Combined Promoting Effects of Specific Organic Functional Groups and Alumina Surface Characteristics for the Design of a Highly Efficient NiMo/Al_(2)O_(3) Hydrodesulfurization Catalyst

To prepare a highly efficient NiMo/Al_(2)O_(3) hydrodesulfurization catalyst,the combined effects of specific organic functional groups and alumina surface characteristics were investigated.First,the correlation between the surface characteristics of four different alumina and the existing Mo species states was established.It was found that the Mo equilibrium adsorption capacity can be used as a specific descriptor to quantitatively evaluate the changes in surface characteristics of different alumina.A lower Mo equilibrium adsorption capacity for alumina means weaker metal-support interaction and the loaded Mo species are easier to transform into MoS2.However,the Mo-O-Al bonds still exist at the metal-support interface.The introduction of cationic surfactant hecadecyl trimethyl ammonium bromide(CTAB)can further improve Mo species dispersion through electrostatic attraction with Mo anions and interaction of its alkyl chain with the alumina surface;meanwhile,the introduction of ethylenediamine tetraacetic acid(EDTA)can complex with Ni ions to enhance the Ni-promoting effect on Mo.Therefore,the NiMo catalyst designed using alumina with lower Mo equilibrium adsorption capacity and the simultaneous addition of EDTA and CTAB exhibits the highest hydrodesulfurization activity for 4,6-dimethyl dibenzothiophene because of its proper metal-support interaction and more well-dispersed Ni-Mo-S active phases.

Response of phytoplankton functional group to spring drought in a large subtropical reservoir

Global warming has caused an increase in the frequency and duration of droughts worldwide.Droughts could trigger large changes in physico-chemical conditions and phytoplankton community in waterbodies,resulting in a shift in the phytoplankton community.Spring diatom blooms in reservoirs have been increasingly observed in the past decade in the Taihu Lake basin.The aim of the present study is to elucidate the impacts of droughts on aquatic environment and to determine the driving factors for the succession of the phytoplankton functional groups based on the analysis of data collected during spring from 2009 to 2020 in the Daxi Reservoir.The unimodal relationship between 1-month aggregated precipitation index and phytoplankton species richness indicated the competitive exclusion occurred in extremely drought period.The structural equation modeling indicated that drought-related low water level conditions intensified sediment resuspension,and increased the phosphorus-enriched nonalgal turbidity in the Daxi Reservoir.Concurrently,a steady shift in the Reynolds phytoplankton functional groups from L 0,TD,J,X 2,and A(phytoplankton taxa preferring low turbidity and nutrient conditions)to TB(pennate diatoms being adapt to turbid and nutrient-rich conditions)was observed.The increased TP and non-algal turbidity in addition to the lowered disturbance contribute to the prevalence of Group TB.Considering the difficulties in nutrient control,timely water replenishment is often a feasible method of controlling the dominance of harmful algae for reservoir management.Finally,alternative water sources are in high demand for ensuring ecological safety and water availability when dealing with drought.

Overstory functional groups indicate the legacy of land use in a secondary tropical forest in southwestern China

Anthropogenic disturbances are widespread in tropical forests and influence the species composition in the overstory.However,the impacts of historical disturbance on tropical forest overstory recovery are unclear due to a lack of disturbance data,and previous studies have focused on understory species.In this study,the purpose was to deter-mine the influence of historical disturbance on the diver-sity,composition and regeneration of overstory species in present forests.In the 20-ha Xishuangbanna tropical sea-sonal rainforest dynamics plot in southwestern China,the historical disturbance boundaries were delineated based on panchromatic photographs from 1965.Factors that drove species clustering in the overstory layer(DBH≥40 cm)were analyzed and the abundance,richness and composition of these species were compared among different tree groups based on multiple regression tree analysis.The coefficient of variation of the brightness value in historical panchro-matic photographs from 1965 was the primary driver of spe-cies clustering in the overstory layer.The abundance and richness of overstory species throughout the regeneration process were similar,but species composition was always different.Although the proportion of large-seeded and vigorous-sprouting species showed no significant differ-ence between disturbed and undisturbed forests in the tree-let layer(DBH<20 cm),the difference became significant when DBH increased.The findings highlight that historical disturbances have strong legacy effects on functional group composition in the overstory and the recovery of overstory species was multidimensional.Functional group composi-tion can better indicate the dynamics of overstory species replacement during secondary succession.

Stabilizing Buried Interface via Synergistic Effect of Fluorine and Sulfonyl Functional Groups Toward Efficient and Stable Perovskite Solar Cells

The interfacial defects and energy barrier are main reasons for interfacial nonradiative recombination.In addition,poor perovskite crystallization and incomplete conversion of PbI_(2) to perovskite restrict further enhancement of the photovoltaic performance of the devices using sequential deposition.Herein,a buried interface stabilization strategy that relies on the synergy of fluorine(F)and sulfonyl(S=O)functional groups is proposed.A series of potassium salts containing halide and non-halogen anions are employed to modify SnO_(2)/perovskite buried interface.Multiple chemical bonds including hydrogen bond,coordination bond and ionic bond are realized,which strengthens interfacial contact and defect passivation effect.The chemical interaction between modification molecules and perovskite along with SnO_(2) heightens incessantly as the number of S=O and F augments.The chemical interaction strength between modifiers and perovskite as well as SnO_(2) gradually increases with the increase in the number of S=O and F.The defect passivation effect is positively correlated with the chemical interaction strength.The crystallization kinetics is regulated through the compromise between chemical interaction strength and wettability of substrates.Compared with Cl−,all non-halogen anions perform better in crystallization optimization,energy band regulation and defect passivation.The device with potassium bis(fluorosulfonyl)imide achieves a tempting efficiency of 24.17%.

Eff ects of stand condition and root density on fi ne-root dynamics across root functional groups in a subtropical montane forest

Fine roots play key roles in belowground C cycling in terrestrial ecosystems.Based on their distinct functions,fi ne roots are either absorptive fi ne roots(AFRs)or transport fi ne roots(TFRs).However,the function-based fi ne root dynamics of trees and their responses to forest stand properties remain unclear.Here,we studied the dynamics of AFRs and TFRs and their responses to stand conditions and root density in a subtropical montane mixed forest based on a 2-a root window experiment.Mean(±SE)annual production,mortality,and turnover rate of AFRs were 7.87±0.17 m m^(−2)a^(−1),8.13±0.20 m m^(−2)a^(−1)and 2.96±0.24 a^(−1),respectively,compared with 7.09±0.17 m m^(−2)a^(−1),4.59±0.17 m m^(−2)a^(−1),and 2.01±0.22 a^(−1),respectively,for TFRs.The production and mortality of fi ne roots were signifi cantly higher in high root-density sites than in low-root density sites,whereas the turnover of fi ne roots was faster in the low root-density sites.Furthermore,root density had a larger positive eff ect than other environmental factors on TFR production but had no obvious impact on AFR production.Tree species diversity had an apparent positive eff ect on AFR production and was the crucial driver of AFR production,probably due to a complementary eff ect,but had no evident impact on TFR.Both tree density and tree species diversity were positively correlated with the mortality of AFRs and negatively related to the turnover of TFRs,suggesting that higher root density caused stronger competition for rooting space and that plants tend to reduce maintenance costs by decreasing TFR turnover.These fi ndings illustrated the importance of root functional groups in understanding root dynamics and their responses to changes in environmental conditions.

Functional groups and seasonal diversity of crustacean zooplankton in adjacent waters of Haizhou Bay,South Yellow Sea

Zooplankton are important linkages in the food web and can respond nonlinearly to environmental changes.Marine organisms thrive from spring to summer.Thus,it is crucial to understand how ecological functions of zooplankton communities may shift under seasonal environmental changes during this period.Samples were collected from May to August(May,June-Ⅰ,June-Ⅱ,July-Ⅰ,July-Ⅱ,and August)in 2018 in Haizhou Bay,Jiangsu,East China for zooplankton and environmental variables.Crustaceans accounted for 75 out of 134 zooplankton taxa and 91.8%of total zooplankton abundance.The average abundance of crustacean varied between 2824.6±635.4 inds./m3 in July-Ⅱand 6502.7±1008.8 inds./m3 in June-Ⅱ.Multivariate analyses results showed that the dissimilarity of community increased gradually in the time series.Body length,feeding type,trophic group,and reproduction mode were used to investigate crustacean community functions.Trait-based functional groups contained species with similar ecological roles.Functional diversity fused the differences of species and trait.The proportion of large-sized species(2-5 mm)decreased with the increasing proportion of medium-sized species(1-2 mm).The proportion of current feeders increased with the drop in the proportion of mixed feeders.Parthenogenesis species increased with decreasing free spawners,and omnivores-carnivores increased with decreasing omnivoresherbivores.Generalized additive models suggested that temperature was the main driver of variations in crustacean zooplankton function.Seven identified functional groups varied with increasing temperature.Omnivorous-herbivorous copepods declined(90.0%-68.0%),whereas the parthenogenetic cladocerans increased(0-24.1%).The small egg-brooding ambush copepods fluctuated(6.5%-9.3%)with increasing water temperature.The other functional groups changed slightly.Functional diversity also varied according to temperature changes.The community structure and ecological function of crustacean zooplankton community showed gradual changes with increasing temperature from spring to summer.

States of graphene oxide and surface functional groups amid adsorption of dyes and heavy metal ions

Water pollution regarding dyes and heavy metal ions is crucial facing the world.How to effectively separate these contaminants from water has been a key issue.Graphene oxide(GO)promises the greenwater world as a long-lasting spotlight adsorbent material and therefore,harnessing GO has been the research hotspot for over a decade.The state of GO as well as its surface functional groups plays an important role in adsorption.And the way of preparation and structural modification matters to the performance of GO.In this review,the significance of the state of existence of stock GO and surface functional groups is explored in terms of preparation,structural modification,and adsorption.Besides,various adsorbates for GO adsorption are also involved,the discussion of which is rarely established elsewhere.

Superior electrocatalytic negative electrode with tailored nitrogen functional group for vanadium redox flow battery

Development of electrodes with high electrocatalytic activity and stability is essential for solving problems that still restrict the extensive application of vanadium redox flow batteries(VRFBs).Here,we designed a novel negative electrode with superior electrocatalytic activity by tailoring nitrogen functional groups,such as newly formed nitro and pyridinic-N transformed to pyridonic-N,from the prenitrogen-doped electrode.It was experimentally confirmed that an electrode with pyridonic-N and nitro fuctional groups(tailored nitrogen-doped graphite felt,TNGF) has superior electrocatalytic acivity with enhanced electron and mass transfer.Density functional theory calulations demonstrated the pyridonic-N and nitro functional groups promoted the adsorption,charge transfer,and bond formation with the vanadium species,which is consistent with expermental results.In addition,the V2+/V3+redox reaction mechanism on pyridonic-N and nitro functional groups was estabilised based on density functional theory(DFT) results.When TNGF was applied to a VRFB,it enabled enhanced-electrolyte utilization and energy efficiencies(EE) of 57.9% and 64.6%,respectively,at a current density of 250 mA cm^(-2).These results are 18.6% and 8.9% higher than those of VRFB with electrode containing graphitic-N and pyridinicN groups.Interestingly,TNGF-based VRFB still operated with an EE of 59% at a high current density of300 mA cm^(-2).The TNGF-based VRFB exhibited stable cycling performance without noticeable decay of EE over 450 charge-discharge cycles at a current density of 250 mA cm^(-2).The results of this study suggest that introducing pyridonic-N and nitro groups on the electrode is effective for improving the electrochemical performance of VRFBs.

Research on Stoichiometry of Early-spring Herbs Functional Group in the Subtropical Artificial Wetland

[Objective]The aim was to carry out stoichiometry on the early-spring herbs functional group in subtropical artificial wetland.[Method]UV-Vis spectrophotometer was used for the determination of nitrate-nitrogen,ammonium nitrogen and phosphorus concentrations.Potassium persulfate absorptiometry was used for the measurement of total N content,while the flame photometer was used to detect the potassium and sodium concentration in plants.All the nutrient determination of plant samples were repeated for four times.[Result]The four nutrient concentrations in almost all samples were in the normal range of natural plant nutrition concentrations;in early-spring herbs functional groups,different species showed diversity on the nutrient concentrations;plant height had no significant effect on the nutrient concentrations in plants;the nutrient concentrations of non-grass group plants were higher than that of grass group plants;the nutrient concentrations of the annual herb were higher than that of perennial herbs.[Conclusion]The study had provided basis for the understanding of the effects of changes in nutritional conditions on species diversity,community structure and succession of the system.

Effect of acidic surface functional groups on Cr(Ⅵ) removal by activated carbon from aqueous solution

The activated carbon with high surface area was prepared by KOH activation.It was further modified by H2SO4 and HNO3 to introduce more surface functional groups.The pore structure of the activated carbons before and after modification was analyzed based on the nitrogen adsorption isotherms.The morphology of those activated carbons was characterized using scanning electronic microscopy （SEM）.The surface functional groups were determined by Fourier transform infrared spectroscopy （FTIR）.The quantity of those groups was measured by the Boehm titration method.Cr（VI） removal by the activated carbons from aqueous solution was investigated at different pH values.The results show that compared with H2SO4,HNO3 destructs the original pore of the activated carbon more seriously and induces more acidic surface functional groups on the activated carbon.The pH value of the solution plays a key role in the Cr（VI） removal.The ability of reducing Cr（VI） to Cr（III） by the activated carbons is relative to the acidic surface functional groups.At higher pH values,the Cr（VI） removal ratio is improved by increasing the acidic surface functional groups of the activated carbons.At lower pH values,however,the acidic surface functional groups almost have no effect on the Cr（VI） removal by the activated carbon from aqueous solution.

Biomass Allocation Patterns of Alpine Grassland Species and Functional Groups along a Precipitation Gradient on the Northern Tibetan Plateau

Variations in the fractions of biomass allocated to functional components are widely considered as plant responses to resource availability for grassland plants. Observations indicated shoots isometrically relates to roots at the community level but allometrically at the species level in Tibetan alpine grasslands. These differences may result from the specific complementarity of functional groups between functional components, such as leaf, root, stem and reproductive organ. To test the component complementary responses to regional moisture variation, we conducted a multi-site transect survey to measure plant individual size and component biomass fractions of common species belonging to the functional groups： forbs, grasses, legumes and sedges on the Northern Tibetan Plateau in peak growing season in 2010. Along the mean annual precipitation （MAP） gradient, we sampled 7o species, in which 2o are in alpine meadows, 20 in alpine steppes, 15 in alpine desert-steppes and 15 in alpine deserts, respectively. Our results showed that the size of alpine plants is small with individual biomass mostly lower than 1.0 g. Plants keep relative conservative component individual responses moisture functional fractions across alpine grasslands at the level. However, the complementary between functional components to variations specifically differ among groups. These results indicate that functional group diversity may be an effective tool for scaling biomass allocation patterns from individual up to community level. Therefore, it is necessary andvaluable to perform intensive and systematic studies on identification and differentiation the influences of compositional changes in functional groups on ecosystem primary services and processes.

Adsorption of cadmium ions from aqueous solutions by activated carbon with oxygen-containing functional groups

The adsorption of aqueous cadmium ions(Cd(Ⅱ)) have been investigated for modified activated carbon(AC-T)with oxygen-containing functional groups.The oxygen-containing groups of AC-T play an important role in Cd(Ⅱ) ion adsorption onto AC-T.The modified activated carbon is characterized by scanning electron microscopy,Fourier transform infrared spectroscopy(FT-IR) and X-ray photoelectron spectroscopy(XPS).The results of batch experiments indicate that the maximal adsorption could be achieved over the broad pH range of 4.5 to 6.5.Adsorption isotherms and kinetic study suggest that the sorption of Cd(Ⅱ) onto AC-T produces monolayer coverage and that adsorption is controlled by chemical adsorption.And the adsorbent has a good reusability.According to the FT-IR and XPS analyses,electrostatic attraction and cation exchange between Cd(Ⅱ) and oxygen-containing functional groups on AC-T are dominant mechanisms for Cd(Ⅱ) adsorption.

The Trace Elements are Bounded by Organic Functional Groups in Coal:A Studying Result Based on FTIR Analysis

The relationship between trace elements in coal and organic functional groups of coal, also some of aromatic structure, was investigated by using curve fitting of infrared spectra. Cluster analysis was also performed according to the degree of affinity of organic groups to the trace elements. The results show that there is a possibility that trace elements, especially LREE, were bound to peripheral organic functional groups of middle rank coal macromolecule. The most possible functional group that binds trace element is the hydroxyl, and to the less degree, the asymmetric -CH3 and 〉CH2 stretching, -CH3 stretching, etc. The degree of affinity of trace elements to different functional groups varies. The tendency obeys the natural structural changing law of trace elements-- the periodic law. The deviation of some trace elements from this regular trend is attributed to the deviation of intrinsic ＂confusion degree＂ （conventional molar entropy） of the matter system of coal basin, which is affected by the inner and outer factors during the evolution.

Influence of Functional Groups and Modification Sites of Metal-Organic Frameworks on CO2/CH4 Separation:A Monte Carlo Simulation Study

In order to explore the influence of modification sites of functional groups on landfill gas （CO2/CH4） separation performance of metal-organic frameworks （MOFs）, six types of or- ganic linkers and three types of functional groups （i.e. -F, -NH2, -CH3） were used to construct 36 MOFs of pcu topology based on copper paddlewheel. Grand canonical Monte Carlo sim- ulations were performed in this work to evaluate the separation performance of MOFs at low （vacuum swing adsorption） and high （pressure swing adsorption） pressures, respectively. Simulation results demonstrated that CO2 working capacity of the unfunctionalized MOFs generally exhibits pore-size dependence at 1 bar, which increases with the decrease in pore sizes. It was also found that -NH2 funetionalized MOFs exhibit the highest CO2 uptake due to the enhanced Coulombic interactions between the polar -NH2 groups and the quadrupole moment of CO2 molecules, which is followed by -CH3 and -F functionalized ones. Moreover, positioning the functional groups -NH2 and -CH3 at sites far from the metal node （site b） exhibits more significant enhancement on CO2/CH4 separation performance compared to that adjacent to the metal node （site a）.

The key environmental factors driving the succession of phytoplankton functional groups in Hongfeng Reservoir, southwest China

Reservoirs are an important water source in many densely populated areas in southwest China.Phytoplankton play an essential role in maintaining the structure and function of reservoir ecosystems.Understanding the succession in phytoplankton communities and the factors driving it are essential for eff ective water quality management in drinking water reservoirs.In this study,water samples were collected monthly at the surface layers from March 2016 to December 2019 in Hongfeng Reservoir,southwest China.The relationship between functional group succession was analyzed based on nonmetric multidimensional scaling analysis(NMDS),redundancy analysis(RDA),succession rate,and other analysis methods.The results showed distinct shifts in the community structure of phytoplankton functional groups within study period.The Cyclotella sp.was dominant in 2016 and 2017,and Pseudanabaena limnetica was the dominant group in 2018 and 2019.It appears that the phytoplankton composition and biomass are closely related to the water temperature and nutrient status in this reservoir.The results clearly showed that the permanganate index(COD_(Mn))was the key factor of dramatic phytoplankton functional group succession,and the change in succession rates was closely caused by total nitrogen concentration(TN).Therefore,the succession pattern and key factors of Hongfeng Reservoir revealed in this study were important guidance for the management of drinking water reservoirs in southwest China.A reasonable limit on exogenous nutrient input should be a priority,especially in high water temperature period.

Nb_(2)CT_(x) MXene: High capacity and ultra-long cycle capability for lithium-ion battery by regulation of functional groups

MXenes are well known for their potential application in supercapacitors due to their high-rate intercalation pseudocapacitance and long cyclability.However,the reported low capacity of pristine MXenes hinders their practical application in lithium-ion batteries.In this work,a robust strategy is developed to control the functional groups of Nb_2 CT_x MXene.The capacity of pristine Nb_2 CT_x MXene can be significantly increased by Li~+ intercalation and surface modification.The specific capacity of the treated Nb_2 CT_x is up to 448 mAh g^(-1) at 0.05 A g^(-1),and at a large current density of 2 A g^(-1) remains a high reversible capacity retention rate of 75% after an ultra-long cycle of 2000 cycles.These values exceed most of the reported pristine MXenes(including the most studied Ti_3 C_2 T_x) and carbon-based materials.It demonstrates that this strategy has great help to improve the electrochemical performance of pristine MXene,and the results enhance the promise of MXenes in the application of lithium-ion batteries.

Synthesis and Adsorption Properties of Polystyrene-supported Chelating Resins Containing Heterocyclic Functional Groups

A series of new chelating resins with incorporating heterocyclic functional groups： pyridine, thiadizole, benzothizole into macroporous chloromethylated polystyrene were synthesized via hydrophilic spacer arm of polyethylene glycol containing sulfur. These chelating resins were found to show high adsorption capacities for Ag^＋, Hg^2＋, Au^3＋ and Pd^2＋, and the presence of spacer arm can enhance adsorption ability due to increase the hydrophilicity of the chelating resins.

Board-invited review: Sensitivity and responses of functional groups to feed processing methods on a molecular basis

In complex feed structures, there exist main chemical functional groups which are associated with nutrient utilization and availability and functionality. Each functional group has unique molecular structure therefore produce unique molecular vibration spectral profile. Feed processing has been used to improve nutrient utilization for many years. However, to date, there was little study on processing-induced changes of feed intrinsic structure and functional groups on a molecular basis within intact tissue. This is because limited research technique is available to study inherent structure on a molecular basis. Recently bioanalytical techniques： such as Synchrotron Infrared Microspectroscopy as well as Diffuse Reflectance Infrared Fourier Transform molecular spectroscopy have been developed. These techniques enable to detect molecular structure change within intact tissues. These techniques can prevent destruction or alteration of the intrinsic protein structures during processing for analysis. However, these techniques have not been used in animal feed and nutrition research. The objective of this review was show that with the advanced technique, sensitivity and responses of functional groups to feed processing on a molecular basis could be detected in my research team. These functional groups are highly associated with nutrient utilization in animals.

Free radicals, apparent activation energy, and functional groups during low-temperature oxidation of Jurassic coal in Northern Shaanxi

Correlations among free radicals, apparent activation energy, and functional groups during lowtemperature oxidation of Jurassic coal in Northern Shaanxi were investigated by examining three coal samples collected from the Ningtiaota, Jianxin, and Shigetai coal mines. Free radical concentrations at less than 120 ℃ were investigated by electron spin resonance experiments while the thermogravimetric experiments were conducted to analyze apparent activation energies. In addition, Fourier transform infrared spectroscopy was employed to study the spectrum of functional groups generated in coal. The results indicated that, in decreasing order, the apparent activation energies were Shigetai 〉Jianxin 〉 Ningtiaota, indicating that, from 50 to 120 ℃, the Ningtiaota coal sample most easily absorbed and reacted with oxygen while the most resistant was the Shigetai coal sample. Free radical concentrations and line heights increased with increased temperature, and the line width and Lande factor showed irregular fluctuations. Functional group variations were different among these coals, and the phenol and alcohol-associated OHs, carboxyls, and aromatic ring double bonds might have had a major impact on free radical concentrations. These results were meaningful for better consideration and management of coal oxidation at low temperatures.

Planktonic protist communities in semi-enclosed mariculture waters: temporal dynamics of functional groups and their responses to environmental conditions

The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao,Shandong Province,China,during a six-month study period （a complete shrimp-culture cycle） from May to October 2002.The results reveal that： （1） the protist communities represented five trophic and functional groups of the species identified,about 60% were photoautotrophs,20% algivores,12% bacterivores,5% raptors and about 3% non-selectives;（2） the photoautotrophs,algivores and bacterivores were the primary contributors to the changes in the protist communities in short temporal scales,the succession of dominance typically being bacterivores→photoautotrophs→algivores,with the raptors dominating the protist communities in a single sample （early June）;（3） the photoautotrophs and non-selectives were the primary contributors to the peak of protist abundance in early October whereas the photoautotrophs,bacterivores,raptors and non-selectives mainly gave rise to two bimodal peaks of biomass in July and October respectively;（4） five functional groups of protist communities represented significant correlations with water nutrients （i.e.,NH 3-N,NO 3-N,and PO 4 ）,either alone or in combination with temperature,of which algivores and raptors were strongly correlated with phosphate and the concentration of Chl a,while bacterivores were strongly related to nitrogen and the concentration of bacteria.These findings confirm that planktonic protists are potentially useful bioindicators of water quality in the semi-enclosed mariculture system.