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The methane (CH4) emissions from municipal solid waste (MSW) landfills in China in 2007 were estimated based on database of the three-dimensional emission factors matrix and point sources, by an IPCC recommended FOD (firstorder decay) model. The location, capacity and age of landfills constitute the three dimensions of the emission factors matrix, which were obtained by laboratory analysis and in situ investigation. Key parameters such as waste composition, degradable organic carbon ratio, CH4 correction factor, oxidation factor and recovery rate, were carefully analyzed in terms of these three dimensions. The point sources database consists of 2,107 MSW landfills in cities and towns of China in 2007. The results show that the CH4 emissions from MSW landfills were 1.186 Mt in 2007. Compared with the CH4 emissions of 2.20 Mt in 2005, the significant discrepancy mainly comes from statistical data of landfills, e.g., number of landfills and amount of waste disposed in landfills. CH4 emissions were lower than 700 t for most of the landfills, whereas there were 279 landfills with emissions larger than 1,000 t, and only 10 landfills with emissions larger than 10,000 t. Jiangsu province ranks the largest emitter with 98,700 t while Tibet is the smallest emitter with 2,100 t. In general, the emissions from eastern provinces, such as Jiangsu, Guangdong and Zhejiang, were larger than those from western provinces, such as Ningxia, Tibet and Qinghai. Citation: Cai, B.-F., Liu, J.-G., Gao, Q.-X., et al., 2014. Estimation of methane emissions from municipal solid waste landfills in China based on point emission sources. Adv. Clim. Change Res. 5(2), doi: 10.3724/SP.J.1248.2014.081.

In this paper, we investigate decays in the framework of the RPV SUSY model. We discuss the tree-level contribution of the sparticles and to these decay branching ratios. In the two channels, the -mediated channel is more sensitive to the parameter product than the -mediated channel to . And the parameter product is severely constrained to the order of by the experiment data with , which is one order of magnitude more stringent than before. In the calculation of hadronic matrix elements, the resonant effects are large than those of nonresonant terms. Especially, the resonant contribution of scalar meson f(980) plays a dominate role in -mediated channel. [ABSTRACT FROM AUTHOR]

High-photostability fluorescent (XZn)Fe 2 O 4 (X = Mg, Mn or Ni) embedded in BiFeO 3 spinel-perovskite nanocomposites were successfully fabricated via a novel bio-induced phase transfer method using shewanella oneidensis MR-1. These nanocomposites have the near-infrared fluorescence response (XZn or Fe)-O-O-(Bi) interfaces (785/832 nm), and the (XZn)Fe 2 O 4 /BiFeO 3 lattices with high/low potentials (572.15–808.77 meV/206.43–548.1 meV). Our results suggest that heavy metal ion (Cr 3+ , Cd 2+ , Co 2+ and Pb 2+ ) d↓ orbitals hybridize with the paired-spin X-Zn-Fe d↓-d↓-d↑↓ orbitals to decrease the average polarization angles (−29.78 to 44.71°), qualitatively enhancing the photovoltage response selective potentials (39.57–487.84 meV). The fluorescent kinetic analysis shows that both first-order and second-order equilibrium adsorption isotherms are in line and meet the Langmuir and Freundlich modes. Highly selective fluorescence detection of Co 2+ , Cr 3+ and Cd 2+ can be achieved using Fe 3 O 4 -BiFeO 3 (Langmuir mode), (MgZn)Fe 2 O 4 -BiFeO 3 and (MnZn)Fe 2 O 4 -BiFeO 3 (Freundlich mode), respectively. Where the corresponding max adsorption capacities (q max ) are 1.5–1.94, 35.65 and 43.7 multiple, respectively, being more competitive than that of other heavy metal ions. The present bio-synthesized method might be relevant for high-photostability fluorescent spinel-perovskite nanocomposites, for design of heavy metal ion sensors. [ABSTRACT FROM AUTHOR]

In order to realize the disposal feasibility of rural garbage by incineration, 72 rural garbage sampling points of 12 provinces in China were chosen to analyse mass fraction of full component and combustible component, moisture content of full component and low heating value of rural garbage in spring, summer, autumn and winter of 2015. The results revealed that the mass fraction of combustible rural garbage components in wet basis followed the order of kitchen residual(13%-53%) > the rubber(10%-18%) > the paper(10%-15%) > the wood(0-10%) > the fabric(0-8%). The compositional difference of rural garbage was not apparent between villages and towns within the same administrative region. The average moisture content of full component in southern rural garbage was higher than that in northern area, and the average moisture content of national rural garbage was about 40.1%. The low heating value of rural garbage in full composition which surpassed 3500 kJ·kg -1 was more than 81% in the north China, but in the south China, it was 44%, 50%, 61% and 72% in spring, summer, autumn and winter, respectively. After sorting, the low heating value increased greatly, but the low heating value of southern rural garbage in spring was still less than 3500 kJ·kg -1 , more than 56% towns and villages of southern rural garbage in summer, autumn and winter and annual northern rural garbage heating value met the heating value requirement of incineration disposal. Therefore, after sorting, the rural garbage by incineration disposal method was feasible to the north China rural garbage, but the south China rural garbage requires strengthened pretreatment process.

The biosorption and biomineralization characteristics of uranium by the duckweed Landoltia punctata was investigated in aqueous solutions enriched with 1 to 250 mg · L(-1) of U(VI) supplied as uranyl nitrate [UO2(NO3)2 · 6H2O]. The maximum uranium removal for the plant cultivar occurred at pH 4~5 of solution and their uranium removal efficiencies exceeded 90% after 24 h. In kinetics studies, the dried powder of duckweed can finished nearly 80% adsorption within 5 min, the batch adsorption equilibrium can be reached within 24 h for the living and dried powder of duckweed, Both for the living and dried powder of duckweed, the experimental data were well fitted by the pseudo-second-order rate model with the degree of fitting (r) higher than 0.99. The adsorption isotherms could be better described by the Freundlich model than the Langmuir model. In addition, Fourier transform infrared spectroscopy (FTIR) revealed that the surface of Landoltia punctata possess many active groups such as hydroxyl, carboxyl, phosphate and amide groups, the hydroxyl, amino groups involved in adsorption of U(VI) by living and dried powder of Landoltia punctata, and the phosphate groups also participated in the adsorption behavior of U(VI) by the living Landoltia punctata. The living Landoltia punctata reduction part of U(VI) to U(IV) was observed by XPS analysis. SEM and energy dispersive X-ray spectroscopy (EDS) of duckweed from 10~200 mg · L(-1) uranium treatments indeed showed root surface of living Landoltia punctata formed a significant portion of U precipitates with nanometer sized schistose structures that consisted primarily U and P, not containing C. Inorganic phosphate was released by the root cells of Landoltia punctata during the experiments providing ligands for formation of insoluble U(VI) and U(IV) phosphates. The distinct uranium peaks in the EDS spectra of the cluster on the root surface can be observed after biosorption and the uranium and phosphorus mass ratio of the cluster spot was measured to be 82.5% and 8.76% of the total component weight, respectively, and the atomic percentage of 30.89% and 25.19%, respectively. It is worth noting that the phosphorus mass ratio and the atomic rate of the control group is only 0.24% and 0.11%, respectively. But there was no similar crystals observed on the surface of dried powder of Landoltia punctata after biosorption. The present work suggests that living and dried powder of Landoltia punctata can remove more than 90% U(VI) from solution simultaneously precipitated together with phosphate by the living Landoltia punctata, and the dried powder of Landoltia punctata adsorption U(VI) is mainly through the effect of electrostatic attraction, ion exchange and complexation coordination, etc. Here, for the first time, the presence of U immobilization mechanisms within one aquatic plant is reported using Landoltia punctata.

As a biological adsorbent, Living Deinococcus radiodurans was used for removing radionuclide uranium in the aqueous solution. The effect factors on biosorption of radionuclide uranium were researched in the present paper, including solution pH values and initial uranium concentration. Meanwhile, the biosorption mechanism was researched by the method of FTIR and SEM/EDS. The results show that the optimum conditions for biosorption are as follows: pH = 5, co = 100 mg · L(-1) and the maximum biosorption capacity is up to 240 mgU · g(-1). According to the SEM results and EDXS analysis, it is indicated that the cell surface is attached by lots of sheet uranium crystals, and the main biosorpiton way of uranium is the ion exchange or surface complexation. Comparing FTIR spectra and FTIR fitting spectra before and after biosorption, we can find that the whole spectra has a certain change, particularly active groups (such as amide groups of the protein, hydroxy, carboxyl and phosphate group) are involved in the biosorption process. Then, there is a new peak at 906 cm(-1) and it is a stretching vibration peak of UO2(2+). Obviously, it is possible that as an anti radiation microorganism, Deinococcus radiodurans could be used for removing radionuclide uranium in radiation environment.

The platanus leaves were used as adsorbent to study uranium removal efficiency from aqueous solution on the basis of adsorption kinetics and isotherm equations. Static adsorption affected by initial pH values and contact time was analyzed, and surface characteristics of platanus leaves and uranium removal mechanism were investigated with the help of SEM, FTIR, XRD and XRF. The adsorption process fits pseudo-second-order kinetic model and Freundlich isotherm equation, and the maximum adsorption capacity for uranium was 19.68 mg x g(-1). Results showed that hydroxyl groups, amides II belt and carboxyl active functional groups were important for uranium removal. Structure characteristic adsorption band of cellulose was found in XRD spectra, uranium was detected, and also Ca and Na elements of the content increased. Mg element content relative decrease was found on platanus leaves after adsorption by XRF, and it proved the reaction feasibility. Speculation for the behavior of uraniu adsorption by platanus leaves was both physical adsorption and chemical adsorption, exhibiting joint action of electrostatic attraction, redox reaction, chelating ligand and ion exchange.

Based on the reducing capacity of zero valent iron, the study investigated the behavior of dechlorination of hexachlorobenzene by bimetals synthetized using Fe with Ag, Pb or Cu as catalysts, respectively. The results showed that bimetals could dechlorinate HCB faster than Fe(0) did, the optimal ratios of Ag/Fe, Pb/Fe and Cu/Fe were 0.2%, 0.5% and 1%. After reacting 2 hours, the dechlorination rates of HCB by Ag/Fe, Pb/Fe and Cu/Fe were 93.5%, 88.5% and 49.6% respectively. The catalyst metal distribution had a great effect on the reductive dechlorination capacity of the bimetal systems, due to more galvanic cells produced by well-distributed catalyst metal and iron. Increasing the amount of bimetal was an effective way to promote HCB dechlorination rate, 88.6% HCB was degraded in 2 h by 0.8 g Pb/Fe while only 38.3% HCB was degraded by 0.1 g Pb/Fe. Besides, HCB dechlorination could be enhanced a little with increasing ionic strength, the HCB dechlorination rates were 93.5%, 98.0% and 98.9% respectively with Na2SO4 concentration at 0, 0.05 and 0.5 mol x L(-1).