JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
·
2015
·
IF 3.615
Yang Li,Lin-Dong Liu,Lu Liu,Ying Liu,Hong-Wei Zhang,Xu Han
In this study, three trivalent Mn (oxyhydr)oxides, bixbyite (α-Mn 2 O 3 ), hausmannite (Mn 3 O 4 ) and manganite (γ-MnOOH) were synthesized and used as persulfate (PS) activators in phenol oxidation. Of these three Mn (oxyhydr)oxides, only γ-MnOOH shows a good catalytic activity in PS activation with more than 80% phenol oxidized within 360 min in the full pH range. With increasing concentrations of PS and γ-MnOOH, phenol removal efficiency increased. TOC results also suggest that phenol oxidation at pH 11 is more complete than those at pH 7 and 3. We further confirm that mechanism involved in phenol oxidation is pH dependent in γ-MnOOH/PS system. Although SO 4 − and OH were both found under acidic and alkaline conditions, they did not contribute equally under different pHs. At pH 11, SO 4 − and OH generated from PS activation efficiently oxidize phenol. At pH 3, the strong oxidation activity of γ-MnOOH and an oxidative intermediate formed between S 2 O 8 2− and γ-MnOOH primarily contribute to phenol oxidation. At pH 7, an oxidative intermediate formed between γ-MnOOH and S 2 O 8 2− is the predominant oxidative species in phenol oxidation.
研究领域:
环境科学
·
化学
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产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2018
·Vol. 25
·期 10
·9636-9646
·
IF 2.8
Li Chenguang,Qu Ruijuan,Chen Jing,Zhang Shuo,Allam Ahmed A.,Ajarem Jamaan,Wang Zunyao
Triclosan (TCS) is an antibacterial and antifungal agent widely used in personal care products, and it has been frequently detected in the aquatic environment. In the present study, the acute toxicity of TCS to Daphnia magna , Photobacterium phosphoreum , Danio rerio , and Limnodrilus hoffmeisteri was assessed under different pH conditions. Generally, TCS was more toxic to the four aquatic organisms in acidic medium. The LC 50 values for D. magna and D. rerio were smaller among the selected species, suggesting that D. magna and D. rerio were more sensitive to TCS. In addition, the oxidative stress-inducing potential of TCS was evaluated in Carassius auratus at three pH values. Changes of superoxide dismutase (SOD) and catalase (CAT) activity, glutathione (GSH) level, and malondialdehyde (MDA) content were commonly observed in all TCS exposure groups, indicating the occurrence of oxidative stress in the liver of C. auratus . The integrated biomarker response (IBR) index revealed that a high concentration of TCS induced great oxidative stress in goldfish under acidic condition. This work supplements the presently available data on the toxicity data of TCS, which would provide some useful information for the environmental risk assessment of this compound.
研究领域:
环境科学
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毒理学
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产品关联
DOI
PubMed
高影响因子
MOLECULES
·
2015
·Vol. 20
·期 9
·16709-16722
·
IF 2.416
Hai-Min Shen,Wen-Jie Zhou,Xin Ma,Hong-Ke Wu,Wu-Bin Yu,Ning Ai,Hong-Bing Ji,Hong-Xin Shi,Yuan-Bin She
A pH-dependence of the Brønsted acid-catalyzed oxidation of sulfides to the corresponding sulfoxides with H2O2is reported for the first time based on our systematic investigation of the catalytic performance of a series of Brønsted acids. For all of the Brønsted acids investigated, the catalytic performances do not depend on the catalyst loading (mol ratio of Brønsted acid to substrate), but rather depend on the pH value of the aqueous reaction solution. All of them can give more than 98% conversion and selectivity in their aqueous solution at pH 1.30, no matter how much the catalyst loading is and what the Brønsted acid is. This pH-dependence principle is a very novel perspective to understand the Brønsted-acid catalysis system compared with our common understanding of the subject.Keywords:sulfide;oxidation;sulfoxide;pH-dependence;Brønsted acid
研究领域:
化学
·
催化科学
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jiayan Wu,Quanyun Ye,Meiqing Chen,Leiye Sun,Sheng Liu,Linqing Liu,Pingxiao Wu,Nengwu Zhu
The heteroaggregation of nanoplastics with minerals has been widely investigated. However, few studies have focused on the interaction between similar negatively charged clay minerals and nanoplastics, especially how their interactions affect the migration of heavy metals. This study investigated heteroaggregation of kaolinite (a model of natural mineral) with polystyrene nanoplastics (PSNPs) and the effect of heteroaggregates on lead (Pb 2+ ) sorption . Dynamic light scattering (DLS) measurement highlighted that PSNPs owned higher colloidal stability than kaolinite in aquatic environments. Due to the surface charge heterogeneity of kaolinite, the heteroaggregation behavior between kaolinite and PSNPs was highly pH-dependent. At pH 3.0 and 6.0, kaolinite particles with positively charged edge surfaces favored the association of PSNPs. PSNPs were found to be primarily attached on the kaolinite edge (010) surface, followed by Al-terminated (001) and Si-terminated (00 1 ¯ ) surfaces based on density functional theory (DFT) calculations. At pH 10.0, they had negligible interaction due to the strong electrostatic repulsion. Interestingly, kaolinite carried more negative charges after heteroaggregation with PSNPs, resulting in slower edge-to-face homoaggregation and higher dispersibility, and thus increasing the sorption capacity for Pb 2+ . This investigation provided a new understanding of nanoplastics interactions with negatively charged minerals and highlighted the vital role of nanoplastics in mineral stability and contaminant migration.
研究领域:
环境科学
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土壤化学
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污染生态学
✓ 已验证
DOI
高影响因子
DYES AND PIGMENTS
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2021
·
IF 4.889
Kui Wang,Qi-Qi Wang,Mi-Ni Wang,Ya-Jing Xie,Xuan Qiao,Siyang Xing,Bolin Zhu
In this work, a water-soluble fluorescent and colouring macrocycle deprotonated-calixpyridinium was obtained by a simple pH modulatory strategy. This type of fluorescent and colouring macrocyclic skeleton as host will be certainly applied in a large number of fields, especially in the sensing area. Herein, a near white-light emission was carried out by an innovative method of deprotonated-calixpyridinium-based host–guest interactions employing camptothecin sodium as the guest. Moreover, the pH-responsive luminescence color change of calixpyridinium–camptothecin sodium complex was further applied for the high selective detection of arginine in pure water and real samples, which is quite important in the accurate diagnosis of various disorders. The newfound pH-dependent luminescent and colouring properties of calixpyridinium will also provide an alternative idea for the development of other novel fluorescent and colorimetric macrocyclic sensors.
研究领域:
分析化学
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生物传感
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医学诊断
✓ 已验证
DOI
高影响因子
ACS ES&T Water
·
2025
·
IF 4.3
Wen-Long Wang,Peng-Hui Liu,Jung-Hyun Son,Hang Su,Min-Yong Lee,Hong-Ying Hu,Qian-Yuan Wu,Uwe Hübner
The combination of ozonation and Mn(II) (O3/Mn(II)) is expected to synergistically eliminate recalcitrant organic micropollutants in water. However, the decay of O3, formation of •OH and reactive manganese species (RMnSs), and synergism in micropollutant degradation have not been comprehensively understood. Herein, the synergism of O3 and Mn(II) was observed to be pH-dependent. Compared to ozonation alone, O3/Mn(II) preferentially formed Mn(V and VI) and slightly increased •OH yield (from 0.22 to 0.30) at acidic pH 4–5, while it preferentially formed Mn(VII) and significantly increased OH yield (from 0.52 to 0.74) at circumneutral pH 6–7. Thereafter, O3/Mn(II) prominently increased RMnS exposure at acidic pH, while it dramatically diminished O3-exposurse to increase •OH exposure at circumneutral pH. As a result, O3/Mn(II) outperformed ozonation alone for the degradation of various O3-resistant micropollutants (3.7–7.9 times faster). For example, the RMnSs (82.7% contribution) and •OH (84.2% contribution) were the dominant contributors to the degradation of the isothiazolinone biocide (5-chloro-2-methyl-4-isothiazolin-3-one) at acidic and circumneutral pH, respectively. Mn(II) can enhance the removal of O3-resistant micropollutants in relatively clean waters (e.g., tap water), but its effectiveness was limited in more contaminated waters (e.g., WWTP effluent). These findings support the practice and pH optimization of the O3/Mn(II) in various water types.
研究领域:
环境科学
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水处理工程
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产品关联
DOI
高影响因子
RSC Advances
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2015
·Vol. 5
·期 100
·82252-82258
·
IF 3.84
Dongjian Shi,Rongjin Liu,Weifu Dong,Xiaojie Li,Hongji Zhang,Mingqing Chen,Mitsuru Akashi
3,4-Dihydroxyphenylalanine (DOPA)-based polymers are well-known to form functional hydrogels with self-healing properties by chelating metal ions. However, DOPA-based hydrogels with self-healing properties are difficult to obtain in the absence of the metal ions, as previously reported. Thus, the aim of this study is to prepare a self-healable DOPA-based hydrogel in the absence of metal ions. Firstly, poly(vinyl alcohol)–DOPA (PVA–DOPA) was synthesized by modifying PVA with DOPA through an esterification reaction. The composition of the PVA–DOPA polymer was determined by proton nuclear magnetic resonance (1H NMR) spectroscopy. Then, the PVA–DOPA hydrogel in a metal-free environment could be easily prepared by dissolving the polymer in buffer solution. Rheological analyses showed that the PVA–DOPA polymers had different dynamic moduli depending on the pH of the buffer solutions. The results from the FTIR and UV-vis spectra indicated that there were hydrogen bond interactions between the PVA–DOPA polymers under low pH conditions, while there were both hydrogen bond and covalent interactions under high pH conditions. The PVA–DOPA hydrogel could be rapidly self-healed within 270 s, which was much quicker than the hydrogel prepared in the presence of Fe3+ (about 600 s). The metal-free PVA–DOPA hydrogel has the potential for application in coating and biomedical fields.
研究领域:
材料科学
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生物医学工程
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Shengtao Xing,Wenqing Li,Bo Liu,Yinsu Wu,Yuanzhe Gao
CuO synthesized by a hydrothermal method was used to activate persulfate (PS) for removing ciprofloxacin (CIP) in water. The influences of reaction parameters and coexisting substances on this process were studied. Under the optimal conditions ([CuO] 0 = 6.3 mmol L −1 , [PS] 0 = 1 mmol L −1 , pH 8), CIP was completely degraded and the total organic carbon removal efficiency was 84.2%. Ca 2+ , Mg 2+ and Cl − had little effect on CIP removal, while fulvic acid showed a slight inhibitory effect. By contrast, bicarbonate enhanced CIP degradation and significantly suppressed Cu leaching. Subsequently, the reactive species for CIP degradation were identified by electron paramagnetic resonance and radical scavenging experiments. Although the decomposition efficiency of PS was significantly accelerated by increasing pH, similar amounts of O 2 − , OH, SO 4 − and 1 O 2 were detected at different pH, suggesting the formation of more surface activated PS at higher pH. The reactive species for CIP degradation were found to be dependent on solution pH. CIP was mainly degraded by SO 4 − and 1 O 2 at acidic conditions. The activated PS might have high selectivity towards CIP and its amount might be higher than that of radicals at pH 8. In addition, the uncharged surface of CuO at pH 8 facilitated the adsorption of CIP, which is beneficial to the surface reaction between CIP and activated PS. Hence, the activated PS was the dominated species for CIP degradation at this pH.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
MACROMOLECULES
·
2010
·
IF 4.539
Zhizhang Guo,Xingyu Chen,Jianyu Xin,Duo Wu,Jianshu Li,Chenlong Xu
The influence of molecular weight and arm number of star polymers on the buildup and pH-dependent morphology changes of multilayer films assembled from star poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) and linear poly(styrenesulfonate) (PSS) was systematically investigated. Well-defined star PDMAEMA, consisting of β-cyclodextrin (CD) core and different arm number (21, 14, and 7) were successfully synthesized via atom transfer radical polymerization (ATRP). It is found that star polymers with certain arm number deposit more mass with the increase of molecular weight. As for the star polymers with almost the same arm length but different arm number, film assembled from 14-arm star PDMAEMA exhibits the fastest growth and the most significant morphology changes upon the pH 2.75 treatment. It is assumed that the interdiffusion of PSS controlled by star PDMAEMA with different structures should be responsible for the different buildup and pH-dependent morphology changes of the multilayer films.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Shiyu Zuo,Yan Wang,Jinquan Wan,Jianxin Yi
A fundamental scientific quandary in environmental has always been the pH dependence in Fenton reaction, that is, the reaction kinetics decreases by approximately 1–3 orders of magnitude upon transitioning from an acidic to an alkaline state. Here, we discovered that protons significantly contribute to the Fenton reaction through an examination of the reaction's interfacial behavior characteristics. Proton transfer mediated by hydrogen bond network connectivity in the electric double layer is responsible for the pH dependence of Fenton reaction kinetics. On this basis, the surface potential of Fenton reaction catalyst was modified to optimize the distribution of H 2 O in the electrical double layer, enhancing the connectivity of the interfacial hydrogen bond network and providing a fast channel for rapid proton transfer. The consecutive hydrogen bond network mediates rapid proton hopping, increasing the proton concentration in the Helmholtz layer, and consequently promoting the proton conductivity from 5.38×10 −7 S·cm −2 to 4.35×10 −6 S·cm −2 in alkaline conditions for Fenton reaction. Meanwhile, the kinetics reaction rate was improved 20 times, and the pH dependence was reduced from 70.9 % to 12.6 %. This discovery clarifies the key role of the interfacial hydrogen bond network and proton transfer in Fenton reaction kinetics pH dependence. It provides new theories and methods for achieving alkaline high Fenton reaction kinetics.
研究领域:
环境科学
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化学
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产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 91
·88030-88037
·
IF 3.289
Yuqun Du,Hongxia Yan,Song Niu,Lihua Bai,Fu Chai
Two kinds of water-soluble fluorescent hyperbranched poly(amino esters) were first synthesized by a convenient one-pot approach via the A2 + B3 Michael addition reaction of trimethylolpropane triacrylate and aliphatic diamines. Their structures and optical properties were determined by FTIR, NMR, GPC, UV-vis, and fluorescence spectra. The hyperbranched poly(amino esters) in aqueous solutions and PVA films state showed strong blue fluorescence when these polymers were excited by a UV lamp. In addition, it was found that their fluorescence exhibited a pH-dependent behavior. It was also noteworthy that the fluorescence could be changed by adding metal ions. The fluorescence of the polymer could be quenched when the concentration of Hg2+ and Fe3+ reached at 10−2 mol L−1. Therefore, the prepared hyperbranched poly(amino ester) is a promising ion probe for detecting Hg2+ and Fe3+.
研究领域:
高分子化学
·
分析化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2017
·
IF 2.905
Jianfeng Song,Xuhong Niu,Xue-Mei Li,Tao He
Hydrophilic nanoporous ion exchange barrier membrane, based on polyethersulfone (PES)/sulfonated polyphenylether sulfone ketone (SPPESK), was utilized for the pH dependent separation of copper and nickel ions with a commercial extractant, LIX84-I. The extraction and stripping performance of the membrane was demonstrated in a single stage membrane contactor as well as in an integrated extraction/stripping system. By adjusting the feed pH to 2.9, a complete separation of copper and nickel was achieved using the membrane contactors, where a copper flux of 1.10 × 10 −8 mol/cm 2 s was observed. In an extraction/stripping integrated sandwiched membrane extraction contactor, significantly higher copper flux was observed due to the coupling of copper stripping. In addition, the PES/SPPESK barrier membrane prevented the loss of the organic extractant, exhibiting high stability in 30 days dynamic test. The results indicated that the membrane extraction contactor system is of great potential for selective extraction of metal ions.
研究领域:
环境科学
·
材料科学
✓ 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）