西北干旱区煤炭基地生态蓄水模式研究

西北干旱区煤炭开采产生的矿井水大多就近排放,利用率低.同时,该地区水资源严重缺乏,尤其是生态用水紧缺,煤炭开采造成地下水资源浪费和生态用水紧缺的矛盾局面.为缓解这一矛盾,提出地面人工湿地及生态储水的设想,构建两种基于生态用水的地面处理储存矿井水的模式,该模式下矿井水通过下渗补给潜水含水层,进而供给地表植被;另一方面,利用干旱区蒸发量大的特点借助低空大气环流输送水份,增加局部降水量,从而实现改善生态环境的目的.     

河北平原潮土中微生物对氮降解特征

了解土壤中微生物对氮素降解规律,对于土壤氮污染修复具有重要现实意义.从河北平原潮土中筛选出8种高效氨化细菌、硝化细菌、异养硝化好氧反硝化细菌,对所筛菌种进行16S r DNA分析,选出最适菌株通过固定化载体将菌种制成菌剂.探讨了用加入所筛菌种及拮抗菌的菌液和地表水分别滴灌小白菜对土壤中的氮降解产生的影响,并测定土样磷脂脂肪酸(PLFA)的值.结果表明:以硅藻土为载体硝化细菌的氨氮降解率达到38%,硝态氮合成率为205%;以硅藻土为载体的氨化细菌氨氮合成率为1 711%,异养硝化好氧反硝化细菌的硝态氮降解率达到367%.加所筛菌液滴灌对土壤总氮和氨氮的降解效果较好,硝化作用也较强,加菌后土壤中微生物量明显增加,且更快到达峰值.对不同土样不同时间磷脂脂肪酸数据分析发现,在白菜生长过程中,土壤中的微生物含量均产生了1次峰值,且加入所筛菌的先到达峰值.对于任丘和阜城土样来说,加入所筛菌后,土壤中微生物种类相应增多,对土壤微生物环境有所改善,微生物也比较活跃.     

链霉菌FX645对偶氮染料红AR30的降解机制研究

从印染厂污泥中筛选到1株对偶氮染料红30(AR30)具有较强脱色降解作用的菌株Streptomyces sp.FX645.通过降解产物的紫外-可见吸收光谱、LC-MS分析及各降解产物在发酵体系中浓度随时间变化的规律,探讨了菌株FX645对AR30的可能降解途径,首先在偶氮还原酶的作用下AR30发生偶氮键的裂解,生成4-硝基-2,6-二氯苯胺与2-[(4-胺苯基)-(2-氰乙基)-氨基]乙酸乙酯,然后分别发生硝基还原、氨基酰化、氰基水解作用,生成一系列的苯胺类化合物.     

氟虫双酰胺在水稻和稻田中的残留动态研究

采用超高效液相色谱法(UPLC)测定了氟虫双酰胺19.8%悬浮剂(SC)在水稻及稻田环境中的残留动态.结果表明,当氟虫双酰胺及其代谢产物NNI-des-iodo的添加量为0.05～1.0 mg·kg-1时,其在水稻田土壤、田水、稻秆、稻米和稻壳中的平均回收率为78.2%～104.8%,变异系数为1.1%～4.4%.氟虫双酰胺在2011年三地(福建福州、天津、江苏南京)的稻田水中的降解半衰期为9.8～17.3 d,土壤中10.8～22.4 d,植株中7.6～17.3 d,其在稻田水样品中检出了代谢产物NNI-des-iodo,而在土壤和植株样品中未检出.在推荐使用剂量下,于末次施药10 d后,氟虫双酰胺在水稻稻米中的残留量均低于美国规定的在稻谷上的最大残留允许量(0.5 mg·kg-1).     

Utilizing surfactants to control the sorption, desorption, and biodegradation of phenanthrene in soil-water system

An integrative technology including the surfactant enhanced sorption and subsequentdesorption and biodegradation of phenanthrene in the soil-water system was introduced and tested. For slightly contaminated agricultural soils, cationic-nonionic mixed surfactant- enhanced sorption of organic contaminants onto soils could reduce their transfer to plants, therefore safe-guarding agricultural production. After planting, residual surfactants combined with added nonionic surfactant could also promote thedesorption and biodegradation of residual phenanthrene, thus providing a cost-effective pollution remediation technology.0ur results showed that the cationic-nonionic mixed surfactantsdodecylpyridinium bromide (DDPB) and Triton X-100 (TX100) significantly enhanced soil retention of phenanthrene. The maximum sorption coefficient Kd* of phenanthrene for contaminated soils treated by mixed surfactants was about24.5 times that of soils without surfactant (Kd ) and higher than the combined effects of DDPB and TX100 individually, which was about 16.7 and 1.5 times Kd , respectively.0n the other hand, TX100 could effectively remove phenanthrene from contaminated soils treated by mixed surfactants, improving the bioavailability of organic pollutants. Thedesorption rates of phenanthrene from these treated soils were greater than 85% with TX100 concentration above2000 mg/L and approached 100% with increasing TX100 concentration. The biodegradation rates of phenanthrene in the presence of surfactants reached over 95% in30days. The mixed surfactants promoted the biodegradation of phenanthrene to some extent in 10-22days, and had no obvious impact on phenanthrene biodegradation at the end of the experiment. Results obtained from this study provide some insight for the production of safe agricultural products and a remediation scheme for soils slightly contaminated with organic pollutants.     

Photocatalytic degradation of carbofuran in TiO2 aqueous solution：Kinetics using design of experiments and mechanism by HPLC/MS/MS

The photocatalytic degradation kinetics of carbofuran was optimized by central composite design based on response surface methodology for the first time. Three variables, TiO2 concentration, initial pH value and the concentration of carbofuran, were selected to determine the dependence of degradation efficiencies on independent variables. Response surface methodology modeling results indicated that the degradation efficiency of carbofuran was highly affected by the initial pH value and the concentration of carbofuran. Then nine degradation intermediates were detected by HPLC/MS/MS. The Frontier Electron Densities of carbofuran were calculated to predict the active sites on carbofuran attacked by hydroxyl radicals and photoholes. Point charges were used to elucidate the chemisorption pattern on TiO2 catalysts during the photocatalytic process. By combining the experimental results and calculation data, the photocatalytic degradation pathways of carbofuran were proposed, including the addition of hydroxyl radicals and the cleavage of the carbamate side chain.     

纳米Fe_3O_4/膨润土的制备、表征及光催化降解焦化废水

以铝柱撑膨润土负载纳米Fe_3O_4制备出性能良好的复合型催化剂。结合X射线粉末衍射(XRD)、扫描电镜(SEM)和比表面孔隙分析(BET)对催化剂的晶相、比表面积和粒度进行表征。负载的纳米Fe_3O_4粒径约为20～30nm,均匀分散到膨润土表面,未发生明显的团聚。在紫外光作用下用该催化剂对焦化厂二沉池出水进行深度处理。结果表明,在催化剂投加量为0.7 g/L,pH为2.5,温度40℃,H_2O_2初始浓度为17.6mmol/L的反应条件下,二沉池出水(化学需氧量COD=140mg/L,色度=400度)经催化氧化降解后,COD和色度可分别降低到54.44 mg/L和10度,达到国家工业再生用水水质标准GB/T 19923-2005(COD≤60 mg/L,色度≤30度)。催化剂重复使用4次时,废水COD和色度去除率保持稳定。     

鄂尔多斯盆地植被覆盖动态监测与评价

基于像元分解模型,利用LANDSATNDVI数据,估算了鄂尔多斯盆地2002年7月和2010年7月植被覆盖度,以量化和可视化的形式分析了鄂尔多斯盆地2002年一2010年间植被覆盖度的时空变化特征,探寻了引起植被覆盖度变化的驱动因素。结果表明：2002年一2010年鄂尔多斯盆地植被覆盖度变化明显,平均覆盖度增加了7．35％,改善和明显改善面积增加了35．67％,退化和明显退化面积增加了1．49％。研究区植被覆盖度增加的主要原因是降雨量的增加和一系列生态建设工程的实施;减少的主要原因是恶劣的生态环境和过度的能源开发活动。     

蚂蚁扰动对青海湖北岸高寒草甸草原群落结构影响

蚂蚁的筑丘活动是草地生态系统中不可忽视的生物干扰因子。本文针对青海湖北岸高 寒草甸草原,调查了不同大小的蚁丘及其周围对照草地的土壤理化性质和植被状况。结果表明： 蚂蚁筑丘活动显著地降低了土壤容重和土壤湿度,增加土壤温度,但对土壤pH 值的影响较小。 蚂蚁扰动改变了群落组成,增加了大部分禾本科和豆科物种的重要值而降低了杂类草的重要值。 以莎草科的矮嵩草（Kobresia humilis）和禾本科的异针茅（Stipa aliena Keng）、赖草（Leymus secalinus）、溚草（Koeleria cristata）等为主的群落逐步演替为以禾本科的异针茅和赖草为主的 群落。植物群落的盖度降低但其地上、地下生物量增加;植物群落丰富度指数降低但均匀度指 数增加。     

水体系中氧氟沙星的光化学降解研究

研究了高压汞灯和氙灯照射下氧氟沙星(OFLX)在蒸馏水、人工海水和天然海水中的光降解过程,探讨了光源、起始浓度、丙酮、表面活性剂等因素对OFLX光化学降解速率的影响.结果表明,OFLX在高压汞灯下的光反应速率比在氙灯下快得多,均符合一级反应动力学过程;在相同光源下,OFLX在海水中降解最快,其次是人工海水;当OFLX初始浓度为2、4、6mg.L-1时,其光解速率常数分别为0.163、0.140和0.132 min-1,随着OFLX初始浓度增大,其光解率降低;不同浓度的丙酮均能促进OFLX光降解的反应,其反应速率常数为0.084 2～0.102 min-1,且光敏效率与丙酮浓度呈正相关关系;然而当十六烷基三甲基溴化铵(CTAB)、十二烷基苯磺酸钠(SDBS)、吐温-20(TW-20)等表面活性剂的浓度为5 mg.L-1,它们均抑制了水体中OFLX光降解反应的进程.另外,利用金藻8701单种培养进行了OFLX光化学降解前后的毒性试验,表明OFLX光解过程产生风险较高的中间产物,随着光解进行,产物毒性降低.