162 research outputs found
Electrokinetic delivery of persulfate to remediate PCBs polluted soils: Effect of different activation methods
Persulfate-based in-situ chemical oxidation (ISCO) for the remediation of organic polluted soils has gained much interest in last decade. However, the transportation of persulfate in low-permeability soil is very low, which limits its efficiency in degrading soil pollutants. Additionally, the oxidation-reduction process of persulfate with organic contaminants takes place slowly, while, the reaction will be greatly accelerated by the production of more powerful radicals once it is activated. Electrokinetic remediation (EK) is a good way for transporting persulfate in low-permeability soil. In this study, different activation methods, using zero-valent iron, citric acid chelated Fe²⁺, iron electrode, alkaline pH and peroxide, were evaluated to enhance the activity of persulfate delivered by EK. All the activators and the persulfate were added in the anolyte. The results indicated that zero-valent iron, alkaline, and peroxide enhanced the transportation of persulfate at the first stage of EK test, and the longest delivery distance reached sections S4 or S5 (near the cathode) on the 6th day. The addition of activators accelerated decomposition of persulfate, which resulted in the decreasing soil pH. The mass of persulfate delivered into the soil declined with the continuous decomposition of persulfate by activation. The removal efficiency of PCBs in soil followed the order of alkaline activation > peroxide activation > citric acid chelated Fe²⁺ activation > zero-valent iron activation > without activation > iron electrode activation, and the values were 40.5%, 35.6%, 34.1%, 32.4%, 30.8% and 30.5%, respectively. The activation effect was highly dependent on the ratio of activator and persulfate
Chemosynthesis and structural characterization of a novel lignin-based bio-sorbent and its strong adsorption for Pb (II)
Efficient and Product-Controlled Depolymerization of Lignin Oriented by Raney Ni Cooperated with Cs x H3 − x PW12O40.
Assessment of structural characteristics of regenerated cellulolytic enzyme lignin based on a mild DMSO/[Emim]OAc dissolution system from triploid of Populus tomentosa Carr.
The structural characteristics of native lignin are essential for the further deconstruction of plant cell walls for value-added application of lignocellulosic biomass.</p
Gold-Catalyzed Tandem Cycloisomerizationand Dimerization of Chiral Homopropargyl Sulfonamides
We are grateful for the financial support from the National Natural Science
Foundation of China (No. 21102119 and 21272191), the Natural Science
Foundation of Fujian Province of China (No. 2012J01051), NFFTBS
(No. J1210014), and PCSIRT. We also thank Professor Dr. Liming Zhang
(University of California Santa Barbara) for the helpful discussions
Improved value and carbon footprint by complete utilization of corncob lignocellulose
Lignocellulose, as the most abundant type of inedible biomass, is considered as a promising renewable feedstock for making fuels, chemicals, and materials. However, its complex structure makes most of current biorefinery processes suffer from low resource utilization rates, high energy consumption or ill-defined market orientation of the obtained products. Here, we propose and evaluate the EXA (Ethanol, Xylose, Adhesive) biorefinery strategy based on current xylose industry. This process integrates four conversion and separation stages to consecutively produce ethanol, xylose, and adhesive with total carbon utilization of 79.6%. The key innovation is the establishment of an easy-to-operate process for direct production of high-quality adhesive from a lignin-rich liquid fraction that makes the overall process significantly more sustainable. Techno-economic analysis (TEA) shows that the revenue of proposed EXA process increases more than 110 times compares with the current process and life cycle assessment (LCA) demonstrates a much lower CO2 footprint from an environmental burden per unit of revenue perspective
Kaj država pričakuje od državnega programa obvadovanja raka
Locked-to-sliding phase transition has been studied in the driven two-dimensional Frenkel-Kontorova model with the square symmetric substrate potential. It is found that as the driving force increases, the system transfers from the locked state to the sliding state where the motion of particles is in the direction different from that of driving force. With the further increase in driving force, at some critical value, the particles start to move in the direction of driving force. These two critical forces, the static friction or depinning force, and the kinetic friction force for which particles move in the direction of driving force have been analyzed for different system parameters. Different scenarios of phase transitions have been examined and dynamical phases are classified. In the case of zero misfit angle, the analytical expressions for static and kinetic friction force have been obtained
Single-photon-assisted entanglement concentration of a multi-photon system in a partially entangled W state with weak cross-Kerr nonlinearity
We propose a nonlocal entanglement concentration protocol (ECP) for
-photon systems in a partially entangled W state, resorting to some
ancillary single photons and the parity-check measurement based on cross-Kerr
nonlinearity. One party in quantum communication first performs a parity-check
measurement on her photon in an -photon system and an ancillary photon, and
then she picks up the even-parity instance for obtaining the standard W state.
When she obtains an odd-parity instance, the system is in a less-entanglement
state and it is the resource in the next round of entanglement concentration.
By iterating the entanglement concentration process several times, the present
ECP has the total success probability approaching to the limit in theory. The
present ECP has the advantage of a high success probability. Moreover, the
present ECP requires only the -photon system itself and some ancillary
single photons, not two copies of the systems, which decreases the difficulty
of its implementation largely in experiment. It maybe have good applications in
quantum communication in future.Comment: 7 pages, 3 figure
Return of 4U~1730--22 after 49 years silence: the peculiar burst properties of the 2021/2022 outbursts observed by Insight-HXMT
After in quiescence for 49 years, 4U~1730--22 became active and had two
outbursts in 2021 \& 2022; ten thermonuclear X-ray bursts were detected with
Insight-HXMT. Among them, the faintest burst showed a double-peaked profile,
placing the source as the 5th accreting neutron star (NS) exhibiting
double/triple-peaked type-I X-ray bursts; the other bursts showed photospheric
radius expansion (PRE). The properties of double-peaked non-PRE burst indicate
that it could be related to a stalled burning front. For the five bright PRE
bursts, apart from the emission from the neutron star (NS) surface, we find the
residuals both in the soft (10 keV) X-ray band.
Time-resolved spectroscopy reveals that the excess can be attributed to an
enhanced pre-burst/persistent emission or the Comptonization of the burst
emission by the corona/boundary-layer. We find, the burst emission shows a rise
until the photosphere touches down to the NS surface rather than the
theoretical predicted constant Eddington luminosity.
The shortage of the burst emission in the early rising phase is beyond the
occlusion by the disk. We speculate that the findings above correspond to that
the obscured part (not only the lower part) of the NS surface is exposed to the
line of sight due to the evaporation of the obscured material by the burst
emission, or the burst emission is anisotropic () in the burst early
phase. In addition, based on the average flux of PRE bursts at their touch-down
time, we derive a distance estimation as 10.4 kpc.Comment: arXiv admin note: substantial text overlap with arXiv:2208.13556;
text overlap with arXiv:2208.1212
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