydroxylation to produce DHB. The results showed that the 3D TiO 2 @Ni 3 Fe 1 -LDH core-shell heterostructure had a suitable energy band structure for the photocatalytic phenol hydroxylation and the heterostructure accelerated the carriers’ separation and transfer. Meanwhile, the high porosity and abundant active sites were conducive to the adsorption of H 2 O 2 and the photogenerated carriers transfer efficiency from the photocatalyst to H 2 O 2 . The 3D TiO 2 @Ni 3 Fe 1 -LDH core-shell heterostructure showed excellent photocatalytic performance of phenol hydroxylation, where the phenol conversion was 48.6%, and the selectivity of DHB was 81.1% at 25 °C and 4 h of light illumination. Furthermore, the as-prepared photocatalysts exhibited good stability after four cycles of experiment. This work provided a convenient and efficient method for the green synthesis of DHB.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Hang Li,Yi Zhai,Xubin Zhang,Guojun Lv,Yu Shen,Xuqing Wang,Tao Jiang,Yuzhou Wu
Hierarchical iron-containing TS-1 zeolites (FTS) were successfully synthesized via post-treatment desilication over microporous Fe-TS-1, which were prepared through a one-step hydrothermal synthesis. The prepared samples were characterized by X-ray diffraction, N2 adsorption–desorption, field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, ultraviolet visible spectroscopy, and X-ray fluorescence spectrometry. The experimental results illustrated that the MFI structure of all the FTS samples remained unchanged after NaOH desilication and acid treatment. The newly created mesopores can be controlled by changing the amount of framework Fe, as the extraction of Si could be affected because of the inhibitory effect of iron species during the desilication process. The catalytic performance of the prepared samples in phenol hydroxylation with H2O2 was investigated. Among all the samples, FTS-50-D showed a highest phenol conversion of 45.2% and a dihydroxybenzene selectivity of 95.2%. Besides, FTS-50-D also showed good reusability for five recycling tests.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 79
·76064-76074
·
IF 3.289
Saifu Long,Shijian Zhou,Fu Yang,Kangchao Lu,Tao Xi,Yan Kong
Surface exposed catalytic active species are thought to be responsible for overall catalytic activity and selectivity. In this paper, controllable contents of iron oxides were in situ introduced into the inner surface of anionic surfactant-templated mesoporous silica (AMS) by the metal-modified anionic surfactant templating route, in which anionic micelles decorated with different amounts of Fe2+ were direct utilized to assemble with organosilicate. The characterization results demonstrated that, after thermal treatments, Fe2O3 species were in situ formed and highly-dispersed in the channels of AMS, and the pore size was accordingly tailored to the microporous level (<2 nm). In each AMS catalyst, Fe2O3 showed better dispersion and stability compared with the post-impregnated method. Moreover, the catalytic performances of phenol hydroxylation on the as-synthesized catalysts were significantly enhanced, and the optimal catalyst (Fe/Si = 3.5 wt%) gave a phenol conversion of 44.3% with a selectivity of 82.6% to dihydroxybenzene. By comparison with some reference mesoporous silica catalysts (0.15Fe/MCM-41 and 0.15Fe/SBA-15), the iron-based micropore-enriched silica catalyst (Fe/AMS) gave an obviously higher selectivity to dihydroxybenzene. Finally, the optimal catalyst was examined for at least 5 runs in phenol hydroxylation.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Applied Spectroscopy
·
2022
·Vol. 89
·期 2
·272-280
·
IF 0.816
Wei Y.,Li L.,Ma Ch.,Wu Y.,Zhu Ch.,Gao H.,Gu J.,Xiong Y.,Li X.,Wang Z.,Wang G.,Guo S.,Chen G.
In order to directly detect the concentration of glucose in milk, carbon dots (CDs) rich in phenolic hydroxyl groups were synthesized in one step as a fluorescent probe. We presented a new glucose oxidase (GOx)-mediated strategy to detect glucose, which allowed the quantitative analysis of hydrogen peroxide (H 2 O 2 ) and glucose. Furthermore, it was possible to detect H 2 O 2 and glucose directly in complex systems such as milk. The result in milk showed that the fluorescence of the CDs was quenched by H 2 O 2 with the concentration range from 1 to 100 μM linearly, and the correlation coefficient was 0.977 with a detection limit of 0.175 μM. Similarly, a linear correlation was built between the fluorescence of the CDs and the concentration of glucose in the range from 10 to 100 μM with a correlation coefficient of 0.968 and a detection limit of 0.686 μM. The recovery rate was 97.30–101.05%, which showed high sensitivity in the detection of glucose in milk. As far as we know, this was the first time that CDs were used as a fluorescent probe to detect glucose in milk directly, which removed the step of pretreating milk and provided a supplement and extension for the detection of glucose in fluorescent spectroscopy.
研究领域:
分析化学
·
生物医学
✓ 已验证
DOI
高影响因子
Journal of Chemistry
·
2021
·
IF 2.506
Renjie Zhou,Gui Chen,Yuejun Ouyang,Hairui Ni,Nonglin Zhou,Bailin Xiang
Using MOF-5 as a template, the porous carbon (MDPC-600) possessing high specific surface area was obtained after carbonization and acid washing. After MDPC-600 was loaded with Cu ions, the catalyst Cu/MDPC-600 was acquired by heat treatment under nitrogen atmosphere. The catalyst was characterized by X-ray powder diffraction (XRD), N2 physical adsorption (BET), field emission electron microscope (SEM), energy spectrum, and transmission electron microscope (TEM). The results show that the Cu/MDPC-600 catalyst prepared by using MOF-5 as the template has a very high specific surface area, and Cu is uniformly supported on the carrier. The catalytic hydrogen peroxide oxidation reaction of phenol hydroxylation was investigated and exhibits better catalytic activity and stability in the phenol hydroxylation reaction. The catalytic effect was best when the reaction temperature was 80°C, the reaction time was 2 h, and the amount of catalyst was 0.05 g. The conversion rate of phenol was 47.6%; the yield and selectivity of catechol were 37.8% and 79.4%, respectively. The activity of the catalyst changes little after three cycles of use.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Xiaonuo Zhang,Xiaoyan Lin,Yu He,Xuegang Luo
Significant concerns had been given raise to the pollution of tetracycline in aquatic environment in recent years. In this study, a novel phenolic hydroxyl (bayberry tannin) functionalized copper alginate microspheres adsorbent for the adsorption of tetracycline from contaminated water environment had been synthesized by a facile gelation and solidification process. The structure and chemical properties were characterized by the various analytical methods. The as-prepared adsorbent displayed the excellent adsorption performance with the maximum adsorption capacity of 153.89 mg·g −1 , and the equilibrium data were well fitted the Langmuir isotherm model and pseudo-second-order kinetic model. In addition, the thermodynamic values (Δ H 0 > 0, Δ S 0 > 0, Δ G 0 < 0) demonstrated that the tetracycline adsorption process was feasible, endothermic and spontaneous in nature. The possible preparation and adsorption mechanisms of as-prepared adsorbent were the result of hydrogen bond, cation bonding bridge, n-π EDA interaction, hydrophobic interaction and π-π EDA interaction. Compared with other adsorbents, the as-prepared adsorbent could be considered a high performance and promising candidate for the effective removal of tetracycline from aquatic environment.
研究领域:
环境科学
·
材料科学
·
生物化学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）