Low-temperature plasma induced phosphate groups onto coffee residue-derived porous carbon for efficient U(VI) extraction

For the continuous utilization of nuclear energy and efficient control of radioactive pollution, low-cost materials with high efficient U(VI) removal are of great importance. In this study, low temperature plasma method was applied for the successful modification of O-phosphorylethanolamine (O-PEA) on the porous carbon materials. The produced materials (Cafe/O-PEA) could adsorb U(VI) efficiently with the maximum sorption capacity of 648.54 mg/g at 1 hr, T=298 K, and pH=6.0, much higher than those of most carbon-based composites. U(VI) sorption was mainly controlled by strong surface complexation. From FTIR, SEM-EDS and XPS analyses, the sorption of U(VI) was related to the complexation with -NH₂, phosphate and -OH groups on Cafe/O-PEA. The low temperature plasma method was an efficient, environmentally friendly and low-cost method for surface modification of materials for the effective enrichment of U(VI) from aqueous solutions.     

Radionuclides in pinon pine (Pinus edulis) nuts from los alamos national laboratory lands and the dose from consumption

Abstract

One of the dominant tree species growing within and around the eastern portion of Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis). Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food—the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of ³H, ¹³⁷Cs, ⁹⁰Sr, ^totU, ²³⁸Pu, ^{239, 240}Pu, and²⁴¹ Am in soils (0‐ to 12‐in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (3) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of ³H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 μSv); this is far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem (1000 μSv). Soil‐to‐nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.     

美军军事极端环境选择的科学表征

介绍了美国陆军研究办公室资助陆军研究实验室环境科学部和陆军军官学校地理与环境工程部,研发了通过地理环境分析提高利用自然环境进行试验和训练的科学判据,实现了表征任意环境试验站点支持试验任务的能力.在地理环境位置分析中,采用了8步骤环境试验站评价分析模型,并给出了理想热带试验区环境条件分析和理想沙漠环境精确的地理学参数分析...     

Tracking land cover change along the western edge of the U.S. Corn Belt from 1984 through 2016 using satellite sensor data: observed trends and contributing factors

The Cropland Data Layers (CDL) are high-resolution geo-referenced data products made available by the U.S. Department of Agriculture. However, the CDL lacks in its ability to be employed as a tool to identify the impact of the gradually evolving drivers of land use change, e.g., climate change, due to its limited historical depth. We implement a robust, phenology-based satellite image classification algorithm to identify historical cropland allocation in eastern South Dakota and North Dakota predating the initial CDL by 13 and 22 years, respectively. Five major land covers, i.e., corn, soybeans, wheat, alfalfa and grass (including native grass, hay and pasture) are identified using archived Landsat-5 surface reflectance data, while achieving CDL-like accuracy. The long-term rate of grassland loss during 1985–2011 is found to be significantly lower (26,781 hectares or 1.5% annually) relative to the near-term rate of grassland loss during 2006-’11 (84,545 hectares or 5.2% annually). We find similar discrepancy in regional corn expansion rates. Our value-added raster data provide opportunities for improved identification of land use drivers, whereas relying solely on the CDL’s restricted historical extent may lead to biased land use change estimates and misguide policy.     

Structuring cooperative behavior under the National Environmental Policy Act of the United States

A trend is presently under way to streamline the compliance requirements of the National Environmental Policy Act of the United States through cooperative assessment procedures. Since the law was enacted in 1970, however, participants in the assessment process have tended to settle disagreements by adversarial rather than cooperative means. This study focuses on a highly acclaimed environmental assessment procedure undertaken by the U.S. Steel Corporation for its proposed $4.0 billion Lakefront Steel Plant. Survey research data were gathered to measure the underlying management philosophy perceived by interorganizational representatives, who attended a series of Technical Team meetings designed to coordinate the assessment effort and to open communication channels. A social psychological scale of behavioral dimensions was adapted from Likert to define the composition and the extent of cooperation at these meetings. A newly constructed scale was used to measure the quantity and quality of representation by each of the major organizations involved. Informal interviews were conducted with project participants to obtain further insight into member interaction. Results indicate that democratic problem solving was in evidence but also suggest a preference by respondents for improved procedures. The paper outlines areas of concern voiced by respondents and offers the means for improving the operating procedures of similar interorganizational environmental assessments.     

Concentrations en plomb du plancton de la Mer Ligure (Mediterrannee Nord-Occidentale)

Plankton samples were collected from different parts of the Ligurian Sea during 1980 and 1983. Lead, but also cadmium, copper and zinc have been determined in these samples. The results indicate that nearshore samples display significantly higher lead concentrations (7.8 μg g^?1) than offshore samples (1.9 μg g^?1).     

Photodegradation and Biodegradation Study of a Starch and Poly(Lactic Acid) Coextruded Material

To simulate the behavior of agricultural mulch coextruded poly(lactic acid)(PLA)/starch films, two stages were carried out. The first was an ultraviolet treatment (UV) at 315 nm, during which glass transition temperature T_g, weight, and molecular weight (MW) decreased and a separation between PLA and starch phase was observed. For the second stage, the mineralization of the carbon of the material was followed using the ASTM (D 5209–92 and 5338–92) and ISO/CEN (14852 and 14855) standard procedures. To measure the biodegradability of polymer material, the assessment of the carbon balance allowed determination of the distribution between the carbon rate used to the biomass synthesis or the respiration process (released CO₂), as well as the dissolved organic carbon into the culture medium and the carbon in the residual insoluble material. The influence of the nature of the medium and the standardized procedures on the final rate of biodegradation was investigated. Whatever the standardized method, the biodegradation percentage was significantly stronger in liquid medium (92.4–93.4) than on inert medium (80–83%). In the case of the compost process, only released CO₂ was measured and corresponded to 79.1–80.3%.     

高岭土胶体对nZVI修复Pb、U污染硅藻土的影响及机制

纳米零价铁 (nZVI) 大量应用于土壤重金属污染的修复,但由于土壤广泛存在的胶体可协同污染物的迁移与扩散,影响nZVI对土壤的修复效果。针对这一问题,通过硅藻土柱实验和重金属运移速率分析,并采用微观结构表征分析 (SEM) 与物相分析 (XRD) 方法,探究高岭土胶体对nZVI修复铅 (Pb) 、铀 (U) 重金属污染土壤的影响机制。结果表明,nZVI可固化Pb和U,阻滞其运移以修复土壤;高岭土胶体的加入可削弱nZVI对重金属的阻滞效果,增强Pb和U的运移能力;但在高岭土胶体与nZVI同等质量浓度下,高岭土胶体对阻滞效果的影响有限;另外,在Pb、U复合体系中,存在竞争吸附现象,nZVI对Pb的阻滞效果优于U,U的运移更易受到高岭土胶体的影响。本研究结果可为土水重金属污染防治提供参考。     

解悟美国气象经济的发展轨迹和经验

美国政府在引导和规范国内气象经济发展的过程中,始终关注并有效抑制国有气象部门的垄断企图,及时果断地采取措施消除不利于气象事业顺应社会经济和技术发展要求的陈规陋习,适时坚定地扶持充满创造活力的民间资本的竞争努力.可以说,没有这种理智而清醒的管理理念,没有这种不昧于时的前赡眼光和超脱手法,没有这种不拘于内的国际视野和全球战略,是断难有其今天的作为的.我国气象经济的起步较美日等发达国家要晚近40年,更因发展思路不明至今已远远落后于诸多国家.如今面对国内社会经济发展对气象信息日益广泛而精细化的迫切需求,面对全球"气候政治"氛围愈益浓烈的全新形势.特别是"WTO'冲击渡带来的沉重的竞争压力,中国气象经济市场势必将在格局和规则方面进行重大调整.我国在推进气象服务市场化进程中亟需借鉴"美国经验",以确保我国气象事业的健康、协调、可持续发展.     

铀尾矿库渗漏地下含水层中六价铀的几种吸附反应运移模型对比

在铀尾矿地区,溶解态U(Ⅵ)渗漏到含水层中会对周围环境造成严重的威胁.使用反应运移软件PHT3D对U(Ⅵ)在含水层中的迁移和吸附过程进行模拟.结果表明,相比于不考虑吸附情形,考虑吸附的U(Ⅵ)反应迁移阻滞现象明显.线性和Langmuir吸附等温线模型在水动力条件复杂、地球化学条件多变时的模拟效果与表面络合模型相比较差,甚至有时得到与实际相反的结果,这说明了传统Kd吸附经验模型的局限性.由表面络合模型计算得出的分配系数Kd值是时空变化的,其更能反映实际中多变水化学条件下的吸附过程,适合描述复杂的不同水文地球化学条件.