The ex vivo and in vivo biological performances of graphene oxide and the impact of surfactant on graphene oxide's biocompatibility

Graphene oxide(GO)displays promising properties for biomedical applications including drug delivery and cancer therapeutics.However,GO exposure also raises safety concerns such as potential side effects on health.Here,the biological effects of GO suspended in phosphate buffered saline(PBS)with or without 1% nonionic surfactant Tween 80 were investigated.Based on the ex vivo experiments,Tween 80 significantly affected the interaction between GO and peripheral blood from mice.GO suspension in PBS tended to provoke the aggregation of diluted blood cells,which could be prevented by the addition of Tween 80.After intravenous administration,GO suspension with or without 1% Tween 80 was quickly eliminated by the mononuclear phagocyte system.Nevertheless,GO suspension without Tween 80 showed greater accumulation in lungs than that containing 1% Tween 80.In contrast,less GO was found in livers for GO suspension compared to Tween 80 assisted GO suspension.Organs including hearts,livers,lungs,spleens,kidneys,brains,and testes did not reveal histological alterations.The indexes of peripheral blood showed no change upon GO exposure.Our results together demonstrated that Tween 80 could greatly alter GO’s biological performance and determine the pattern of its biodistribution in mice.     

Pre-oxidation enhanced cyanobacteria removal in drinking water treatment: A review

Cyanobacterial bloom has many adverse effects on source water quality and drinking water production. The traditional water treatment process can hardly achieve satisfactory removal of algae cells. This review examines the impact of pre-oxidation on the removal of cyanobacteria by solid-liquid separation processes. It was reported that the introduction of chemical oxidants such as chlorine, potassium permanganate, and ozone in algae-laden water pretreatment could improve algae removal by the subsequent solid-liquid separation processes. However, over dosed oxidants can result in more serious water quality risks due to significant algae cell lysis and undesirable intracellular organic matter release. It was suggested that moderate pre-oxidation may enhance the removal of cyanobacteria without damaging algae cells. In this article, effects of moderate pretreatment on the solid-liquid separation processes (sedimentation, dissolved air flotation, and membrane filtration) are reviewed.     

Review on heterogeneous oxidation and adsorption for arsenic removal from drinking water

The long term exposure of arsenic via drinking water has resulted in wide occurrence of arsenisim globally, and the oxidation of the non-ionic arsenite (As(III)) to negatively-charged arsenate (As(V)) is of crucial importance for the promising removal of arsenic. The chemical oxidants of ozone, chlorine, chlorine dioxide, and potassium permanganate may achieve this goal; however, their application in developing countries is sometimes restricted by the complicate operation and high cost. This review paper focuses on the heterogeneous oxidation of As(III) by solid oxidants such as manganese oxide, and the adsorption of As(V) accordingly. Manganese oxide may be prepared by both chemical and biological methods to achieve good oxidation performance towards As(III). Additionally, manganese oxide may be combined with other metal oxides, e.g., iron oxide, to improve the adsorption capability towards As(V). Furthermore, manganese oxide may be coated onto porous materials of metal organic frameworks to develop novel adsorbents for arsenic removal. To achieve the application in engineering works, the adsorbents granulation may be achieved by drying and calcination, agglomeration, and the active components may also be in situ coated onto the porous materials to maintain the oxidation and adsorption activities as much as possible. The novel adsorbents with heterogeneous oxidation and adsorption capability may be carefully designed for the removal of arsenic in household purifiers, community-level decentralized small systems, and the large-scale drinking water treatment plants (DWTPs). This review provides insight into the fundamental studies on novel adsorbents, the development of innovative technologies, and the demonstration engineering works involved in the heterogeneous oxidation and adsorption, and may be practically valuable for the arsenic pollution control globally.     

Behaviour of cement-treated MSWI bottom ash

MSWI bottom ash is the residue of combustion. The use of bottom ash in road construction is wide spread. French legislation forbids the disposal of resuable waste in special landfill from 2002. Moreover, "arrêté du 9 mai 1994" provides environmental criteria (leaching threshold, etc.), and evaluates this material according to utilisation in road construction. In such application, bottom ash is often treated with binder to improve its mechanical features. Nevertheless, bottom ash is subject to chemical problems. These problems induce an expansion which brings about cracking and finally road destruction. Therefore, it is necessary to estimate the swelling potential of MSWI bottom ash prior utilisation. This is one of the aims of the European contract "Mashroad" (contract BRST CT97-5150). This study involved 4 years of work on cement-treated MSWI bottom ash. It examined different tests that show the importance of oxidation of aluminium in the swelling reaction and the efficiency of different treatments. Different binders were used in order to have different proportions of clinker. The kinetic aspects of aluminium-binder reaction were also studied. Finally, we present a special cell to measure the swelling pressure of these materials is presented.     

Resource and Environmental Issues in Transitional China: A Perspective from the Interaction Among Market,Government and Society

Abstract

Along with the rapid growth of economy in the postreform period after 1979, China has faced severe problems of resource overusing and environmental degradation which would threaten the sustainable development of economy and society. This article explores an effective mechanism of managing resource and environment in China. It examines some major resource and environmental issues, and constructs a framework of institution innovation to cover three sectors (government, market and society). In addition, the article analyzes their experience and evaluation in resource management and environmental conservation during the transitional period. We argue that the combination of market regulation, government intervention and public participation is an effective way of allocating resource and protecting environment. Some suggestions are put forward to balance the relationship between them, including coordinating role of government and market, building platform for market operation and creating an atmosphere of public participation.     

Agricultural Structure in Western China by Comparing with before and after CFFG Based on Shift-share Method

Abstract

Based on shift-share method, this article employs regional share, structural shift and competitive shift to analyze the structural benefit and competitive position of agricultural structure in western China by comparing with agriculture, foresting, stockbreeding and fishing before and after Conversion of Farmland to Forest and Grassland (CFFG). Then authors draw following conclusion: while CFFG program has been put in practice, the agricultural structure in western China has some typical characteristics, such as growth faster, structural predominance obvious and more competitive. But the contributiveness from the competition is not too much yet, and the structural benefit of forest estate and stockbreeding are restrained.     

降低采油污水处理中污泥产生量技术研究——室内试验研究——

为了降低采油污水处理过程中产生的污泥量,对“降低采油污水处理中污泥产生量技术”进行了研究,并在采油一厂文一污水站进行了为期66天的现场实验。结果表明,降低采油污水处理污泥产生量技术通过化学反应将污水中的部分离子转变为对污水净化有用的组分,并通过控制污水中的氧含量、pH及离子平衡,达到去除水中悬浮物、控制腐蚀、维持水中离子平衡的目的。当复合碱按600 mg/L加入并使系统的pH值控制在7.0～7.3且絮凝剂、助凝剂加入浓度分别为150 mg/L、100 mg/L时,污水的pH、含油量、总铁、悬浮物由处理前的6.0、109 mg/L、13.5 mg/L、78 mg/L下降为7.0、0、0～0.42、1～2,滤膜系数为35;污水腐蚀速率为0.0691 mm/a;处理后水中SRB、TGB含量分别为0、101个/mL;经中国科学院渗流流体力学研究所等单位监测和技术评价证实,处理后污水与地层水配伍性良好,对地层不伤害,所产生污泥可初步用做建筑材料。     

Institutions,policies and soil degradation:theoretical examinations and case studies in Southeast China

Southeast China is one of the severe soil degradation areas in China. This paper theoretically examines the impact of some important institutional arrangements and policies, like land management pattern, the rural off-farm employment, land property change and changes in prices of agricultural products, on soil degradation in this area. It further conducts some case studies to confirm the potential relationship between the institutions & policies and soil degradation, applying the surveyed and the second hand data. The paper at last makes some conclusions and proposes some suggestions on how to promote soil conservation by improving the ways of policy decision-making and the effects of policies on land use.     

An overview of emissions of SO2 and NOx and the long-range transport of oxidized sulfur and nitrogen pollutants in East Asia

The long-range transport of oxidized sulfur(sulfur dioxide(SO_2) and sulfate) and oxidized nitrogen(nitrogen oxides(NO_x ) and nitrate) in East Asia is an area of increasing scientific interest and political concern. This paper reviews various published papers, including ground- and satellite-based observations and numerical simulations. The aim is to assess the status of the anthropogenic emissions of SO_2 and NO_x and the long-range transport of oxidized S and N pollutants over source and downwind region. China has dominated the emissions of SO_2 and NO_x in East Asia and urgently needs to strengthen the control of their emissions, especially NO_x emissions. Oxidized S and N pollutants emitted from China are transported to Korea and Japan, due to persistent westerly winds, in winter and spring.However, the total contributions of China to S and N pollutants across Korea and Japan were not found to be dominant over longer time scales(e.g., a year). The source–receptor relationships for oxidized S and N pollutants in East Asia varied widely among the different studies. This is because:(1) the nonlinear effects of atmospheric chemistry and deposition processes were not well considered, when calculating the source–receptor relationships;(2) different meteorological and emission data inputs and solution schemes for key physical and chemical processes were used; and(3) different temporal and spatial scales were employed. Therefore, simulations using the same input fields and similar model configurations would be of benefit, to further evaluate the source–receptor relationships of the oxidized S and N pollutants.     

Removal of tetracycline from water by Fe-Mn binary oxide

Significant concerns have been raised over the presence of antibiotics including tetracyclines in aquatic environments. A series of Fe-Mn binary oxide with different Fe:Mn molar ratios was synthesized by a simultaneous oxidation and coprecipitation process for TC removal. Results showed that Fe-Mn binary oxide had higher removal efficiency than that of hydrous iron oxide and hydrous manganese oxide, and that the oxide with a Fe:Mn molar ratio of 5:1 was the best in removal than other molar ratios. The tetracycline removal was highly pH dependent. The removal of tetracycline decreased with the increase of initial concentration, but the absolute removal quantity was more at high concentration. The presence of cations and anions such as Ca²⁺, Mg²⁺, CO₃^2- and SO₄^2- had no significant effect on the tetracycline removal in our experimental conditions, while SiO₃^2- and PO₄^3- had hindered the adsorption of tetracycline. The mechanism investigation found that tetracycline removal was mainly achieved by the replacement of surface hydroxyl groups by the tetracycline species and formation of surface complexes at the water/oxide interface. This primary study suggests that Fe-Mn binary oxide with a proper Fe:Mn molar ratio will be a very promising material for the removal of tetracycline from aqueous solutions.