Search

[Display omitted] • A method based on ion–dipole interactions to manipulate the PVDF polymorphism was proposed. • The method is easy to be applied on large-scale. • The pure β-phase PVDF membranes was successfully prepared with the help of this method. • The elevated β phase content and the increased water flux were simultaneously observed. The β-phase PVDF membranes with excellent piezo-, pyro-, and ferro-electric properties are increasingly drawing broad attention from various fields. However, the current methods to manipulate the polymorphism of PVDF membranes is suffering from complicated preparation procedures and easily lowering membrane permeability. Herein, an efficient method based on the robust ion–dipole interactions (IDI) between cationic surfactant and the CH 2 /CF 2 dipoles of PVDF was employed to manipulate the polymorphism of PVDF membranes. The pure β-phase PVDF membranes was easily obtained only by introducing dodecyl trimethyl ammonium chloride (DTAC) into the dope solutions in nonsolvent induced phase separation (NIPS) process. The IDI between DTAC and PVDF chains was conducive to improving the relative content of the β phase, which further could be elevated to nearly 100% with the increase of DTAC concentrations as validated by XRD, DSC, and FTIR testing. Different from the findings of previous studies, the elevated β phase content and the increased water flux were simultaneously observed in the IDI-prepared PVDF membranes in this study. As a result, a PVDF membrane with nearly 100% β-phase content and water flux increased by nearly 4.0 times was successfully prepared. Moreover, the pure β-phase PVDF membranes exhibited better fouling durability and moderate mechanical strength compare with these of the virgin PVDF membranes. [ABSTRACT FROM AUTHOR]

Ferro-alloys have been extensively studied in the field of electrochemical sensing due to their abundant earth reserves and excellent performances. In this work, serials of bimetallic Fe/Co nanoalloy@carbon composites (Fe/Co@C) were successfully prepared using Co-doped MIL-101(Fe) as templates and developed as excellent electrochemical sensors for acetaminophen (AP) detection. It was found that the atomic ratio of Fe/Co in the templates can significantly affect the electrochemical activity of the product. Among the prepared composites, Fe/Co@C-G2 (Fe/Co = 2:1) with high conductivity and large specific surface area presents the best electrochemical sensing performance. Under the optimal conditions, Fe/Co@C-G2 has a high sensitivity of 55.2 μA μM−1cm−2, a wide linear range of 0.29-407.15 μM, a low LOD of 0.09 μM, good selectivity, excellent stability, and good repeatability. In addition, Fe/Co@C-G2 can also be used for real sample testing. This work expands the application of Fe/Co@C-based composites in electrochemical sensing.

Anionic metal–organic frameworks (MOFs) have attracted increasing attention due to the enhanced electrostatic interactions between their anionic frameworks and counter-ionic guests. Owing to these special host–guest interactions, anionic MOFs are beginning to have a large impact in the field of absorption and separation of ionic molecules and selective sensing of metal ions. Herein, two mesoporous anionic metal–organic frameworks, namely, [(CH3)2NH2]6[In6(OX)6(TCA)4]·solvents (JOU-11) and [(CH3)2NH2]6[In6(OX)6(TCPA)4]·solvents (JOU-12) (H3TCA = tricarboxytriphenylamine; H3TCPA = tris((4-carboxyl)phenylduryl)amine; OX = oxalate), have been synthesized by using wheel-type [In6(OX)6(COO)12]6–as building blocks. Structural analyses show that JOU-11and JOU-12show isoreticular three-dimensional frameworks with pyrtopology. Due to their anionic frameworks and tunable pore window sizes, both compounds can be exploited for absorbing and separating cationic organic dyes. In addition, JOU-11can be developed as a fluorescence “turn-off” sensor for selectively sensing Fe3+, whereas JOU-12can be used for fluorescence “turn-on” sensing of Cu2+and Co2+ions.

Nickel nanoparticles (Ni NPs) are attracting more and more attention in the field of electrochemistry due to their high conductivity and good catalytic properties. However, Ni NPs are susceptible to corrosion or agglomeration, leading to low stability. In this work, nickel@carbon nanomaterials (Ni@CNS) were prepared by pyrolysis nickel-based metal-organic framework (Ni-MOF) template, and characterized by powder X-ray diffraction (PXRD), transmission electron microscopy, scanning electron microscopy, Brunauer–Emmett–Teller method, and X-ray photoelectron spectroscopy (XPS). The prepared Ni@CNS composite reveals uniform core-shell structure, where the thin carbon shell not only protects the Ni NPs from being corroded, but also accelerates the migration of electrons, so as to promote its sensing performance. Ni@CNS composite presented as a black powder with mesoporous structure. The average size of Ni NPs was about 15.01 nm with a standard deviation of 3.21 nm. The specific surface area of Ni@CNS was as high as 116.12 m2g−1, which is beneficial to increase the effective surface area of the modified electrode. These structural advantages enhance its electrochemical performance toward paracetamol (PA) sensing. The Ni@CNS modified electrode has high sensitivity for quantitative detection of PA. The linear ranges were determined to be 0.570 μM and 70432 μM with a low detection limit of 0.028 μM (S/N= 3). In addition, due to its excellent electrochemical performances, the constructed electrode was used to detect PA in real water samples. This work expands the application of Ni- and C-based composites in electrochemistry sensing.

Iron disulfide (FeS2) has attracted extensive research interest due to its excellent catalytic efficiency. In this work, FeS2was composited with carbon matrix to prepare a highly efficient electrocatalyst for hydrogen evolution. Two uniformly composites, namely, FeS2@carbon nanotube (FeS2@CNT) and FeS2@carbon particle (FeS2@CP), were successfully prepared by pyrolysis and sulfuration processes. The structures of the synthesized composites were characterized by powder X-ray diffraction (PXRD), scanning electron microscope, transmission electron microscope, and X-ray photoelectron spectroscopy. It was found that the catalytic performances of the composites were obviously improved compared to pure FeS2. Moreover, compared to FeS2@CP, the FeS2@CNT nanotubes achieved a much lower overpotential and a smaller Tafel slope. The enhanced HER kinetics and hydrogen generation rate of FeS2@CNT may be due to its more efficient charge transport, uniform distribution of active sites, and higher surface areas. This work provides a new clue for the preparation of FeS2-based composite for hydrogen evolution.

A serial of cerium phosphate/reduced graphene oxide (CePO4-rGO) composites were synthesized for the first time by one-pot hydrothermal method. Structural analyses revealed that flaky CePO4and few-layer rGO were composited homogeneously. It is found that rGO can greatly enhance the conductivity and the adsorption capacity of the composite. With these advantages, the constructed composites were used for electrochemical detection of dopamine (DA) and acetaminophen (APAP). Further studies show that the loading amount of rGO was also very important. When CePO4−0.6rGO was used, wide linear ranges of 1.2−50 μM for DA and 0.5−30 μM for APAP can be obtained, respectively. The detection limits of DA and APAP were 0.013 μM and 0.025 μM with high sensitivities of 25.58 μA μM−1cm−2and 13.30 μA μM−1cm−2, respectively. Moreover, the modified electrode also has high selectivity, good stability and satisfactory reproducibility. In addition, the modified electrode was also successfully applied to detect DA and APAP in real urine samples. This work provides a simple method for preparing new electrode materials for detecting small biomolecules.

Water Storage and Controlled-release Film (WSCF) is a new kind of polymer composite with the function of releasing water slowly in a given period. Micro-organism culture was carried out to study the process of film’s degradation. The results showed that the degradation rate of WSCF added with fungi suspension was increased by 0.6% more than that of WSCF without fungi suspension. The degradation rate of WSCF added with soil suspension was increased by about 1% more than the film without soil suspension. Compared different culture mediums, the order of degradation rates of WSCF was: bacteria medium > actinomyces medium > fungi medium. The degradation rate of WSCF with field soil suspension was the highest one. The degradation rate of WSCF was higher than ordinary plastic film, increased by 3-5%. The results of tests under liquid culture indicated that mixed bacterium were helpful to the degradation of WSCF, the degradation rate of WSCF under liquid culture was higher than that of soil culture, increased by about 2%.

Water Storage and Controlled-release Film (WSCF) is a new kind of polymer composite with the function of releasing water slowly in a given period. This paper resumptively introduces the importance of water storage and controlled-release film (WSCF) material for tree planning in desertified regions. Microstructures of WSCF were studied and experiments were also carried out successively in various environmental conditions.

In this work, ?-Fe2O3/CNTs composite was facile synthesized by simple hydrothermal method and hydrazine hydrate treatment at low temperature (CNTs = carbon nanotubes). The result of VSM shows that the saturation magnetization of Fe2O3/CNTs composites increase from 0 to 1.29 emu g?1after hydrazine hydrate treatment, indicating that the Fe2O3in the composite transforms from ?phase to ?phase. Moreover, the electrochemical properties of both ?-Fe2O3/CNTs and ?-Fe2O3/CNTs was studied. Compared with ?-Fe2O3/CNTs, ?-Fe2O3/CNTs shows enhanced electrochemical performance toward paracetamol determination. Under optimum condition, the ?-Fe2O3/CNTs modified electrode exhibits two linear ranges of 2.5 ?M?385 ?M and 593 ?M?1550 ?M and a low detection limit of 0.046 ?M. In addition, the constructed sensor can be successfully utilized for detecting paracetamol in different water bodies. This work provides a new clue for the design and construction of excellent electrochemical sensor for paracetamol determination.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.