Search

Bioconversion of CO2 into liquid fuels or chemicals, preferred medium chain carboxylic acids (caproic and caprylic acid), is an attractive CO2 utilization technology. The present study aims to investigate the effects of different ratios of H2/CO2 on regulating the distribution of C2‐C8 carboxylic acid products, while the headspace pressure of 1.5 bar was set to amplify the effect of different ratios. The H2/CO2 ratio of 4:1 was more suitable for preparing acetic acid, where the highest acetic acid yield was 17.5 g/L. And the H2/CO2 ratio of 2:1 showed excellent chain elongation ability with the highest n‐caprylic yield of 2.4 g/L. Additionally, the actual H2/CO2 ratios of 4:1 reactors were higher than that in 2:1 may be course chain elongation often accompanied by H2 production. The 16S rRNA genes analysis shows that the genus Terrisporobacter and Coriobacteriales may be related to acetic acid production enriched in H2/CO2 ratio 4:1 reactors, and the genus Clostridium and Paenibacillaceae may associate with the chain elongation pathway were enriched in H2/CO2 ratio 2:1 reactors. [ABSTRACT FROM AUTHOR]

A promising strategy to alleviate the plastic pollution from traditional petroleum‐based plastics is the application of biodegradable plastics, in which polyhydroxyalkanoates (PHAs) have received increasing interest owing to their considerable biodegradability. In the PHAs family, poly(3‐hydroxybutyrate‐co‐3‐hydroxvalerate) (PHBV) has better mechanical properties, which possesses broader application prospects. With this purpose, the present study adopted Cupriavidus necator to synthesize PHBV utilizing volatile fatty acids (VFAs) as sole carbon sources. Results showed that the concentration and composition of VFAs significantly influenced the production of PHAs. Especially, even carbon VFAs (acetate and butyrate) synthesized only poly(3‐hydroxybutyrate) (PHB), while the addition of odd carbon VFAs (propionate and valerate) resulted in PHBV production. The 3‐hydroxyvalerate (3HV) contents in PHBV were directly determined by the specific VFAs compositions, in which valerate was the preferred substrate for 3HV accumulation. After optimization by response surface methodology, the highest PHBV accumulation achieved 79.47% in dry cells, and the conversion efficiency of VFAs to PHBV reached 40%, with the PHBV production of 1.20 ± 0.05 g/L. This study revealed the metabolic rule of VFAs converting into PHAs by C. necator and figured out the optimal VFAs condition for PHBV accumulation, which provides a valuable reference for developing downstream strategies of PHBV production in industrial applications in future. [ABSTRACT FROM AUTHOR]

The effects of alkalinity addition with different strategies on the start‐up, performance, and microbial community of completely autotrophic nitrogen removal over nitrite (CANON) were investigated over 450 days. In phase I, the alkalinity was increased gradually from 300 to 2,000 mg/L to obtain the optimal range. In phase II, the reactor was restarted to verify the appropriate alkalinity value of 1,600 mg/L. The fact that it only took 90 days (phase I: 170 days) to complete the start‐up of CANON in phase II demonstrated that an alkalinity value of 1,600 mg/L was suitable when the influent NH4+‐N concentration was 200 mg/L (alkalinity/NH4+‐N = 8:1). The slope (k = 2.00) of NH4+‐N concentration decrease in phase II during the start‐up process was significantly higher than that in phase I (k = 1.50). High removal efficiencies of NH4+‐N (98%) and TN (80%) were attained in both phases. Specific anaerobic ammonium oxidation (anammox) activity tests showed that the anammox activity of the two phases reached 3.31 and 5.31 mg TN/(g VSS·h), respectively. High‐throughput sequencing analysis revealed that appropriate alkalinity could promote the enrichment of Candidatus Brocadia, C. Jettenia, and C. Kuenenia (total abundance of 31.96%) while effectively inhibiting Nitrospira (abundance of less than 0.50%). Practitioner Points: An alkalinity/NH4+‐N ratio of 8 promoted the rapid start‐up and stable performance of CANON.NH4+‐N and TN removal efficiencies of 98% and 80%, respectively, were obtained.High alkalinity promoted the enrichment of Candidatus Brocadia, Candidatus Jettenia, Candidatus Kuenenia and inhibited Nitrospira.Nitrogen concentration of influent and effluent in Phase Ⅰ and Ⅱ. [ABSTRACT FROM AUTHOR]

Vinegar residue (VR), a major by‐product in the vinegar brewing process, is generated at least three million tons annually in China. Currently major part of the disposal of VR is fulfilled by landfill and incineration, however, serious environment pollution along with such processes is a challenging issue. Anaerobic digestion (AD) can provide benefits of environment and renewable methane generation, which seems to be a reasonable alternative to traditional treatment. Noticeably, total solids (TS) is an important influential parameter to AD performance. Therefore, VR was evaluated for methane production and associated kinetic characteristics during the liquid‐state AD (LS‐AD) and solid‐state AD (SS‐AD) in this study. The results indicated that the highest specific methane yield of 194.8 mL gVS−1 and volumetric methane yield of 9.4 Lmethane Lreactor volume−1 were achieved in LS‐AD (TS = 10%) and SS‐AD (TS = 20%), respectively. The kinetic analysis showed a higher specific methane production rate for LS‐AD than SS‐AD, while volumetric methane production rate presented a reverse trend. This study provides useful guidance for the sustainable utilization of VR while contributes to environmental protection and alleviates the dependence on fossil fuels. [ABSTRACT FROM AUTHOR]

Objectives The purpose of this study was to evaluate distending the stomach with water for ultrasound detection of focal lesions in the elongated left lobe of the liver. Methods A total of 13,277 patients undergoing liver ultrasound were evaluated for the presence of an elongated left lobe of the liver and a focal lesion. Patients with an elongated left lobe of the liver had their stomach distended with oral water for further evaluation of a focal lesion. A portion of the patients had computed tomography (CT) examinations, which were compared with the ultrasound studies. Results A total of 643 patients were found with elongated left lobe of the liver by ultrasound; of them, 451 underwent CT, 259 out of the 451 patients meeting the inclusion criteria underwent second ultrasound and final analysis, and 16 of these 259 patients had focal lesion in the elongated left lobe of the liver on CT study. The sonographic visualization of the liver and spleen at the same scan view before and after distending the stomach were 7% (7 of 100) and 100% (100 of 100), respectively ( P < .001). The sonographic detection of the lesions before and after distending the stomach were zero and 87.5%, respectively ( P < .001). Conclusions Distending the stomach with water can greatly increase ultrasound detection of focal lesions in the elongated left lobe of the liver. [ABSTRACT FROM AUTHOR]

Natural gas (NG), as a renewable and clean energy gas, is considered to be one of the most attractive energy carriers owing to its high calorific value, low price, and less pollution. Efficiently capturing CO2 from NG is a very important issue since CO2 reduces energy density of natural gas and corrodes equipment in the presence of water. In this study, the authors use holey graphene-like carbon derived from covalent organic polymers (COP) impregnated with nonprecious metals, i.e., COP graphene, as highly efficient separation materials. The dual-site Langmuir-Freundlich adsorption model based ideal absorbed solution theory is applied to explore the adsorption selectivity. The experimental results along with first principles calculations show Mn-impregnated COP graphene exhibits greater CO2/CH4 selectivity than Fe and Co impregnated materials. Particularly, the selectivity of C-COP-P-Mn reaches 11.4 at 298 K and 12 bars, which are much higher than those in many reported conventional porous materials and can be compared to the highest separation performance under similar condition. Importantly, all the three COP graphene show remarkably high regenerability ( R > 77%), which are much better than many reported promising zeolites, active carbon, and metal organic frameworks. Accordingly, COP graphene are promising cyclic adsorbents with high selectivity for separation and purification of CO2 from natural gas. [ABSTRACT FROM AUTHOR]

Polarization rotation engineering is a promising path to giant dielectric and electromechanical responses in ferroelectric materials and devices. This work demonstrates robust and reversible in- to out-of-plane polarization rotation in ultrathin (nanoscale) epitaxial (001) tetragonal PbZr0.3Ti0.7O3 (PZT-T)/rhombohedral PbZr0.55Ti0.45O3 (PZT-R) ferroelectric bilayers. An underlying 20 nm thick PZT-R layer reduces the symmetry in a 5 nm thick PZT-T layer by imposing an in-plane tensile strain while simultaneously decoupling the PZT-T layer from the substrate. This prevents clamping and facilitates large-scale polarization rotation switching (≈60 μC cm−2) and an effective d33 response 500% (≈250 pm V−1) larger than the PZT-R layer alone. Furthermore, this enhancement is stable for more than 107 electrical switching cycles. These bilayers present a simple and highly controllable means to design and optimize rotational polar systems as an alternate to traditional composition-based approaches. The precise control of the subtle interface-driven interactions between the lattice and the external factors that control polarization opens a new door to enhanced-or completely new-functional properties. [ABSTRACT FROM AUTHOR]

Despite the impressive progress in the development of doped carbon catalysts for the oxygen reduction reaction (ORR), the current mono-heteroatom-doped carbon-based catalysts are still far from satisfactory for large-scale applications in fuel cells. The development of dual-heteroatom-doped nanoporous carbon electrocatalysts for the ORR is particularly attractive as a feasible solution for the commercialization of fuel-cell technology. Herein, a series of UiO-66-NH2-derived phosphorus-nitrogen-codoped porous carbon materials (P-N-carbons) are prepared from phosphorus-doped UiO-66-NH2 through postsynthetic modification (PSM) followed by one-step pyrolysis at various temperatures. The newly developed P-N-carbons exhibit high catalytic activity that is nearly equal to those of commercial Pt/C catalysts along with superior long-term stability and excellent methanol tolerance. This work shows not only that UiO-66-NH2 can be considered as a self-sacrificial precursor and nitrogen source but also that metal-organic frameworks (MOFs) with active functional groups may be developed as efficient alternative precursors. Owing to the versatility of MOF structures, the MOF-derived porous carbon materials would broaden the family of nanoporous carbon materials significantly and provide new structures and multifunctional properties for use in electrocatalysts, sensors, supercapacitors, and batteries, for example. [ABSTRACT FROM AUTHOR]

A novel type of calcium phosphate and iron(III) scale inhibitor acrylic acid-allylpolyethoxy carboxylate AA-APEL n (AL n) was synthesized. The observation shows that the adsorption of the AL n copolymer on the crystal surface caused deformation of calcium phosphate crystal morphology. Furthermore, both calcium phosphate and iron(III) inhibition increase with increasing the degree of polymerization of AL n from 5 to 15, and the dosage of AL n plays an important role on calcium phosphate and iron(III) inhibition. Inhibition mechanism is proposed that the interactions between calcium or iron ions and polyethylene glycol (PEG) are the fundamental impetus to restrain the formation of the scale in cooling water systems. [ABSTRACT FROM AUTHOR]

ABSTRACT A polyether-based copolymer of acrylic acid-allylpolyethoxy maleic carboxylate (AA-APEY) was prepared by copolymerization of allylpolyethoxy carboxylate (APEY) and acrylic acid (AA) at different mole ratios. The main aim of this work was to investigate the influence of AA-to-APEY mole ratios on the copolymer properties and scale inhibition performance for gypsum. The synthesized copolymer was characterized by Fourier-transform infrared (FT-IR) and further conformed by 1H NMR. The effect of AA-APEY on controlling calcium sulfate deposits was studied through static scale inhibition tests under standard solution conditions. And the result was compared with that of other polycarboxylates, which are similar to AA-APEY in structure. Scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and X-ray powder diffraction (XRD) analysis were carried out to study the morphology and structure changes of calcium sulfate crystals in the presence of AA-APEY. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40193. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, we synthesized a novel double-hydrophilic poly(ethylene glycol) (PEG)-based crystal growth modifier polyethylene glycol double-ester of maleic anhydride/ acrylic acid named PEGDMA/AA, whose structure was still linear but also had some differences from a traditional chelating linear polymer, in which the PEG segment was incorporated. The scale inhibition behavior of PEGDMA/AA was evaluated by means of a static scale inhibition method. As the polymerization degree of PEG nDMA was 8 ( n = 8), the maximum inhibitory toward calcium carbonate (CaCO3) and calcium sulfate (CaSO4) were 89.0 and 98.8% at dosage levels of 12 and 3 mg/L, respectively. Comparisons with other inhibitors were also carried out. Characterization of the CaCO3 and CaSO4 scales with scanning electron microscopy and transmission electron microscopy proved that great changes in the size and morphology of the calcium scales took place under the influence of PEG8DMA/AA. X-ray diffraction and diffraction patterns further confirmed the impact of PEG8DMA/AA as a crystal growth modifier. The three supposed mechanisms, (1) chelating solubilization, (2) multilayer type of adsorption, and (3) electrostatic repulsion function, are also described in detail. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39792. [ABSTRACT FROM AUTHOR]

Allyloxy polyethoxy ether (APEG) and succinic anhydride were used to prepare allyloxy polyethoxy carboxylate (APEL). 8-hydroxy-1,3,6-pyrene trisulfonic acid trisodium salt (PY) was reacted with allyl chloride to produce fluorescent monomer 8-allyloxy-1,3,6-pyrene trisulfonic acid trisodium salt (PA). APEL and PA were copolymerized with maleic anhydride (MA) to synthesize PA tagged no phosphate and nitrogen-free calcium phosphate inhibitor POLY(MA-APEL-PA). Structures of PA, APEG, APEL, and POLY(MA-APEL-PA) were carried out by FTIR and 1H-NMR. Different MA : APEL mole ratios were employed for the manufacture of POLY(MA-APEL-PA) to study the effect of mole ratio on performance of POLY(MA-APEL-PA). Relationship between POLY(MA-APEL-PA)'s fluorescent intensity and its dosage was studied. The results indicate that capability of POLY(MA-APEL-PA) is heavily depended on the mole ratio of MA : APEL. Correlation coefficient r of POLY(MA-APEL-PA)'s fluorescent intensity and its dosage is 0.9999, and detection limit of POLY(MA-APEL-PA) is 0.86 mg/L. POLY(MA-APEL-PA) can be used to accurately measure polymer consumption on line besides providing excellent calcium phosphate inhibition. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]