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Net primary production (NPP) is one of the approaches used to estimate the amount of carbon sequestration by plants. This research aims to estimate the total carbon flux exchanged from different ages of oil palm using remote sensing. The study site was at the PTPN VI Batang Hari, Jambi, Sumatra, Indonesia. The amount of carbon sequestration by oil palm plantations at PTPN VI Batang Hari, Jambi can be estimated using remote sensing based on the light use efficiency (LUE) model. The results showed that the oil palm age affects the amount of carbon sequestrated. The lowest Net primary production value was found at one year of planting 4.28 gCm-2day-1, and the highest was 9.38 gCm-2day-1 at 20 years of planting. The model LUE output was validated using Eddy covariance data and the results showed a low error and a high accuracy rate with RMSE = 0.05 gCMJ-1, R² = 92%, and p-value = 0.04. We concluded that the LUE model can be used with high accuracy to estimate the amount of carbon absorption of oil palm when direct measurement is unavailable. [ABSTRACT FROM AUTHOR]

One of the main sources of global warming is greenhouse gasses; the most important of which is carbon dioxide. Reducing CO2 emissions, and its utilization or storage, is a global challenge to tackle climate change. In this work, the operating conditions of the pilot CO2 capture unit are studied using the ASPEN PLUS® software. This study describes the methodology of the simulations and the main results. The unit consists of one scrubber and one stripper. For carbon dioxide absorption from gas streams, the aqueous solvent K2CO3 is used. The effect on the absorption of CO2, and regeneration of carbon dioxide and potassium carbonate were studied by varying parameters of pressure, temperature, and concentration of solvent. For each parameter, three values were evaluated with the following ranges: pressure 0.3–1 bar; temperature 80–100 °C; and concentration of potassium carbonate 15–25 wt%. The optimum operating conditions of the pilot unit are pressure of 0.3 bar, stripper temperature of 100 °C, and solvent concentration of 15 wt%. Under these conditions, 99.91% CO2 capture and 85.46% CO2 regeneration were achieved. The present research aims to find the optimal operating parameters of the pilot plant to validate the model with the experimental data. In this way, the model parameterization can be used to design large-scale CO2 capture units. [ABSTRACT FROM AUTHOR]

The porous liquid (PLs) is a new material containing both permanent porosity of porous materials and liquid fluidity of solvent at room temperature, which has shown a great potential in gas separation. In this study, a novel type III porous liquids were prepared using 2-methylimidazole zinc salt (ZIF-8) modified by tetraethylenepentamine (TEPA) as the main units and 1-Ethyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)-imide ([EMlm][NTf2]) as the sterically hindered solvent. The effect of amine loading on the CO2 absorption performance of PLs was investigated. When amine load was 30 wt%, 30TEPA@ZIF-8 not only had the pore structure inside but also effectively increased the CO2 absorption capacity of PLs. When the effect of different parameters on CO2 absorption capacity was investigated, it was found that the optimal adsorption temperature was 60 °C, and the optimal concentration of the main units was7.5 wt%. After five cycles, the absorbent's cycle efficiency and desorption efficiency were more than 98 %. All the results indicate that the prepared PLs in this paper had an application potential in CO2 capture. [ABSTRACT FROM AUTHOR]

In this work, the active carbon adsorption and TiO2/UV decolorization of black liquor were studied through experimental analysis (planned using Design of Experiments), modelling and optimization (with Response Surface Method and Differential Evolution). The aim is to highlight the importance of optimization methods for increasing process efficiency. For active carbon adsorption, the considered process parameters were: quantity of active carbon, dilution, and contact time. For TiO2 promoted photochemical decolorization the process parameters were: TiO2 concentration, UV path length and irradiation time. The determined models had an R squared of 93.82% for active carbon adsorption and of 92.82% for TiO2/UV decolorization. The optimization of active carbon resulted in an improvement from 83.08% (corresponding to 50 g/L quantity of active carbon, 30 min contact time and 200 dilution) to 100% (corresponding to multiple combinations). The optimization of TiO2/UV decolorization indicated an increase of efficiency from 36.63% (corresponding to 1 g/L TiO2 concentration, 60 min irradiation time and 5 cm UV path length) to 46.83% (corresponding to 0.4 g/L TiO2 concentration, 59.99 min irradiation time and 2.85 cm UV path length). These results show that the experiments and the subsequent standard RSM optimization can be further improved, leading to better performance. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs) are released from the recycling process of PBDE-containing waste printed circuit board (WPCB), but studies on the mechanism of PBDE emission and migration are limited. In this study, PBDE concentrations in particulate matter (PM), dust, and fumes collected in a pilot-scale workshop for the WPCB de-soldering process were measured, and PBDE emission after gas treatment was estimated. The results showed that the mean concentrations of ∑8PBDEs in TSP and PM2.5 in the workshop were 20.3 ng/m3 (24.7 μg/g) and 16.1 ng/m3 (115 μg/g), respectively. In practice, the fumes containing gaseous and particulate PBDEs were treated by the combination of alkaline solution absorption and activated carbon adsorption. Compared to PBDE concentration in workshop floor dust (2680 ng/g), PBDE concentrations in solution scum (68,000 ng/g) and hood inside dust (20,200 ng/g) were condensed. The concentrations of ∑6PBDEs at the stack outlet (416 pg/m3) after gas treatment were lower than those in the stack pipe (1310 pg/m3) and hood inside (7440 pg/m3). The PBDEs in fumes were removed through physical adsorption of alkaline solution and activated carbon, and solution scum constituted the main mass discharges of PBDEs. The emission factor of PBDEs at the stack outlet was 47.3 ng ∑6PBDEs/kg WPCB. As a result, the WPCB de-soldering process is an important source of PBDE pollution, and gas treatment of solution absorption and activated carbon adsorption can reduce PBDE emission to some extent. [ABSTRACT FROM AUTHOR]

Based on nonequilibrium Green’s function approach and density functional theory, we report first principles investigation on ac transport of four carbon atomic chain connected by two semi-infinite aluminum leads, Al–C4–Al. For small alternating external bias voltage, we expanded nonequilibrium Green’s function to the first order in the external voltage and calculated the dynamical conductance. The suppression of the dynamic conductance was obtained near the resonant level, while far away from the resonance, the large enhancement of the dynamic conductance was observed. These behaviors can be understood well under the wide-band limit. By changing the coupling distance between the carbon atom and the aluminum leads, the system could change its transport response between capacitivelike and inductivelike. [ABSTRACT FROM AUTHOR]

The blending of primary amines, with fast reaction kinetic, together with tertiary amines, with a large loading capacity, is an increasingly popular approach to develop high-performance CO 2 capture sorbents with low energy requirements for regeneration. In this study, we investigated the CO 2 absorption performance of several aqueous solutions obtained by mixing ethanolamine (MEA) and diethylethanolamine (DEEA) and compared them with that of individual MEA and DEEA. CO 2 loadings at equilibrium were measured experimentally under a wide range of operating conditions, at temperatures between 298 and 323 K, CO 2 partial pressures in the range 5–60 kPa, and different amine mixing ratios. In addition, 13C NMR spectroscopy was employed to elucidate the reaction mechanisms and identify the species formed during CO 2 capture. The results of the study reveal the intricate interplay of MEA and DEEA in CO 2 capture, where MEA carbamate formation predominates in the early stages, gradually shifting to bicarbonate formation as the amine concentration decreases. Moreover, excess properties, which reflect non-ideal behaviors in amine blends, were introduced as a key parameter in the study. An excess property model, based on excess CO 2 loading, was developed to accurately predict the CO 2 equilibrium solubility without constant experimental measurement. As a result, good agreement was found between the experimental data and those calculated with the model (excess CO 2 loading) under the same operating conditions, with a average relative deviation of 1.1%. [Display omitted] • CO 2 equilibrium solubility determined for aqueous MEA/DEEA blends. • Role of amines in solution during CO 2 uptake explained by 13C NMR speciation study. • Excess CO 2 loading introduced to describe deviation from ideal amine mixing. • Development of an excess property model to predict CO 2 equilibrium solubility. [ABSTRACT FROM AUTHOR]

Patulin (PAT) is a type of mycotoxin produced by the P. expansum, Aspergillus, Penicillium , and Paecilomyces fungal species and constitutes serious food-related and environmental health threats to consumers. In this study, a novel magnetic multi-walled carbon nanotube (MWCNT) adsorbent was successfully synthesized, and its adsorption properties for the efficient removal of PAT from aqueous solution were investigated. The effects of adsorption parameters, such as pH, initial PAT concentration, adsorption time and temperature, were investigated for optimization of the adsorption process. The kinetic and isotherm studies revealed that PAT adsorption was well described by a pseudo-second order model and the Freundlich model, respectively. The maximum adsorption capacity of the as-prepared magnetic MWCNTs reached 640.2 μg/g, which was much higher than that of biological material-based absorbents (p < 0.05), and the adsorption equilibrium time was significantly shortened to 1 h (p < 0.05). Thermodynamic studies revealed that the adsorption process was exothermic. The adsorption activation energy determined from the Arrhenius equation was found to be approximately −27.31 kJ mol−1, suggesting that the adsorption of PAT on magnetic MWCNTs was random and spontaneous in nature within the experimental temperatures. Moreover, the recycling, separation and regeneration of the spent magnetic MWCNTs were evaluated, and the results demonstrated that the spent magnetic MWCNTs could be separated magnetically and regenerated by sodium hydroxide solution for recycling uses up to four cycles without significantly losing adsorption efficiency. Therefore, this novel magnetic MWCNT-based adsorbent could be a potential adsorbent to be applied for PAT removal from many aqueous systems. • A novel Fe 3 O 4 -MWCNTs adsorbent was used to remove PAT from the aqueous solution. • The adsorption of PAT by the Fe 3 O 4 -MWCNTs was spontaneous, endothermic and random. • The adsorbent could be recycled for 4 times without losing adsorption efficiency. • The adsorbent has higher absorption capacity compared with biological material-based ones. [ABSTRACT FROM AUTHOR]

Abstract Adsorption behaviors and mechanisms of metal endocrine disruptors (Pb2+, Cd2+, and Hg2+) by pyrogenic carbonaceous materials including engineered carbons (biochar and activated carbon) and carbon nanomaterials (multi-walled carbon nanotubes and graphene oxide) have been investigated by experimental and density functional theory (DFT) studies. The adsorption isotherms of metal endocrine disruptors on carbonaceous materials were better fitted by Langmuir models. The adsorption capacities were in the order as follows: GO > BC600 > BC300 > CNT > AC for Pb2+, GO > BC300 > AC > BC600 > CNT for Cd2+, and GO > BC300 ≥ AC > CNT > BC600 for Hg2+, respectively. The DFT-computed binding energy (kcal/mol) of different oxygen-containing functional groups with metal endocrine disruptors followed the orders: (ⅰ) CM COC Pb (−136.70) > CM-COO--Pb (−91.58) > CM CO Pb (−33.57) > CM OH Pb (−4.69), (ⅱ) CM-COO--Cd (−45.91) > CM COC Cd (−4.49) > CM OH Cd (−3.68) > CM CO Cd (1.08), (ⅲ) CM-COO--Hg (−25.51) > CM COC Hg (−3.58) > CM OH Hg (−0.63) > CM CO Hg (0.23). And COC has the highest binding energy for Pb2+, whereas COC has much lower binding energy for Cd2+ and Hg2+. Comprehensively considering DFT calculations, competitive adsorption results and the cost analysis, this work may provide insights into the design of selective adsorbent for specific contaminant. Graphical abstract Image 1 Highlights • Adsorption capacity of the adsorbents for metal endocrine disruptors was compared. • DFT calculation was used to study the effect of oxygen-containing groups. • COO- has the highest binding energy for Cd2+ and Hg2+. • COC has the highest binding energy for Pb2+, followed by COO-. • Biochar was found suitable for large scale environmental remediation. [ABSTRACT FROM AUTHOR]

Brown carbon (BrC) affects the Earth's radiative balance due to its strong light absorption at short wavelengths. A custom‐made combustion chamber was used to simulate biomass and coal burning and to investigate the emission characteristics of BrC absorption. Absorption Ångström exponents (AAEs) at the wavelength pair of 370 and 880 nm ranged from 1.19 to 3.25, suggesting the possible existence of BrC in biomass‐ and coal‐burning emissions. Based on the assumption that AAEBC = 1.0, BrC from biomass burning contributed to 41–85% of the total particles light absorption at 370 nm, which is much higher than that from coal burning (15–18%). The estimated absorption emission factors of BrC at 370 nm for biomass and coal burning were 15–47 and 2–13 m2/kg, respectively. A 10 × 10 km gridded BrC optical emission inventory for biomass and coal burning in China for 2015 was developed based on the measured absorption emission factors of BrC values and high‐resolution activity data. The total annual BrC absorption cross section emissions from biomass and residential coal burning were 4,194 Gm2 (relative uncertainty at the 95% confidence level of −33.2, 41.2%) and 615 Gm2 (−39.3, 40.1%), respectively. These results should be useful for improving estimates of the radiative effects of BrC in China. Key Points: Brown carbon contributes 15–18% to the total particles light absorption at 370 nm from residential coal burning based on AAEBC = 1.0Residential coal burning has lower absorption emission factors of brown carbon at 370 nm than biomass burningHigh‐resolution maps of optical emission inventories for biomass and residential coal burning were developed for China [ABSTRACT FROM AUTHOR]

Abstract Owing to a unique combination of low density, high mechanical stiffness, and high neutron capture cross section, boron rich solids are of interest for a number of applications ranging from fusion shielding and neutron absorbing materials to solid state neutron detection. In many of these applications, the boron containing materials may be exposed to extreme temperatures and thermal gradients where heat dissipation is a significant concern. While there have been several reports of the thermal conductivity for crystalline boron solids, comparitively little is known regarding the thermal conductivity for amorphous boron thin films used in many nuclear applications. In this investigation, we report time-domain thermoreflectance (TDTR) measurements for a series of plasma deposited boron rich thin films with nominal compositions of a-B:H and a-BP:H. The results were compared to additional measurements performed on a-C:H films with similar mass density and which are also utilized as fusion plasma shielding materials. The values of thermal conductivity determined by TDTR for the a-B:H and a-BP:H films ranged from 1 to 2 W/mK. These values are reduced relative to those reported for crystalline boron (4–400 W/mK) but compare well to those obtained for a-C:H (0.5–1.5 W/mK). Highlights • Time domain thermoreflectance used to measure amorphous boron thermal conductivity. • Amorphous boron thermal conductivity determined to be 1–2 W/mK. • Young's modulus for amorphous boron determined to be > 300 GPa. • Amorphous boron and carbon thermal-mechanical properties compared. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Mass transfer of CO 2 absorption into [bmim][BF4] aqueous solution was investigated. • Length of mass transfer zone decreases with liquid flow rate and IL concentration. • A dimensionless correlation predicting mass transfer coefficient was proposed. Abstract The mass transfer characteristics of CO 2 absorption into aqueous solution of ionic liquid in microchannel was investigated experimentally by a high speed camera. The influences of the ratio of gas and liquid flow rates (Q G / Q L) and the concentration of ionic liquid on the liquid side volumetric mass transfer coefficient (k L a), liquid side mass transfer coefficient (k L) and length of mass transfer zone (L M) were studied systematically. The results show that both k L a and k L increase but L M decreases with the increasing Q G / Q L and the concentration of ionic liquid. Taking the enhancement of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) on the mass transfer into account, a dimensionless correlation for predicting k L a was proposed. This work is conducive to the design, optimization and the application of the microchannel reactor for CO 2 capture and removal. [ABSTRACT FROM AUTHOR]

Light-absorbing organic carbon (or brown carbon, BrC) in atmospheric particles has received much attention for its potential role in global radiative forcing. While a number of field measurement campaigns have differentiated light absorption by black carbon (BC) and BrC, the chemical characteristics of BrC are not well understood. In this study, we present co-located real-time light absorption and chemical composition measurements of atmospheric particles to explore the relationship between the chemical and optical characteristics of BrC at a suburban site downwind of Guangzhou, China, from November to December 2014. BrC and BC contributions to light absorption were estimated using measurements from a seven-wavelength aethalometer, while the chemical composition of non-refractory PM1 was measured with a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Using the absorption Ångström exponent (AAE) method, we estimated that BrC contributed 23.6% to the total aerosol absorption at 370 nm, 18.1% at 470 nm, 10.7% at 520 nm, 10.7% at 590 nm, and 10.5% at 660 nm. Biomass burning organic aerosol (BBOA) has the highest mass absorption coefficient among sources of organic aerosols. Its contribution to total brown carbon absorption coefficient decreased but that of low-volatility oxygenated organic aerosol (LVOOA) increased with increasing wavelength, suggesting the need for wavelengthdependent light absorption analysis for BrC in association with its chemical makeup. Clear correlations of N-containing ion fragments with absorption coefficient were observed. These correlations also depended on their degrees of unsaturation/ cyclization and oxygenation. While the current study relates light absorption by BrC to ion fragments, more detailed chemical characterization is warranted to constrain this relationship. [ABSTRACT FROM AUTHOR]

This study prepared a novel low-cost surface functionalized carbon adsorbent (PPC) from biomass waste (pomelo peel) through a facile low-temperature (250 °C) one-step method under regular air atmosphere. The adsorption performance and mechanism of the carbon material for Ag(I) and Pb(II) were investigated by a range of sorption experiments and characterizations including SEM, EDX, XRD and FTIR. Sorption experimental results suggested that PPC had high adsorption capacities of 137.4 and 88.7 mg/g for Ag(I) and Pb(II), respectively, with adsorbent dosage of 2 g/L at unadjusted solution pH and room temperature (23 ± 1 °C). The characterization results indicated high-efficiency removal of the heavy metals by PPC was attributed to the strong chemical adsorption involving that Ag(I) ions were reduced as metallic Ag particles by oxygenic functional groups and Pb(II) ions were precipitated as Pb 5 (PO 4 ) 3 OH crystals by phosphorous functional groups on the carbon surfaces. This study provides the possibility of synthesis high-efficient adsorbent using economic and environmental-friendly approach with low energy consumption. [ABSTRACT FROM AUTHOR]

Highlights • This is a joint theory/experiment on atomistic probe of ion trap electrode surface dynamics. • This work lays out measurements and complimentary calculations of the work function variation with adatom contaminant on trap surfaces. • As experiment can deterministically deposit carbon adatoms on gold surfaces, the adsorption dynamics is described with mobile fluctuating dipoles on reconstructed gold surface. Abstract The variation of the work function upon carbon adsorption on the reconstructed Au(110) surface is measured experimentally and compared to density functional calculations. The adsorption dynamics is simulated with ab-initio molecular dynamics techniques. The contribution of various energetically available adsorption sites on the deposition process is analyzed, and the work function behavior with carbon coverage is explained by the resultant electron charge density distributions. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Identifying the exact mechanism of C C chain formation in syngas conversion to C 2 oxygenate is a significant yet challenging issue. Based on a detailed density functional theory study, we find for the first time that γ-AlOOH (0 0 1) surface not only has specific activity for the carbon chain growth but also prefers an unconventional route for syngas conversion to ethanol. Our results reveal that the optimal route starts with CO hydrogenation to CHO, followed by reacting with CO to form key intermediate CH and release CO 2 , then the initial C C chain is formed via CO insertion into CH along with conquering a 0.76 eV barrier and exothermic by 1.90 eV, finally CHCO undergoes successive hydrogenation to produce ethanol in which the step of CH formation is identified as the rate-determining step of the overall process. In addition, as determined from the Bader charge analysis, carbon chain growth proceeding by CO insertion into CH is more facile. Moreover, the arising of CO 2 during the process of syngas conversion to ethanol is inevitable, which is well consistent with our previous experiments. Notably, compared to our previously reported γ-AlOOH (1 0 0) surface, the γ-AlOOH (0 0 1) surface is inclined to trigger syngas conversion because the more saturated adsorption sites on the γ-AlOOH (0 0 1) surface lower the barriers associated with corresponding steps by weakening the absorption of key intermediates with suitable binding energy. The insights might be valuable for rational tailoring and designing of better, stable catalysts with superior reactivity involved in syngas conversion. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The hollow structure MnO 2 @NHCS was prepared for BPA degradation. • The synergy between adsorption (NHCS) and oxidization (MnO 2) was realized. • The removal rate of BPA was 95.3% within 10 min by MnO 2 @NHCS. • The possible degradation pathways of BPA were proposed. Abstract In this research, a novel efficiency MnO 2 @Nano hollow carbon sphere (MnO 2 @NHCS) nanocomposite was prepared by one-pot hydrothermal reaction with KMnO 4 solution. The adsorption and oxidization performance of MnO 2 @NHCS were assessed by degradation of bisphenol A (BPA) at different conditions. The effect of dosage of MnO 2 @NHCS, pH, initial concentration of BPA, temperature and humic acid were investigated systematically. Moreover, the characterizations of MnO 2 @NHCS were measured by a series of techniques, such as XRD, FESEM, HRTEM, TGA and XPS. Notably, hollow structure of nano carbon sphere was still retained with uniform MnO 2 nanosheets covered. The results show that the removal rate of BPA was 95.3% within 10 min and BPA can be almost decomposed in 30 min under the optimal conditions. Additionally, the MnO 2 @NHCS remained stable and had a high regeneration efficiency (more than 85%) after 3 cycles (360 min). The reaction intermediates/products of oxidation of BPA were analyzed and the possible degradation pathways of BPA were proposed. These research results demonstrate that the MnO 2 @NHCS is a fleet and efficient material for BPA degradation in aqueous environment. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pyrolysis of pecan nut shell was studied by microwave heating. • Carbons were obtained in one step without any additional activation process. • The processing times with microwave heating are short. • Textural properties of carbons control the adsorption of dyes. Abstract In the present work, the pyrolysis of pecan nut shell was studied using microwave technology at different input power and exposure time. The carbonaceous products were characterized using elemental analysis, potentiometric titration, thermogravimetric analysis, N 2 adsorption isotherms at −196 °C and FT-IR spectroscopy. The characteristics of microwave carbonaceous products were compared with carbons prepared by conventional heating and commercial carbons and finally, the interaction of textile dyes with the carbonaceous materials was studied. The results are indicating that it is possible to obtain carbonaceous materials with similar textural parameters in conventional and microwave systems, but for microwave heating the processing times are short (3 min). Also, the exposure time of 2 min of microwave are not enough for the complete depolymerization of the lignocellulosic matrix of the pecan nut shell and significant amount of cellulose and hemicelluloses remain in char after microwave treatment. Finally, all the carbons obtained by microwave heating are microporous materials with a high number of basic groups on their surface and the high molecular size of dyes is controlling the adsorption on these materials. [ABSTRACT FROM AUTHOR]

Amine and polyamine-based materials have been widely cited as solid CO 2 sorbents and as catalyst modifiers for CO 2 electrochemical reduction, however, lab-scale research into a pilot or industrial-scale application is challenging, beginning with the identification of an effective adsorbent. In this investigation, a membrane with a strong affinity for the adsorption and absorption of carbon dioxide is made by blending small molecular amines and a poly(allylamine) (PAA) solution. The membrane was characterized using Fourier-transform infrared spectroscopy (FTIR) and Scanning Electron Microscope (SEM). The results show that Ethylenediamine (EDA)/Methyldiethanolamine (MDEA) is cross-linked with PAA via hydrogen bonds. We change the proportion of EDA/MDEA with PAA to determine the carbon dioxide separation and selectivity of membranes in ambient air. Results from the separation effectiveness deterioration test for MDEA and PAA, with the same ratio 7 wt% at 200 mbar pressure, show decreased CO 2 concentrations of 98 and 35 ppm, respectively. [ABSTRACT FROM AUTHOR]

The effect of palladium segregation was studied which resulted from the effect of CO and O2 on the surface structure and catalytic characteristics of the Pd-Ag2/Al2O3 catalyst. The IR-spectroscopic study of adsorbed CO showed that Pd1 centers isolated from each other by silver atoms predominated on the surface of reduced Pd-Ag2/Al2O3, as evidenced by the almost complete absence of absorption bands typical for the multicentred CO adsorption. In the course of catalyst treatment with CO and O2, the intensity of absorption bands characteristic of the multicenter CO adsorption considerably increased due to the transformation of a portion of monatomic Pd1 centers into multiatomic Pdn ones as a result of the surface segregation of Pd. In this case, a substantial increase in the catalyst activity in the liquid-phase hydrogenation of diphenylacetylene was observed. It was established that, after treatment with CO, the catalyst selectivity for the formation of a target olefin (stilbene) remained almost constant, whereas the treatment with O2 led to a decrease in the selectivity because of more considerable surface modification. [ABSTRACT FROM AUTHOR]

For the purpose of producing carbons with developed mesoporosity, a wood biochar was thermally treated at 600–800 °C in the air/nitrogen atmosphere. The mesopore development was observed when the air flux increased to 50–90 mL/min, and the carbon product having high mesopore surface area (316 m 2 /g) and mesopore pore volume (0.284 cm 3 /g) was produced at the treatment temperature of 700 °C. The mesopores were developed mainly in the temperature holding stage of thermal treatment, with size mainly ranged from 20 to 60 Å. The carbons’ adsorption to the antibiotic tetracycline was enhanced by 5.5–9.2 folds when the air/nitrogen mixture was used instead of nitrogen atmosphere in thermal treatment, and the enhanced adsorption is positively related to the mesopore development. In general, this research provides a facile way to produce carbons with developed mesoporosity, so as to improve their adsorption to bulky organic molecules. [ABSTRACT FROM AUTHOR]

A Middle East-based amine sweetening unit, with an overall capacity of about 2.2 BSCFD of gas, is among the world’s largest process plants and currently processes sour gas with 10 mol% of hydrogen sulfide (H2S) and carbon dioxide (CO2) put together. Current expectation is that acid gas contents in the feed may increase beyond the design limit of the plant. The present work is an effort to quantify the effects of the feed gas CO2 increase on the plant and to proffer solutions to handle these effects efficiently. We revised the kinetics of amine-based CO2 absorption correlation of an existing model using real-data-driven parameters re-estimation. Evolutionary technique that employs particle swarm optimization algorithm is used for this purpose. The new CO2 kinetic model is inserted in a first-principle process simulator, ProMax® V4.0, in order to analyze various solutions necessary to mitigate the operational challenges due to increased feed CO2. The process plant with present design and operating conditions is determined to handle up to 8.45 mol% CO2 contents in the sour gas feed. Further results revealed that methyldiethanolamine, diethanolamine, and dimethyl ether propylene glycol (DEPG) could not handle this high feed CO2 challenge, even at maximum (design) steam and solvent usage. However, diglycolamine exclusively renders the solution as it treats high CO2 feed gas efficiently with allowable utility consumption, while satisfying the constraints imposed by product gas specifications. [ABSTRACT FROM AUTHOR]

We have examined the transmission of soft X-ray pulses from the FERMI free electron laser through carbon films of varying thickness, quantifying nonlinear effects of pulses above and below the carbon K-edge. At typical of soft X-ray free electron laser intensities, pulses exhibit linear absorption at photon energies above and below the K-edge, ∼308 and ∼260 eV, respectively; whereas two-photon absorption becomes significant slightly below the K-edge, ∼284.2 eV. The measured two-photon absorption cross section at 284.18 eV (∼6 × 10 −48  cm 4  s) is 7 orders of magnitude above what is expected from a simple theory based on hydrogen-like atoms – a result of resonance effects. [ABSTRACT FROM AUTHOR]

Hexagonal Co/C composites have been successfully prepared by hydrothermal method. And the preparation of hexagonal Co/C composites can provide possibilities for fabricating other metal/C composites. With different content carbon, the absorbing capacities of hexagonal Co/C are different. By analyzing the electromagnetic parameters, we have proved the similar Cole-Cole semicircles in μ ″- μ ′ curves and each similar Cole-Cole corresponds to a loss of resonance. However, the first similar Cole-Cole semicircle has more important to reflection loss ( RL ). The optimum RL value is −47.5 dB, and the broadest band of RL  ≤ -10 dB is 5.6 GHz. [ABSTRACT FROM AUTHOR]

The photosynthetic quantum yield (Φ), defined as carbon fixed or oxygen evolved per unit of light absorbed, is a fundamental but rarely determined biophysical parameter. A method to estimate Φ for both net carbon uptake and net oxygen evolution simultaneously can provide important insights into energy and mass fluxes. Here we present details for a novel system that allows quantification of carbon fluxes using pH oscillation and simultaneous oxygen fluxes by integration with a membrane inlet mass spectrometer. The pHOS system was validated using Phaeodactylum tricornutum cultured with continuous illumination of 110 μmole quanta m-2 s-1 at 25°C. Furthermore, simultaneous measurements of carbon and oxygen flux using the pHOS-MIMS and photon flux based on spectral absorption were carried out to explore the kinetics of Φ in P. tricornutum during its acclimation from low to high light (110 to 750 μmole quanta m-2 s-1). Comparing results at 0 and 24 hours, we observed strong decreases in cellular chlorophyll a (0.58 to 0.21 pg cell-1), Fv/Fm (0.71 to 0.59) and maximum ΦCO2 (0.019 to 0.004) and ΦO2 (0.028 to 0.007), confirming the transition toward high light acclimation. The Φ time-series indicated a non-synchronized acclimation response between carbon uptake and oxygen evolution, which has been previously inferred based on transcriptomic changes for a similar experimental design with the same diatom that lacked physiological data. The integrated pHOS-MIMS system can provide simultaneous carbon and oxygen measurements accurately, and at the time-resolution required to resolve high-resolution carbon and oxygen physiological dynamics. [ABSTRACT FROM AUTHOR]

Herein, we report an efficient separation and enrichment method for chlorogenic acid from crude extracts of Eucommia ulmoides leaves using carbon adsorbents. The effects of the pore structure of the carbon adsorbents on the adsorption capacity were studied. Of the four adsorbents investigated, mesoporous carbon (MC3) showed the highest adsorption capacity (294 mg/g of carbon) for chlorogenic acid due to its high mesopore volume. The static adsorption of CGA on carbon can be accurately described using the Freundlich equation. The kinetics of adsorption follow a pseudo-second-order process. External mass transfer was the controlling step of the adsorption process. Dynamic adsorption on MC3 demonstrated that chlorogenic acid began to break through after 28 bed volumes of extract was loaded. This mesoporous carbon-treatment procedure is safe, economic and has the potential to be scaled up for commercial application. [ABSTRACT FROM AUTHOR]

A novel magnetic carbon nitrogen adsorbent (Fe 3 O 4 &g-C 3 N 4 ) was first prepared by one step method and applied to remove Zn(II), Pb(II) and Cd(II) from aqueous solution. Scanning electron microscope (SEM), transmission electron microscope (TEM), fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermo-gravimetric analyzer (TGA), X-Ray fluorescence (XRF) and vibrating sample magnetometer (VSM) were used to character Fe 3 O 4 &g-C 3 N 4 . The adsorption performance of Fe 3 O 4 &g-C 3 N 4 was evaluated by batch experiments with different pH, contact time, initial concentration and ionic strength. Pseudo-second-order model and intraparticle diffusion mode can well describe the adsorption kinetics data. Isothermal adsorption data was best fitted by Freundlich model and the adsorption capacity were 45, 137 and 102 mg/g (initial concentration: 200 mg/L) for Zn(II), Pb(II) and Cd(II), respectively. The result of X-ray photoelectron spectroscopy (XPS) survey spectrum suggested that the formation of conjugation of Fe 3 O 4 &g-C 3 N 4 with heavy metal ions is the main adsorption mechanism for heavy metal ions on Fe 3 O 4 &g-C 3 N 4 . Moreover, the metal ions adsorbed Fe 3 O 4 &g-C 3 N 4 could be regenerated by EDTA and the adsorption capacity of regenerative Fe 3 O 4 &g-C 3 N 4 could maintain 88.9% after five cycles. Therefore, the Fe 3 O 4 &g-C 3 N 4 is a potential adsorbent for separating Zn(II), Pb(II) and Cd(II) from wastewater. [ABSTRACT FROM AUTHOR]

Although experimental design is important in many fields and industries, most undergraduate students do not get exposure to this in a standard lab curriculum. This work describes a student-designed, multiple-week, flexible chemistry experiment with environmental applications that include factorial experimental design and analysis of variance statistical analysis. Through the experiment, students attempt to gain a better understanding of activated carbon adsorption of dyes under a set of factors, which could include type of dye, type of carbon, pH, salinity, hardness, and time of contact, each at multiple levels. The experiment is easily adaptable for a range of student enrollments and uses only common laboratory glassware and any visible spectrometer. [ABSTRACT FROM AUTHOR]

The carbon adsorbents used for flue gas desulfurization in a moving bed reactor often suffer from serious abrasion loss, which has significantly increased the operation cost and reduced the continuous operating period. Here, we present a novel approach to reinforcing N-doped mesoporous carbons (NMPCs) by adding a small amount of N-doped carbon nanotubes (NCNTs). Compared to the undoped carbon nanotubes, the NCNTs exhibit better dispersibility in solvent and enhanced interface combination with NMPCs, which has efficiently enhanced the mechanical strength of the NCNT-NMPC composite materials. The largest fracturing strength and the best attrition resistance are obtained at a NCNT addition of 0.1 wt %. Meanwhile, the NCNT-NMPC composite delivers an average SO2 adsorption capacity of 21.2 mg/g, which is 84% higher than the undoped mesoporous carbon. Our results indicate that the defective sites introduced by N doping can help to improve the interface combination between different carbon species, and that the as-prepared NCNT-NMPC composite material is a promising high performance absorbent for flue gas desulfurization. [ABSTRACT FROM AUTHOR]

Coral reefs in Malaysia face the critical threat of bleaching due to a considerable increase of both atmospheric temperatures and sea temperatures. Acidification of oceans, due to the increase of carbon absorbed by the sea, also contributes to the bleaching of coral reefs. Mangroves are known as ‘blue carbon sinks’ due to their ability to transfer and store carbon in their sediments and within plant parts at rates far greater than terrestrial forests. However, the destruction of mangroves has released the carbon stored within them, which has in turn contributed to the increase of atmospheric temperature. Under Malaysia’s National Forestry Act, logging of mangroves is permitted with licences granted by the Ministry of Forestry. Therefore, we attempt to investigate and propose a new legislation, the Mangroves Act and amend the existing National Forestry Act to remedy this current phenomenon. Qualitative methodology with analytical, historical and comparative approaches were adopted in this study and the results indicate that mangroves have great potential to conserve and protect coral reefs due to their role of controlling the increase of atmospheric temperature by storing carbon for decades. [ABSTRACT FROM AUTHOR]

The effect of single frothers and their blends on bubble size, froth stability, and unburned carbon (UC) flotation performance was studied. Methyl isobutyl carbinol that produces smaller bubbles is efficient in floating ultrafine particles and producing concentrate. DF-250 that gives higher froth stability is effective for recovering coarse particles and improving recovery. The presence of DF-250 in the blend increases bubble size and significantly enhances froth stability, and hence the optimal flotation performance is achieved with 75% DF-250. It indicates that the frother giving high froth stability is better in UC flotation due to the little effect of UC on froth stability. [ABSTRACT FROM AUTHOR]

For the first time, paint sludge waste (PS) was used as a pore forming agent in the preparation of sewage sludge derived carbon (SC). The tuning role and mechanism of PS for characteristics of SC were explored. It was found that a sludge carbon (SC PS-Zn ) with rich macro-, meso- and micro- porous could be produced by one-step pyrolytic process of sludge in the presence of PS and ZnCl 2. Its surface area could reach as high as 680.5 m 2 g −1 as 88.4 times and 4.8 times of sludge carbon without addition of PS and ZnCl 2 (SC) and only addition of ZnCl 2 (SC Zn ) , respectively. The macro- pores fabricated by PS provided much inner-space for ZnCl 2 to generate meso- and micro- porous, leading to a hierarchical porous structure. SC PS-Zn showed a high adsorption capacity of 685.4 mg g −1 for Chrysophenine, which is 1.3 and 1.7 times that of SC PS and SC Zn respectively. The adsorption difference could be simply attributed to the fact that the great molecules were difficult to enter micro- pores of SC Zn . It was also found that the difference was also dependent on orientation of Chrysophenine, which was related to pH value of solution. [ABSTRACT FROM AUTHOR]

Waste Polyethylene terephthalate (PET) bottles were pyrolyzed in the presence of nitrogen and converted into activated carbon (PETAC) by physical activation in carbon dioxide flow. An ex-situ precipitation and external reduction method were applied for the intercalation of ferromagnetic iron oxides onto the PETAC matrix. The characteristic structural and chemical properties of PETAC and magnetic PETAC (M-PETAC) were studied by Brunauer Emmett Teller (BET) surface area analysis, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) analysis, Raman spectroscopy, X-Ray Diffraction (XRD) analysis, Energy Dispersive analysis of X-rays (EDAX), Vibrating Sample Magnetometer (VSM), Thermal gravimetric analysis (TGA) and elemental analysis. Characterization results indicated that PETAC exhibited a relatively smooth and microporous texture with a surface area of 659.6 m 2 g -1 while M-PETAC displayed a rugged morphology with a diminished surface area of 288.8 m 2 g -1 . XRD measurements confirmed the formation of iron oxide nanocrystallites with an average Scherrer crystallite size of 19.2 nm. M-PETAC delivered a quick response to an external magnet and exhibited saturation magnetization value of 35.4 emu g −1 . PETAC and M-PETAC were explored as potential adsorbents for the adsorption of a pharmaceutical (cephalexin) from water. Isotherm analysis revealed that M-PETAC exhibited a superior adsorption capacity (71.42 mg g −1 ) compared to PETAC (21.27 mg g −1 ). FTIR analysis of the adsorbents after CEX adsorption revealed the role of Fe O as the nucleation site for enhanced adsorption of cephalexin by M-PETAC. [ABSTRACT FROM AUTHOR]

We use first-principles calculations to study the carbon adsorption on copper slabs of (100) and (111) surfaces predosed by oxygen atoms. Our results show that on both surfaces, an incoming carbon atom has the ability to replace and completely desorb a previously surface-adsorbed oxygen atom producing CO and CO2 molecules in the gas phase. By comparison, the (111) surface is better suited for oxygen desorption, and an incoming carbon atom can more easily bond to and desorb oxygen atoms even at low oxygen coverages. We examine this mechanism at two different temperatures for both surfaces at 0.5 ML oxygen coverage. An implication of this process is the experimentally proven cleaning effect of predosing copper surfaces with oxygen before graphene growth in the chemical vapor deposition process. Conversely, adsorption and diffusion of carbon atoms, both of which are necessary for the nucleation and growth of carbon nanotubes, may be hindered by the presence of the oxidized or partially oxidized surfaces. [ABSTRACT FROM AUTHOR]

Pristine graphene oxide (GO) sheets were pretreated with polyethyleneimine (PEI) to prepare PEI-modified GO (PEI-GO), which was further inserted with ZIF-8 crystals to form a novel PEI-GO@ZIF-8 nanocomposite for CO 2 capture. The good dispersion of PEI and interlayer growth of ZIF-8 within the GO sheets is helpful for high CO 2 adsorption. Therefore, the PEI-GO@ZIF-8 nanocomposite show high surface area and enhanced CO 2 adsorption capacity. The adsorption capacity of the PEI-GO@ZIF-8 nanocomposite was six times higher than that of the pristine GO and ZIF-8. The CO 2 /N 2 adsorption selectivity was significantly improved due to amine groups loading which provide more sites for CO 2 adsorption. The preferential adsorption of CO 2 over N 2 makes PEI-GO@ZIF-8 nanocomposite be a promising candidate in the field of CO 2 capture. [ABSTRACT FROM AUTHOR]

A nucleophilic aromatic substitution reaction was proposed to synthesize porous carbon nanotubes (CNTs) to avoid their aggregation in solution. Hydroxylated carbon nanotubes (CNTs-OH) were reacted with different concentrations of rigid decafluorobiphenyl (DFB) to form the different CNTs-based adsorbents (CNT-DFB0.9, CNT-DFB1.8, CNT-DFB2.7 and CNT-DFB3.6). Among them, CNT-DFB1.8 exhibited the highest adsorption capacity for carbamazepine (CBZ) and tetracycline (TC) due to its higher specific surface area and pore volume than powdered CNTs. The proposed reaction was verified and the textural properties of the CNT-DFB adsorbent were characterized. The CNT-DFB1.8 adsorbent exhibited faster adsorption for CBZ than TC, and the maximum adsorption capacities for CBZ and TC were 403.0 and 456.5 μmol/g respectively, according to the Langmuir fitting. With the increase of solution pH, TC adsorption on CNT-DFB1.8 decreased while CBZ adsorption increased. In addition, a simple thermal method was applied to regenerate the spent CNT-DFB1.8 by heating in air at 400 °C, and the adsorption capacity changed little in the five adsorption cycles. This study provided a novel method to increase the dispersion of CNTs in the prepared adsorbent, showing the potential application for the removal of pharmaceuticals in water or wastewater treatment. [ABSTRACT FROM AUTHOR]

In order to enhance the solar thermal energy conversion efficiency, we propose to use carbon-gold core-shell nanoparticles dispersed in liquid water. This work demonstrates theoretically that an absorbing carbon (C) core enclosed in a plasmonic gold (Au) nanoshell can enhance the absorption peak while broadening the absorption band; giving rise to a much higher solar absorption than most previously studied core-shell combinations. The exact Mie solution is used to evaluate the absorption efficiency factor of spherical nanoparticles in the wavelength region from 300 nm to 1100 nm as well as the electric field and power dissipation profiles inside the nanoparticles at specified wavelengths (mostly at the localized surface plasmon resonance wavelength). The field enhancement by the localized plasmons at the gold surfaces boosts the absorption of the carbon particle, resulting in a redshift of the absorption peak with increased peak height and bandwidth. In addition to spherical nanoparticles, we use the finite-difference time-domain method to calculate the absorption of cubic core-shell nanoparticles. Even stronger enhancement can be achieved with cubic C-Au core-shell structures due to the localized plasmonic resonances at the sharp edges of the Au shell. The solar absorption efficiency factor can exceed 1.5 in the spherical case and reach 2.3 in the cubic case with a shell thickness of 10 nm. Such broadband absorption enhancement is in great demand for solar thermal applications including steam generation. [ABSTRACT FROM AUTHOR]

Although research attentions for CO 2 injection in gas-bearing reservoirs have been drawn to CO 2 sequestration with enhanced gas recovery (CS-EGR), the microscopic competitive adsorption mechanism of methane (CH 4 ) and carbon dioxide (CO 2 ) considering the effect of organic type and moisture remains to be determined. In this work, we focus on the competitive adsorption behaviors of CH 4 and CO 2 on dry and moist realistic kerogen models of different organic types by performing combined molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations. The effects of organic type and moisture content on kerogen pore structures, moisture distribution and interaction between CH 4 /CO 2 and kerogen surfaces are discussed in details. Simulation results show that CO 2 /CH 4 adsorption capacity and adsorption selectivity are in the order of kerogen IA < IIA < IIIA, consistent with the sequence of enterable pore volume fraction (IA, 9.38%; IIA, 13.59%; IIIA, 28.88%). H 2 O molecules are preferentially adsorbed on the sulfur- and oxygen-containing groups at low moisture, and then migrate and aggregate into clusters in the middle of enterable pores at high moisture. The CO 2 /CH 4 adsorption capacity decreases with increasing moisture content, while the CO 2 /CH 4 adsorption selectivity, specific adsorption energy and CO 2 isosteric heat decrease at the beginning, and then increase with the moisture content. Moisture has a bigger effect on the adsorption of CO 2 than that of CH 4 . This study indicates that kerogen IIIA is the optimized organic type for CS-EGS due to its large and stable CO 2 storage capacity. Despite its negative effect on gas adsorption capacity, moisture can potentially boost the displacement of CH 4 by CO 2 at certain moisture conditions. Results of this study lay the foundation for future optimization design of CS-EGR projects with application to coal and shale systems. [ABSTRACT FROM AUTHOR]

Biomass derived amorphous carbon has received considerable attention in recent years for its great potential applications. In this work, the cellulosic biomass carbon based montmorillonite composite is synthesized by using carbon-bed pyrolysis method. The micro-structure and properties of samples are characterized by Raman, XRD, FT-IR, SEM, TEM and adsorption analyses. The results demonstrates that the montmorillonite components used to enhance the surface performance (granule-layer structure) also has strengthened the Methylene Blue adsorption capacity of biomass carbon in composite, the adsorption capacity is enhanced as the MT concentration increases, the maximum equilibrium value is obtained for 15 wt% montmorillonite mixed biomass carbon composite (93.5 mg/g), which confirms the effects of clay mineral (montmorillonite) on the biomass carbon in carbon-clay composite system. The isotherm data fits the Freundlich isotherm model (R 2 = 0.927) corresponding to the physical adsorption (n = 1.214, favorable adsorption). The kinetic data is well described by the intraparticle diffusion model (R 2 = 0.939), indicating the intraparticle diffusion controlled adsorption process. [ABSTRACT FROM AUTHOR]

Carbon fiber adsorbents based on hydrated cellulose fiber, in which the transport porosity is absent, due to which the micropores become readily accessible towards adsorptive molecules have been studied. The aim of this work is to study the influence of the conditions of sorbent synthesis on their adsorption properties. The state of the surface of pristine carbon fiber has been determined, and the porous structure of activated carbon fibers has been estimated. It has been found that, when activating the cloth with a temperature of heat treatment of 1070-1270 K, it becomes possible to obtain the adsorbent with good molecular-sieve characteristics, although with the relatively small micropore volume. It has been suggested that it is linked with the restructuring of the carbon fiber structure that takes place at the activation temperature in cloths. During the study, it has been experimentally found and confirmed that the adsorption properties of sorbents obtained differ depending on the synthesis conditions and the surface state. [ABSTRACT FROM AUTHOR]

The interactions of CO with amorphous, monoclinic, and tetragonal zirconia were investigated by diffuse reflectance infrared (DRIFT) and transmission FT-IR spectroscopy to determine the active sites for CO adsorption. The results showed that zirconia polymorphs exerted a great influence on CO bands and the formation of surface intermediates. Meanwhile, differences of CO bands and surface intermediates were observed between DRIFT and transmission FT-IR spectra. Two ways were proposed to produce active sites for CO adsorption, one way was thermal dehydroxylation in vacuum and the other was CO reaction with hydroxyls at high temperature. The former was the main way to produce active sites for CO adsorption in transmission FT-IR spectra, and the latter was the main way to produce active sites for CO adsorption in DRIFT spectra. [ABSTRACT FROM AUTHOR]

Carbon quantum dots (CQDs) was successfully functionalized with Mal-PEG-NHS linked RGERPPR. They exhibit double functions of both tissue imaging and targeting to brain gliomas. The mean size of the functionalized CQDs about 9.0 ± 2.0 nm. The maximum absorption wavelength of the functionalized CQDs appear at 230 nm. The peak of the fluorescence spectra for the functionalized CQDs is at 460 nm, red shifted by 20 nm comparing with the unmodified CQDs. This may be due to the increased particle size. The functionalized CQDs were successfully applied to imaging and targeting gliomas. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: The growth limitation hypothesis (GLH) and carbon limitation hypothesis (CLH) are two dominant explanations for treeline formation. The GLH proposes that low temperature drives the treeline through constraining C sinks more than C sources, and it predicts that non-structural carbohydrate (NSC) levels are static or increase with elevation. Although the GLH has received strong support globally for evergreen treelines, there is still no consensus for deciduous treelines, which experience great asynchrony between supply and demand throughout the year. METHODS: We investigated growth and the growing-season C dynamics in a common deciduous species, Erman's birch (Betula ermanii), along an elevational gradient from the closed forest to the treeline on Changbai Mountain, Northeast China. Samples were collected from developing organs (leaves and twigs) and main storage organs (stems and roots) for NSC analysis. KEY RESULTS: Tree growth decreased with increasing elevation, and NSC concentrations differed significantly among elevations, organs, and sampling times. In particular, NSC levels varied slightly during the growing season in leaves, peaked in the middle of the growing season in twigs and stems, and increased continuously throughout the growing season in roots. NSCs also tended to increase or vary slightly in developing organs but decreased significantly in mature organs with increasing elevation. CONCLUSIONS: The decrease in NSCs with elevation in main storage organs indicates support for the CLH, while the increasing or static trends in new developing organs indicate support for the GLH. Our results suggest that the growth limitation theory may be less applicable to deciduous species' growth than to that of evergreen species. [ABSTRACT FROM AUTHOR]