Reduced graphene oxide-nano zero value iron(rGO-nZVI) micro-electrolysis accelerating Cr(Ⅵ) removal in aquifer

Nanoscale zero-valent iron(nZVI) assembled on graphene oxide(GO)(rGO-nZVI) composites were synthesized by reduction of GO and ferrous ions with potassium borohydride,for use in Cr(VI) removal from aqueous solution.The results showed that the two-dimensional structure of GO could provide a skeleton support for Fe~0,thus overcoming the bottleneck of aggregation for nZVI.Also,rGO-nZVI would form a ferric-carbon micro-electrolysis system in Cr(VI)-contaminated aquifers,enhancing and accelerating electron transfer,exhibiting high rate and capacity for Cr(VI) removal.The optimum dosage of the applied r GO-nZVI was linearly correlated with the initial Cr(VI) concentration.Characterization of rGO-nZVI before and after reaction with Cr(VI) revealed the process of Cr(VI) removal:r GO-nZVI firstly transferred electrons from Fe~0 cores via their Fe(II)/Fe(III) shells to the GO sheet;there,negatively charged Cr(VI) received electrons and changed into positively charged Cr(III),which was adsorbed by the negatively charged GO sheet,avoiding the capping and passivating of nZVI.rGO-nZVI formed a good electrically conductive network,and thus had long-term electron releasing properties,which was important for groundwater remediation.     

城镇油气管道事故应急疏散决策优化

为实现油气管道事故中城镇大规模应急疏散的智慧决策,构建基于改进的自适应蚁群算法的应急疏散路径优化模型,开发基于油气管道典型事故后果分析的城镇大规模应急疏散决策优化系统平台(LSSED)。LSSED在地理信息系统平台上,针对油气管道泄漏引起的扩散、喷射火、池火、BLEVE、蒸气云爆炸等典型事故进行事故后果分析,对疏散通道当量长度和疏散时间成本函数进行定量评价,实现大规模应急疏散方案的智慧决策和避难方案的全局优化。案例分析表明,LSSED平台实现了基于地理信息系统的典型事故时变环境信息和应急疏散路径优化算法的数据传递及系统集成,实现了基于事故后果分析的城镇大规模人群疏散路径和避难方案优化,可为城镇安全规划和应急管理提供参考和借鉴。     

企业全员危险源管理实践

为了预防企业生产安全事故发生,围绕危险源的管理,综合运用多种安全评价方法,通过小组活动自下而上开展全员危险源辨识、风险评价、现有风险控制措施评估,结合危险源辨识成果随机抽查、行为安全观察等管理活动,形成了企业全员危险源管理的企业文化氛围。对开展全员危险源管理1年以上的13家不同类型企业进行安全文化绩效评估,结果显示,开展THM对安全行为、安全教育、全员参与等安全文化绩效评价指标有显著提升作用。     

区域物质流规模结构分析评价方法及应用研究

生态经济体系中环境的引导和调控作用是经济系统物质代谢的重要组成部分.为了更为完善地分析评价经济发展和环境压力的关系,在输入端、输出端物质流规模和结构分析中侧重于物质隐藏流的综合计算,并以广州市南沙区为例进行实证研究.研究结果表明:南沙区域出口与出口物质隐藏流呈逐步上升趋势;南沙区的区内生产过程排放呈现"先降后增、总体递增"的趋势,今后南沙区应加强对工业生产过程中工业固废和二氧化硫排放的监控.     

Structural and metabolic responses of microbial community to sewage-borne chlorpyrifos in constructed wetlands

Long-term use of chlorpyrifos poses a potential threat to the environment that cannot be ignored, yet little is known about the succession of substrate microbial communities in constructed wetlands(CWs) under chlorpyrifos stress. Six pilot-scale CW systems receiving artificial wastewater containing 1 mg/L chlorpyrifos were established to investigate the effects of chlorpyrifos and wetland vegetation on the microbial metabolism pattern of carbon sources and community structure, using BIOLOG and denaturing gradient gel electrophoresis(DGGE) approaches. Based on our samples, BIOLOG showed that Shannon diversity(HV) and richness(S) values distinctly increased after 30 days when chlorpyrifos was added. At the same time, differences between the vegetated and the non-vegetated systems disappeared. DGGE profiles indicated that H Vand S had no significant differences among four different treatments. The effect of chlorpyrifos on the microbial community was mainly reflected at the physiological level. Principal component analysis(PCA) of both BIOLOG and DGGE showed that added chlorpyrifos made a difference on test results.Meanwhile, there was no difference between the vegetation and no-vegetation treatments after addition of chlorpyrifos at the physiological level. Moreover, the vegetation had no significant effect on the microbial community at the genetic level. Comparisons were made between bacteria in this experiment and other known chlorpyrifos-degrading bacteria. The potential chlorpyrifos-degrading ability of bacteria in situ may be considerable.     

缺水地区人类活动净氮输入与河流响应特征——以海河流域为例

人类活动净氮输入(NANI)是影响河流氮输出的重要因素,研究两者的响应关系对制定氮污染的削减策略具有重要意义.基于NANI核算模型,评估了海河流域人为氮输入强度,并采用实测数据估算了同期的河流氮输出,最终得到干旱缺水区河流氮输出对NANI的响应特征.结果表明,海河流域2008—2012年均NANI输入强度为13258 kg·km~(-2)·a~1,化肥施用、食品与饲料输入、大气沉降和农作物固氮分别占76%、17%、5%和2%;在空间分布上,黑龙港运东子流域的NANI负荷最高,达到24238 kg·km~(-2)·a~(-1),最小的是永定河子流域,为5320 kg·km~(-2)·a~(-1);海河流域主要河流的氮通量与子流域NANI输入呈现显著正相关关系(p0.05),NANI变化可解释67%的河流氮通量变化.然而,仅2%的NANI由河流输出,这一比例低于其他地区研究成果,表明缺水地区河流作为氮输出的功能被削弱,河流不是流域氮输出的主要途径.     

BiPO_4-BiVO_4复合光催化剂的制备及其光催化性能

采用水热法制备了BiPO_4-BiVO_4复合光催化剂,运用XRD,SEM,UV-Vis DRS技术对其进行了表征,并以亚甲基蓝为目标降解物考察了复合光催化剂在模拟太阳光下的光催化性能。实验结果表明:当BiPO_4与BiVO_4的摩尔比(磷钒比)为2∶8时BiPO_4-BiVO_4的光催化性能最优,光照180 min时对亚甲基蓝(初始质量浓度5mg/L)的降解率达96.20%,反应速率常数为0.018 1 min-1,明显优于单纯BiPO_4和BiVO_4。表征结果显示:单斜相的BiPO_4与BiVO_4晶粒实现了复合生长,BiPO_4-BiVO_4(磷钒比2∶8)的晶粒粒径比单纯BiPO_4和BiVO_4小;复合光催化剂在紫外光和可见光区均具有较好的光响应,且其禁带宽度较BiPO_4明显减小。     

PPP 模式在荒漠治理中的应用研究

作为世界上荒漠化最严重的国家之一,中国的土地荒漠化已经呈现出不断蔓延的趋势,而现有的荒漠化治理在虽然取得了一定的成果,但并未能从根本上遏制荒漠化地蔓延,主要问题在于治理的方式和投资资金的管理能力不足。在荒漠化治理中引入PPP模式,使政府部门和私营部门之间实现优势互补,风险共担,将政府在治理荒漠化中的社会责任感和私营企业高效的运营能力相结合,实现荒漠化治理中的共赢,才能够有效的解决当前面临的荒漠化形势。     

慈溪大气PM10及其水溶性离子污染特征研究

研究了慈溪市大气中PM10及其水溶性离子的分布特征。通过对慈溪市四个季度的PM10监测,获得其年间浓度水平变化,了解其时空分布及相关性。对实验数据分析得知,PM10及其水溶性离子浓度与气压、气温有关。含量最高的水溶性离子是NH4+离子,浓度范围在0.01~10.85μg/m3;其次是NO3-,浓度范围在0.14~7.78μg/m3;再次是SO42-,浓度范围在0.05~6.62μg/m3;最低的Cl-的浓度范围在0.02~1.82μg/m3。SO42-、NO3-、Cl-的浓度市区高于乡镇。NH4+的浓度乡镇高于市区。水溶性离子的浓度整体冬季浓度高于夏季。污染主要来源于汽车尾气与工业燃煤。     

海水对含水层沉积物中镭解吸的模拟实验

本研究采用莱州湾沿岸含水层中的沉积物,通过渗滤实验模拟镭的解吸过程。结果表明,在典型的地下水流速范围内(0.02~0.30 cm/min),镭同位素(223Ra、224Ra、226Ra)的解吸没有显著变化。在海水与淡水的混合过程中,解吸的镭比活度与水的盐度呈显著的线性正相关关系。当盐度超过海水盐度时(如S=80的卤水中),解吸的镭比活度则趋于最值平台。对比模拟估算的地下水中镭的比活度与莱州湾沿岸实测间隙水中镭的比活度,223Ra和224Ra的结果基本一致,而226Ra的实测结果较模拟估算结果偏小。可能由于含水层中226Ra经反复解吸后得不到母体核素及时补充所致。本研究将为更好地理解镭同位素在含水层中的地球化学行为提供科学依据,为合理地选择量化海底地下水排放(submarine groundwater discharge,SGD)模型的镭端元值提供新的参考视角。