CFD modeling of pretreatment reactors at very high lignocellulose solids content requires the characterization of rheological properties of this specific system. In this study, the non-Newtonian rheological properties of the corn stover–water mixture at high solid loading up to 50% with helical ribbon agitation were characterized. The rheological model was developed by introducing the power law model and measuring the torque values of the mixing system in a small reactor (5 L), and then applied to the larger reactors (50 L and 500 L). The CFD model was developed based on the determined rheological properties. The fluid dynamics experiments in three reactors with different scales were used for validation of the rheological model. The calculated power consumption and mixing efficiency by CFD modeling were in good agreements with the experimental results. This study provided a practical method for the rheology characterization and CFD model at high solids loading. The CFD model could be applied to the design and structure analysis of pretreatment reactors in lignocellulose biorefining processes.
Lithium-ion technologies show great promise to meet the demands that the transition towards renewable energy sources and the electrification of the transport sector put forward. However, concerns regarding lithium-ion batteries, including limited material resources, high energy consumption during production, and flammable electrolytes, necessitate research on alternative technologies for electrochemical energy storage. Organic materials derived from abundant building blocks and with tunable properties, together with water based electrolytes, could provide safe, inexpensive and sustainable alternatives. In this study, two conducting redox polymers based on poly(3,4-ethylenedioxythiophene) (PEDOT) and a hydroquinone pendant group have been synthesized and characterized in an acidic aqueous electrolyte. The polymers were characterized with regards to kinetics, pH dependence, and mass changes during oxidation and reduction, as well as their conductance. Both polymers show redox matching, i.e. the quinone redox reaction occurs within the potential region where the polymer is conducting, and fast redox conversion that involves proton cycling during pendant group redox conversion. These properties make the presented materials promising candidates as electrode materials for water based all-organic batteries.
Aporphine alkaloids from the leaves of Nelumbo nucifera Gaertn are substances of great interest because of their important pharmacological activities, particularly anti-diabetic, anti-obesity, anti-hyperlipidemic, anti-oxidant, and anti-HIV's activities. In order to produce large amounts of pure alkaloid for research purposes, a novel method using high-speed counter-current chromatography (HSCCC) was developed. Without any initial cleanup steps, four main aporphine alkaloids, including 2-hydroxy-1-methoxyaporphine, pronuciferine, nuciferine and roemerine were successfully purified from the crude extract by HSCCC in one step. The separation was performed with a simple two-phase solvent system composed of n-hexane-ethyl acetate-methanol-acetonitrile-water (5:3:3:2.5:5, v/v/v/v/v). In each operation, 100 mg crude extracts was separated and yielded 6.3 mg of 2-hydroxy-1-methoxyaporphine (95.1% purity), 1.1 mg of pronuciferine (96.8% purity), 8.5 mg of nuciferine (98.9% purity), and 2.7 mg of roemerine (97.4%) respectively. The chemical structure of four aporphine alkaloids are identified by means of electrospray ionization MS (ESI-MS) and nuclear magnetic resonance (NMR) analysis. Moreover, the effects of four separated aporphine alkaloids on insulin-stimulated glucose consumption were examined in 3T3-L1 adipocytes. The results showed that 2-hydroxy-1-methoxyaporphine and pronuciferine increased the glucose consumption significantly as rosiglitazone did.
In this study, a side-by-side comparison of two pilot-scale vertical subsurface flow constructed wetlands (6.2 m × 0.85 m, = 95 L/m d, = 3.5 d) handling primary treated domestic sewage was conducted. One system (VA-i) was set to intermittent aeration while the other was aerated continuously (VAp-c). Intermittent aeration was provided to VA-i in an 8 h on/4 h off pattern. The intermittently aerated wetland, VA-i, was observed to have 70% less nitrate nitrogen mass outflow than the continuously aerated wetland, VAp-c. Intermittent aeration was shown to increase treatment performance for TN while saving 33% of running energy cost for aeration. Parallel tracer experiments in the two wetlands showed hydraulic characteristics similar to one Continuously Stirred Tank Reactor (CSTR). Intermittent aeration did not significantly affect the hydraulic functioning of the system. Hydraulic efficiencies were 78% for VAp-c and 76% for VA-i.
In order to solve the problem of slag recycling and dyeing wastewater treatment synchronously, the slag particles is used as raw material to prepare the particle electrodes, and the optimum preparation conditions of the slag particle electrodes is obtained through orthogonal test. Scanning electron microscopy, X-ray diffractometer and micro-hole physics and chemical adsorption analyzer are used to characterize and analyze the surface morphology, crystal structure, specific surface area and pore shape of the particle electrode. The operating parameters of the reaction system are optimized, and the energy consumption per order is calculated in optimized experimental conditions. The radical scavenging mechanism of three free radical scavengers (methanol, tert-butanol, and phenol) is studied, and the type of the main active substance participating in degradation of Methylene blue and the location of the degradation reaction are determined. It is speculated that the degradation reaction of Methylene blue occurs in the boundary layer on the external surface of the particle electrodes, not in the aqueous solution.
Polymeric forms of metal coagulants in water treatment have become increasingly used due to their wider availability and reduction in cost. These specialized coagulant forms and products are claimed by manufacturers to be superior to conventional coagulants in particulate and/or organic removal with inherent advantages of lower alkalinity consumption and lesser sludge production. However, due to their proprietary nature, little is known about their chemical composition. To determine and understand the effectiveness of these alternative coagulants, a comprehensive study was undertaken to characterize metal coagulants, and to comparatively evaluate them on a well-characterized source water. The objective of this study was to provide a scheme for utilities that could be employed as a screening process and a method of selecting an appropriate coagulant based on raw water characteristics and insight into the coagulatability of the source water. Characterizations of coagulants included: (i) active metal content, (ii) anion content, (iii) acidity, (iv) alkalinity consumption, (v) charge reversal by colloidal titration, and (vi) molecular weight determination. A total of five poly-aluminum chlorides (PACl), along with a conventional coagulant (aluminum sulfate or alum) were evaluated. Results show that through the characterization scheme, an effective coagulant (conventional versus alternative) and coagulant type (among various PACl) can be chosen before undertaking time-consuming bench or pilot-scale evaluation.
Deadlegs are the pipe sections used for specific services in production and transportation of oil and gas, and they often encounter hydrate management challenges. Despite stagnant fluids in deadlegs, warm water vapor readily condenses on the cold pipe wall, resulting in a risk of hydrate blockages by deposition. Proper management of hydrates in deadlegs is therefore required for economic and safety reasons. Here, we discuss the development of an 1-in. vertical pipe system that is designed to study hydrate deposition from water saturated gas. From a series of hydrate formation and dissociation, the hydrate deposits are characterized to obtain gas/water consumption, thickness/volume hydrate deposit distribution, hydrate morphology, and hydrate porosity and wetness. These characteristic properties are correlated with the header temperature and the time duration for hydrate deposition. Qualitative and quantitative information obtained from the present study contribute to our understandings of hydrate deposition and give insight into establishing management strategies to avoid or minimize the risk of hydrate deposition in deadlegs in oil and gas production and transportation systems.
Novel Ti/Cu-NRs/SnO -Sb electrode modified by copper (Cu) nanorods was fabricated through anodic aluminum oxide (AAO) template assisted electrochemical deposition (ECD) for wastewater treatment. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and electrochemical methods such as linear sweep voltammetry (LSV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the surface morphology, crystal structure and electrochemical performance of the electrodes. Acid dye AR 73 was selected as target pollutants to investigate the electro-catalyst behavior, and UV/vis spectroscopy was used to monitor the concentration changes with time. The results indicated that the presence of Cu nanorods on the Ti substrate promoted the electrodes' property obviously. Ti/Cu-NRs/SnO -Sb anode possessed smaller charge transfer resistance and longer service life than Ti/SnO -Sb anode. The oxygen evolution potential (OEP) of Ti/Cu-NRs/SnO -Sb electrodes reach 2.17 V (vs. Ag/AgCl). Removal of pollutants and reaction rate were all promoted due to the introduction of Cu nanorods in the process of AR 73 decomposing with Ti/Cu-NRs/SnO -Sb electrodes. And specific energy consumption also reduced remarkably. Our study has shown that the fabricated Ti/Cu-NRs/SnO -Sb electrodes are very promising for the electrochemical treatment of wastewater.
We provide a kinetic characterization of (Na , K )-ATPase activity in a posterior gill microsomal fraction from a hololimnetic population of the diadromous Amazon River shrimp Sucrose density gradient centrifugation reveals two distinct membrane fractions showing considerable (Na , K )ATP-ase activity, but also containing other microsomal ATPases. Only a single immune-reactive (Na , K )-ATPase with M of ≈110 kDa is present that hydrolyzes ATP with V = 130.3 ± 4.8 nmol Pi min mg protein and K = 0.065 ± 0.00162 mmol L , exhibiting site-site interactions. Stimulation by Na (V = 127.5 ± 5.3 nmol Pi min mg protein , K = 5.3 ± 0.42 mmol L ), Mg (V = 130.6 ± 6.8 nmol Pi min mg protein , K = 0.33 ± 0.042 mmol L ), K (V = 126.7 ± 7.7 nmol Pi min mg protein , K = 0.65 ± 0.0079 mmol L ) and NH (V = 134.5 ± 8.6 nmol Pi min mg protein , K = 1.28 ± 0.44 mmol L ) also obeys cooperative kinetics. Ouabain (K = 0.18 ± 0.058 mmol L ) inhibits total ATPase activity by ≈70%. This study reveals considerable differences in the kinetic characteristics of the gill (Na , K )-ATPase in a hololimnetic population that appear to result from the adaptation of diadromous populations to different limnic habitats
A new family of ruthenium complexes based on the N‐pentadentate ligand Py 2 Me tacn ( N ‐methyl‐ N′ , N′′ ‐bis(2‐picolyl)‐1,4,7‐triazacyclononane) has been synthesised and its catalytic activity has been studied in the water‐oxidation (WO) reaction. We have used chemical oxidants (ceric ammonium nitrate and NaIO 4 ) to generate the WO intermediates [Ru II (OH 2 )(Py 2 Me tacn)] 2+ , [Ru III (OH 2 )(Py 2 Me tacn)] 3+ , [Ru III (OH)(Py 2 Me tacn)] 2+ and [Ru IV (O)(Py 2 Me tacn)] 2+ , which have been characterised spectroscopically. Their relative redox and pH stability in water has been studied by using UV/Vis and NMR spectroscopies, HRMS and spectroelectrochemistry. [Ru IV (O)(Py 2 Me tacn)] 2+ has a long half‐life (>48 h) in water. The catalytic cycle of WO has been elucidated by using kinetic, spectroscopic, 18 O‐labelling and theoretical studies, and the conclusion is that the rate‐determining step is a single‐site water nucleophilic attack on a metal‐oxo species. Moreover, [Ru IV (O)(Py 2 Me tacn)] 2+ is proposed to be the resting state under catalytic conditions. By monitoring Ce IV consumption, we found that the O 2 evolution rate is redox‐controlled and independent of the initial concentration of Ce IV . Based on these facts, we propose herein that [Ru IV (O)(Py 2 Me tacn)] 2+ is oxidised to [Ru V (O)(Py 2 Me tacn)] 2+ prior to attack by a water molecule to give [Ru III (OOH)(Py 2 Me tacn)] 2+ . Finally, it is shown that the difference in WO reactivity between the homologous iron and ruthenium [M(OH 2 )(Py 2 Me tacn)] 2+ (M=Ru, Fe) complexes is due to the difference in the redox stability of the key M V (O) intermediate. These results contribute to a better understanding of the WO mechanism and the differences between iron and ruthenium complexes in WO reactions. Target acquired : New ruthenium complexes based on an N‐pentadentate ligand (see figure; ET=electron transfer, WNA=water nucleophilic attack) allow characterisation of the water‐oxidation (WO) intermediates Ru II (OH 2 ), Ru III (OH 2 ), Ru III (OH) and Ru IV (O) by using UV/Vis and NMR spectroscopies, HRMS and spectroelectrochemistry. Elucidation of the catalytic cycle leads to a Ru V (O) intermediate prior to an attack by a water molecule on the metal‐oxo species.