Anaerobic tapered fluidized bed reactor for starch wastewater treatment and modeling using multilayer perceptron neural network

treatability of synthetic sago wastewater was investigated in a laboratory anaerobic tapered fluidized bed reactor （ATFBR） with a mesoporous granular activated carbon （GAC） as a support material. The experimental protocol was defined to examine the effect of the maximum organic loading rate （OLR）, hydraulic retention time （HRT）, the efficiency of the reactor and to report on its steady- state performance. The reactor was subjected to a steady-state operation over a range of OLR up to 85.44 kg COD/（m^3·d）. The COD removal efficiency was found to be 92% in the reactor while the biogas produced in the digester reached 25.38 m^3/（m^3·d） of the reactor. With the increase of OLR from 83.7 kg COD/（m^3·d）, the COD removal efficiency decreased. Also an artificial neural network （ANN） model using multilayer perceptron （MLP） has been developed for a system of two input variable and five output dependent variables. For the training of the input-output data, the experimental values obtained have been used. The output parameters predicted have been found to be much closer to the corresponding experimental ones and the model was validated for 30% of the untrained data. The mean square error （MSE） was found to be only 0.0146.

A New Example of Retrograde Solubility Model for Carbonate Rocks

Objective The dissolution and precipitation of carbonate during burial diagenetic process controls the reservoir property in deep buried strata. The geological process related with it has become a research focus during recent years. The most important dissolution fluids to carbonates are probably H2S and CO2 as byproducts of sulfate reduction in deep-buried setting with sulfate minerals, but carbonates are more soluble in relatively low temperature, which is the so-called retrograde solubility. Several geological processes can result in the decrease of temperature, including the upward migration of thermal fluids and tectonic uplift.

A Two-Dimensional Zonally Averaged Ocean Carbon Cycle Model

An ocean carbon cycle model driven by a constant flow field produced by a two-dimensional thermohaline circulation model is developed. Assuming that the biogenic carbon in the oceans is in a dynamic equilibrium, the inorganic carbon cycle is investigated. Before the oceanic uptake of CO_2 is carried out, the investigation of 14C distributions in the oceans, including natural and bomb-produced 14C,is conducted by using different values of the exchange coefficient of CO_2for different flow fields (different vertical diffusivities) to test the performance of the model. The suitable values of the exchange coefficient and vertical diffusivities are chosen for the carbon cycle model. Under the forcing of given preindustrial atmospheric CO_2 concentration of 280 ppmv, the carbon cycle model is integrated for seven thousand years to reach a steady state. For the human perturbation, two methods including the prescribed atmospheric pCO_2 and prescribed industrial emissions are used in this work. The results from the prescribed atmospheric pCO_2 show that the oceans take up 36% of carbon dioxide released by human activities for the period of 1980-1989, while the results from the prescribed industrial emission rates show that the oceans take up 34% of carbon dioxide emitted by industrial sources for the same period. By using the simple method of subtracting industrial emission rate from the total atmosphere+ocean accumulating rate, it can be deduced that before industrial revolution a non-industrial source exists, while after 1940 an extra sink is needed, and that a total non-industrial source of 45 GtC is obtained for the period of 1790-1990.

Estimating the carbon fluxes of forests with an individual-based forest model

Background： Capturing the response of forest ecosystems to inter-annual climate variability is a great challenge.In this study, we tested the capability of an individual-based forest gap model to display carbon fluxes at yearly and daily time scales.The forest model was applied to a spruce forest to simulate the gross primary production（GPP）, respiration and net ecosystem exchange（NEE）.We analyzed how the variability in climate affected simulated carbon fluxes at the scale of the forest model.Results： Six years were simulated at a daily time scale and compared to the observed eddy covariance（EC） data.In general, the seasonal cycle of the individual carbon fluxes was correctly described by the forest model.However, the estimated GPP differed from the observed data on the days of extreme climatic conditions.Two new parameterizations were developed： one resulting from a numerical calibration, and the other resulting from a filtering method.We suggest new parameter values and even a new function for the temperature limitation of photosynthesis.Conclusions： The forest model reproduced the observed carbon fluxes of a forest ecosystem quite wel.Of the three parameterizations, the calibrated model version performed best.However, the filtering approach showed that calibrated parameter values do not necessarily correctly display the individual functional relations.The concept of simulating forest dynamics at the individual base is a valuable tool for simulating the NEE, GPP and respiration of forest ecosystems.

The carbon fluxes in different successional stages:modelling the dynamics of tropical montane forests in South Ecuador

Background： Tropical forests play an important role in the global carbon（C） cycle.However, tropical montane forests have been studied less than tropical lowland forests, and their role in carbon storage is not well understood.Montane forests are highly endangered due to logging, land-use and climate change.Our objective was to analyse how the carbon balance changes during forest succession.Methods： In this study, we used a method to estimate local carbon balances that combined forest inventory data with process-based forest models.We utilised such a forest model to study the carbon balance of a tropical montane forest in South Ecuador, comparing two topographical slope positions（ravines and lower slopes vs upper slopes and ridges）.Results： The simulation results showed that the forest acts as a carbon sink with a maximum net ecosystem exchange（NEE） of 9.3 Mg C？（ha？yr）-1during its early successional stage（0–100 years）.In the late successional stage, the simulated NEE fluctuated around zero and had a variation of 0.77 Mg C？（ha？yr）–1.The simulated variability of the NEE was within the range of the field data.We discovered several forest attributes（e.g., basal area or the relative amount of pioneer trees） that can serve as predictors for NEE for young forest stands（0–100 years） but not for those in the late successional stage（500–1,000 years）.In case of young forest stands these correlations are high, especially between stand basal area and NEE.Conclusion： In this study, we used an Ecuadorian study site as an example of how to successfully link a forest model with forest inventory data, for estimating stem-diameter distributions, biomass and aboveground net primary productivity.To conclude, this study shows that process-based forest models can be used to investigate the carbon balance of tropical montane forests.With this model it is possible to find hidden relationships between forest attributes and forest carbon fluxes.These relationships promote a better understanding of the role of tropical montane forests in the context of global carbon cycle, which in future will become more relevant to a society under global change.

Temporal and spatial variability of the carbon cycle in the east of China's seas:a three-dimensional physical-biogeochemical modeling study

In the east of China＇s seas, there is a wide range of the continental shelf. The nutrient cycle and the carbon cycle in the east of China＇s seas exhibit a strong variability on seasonal to decadal time scales. On the basis of a regional ocean modeling system（ROMS）, a three dimensional physical-biogeochemical model including the carbon cycle with the resolution（1/12）°×（1/12）° is established to investigate the physical variations, ecosystem responses and carbon cycle consequences in the east of China＇s seas. The ROMS-Nutrient Phytoplankton Zooplankton Detritus（NPZD） model is driven by daily air-sea fluxes（wind stress, long wave radiation, short wave radiation, sensible heat and latent heat, freshwater fluxes） that derived from the National Centers for Environmental Prediction（NCEP） reanalysis2 from 1982 to 2005. The coupled model is capable of reproducing the observed seasonal variation characteristics over the same period in the East China Sea. The integrated air-sea CO_2 flux over the entire east of China＇s seas reveals a strong seasonal cycle, functioning as a source of CO_2 to the atmosphere from June to October, while serving as a sink of CO_2 to the atmosphere in the other months. The 24 a mean value of airsea CO_2 flux over the entire east of China＇s seas is about 1.06 mol/（m^2·a）, which is equivalent to a regional total of3.22 Mt/a, indicating that in the east of China＇s seas there is a sink of CO_2 to the atmosphere. The partial pressure of carbon dioxide in sea water in the east of China＇s seas has an increasing rate of 1.15 μatm/a（1μtm/a=0.101 325Pa）, but p H in sea water has an opposite tendency, which decreases with a rate of 0.001 3 a^（–1） from 1982 to 2005.Biological activity is a dominant factor that controls the pCO_2 air in the east of China＇s seas, and followed by a temperature. The inverse relationship between the interannual variability of air-sea CO_2 flux averaged from the domain area and Ni？o3 SST Index indicates that the carbon cycle in the east of China＇s seas has a high correlation with El Ni？o-Southern Oscillation（ENSO）.

The inventory of the carbon stocks in sub tropical forests of Pakistanfor reporting under Kyoto Protocol

The United Nations Framework Convention on Climate Change （UNFCCC） requires reporting net carbon stock changes and anthropogenic greenhouse gas emissions, including those related to forests. This paper describes the status of carbon stocks in sub tropical forests of Pakistan. There are two major sub types in subtropical forests of Pakistan viz a viz Subtropical Chir Pine and Subtropical broadleaved forests. A network of sample plots was laid out in four selected site. Two sites were selected from sub tropical Chir Pine （Pinus roxburghii） forests and two from Subtropical broadleaved forests. Measurement and data acquisition protocols were developed specifically for the inventory car- ried out from 2005 to 2010. In total 261 plots （each of lha.） were established. Estimation of diameter, basal area, height, volume and biomass was carried out to estimate carbon stocks in each of the four carbon pools of above- and below-ground live biomass. Soil carbon stocks were also determined by doing soil sampling. In mature （-100 years old） pine forest stand at Ghoragali and Lehterar sites, a mean basal area of 30.38 and 26.11 m2.ha-1 represented mean volume of 243 and 197 m3·ha-1, respectively. The average biomass （t.ha-1） was 237 in Ghoragali site and 186 tha-1 in Lehterar site, which is equal to 128 and 100 t·ha-1 including soil C. However, on average basis both the forests have 114.5± 2.26 t.ha-1 of carbon stock which comprises of 92% in tree biomass and only 8% in the top soils. In mixed broadleaved evergreen forests a mean basal area （m2.ha-1）was 3.06 at Kherimurat with stem volume of 12.86 and 2.65 at Sohawa with stem volume of 11.40 m3.ha-1. The average upper and under storey biomass （t·ha-1） was 50.93 in Kherimurat site and 40.43 t.ha-1 in Sohawa site, which is equal to 31.18 and 24.36 t ·ha-1 including soil C stocks. This study provides a protocol monitoring biomass and carbon stocks and valuable baseline data for in Pakistan＇s managed and unmanaged sub-tropical forests.

Vacuum pressure swing adsorption process for coalbed methane enrichment

The enrichment of low concentration coalbed methane using adsorption process with activated carbon adsorbent was studied in this work.Adsorption isotherms of methane,nitrogen and carbon dioxide on activated carbon were measured by volumetric method,meanwhile a series of breakthrough tests with single component,binary components and three components feed mixture has been performed for exploring dynamic adsorption behaviors.Moreover,a rigorous mathematical model of adsorption bed containing mass,energy,and momentum conservation equation as well as dualsite Langmuir model with the Linear driving force model for gassolid phase mass transfer has been proposed for numerical modeling and simulation of fixed bed breakthrough process and vacuum pressure swing adsorption process.Furthermore,the lumped mass transfer coefficient of methane,nitrogen and carbon dioxide on activated carbon adsorbent has been determined to be 0.3 s^(-1),1.0 s^(-1) and 0.06 s^(-1) by fitting the breakthrough curves using numerical calculation.Additionally,a six bed VPSA process with twelve step cycle sequence has been proposed and investigated for low concentration coalbed methane enrichment.Results demonstrated that the methane molar fraction in feed mixture ranged from 10%to 50%could be enriched to 32.15%to 88.75%methane in heavy product gas with a methane recovery higher than 83%under the adsorption pressure of 3 bar(1 bar=105 Pa)and desorption pressure of 0.1 bar.Energy consumption of this VPSA process was varied from 0.165 k·W·h·m^(-3) CH_(4)to 0.649 k·W·h·m^(-3) CH_(4).Finally,a dualstage VPSA process has been successfully developed to upgrade a low concentration coalbed methane containing 20%methane to a target product gas with methane purity higher than 90%,meanwhile the total methane recovery was up to 98.71%with a total energy consumption of 0.504 k·W·h·m^(-3)CH_(4).

Remote Sensing and Forest Carbon Monitoring——a Review of Recent Progress,Challenges and Opportunities

Remote sensing provides key inputs to a wide range of models and methods developed for quantifying forest carbon.In particular,carbon inventory methods recommended by IPCC require biomass data and a suite of forest disturbance products.Significant progress has been made in deriving these products by leveraging publicly available remote sensing assets,including observations acquired by the legendary Landsat mission and new systems launched within the past decade,including Sentinel-2,Sentinel-1,GEDI,and ICESAT-2.With the L-band NISAR and P-band BIOMASS missions to be launched in 2023,the Earth’s land surfaces will be imaged by optical and multi-band(including C-,L-,and P-bands)radar systems that can provide global,sub-weekly observations at sub-hectare spatial resolutions for public use.Fine scale products derived from these observations will be crucial for developing monitoring,reporting,and verification(MRV)capabilities needed to support carbon trade,REDD+,and other market-driven tools aimed at achieving climate mitigation goals through forest management at all levels.Following a brief discussion of the roles of forests in the global carbon cycle and the wide range of models and methods available for evaluating forest carbon dynamics,this paper provides an overview of recent progress and forthcoming opportunities in using remote sensing to map forest structure and biomass,detect forest disturbances,determine disturbance attribution,quantify disturbance intensity,and estimate harvested timber volume.Advances in these research areas require large quantities of well—distributed reference data to calibrate remote sensing algorithms and to validate the derived products.In addition,two of the forest carbon pools-dead organic matter and soil carbon—are difficult to monitor using modern remote sensing capabilities.Carefully designed inventory programs are needed to collect the required reference data as well as the data needed to estimate dead organic matter and soil carbon.

Historical simulation and twenty-first century prediction of oceanic CO_2 sink and pH change

A global ocean carbon cycle model based on the ocean general circulation model POP and the improved biogeochemical model OCMIP-2 is employed to simulate carbon cycle processes under the historically observed atmospheric CO 2 concentration and different future scenarios （called Rep- resentative Concentration Pathways, or RCPs）. The RCPs in this paper follow the design of Inter- governmental Panel on Climate Change （IPCC） for the Fifth Assessment Report （AR5）. The model results show that the ocean absorbs CO 2 from atmosphere and the absorbability will continue in the 21st century under the four RCPs. The net air-sea CO 2 flux increased during the historical time and reached 1.87 Pg/a （calculated by carbon） in 2005; however, it would reach peak and then decrease in the 21st century. The ocean absorbs CO 2 mainly in the mid latitude, and releases CO 2 in the equator area. However, in the Antarctic Circumpolar Current （ACC） area the ocean would change from source to sink under the rising CO 2 concentration, including RCP4.5, RCP6.0, and RCP8.5. In 2100, the anthropogenic carbon would be transported to the 40 S in the Atlantic Ocean by the North Atlantic Deep Water （NADW）, and also be transported to the north by the Antarctic Bottom Water （AABW） along the Antarctic continent in the Atlantic and Pacific oceans. The ocean pH value is also simulated by the model. The pH decreased by 0.1 after the industrial revolution, and would continue to decrease in the 21st century. For the highest concentration sce- nario of RCP8.5, the global averaged pH would decrease by 0.43 to reach 7.73 due to the absorption of CO 2 from atmosphere.

Long-term organic and inorganic fertilizations enhanced basic soil productivity in a fluvo-aquic soil

The improvement of soil productivity depends on a rational input of water and nutrients, optimal field management, and the increase of basic soil productivity（BSP）. In this study, BSP is defined as the productive capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local field management. Based on 19-yr data of the long-term agronomic experiments（1989–2008） on a fluvo-aquic soil in Zhengzhou, Henan Province, China, the decision support system for agrotechnology transfer（DSSAT ver. 4.0） crop growth model was used to simulate yields by BSP of winter wheat（Triticum aestivium L.） and summer maize（Zea mays L.） to examine the relationship between BSP and soil organic carbon（SOC） under long-term fertilization. Five treatments were included：（1） no fertilization（control）,（2） nitrogen, phosphorus and potassium fertilizers（NPK）,（3） NPK plus manure（NPKM）,（4） 1.5 times of NPKM（1.5NPKM）, and（5） NPK plus straw（NPKS）. After 19 yr of treatments, the SOC stock increased 16.7, 44.2, 69.9, and 25.2% under the NPK, NPKM, 1.5NPKM, and NPKS, respectively, compared to the initial value. Among various nutrient factors affecting contribution percentage of BSP to winter wheat and summer maize, SOC was a major affecting factor for BSP in the fluvo-aquic soil. There were significant positive correlations between SOC stock and yields by BSP of winter wheat and summer maize（P〈0.01）, and yields by BSP of winter wheat and summer maize increased 154 and 132 kg ha^（–1） when SOC stock increased 1 t C ha^（–1）. Thus, increased SOC accumulation is a crucial way for increasing BSP in fluvo-aquic soil. The manure or straw combined application with chemical fertilizers significantly enhanced BSP compared to the application of chemical fertilizers alone.

Emission Inventories of Carbon-containing Greenhouse Gases in China and Technological Measures for Their Abatement

The report summarizes surveys on carbon inventories and initiatives on sustainable carbon cycling taken by the Research Center for Eco-Environmental Sciences, where the authors work/worked. The first part of the report, which appeared in the preceding issue of this journal, deals with the concept of sustainable carbon cycling, the historic evolution of carbon cycling processes in China, carbon pool enhancement, value addition, carbon sequestration and carbon balance. This very paper, as the second part of the report, covers the results of carbon dynamics modeling, emission inventories of various carbon-containing greenhouse gases and their potential abatement measures.

Characterization of P-nitrophenol Adsorption Kinetic Properties in Batch and Fixed Bed Adsorbers

P-nitrophenol（PNP） adsorption in batch and fixed bed adsorbers was studied. The homogeneous surface diffusion model（HSDM） based on external mass transfer and intraparticle surface diffusion was used to describe the adsorption kinetics for PNP in stirred batch adsorber at various initial concentrations and activated carbon dosages. The fixed bed model considering both external and internal mass transfer resistances as well as axial dispersion with non-linear isotherm was utilized to predict the fixed bed breakthrough curves for PNP adsorption under the conditions of different flow rates and inlet concentrations. The equilibrium parameters and surface diffusivity（Ds） were obtained from separate experiments in batch adsorber. The obtained value of Ds is 4.187×1012 m2/s. The external film mass transfer coefficient（kf） and axial dispersion coefficient（DL） were estimated by the correlations of Goeuret and Wike-Chang. The Biot number determined by HSDM indicated that the adsorption rate of PNP onto activated carbon in stirred batch was controlled by intraparticle diffusion and film mass transfer. A sensitivity analysis was carried out and showed that the fixed bed model calculations were sensitive to Ds and kf, but insensitive to DL. The sensitivity analysis and Biot number both confirm that intraparticle diffusion and film mass transfer are the controlling mass transfer mechanism in fixed bed adsorption system.

Seismic analysis of early-mid Miocene carbonate platform in the southern Qiongdongnan Basin, South China Sea

The southern uplift of the Qiongdongnan Basin is a deepwater area in which no wells have beens drilled. The Miocene-Quaternary strata in the Xisha Islands, which are located 40–100 km to the south, are composed of carbonate reef formations. Paleotectonic and paleogeographic analyses of the basin suggest that the southern uplift experienced favorable geological conditions for the development of carbonate reefs during the Miocene.The high-impedance carbonates have high amplitudes and low frequencies on seismic profiles. The reefs are distributed on paleotectonic highs and are thicker than the contemporaneous formations. A forward model of the variation in carbonate thickness based on lithological and velocity information from wells in nearby regions can simulate the seismic response of carbonates with different thicknesses. We identified several important controlling points for determining the thickness of carbonates from seismic profiles, including the pinchout point,the λ/4 thickness point, and the λ/2 thickness point. We depict a carbonate thickness map in the deepwater area of the southern Qiongdongnan Basin based on this model. The carbonate thickness map, the paleotectonic and paleogeographic background, and the seismic response characteristics of reefs suggest that the carbonates that developed on the southern uplift of the Qiongdongnan Basin during the Miocene were mainly an isolated carbonate platform peninsula and ramp deposits. It consisted of gentle ramp platform, steep slope platform,platform depression, gravity flow, and reef bank facies.

Development of monitoring and assessment of forest biomass and carbon storage in China

Addressing climate change has become a common issue around the world in the 21st century and equally an important mission in Chinese forestry.Understanding the development of monitoring and assessment of forest biomass and carbon storage in China is important for promoting the evaluation of forest carbon sequestration capacity of China.The author conducts a systematic analysis of domestic publications addressing＂monitoring and assessment of forest biomass and carbon storage＂in order to understand the development trends,describes the brief history through three stages,and gives the situation of new development.Towards the end of the 20th century,a large number of papers on biomass and productivity of the major forest types in China had been published,covering the exploration and efforts of more than 20 years,while investigations into assessment of forest carbon storage had barely begun.Based on the data of the 7th and 8th National Forest Inventories,forest biomass and carbon storage of the entire country were assessed using individual tree biomass models and carbon conversion factors of major tree species,both previously published and newly developed.Accompanying the implementation of the 8th National Forest Inventory,a program of individual tree biomass modeling for major tree species in China was carried out simultaneously.By means of thematic research on classification of modeling populations,as well as procedures for collecting samples and methodology for biomass modeling,two technical regulations on sample collection and model construction were published as ministerial standards for application.Requests for approval of individual tree biomass models and carbon accounting parameters of major tree species have been issued for approval as ministerial standards.With the improvement of biomass models and carbon accounting parameters,thematic assessment of forest biomass and carbon storage will be gradually changed into a general monitoring of forest biomass and carbon storage,in order to realize their dynamic monitoring in national forest inventories.Strengthening the analysis and assessment of spatial distribution patterns of forest biomass and carbon storage through application of remote sensing techniques and geostatistical approaches will also be one of the major directions of development in the near future.

Inter-provincial carbon emission intensity factor analysis and carbon intensity projection calculation in China

The extended “STIRPAT” model and the GM(1,1) model are used to predict the factors influencing inter-provincial carbon emission intensity and carbon intensity in China respectively. In this paper, based on the collation of inter-provincial carbon emission data, the extended “STIRPAT” model is formulated for carbon dioxide emissions and carbon intensity emissions, and the Hausman test is used to determine the influence form of the models. The main influencing factors of carbon intensity were identified: economic development level, energy intensity, and energy consumption structure. The paper constructs GM(1,1) model for carbon emission intensity from 2010-2019 using the gray prediction method,and calculates the carbon emission intensity of China’s inter-provincial 2022 by residual test, correlation test, variance, and small error probability test, and then predicts the carbon demand of each province and city in 2022 according to the expected average annual growth rate, and finally concludes that using carbon emission intensity as the carbon emission reduction target of each region, and it cannot fundamentally solve the problem of carbon pollution in China. Compared to the regional carbon emission reduction target, there is a greater degree of regional imbalance in carbon intensity between provinces in China, and the target of reducing carbon emission intensity somehow avoids the fact that the carbon emission reduction intensity target can be achieved without reducing the absolute amount of carbon emissions that continue to increase. The focus of achieving the “double carbon” target lies in the reduction of total carbon emissions, and the target of reducing carbon intensity will eventually be transformed into a binding target of total carbon emissions in the process of implementation, so attention should be shifted from recessiontype carbon reduction and efficiency-type carbon reduction to innovative carbon reduction. It is necessary to increase investment in renewable energy, and gradually expand the scope of application of photovoltaic, and wind power to ensure the reduction of total carbon emissions.

Structure modeling of activated carbons used for simulating methane adsorption-A review

Activated carbons(ACs)are highly porous materials with a broad range of applications in industry such as gas storage,water and air purification,gas separation,and catalysis.The microstructure for ACs is still not clearly known in spite of their wide industrial uses.There have been efforts to describe the structure of activated carbons experimentally in relation to its methane adsorption characteristics.In this review,it is assumed that natural gas is sorely composed of CH_(4)for simplicity(because CH_(4)is the major component,>90%).Experimental means to unveil the microstructure and many other properties for these ACs have some limitations,to overcome these limitations,ACs structural modeling and simulation become very important to match the properties with the desired methane adsorption characteristics.The major challenge that methane adsorption simulation faces for so long,is the lack of realistic AC models.This paper reviews the current efforts to develop the realistic AC models for methane adsorption,most of the built models are based on experimental carbon structural findings from the previous studies.The structural parameters including pore size distribution(PSD),specific surface area(SSA),pore volume and extent of curvature in the carbon materials and their role to methane adsorption are discussed.The role of chemical properties,such as presence of functional groups and the nature of the functional groups to the adsorption properties of methane,are also introduced.Different pore morphologies(such as slit pore,platelet,spherical,etc.)are studied with their effect on methane adsorption and presented too.It is found that each of the mentioned parameters has its own bearing to methane adsorption.Furthermore,this work analyzes different current techniques used in modeling natural gas adsorption,and the mechanisms are able to reproduce the specific carbon materials for a certain desired set of adsorption characteristic.Some future works are also recommended in this area,so that better representations of ACs can be obtained for methane storage purposes.

Removal of perfluorinated surfactants from wastewater by adsorption and ion exchange--Influence of material properties,sorption mechanism and modeling

Perfluorooctane sulfonate（PFOS） has attracted increasing concern in recent years due to its world-wide distribution, persistence, bioaccumulation and potential toxicity. The influence of sorbent properties on the adsorptive elimination of PFOS from wastewater by activated carbons, polymer adsorbents and anion exchange resins was investigated with regard to their isotherms and kinetics. The batch and column tests were combined with physicochemical characterization methods, e.g., N2 physisorption, mercury porosimetry, infrared spectroscopy, differential scanning calorimetry, titrations, as well as modeling. Sorption kinetics was successfully modelled applying the linear driving force（LDF） approach for surface diffusion after introducing a load dependency of the mass transfer coefficient βs.The big difference in the initial mass transfer coefficient βs,0, when non-functionalized adsorbents and ion-exchange resins are compared, suggests that the presence of functional groups impedes the intraparticle mass transport. The more functional groups a resin possesses and the longer the alkyl moieties are the bigger is the decrease in sorption rate.But the selectivity for PFOS sorption is increasing when the character of the functional groups becomes more hydrophobic. Accordingly, ion exchange and hydrophobic interaction were found to be involved in the sorption processes on resins, while PFOS is only physisorptively bound to activated carbons and polymer adsorbents. In agreement with the different adsorption mechanisms, resins possess higher total sorption capacities than adsorbents. Hence, the latter ones are rendered more effective in PFOS elimination at concentrations in the low μg/L range, due to a less pronounced convex curvature of the sorption isotherm in this concentration range.

A SIMULATION OF CO2 UPTAKE IN A THREE DIMENSIONAL OCEAN CARBON CYCLE MODEL

A three-dimensional ocean carbon cycle model which is a general circulation model coupled with simple biogeochemical processes is used to simulate CO_2 uptake by the ocean.The OGCM used is a modified version of the Geophysical Fluid Dynamics Laboratory modular ocean model (MOM2).The ocean chemistry and a simple ocean biota model are included.Principal variables are total CO_2,alkalinity and phosphate.The vertical profile of POC flux observed by sediment traps is adopted,the rain ratio,a ratio of production rate of calcite against that of POC,and the bio-production efficiency should be 0.06 and 2 per year,separately.The uptake of anthropogenic CO_2 by the ocean is studied.Calculated oceanic uptake of anthropogenic CO_2 during the 1980s is 2.05×10~(15)g(Pg)per year.The regional distributions of global oceanic CO_2 are discussed.

Hippocampus hypoxia-inducible factor-1 alpha and heme oxygenase-1 expression in the delayed encephalopathy after acute carbon monoxide poisoning rat model

Objective To research the expression of hypoxia-inducible factor-1 alpha(HIF-1α)and heme oxygenase-1(HO-1)in hippocampus of rats with delayed encephalopathy after acute carbon monoxide poisoning(DEACMP)and its functions.Methods One hundred and fiftysix rats were selected and randomly divided into