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A novel metal–organic framework, ZJU-196, with extraordinary acid–base resistant stability has been successfully synthesized, exhibiting highly efficient separation of acetylene from C2H2/CO2 mixtures under ambient conditions. [ABSTRACT FROM AUTHOR]

By using different N-donor organic species as additional auxiliary ligands with structure-directing roles, four three-dimensional (3D) calcium-based coordination complexes, [Ca(dbt)(H2O)]n1, [Ca(H-dbt)2(5,5′-dmbpy)2]n2, (4,4′-bpy)0.5[Ca(dbt)(H2O)2]n3, and (H2-dib)[Ca3(dbt)4(H2O)4·2H2O]n4 (H2-dbt = 2,5-dibromoterephthalic acid, 2,2′-bpy = 2,2′-bipyridine, 5,5′-dmbpy = 5,5′-dimethyl-2,2′-bipyridine, 4,4′-bpy = 4,4′-bipyridine, dib = 1,4-di(1H-imidazol-1-yl)benzene), have been successfully synthesized under similar solvothermal conditions and structurally characterized. The organic amine molecules play different roles in the formation of four different metal–organic skeletons with diverse structural topologies, in which complexes 1–3 are neutral, and 4 comprises a negatively charged framework with diprotonated dib as the counterion. Complex 1 features a 3D (6,6)-connected framework structure composed of edge-sharing 1D Ca–O–Ca inorganic chains and dbt ligands. The 2,2′-bpy molecule plays an important role in the synthesis of 1 as the structure-directing agent (SDA). Complex 2 shows a 3D 2-fold interpenetrated diamondoid framework (dia, 66) formed by single metal nodes via linear H-dbt anions and bidentate chelating 5,5′-dmbpy ligands, while complex 3 exhibits a 3D noninterpenetrated pcu network with {412·63} topology constructed from binuclear [Ca2(CO2)4] secondary building units and two types of dbt ligands, in which 4,4′-bpy molecules are ordered within the 3D neutral calcium-based framework as template and space filling agents. Complex 4 is a unique (4,4,4,4,5)-connected 5-nodal topology net, in which the diprotonated dib molecules provide space filling to balance the negatively charged framework. In addition, the thermal stability and the fluorescence properties of complexes 1–4 have been investigated. [ABSTRACT FROM AUTHOR]

This study investigated the annealing effects on structural and mechanical properties of pure (pure TiO 2 ) and carbon doped titania (C-TiO 2 ) thin films. The amorphous films of pure TiO 2 and C-TiO 2 were deposited on the substrates of Si wafer (100) at 100 °C by reactive magnetron sputtering. Through annealing at different temperatures, times and atmospheres, the crystallinity and defect density of the films could be varied. Under H 2 annealing, oxygen vacancies are generated in the films which facilitate the phase transformation from amorphous to anatase at a lower onset temperature than those under air annealing. The onset temperature of crystallization for C-TiO 2 is higher than that for pureTiO 2 due to the existence of carbon atoms which impairs the diffusion of Ti and O atoms for crystallization. The hardness of the films by nano-indentation test ranges from ~ 7 GPa for the amorphous to ~ 12 GPa for the crystallized films and is affected by the phase, degree of crystallinity, grain size and defect density. When the amorphous titania film fully transforms to a crystalline phase of small grains at temperatures ranging from 300 to 500 °C, its hardness will reach a maximum. However, at temperatures over 400 to 500 °C, the film hardness declines conversely with increasing temperatures or extending annealing time due to increase in grain size and change in defect density. [ABSTRACT FROM AUTHOR]

Abstract: Metallic, diamond-like carbon (Me-DLC) coatings are widely used in the mold industry due to their excellent wear resistance. In this paper, zirconium-containing DLC (Zr-DLC) coatings are prepared using an unbalanced magnetron sputtering process. Factors that affect the wear resistance of coatings consist of friction coefficients, hardness and anti-sticking properties. This paper aims to develop a method that optimizes the multi-objective properties of Zr-DLC coatings. For statistical purposes, the experimental parameters for the Zr-DLC coatings were put in place with a L18(35) orthogonal array. In order to optimize these properties, a method combining the grey, fuzzy and Taguchi approaches was established. While using the developed grey-fuzzy Taguchi method (GFTM), the experimental results from four properties can be integrated into a performance index. A comparison of the integrated performance index between the initial and optimal conditions shows that the magnitude increases from 0.46 to 0.81. The gain for each property by the GFTM from the initial condition is reported as 35% positive. [Copyright &y& Elsevier]

A series of hydrothermal reactions of metallic salts (CoCl2, CdSO4and ZnCl2), carboxylates (oxalic acid and 1,4-H2BDC) and organic amines (o-PD, Him) have been investigated. Five coordination complexes, [Zn2(bim)4]n(1), Cd(H2bbim)2SO4·1/3(H2O) (2), [Co2(H2bbim)4(bbim)]Cl2(3), [Co(Hbim)(Him)(C2O4)]n(4) and [Zn(H2bbim)(1,4-BDC)]n(5) (o-PD = o-phenylenediamine, Hbim = benzimidazole, H2bbim = 2,2′-bisbenzimidazole, Him = imidazole, 1,4-H2BDC = 1,4-benzenedicarboxylic acid), were prepared and characterized by elemental analyses, IR, single-crystal X-ray diffraction, fluorescence and magnetic analyses. Interestingly, two different ligands Hbim and H2bbim were generated viahydrothermal in situreactions of o-PD and oxalic acid during the formation processes of these compounds. In 1, bim ligands bridge each pair of Zn atoms into a single-stranded helical chain through metal–ligand interactions to generate a 2-D grid-like structure. Complex 2features a mononuclear structure due to the large steric hinderance of H2bbim ligand. Through N–HCl hydrogen bonds, the dinuclear units of 3are alternately arranged to afford a unique 1-D helical chain. Complex 4exhibits a 1-D zig-zag chain which consists of [Co(Hbim)(Him)]2+units bridged by oxalate ligands, and 5displays a 1-D chain structure consisting of Zn(H2bbim)2+units linked by 1,4-BDC ligands. [ABSTRACT FROM AUTHOR]

Abstract This study evaluated strategies targeting macro- and micro-organic contaminant mitigation using low-energy titanium dioxide photocatalysis. Energy inputs of 1, 2, and 5 kWh m−3 resulted in incomplete oxidation of macro-organic natural organic matter, signified by greater reductions of UV 254 and specific ultraviolet UV absorbance (SUVA) in comparison to dissolved organic carbon (DOC). The rate of UV 254 removal was 3 orders of magnitude greater than the rate of DOC degradation. Incomplete oxidation improved operation of downstream filtration processes. Photocatalysis at 2 kWh m−3 increased the bed life of downstream granular activated carbon (GAC) filtration by 340% relative to direct filtration pretreatment. Likewise, photocatalysis operated ahead of microfiltration decreased fouling, resulting in longer filter run times. Using 2 kWh m−3 photocatalysis increased filter run time by 36 times in comparison to direct filtration. Furthermore, levels of DOC and UV 254 in the membrane permeate improved (with no change in removal across the membrane) using low-energy photocatalysis pretreatments. While high-energy UV inputs provided high levels of removal of the estrogenic micro-organics estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethynlestradiol (EE2), low-energy photocatalysis did not enhance removal of estrogens beyond levels achieved by photolysis alone. In the cases of E1 and E3, the addition of TiO 2 as a photocatalyst reduced degradation rates of estrogens compared to UV photolysis. Overall, process electrical energy per order magnitude reductions (EEOs) greatly improved using photocatalysis, versus photolysis, for the macro-organics DOC, UV 254 , and SUVA; however, energy required for removal of estrogens was similar between photolysis and photocatalysis. Graphical abstract Image 1 Highlights • ≤5 kWh m−3 low-energy TiO 2 photocatalysis significantly reduced NOM aromaticity. • 2 kWh m−3 low-energy TiO 2 photocatalysis extended subsequent GAC bed life 340%. • 2 kWh m−3 photocatalysis extended membrane filter runtime 36x, no effluent decline. • Photocatalysis generally did not improve removal of E2, E3, or EE2 beyond UV alone. • E1 was removed well by photolysis; photocatalysis hindered E1 removal. [ABSTRACT FROM AUTHOR]

Abstract: The occurrence of alkylphenols (APs) including nonylphenol (NP) and octylphenol (OP) in the riverine sediments from the Pearl River Delta (PRD), South China was investigated and compared by Soxhlet extraction (S-APs) with dichloromethane and by sequential accelerated solvent extraction (ASE) (A-APs) with 1:6 toluene/methanol, respectively. Concentrations of OP and NP range from <1 to 463ng/gdw and 31–21,885ng/gdw, respectively, demonstrating that the contamination level of APs in the PRD is one of the highest in the world. Moreover, the A-APs contents are highly significantly related to and on average 1.5 times the S-APs contents. For sequential two ASE extractions, APs in the first extract accounts for 82.2–99.2% of their total contents in the sequential two extractions. The correlation analysis shows that S-APs and A-APs are both significantly associated with the contents of total organic carbon (TOC), suggesting that the variable extraction efficiency of these two methods is related to the presence of condensed organic matter in the sediments. [Copyright &y& Elsevier]

In this study, a highly efficient photocatalyst, NH 2 -MIL-125(Ti)/g-C 3 N 4 /NiPd (NH 2 -MIL-125(Ti)/CN/NiPd), was successfully synthesized for photocatalytic water reduction to produce H 2 . Under visible-light irradiation, the prepared NH 2 -MIL-125(Ti)/CN/NiPd composite clearly showed enhanced photocatalytic performance for H 2 evolution compared to NH 2 -MIL-125(Ti), NH 2 -MIL-125(Ti)/CN, and NH 2 -MIL-125(Ti)/NiPd. The as-synthesized NH 2 -MIL-125(Ti)/0.75CN/Ni 15.8 Pd 2.1 photocatalyst exhibited a high H 2 production rate of 8.7 mmol g −1 h −1 , 322 and 1.3 times higher than those of NH 2 -MIL-125(Ti)/0.75CN and NH 2 -MIL-125(Ti)/Ni 15.8 Pd 4.1 , respectively. The enhanced photocatalytic performance can be attributed to the intimate interfacial contact between NH 2 -MIL-125(Ti) and CN, accelerating the charge transfer, as well as loaded NiPd nanoparticles, increasing the light-absorbing capacity and accelerating the charge transfer of NH 2 -MIL-125(Ti)/CN. This work demonstrates that the addition of appropriate co-catalysts onto MOF/CN hybrid with intimate contact interface provides a new approach to design highly efficient and solar-energy-harvesting photocatalysts. [ABSTRACT FROM AUTHOR]

The dynamics of iron (Fe)-bound organic carbon (OC) during dissimilatory microbial Fe(III) reduction has the potential to play an important role in regulating the biogeochemical cycling of carbon (C) in permanently or transiently anoxic soils and sediments. In this study, we investigated the release and transformation of ferrihydrite (Fh)-bound OC during microbial reduction of Fe by Shewanella putrefaciens strain CN32 under a fixed Fe concentration of 13 mM and varying C/Fe molar ratios. We found that reduction of Fe and reductive release of OC was dependent on the C/Fe molar ratio, with high C/Fe ratio enhancing both reduction of Fe and release of OC. For Fh-OC co-precipitates with C/Fe ratio of 3.7, 54.7% of Fh-bound OC was released to solution phase when 25.1% of Fe was reduced. The presence of OC inhibited the transformation of Fh to more crystalline Fe phases both in the bulk and on the surface. Upon reduction, Fh-bound OC became more concentrated on the surface of Fh-OC co-precipitates, and surface components were enriched with carboxylic functional groups. Reduction increased the lability of Fh-bound OC for Fh-OC co-precipitate with C/Fe ratio of 3.7, and aromatic OC was preferentially retained within the co-precipitates. Our results indicate that microbial reduction altered the quantity and composition of OC released from Fh-OC co-precipitates, depending on the C/Fe ratio and associations between Fe and OC. Assuming higher availability of released OC compared to original Fh-bound OC, reduction of Fh can likely lead to enhanced degradation of OC and result in a shorter residence time for OC in soils and sediments. [ABSTRACT FROM AUTHOR]

Solid-phase iron (Fe) plays an important role in the accumulation and stabilization of soil organic matter (SOM). However, ferric minerals are subject to redox reactions, which can compromise the stability of Fe-bound SOM. To date, there is limited information available concerning the fate of Fe-bound SOM during redox reactions at Fe mineral surfaces. In this study, we investigated the release kinetics of hematite-bound organic carbon (OC) during the abiotic reduction of hematite–humic acid (HA) complexes by dithionite, to elucidate important processes governing the stability and fate of organic matter during the redox processes. Our results indicate that the reductive release of Fe obeyed first-order kinetics with release rate constants of 6.67–13.0 × 10 − 3 min − 1 . The Fe-bound OC was released rapidly during the initial stage with release rate constants of 0.011–1.49 min − 1 , and then became stable with residual fractions of 4.6–58.2% between 120 and 240 min. The release rate of aromatic OC was much faster than for the non-aromatic fraction of HA, and 90% of aromatic OC was released within the first hour for most samples. Our findings show that in the reductive reaction the mobilization of Fe-bound OC was asynchronous with the reduction of Fe, and aromatic OC was released more readily than other components of SOM. This study highlights the importance of evaluating the release of SOM bound with Fe during the redox reactions, especially the influence of the physicochemical properties of SOM. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new metal–organic framework (ZJU-26) was synthesized. [•] ZJU-26 displays large adsorption enthalpies of 32.7kJ/mol for C2H2. [•] ZJU-26 exhibited high separation selectivity for C2H2/CH4 and C2H2/CO2. [ABSTRACT FROM AUTHOR]

Abstract: For the purpose of evaluating the stability of municipal solid waste (MSW) excavated from a landfill, dissolved organic matter was extracted and characterized by physicochemical and spectroscopic methods. Results showed that dissolved organic carbon concentration, ratio of dissolved organic carbon to dissolved organic nitrogen, and specific ultraviolet absorbance at 254nm were in the range of 0.383–3.502gkg−1, 0.388–3.693 and 2.700–4.629Lmg−1 m−1, respectively, indicating the stability of MSW. Results obtained from Fourier transform infrared spectra have demonstrated that the stability of excavated MSW was characterized by disappearance of some easily biodegradable compounds; and the 1635/1406 ratio varied from 0.979 to 1.840 and was higher than that of the matured compost. The excitation–emission matrix spectra have shown that the principal components in excavated MSW comprised humic substances and the MSW was stable by the presence of a peak with wavelength pair of ∼280/420nm. [ABSTRACT FROM AUTHOR]