Co3O4/介孔分子筛催化剂对苯催化完全氧化的研究

分别以介孔分子筛MCM-41、MCM-48、SBA-15为载体，采用等体积浸渍法制备了氧化钴/介孔分子筛催化剂，利用N₂吸附、X射线衍射、程序升温还原等技术对催化剂进行了表征，考察了Co₃O₄的负载量及载体的孔结构对催化剂完全催化氧化苯的性能的影响。结果表明，Co₃O₄的负载量为20%时，催化剂的催化活性最好；载体的孔径和催化剂的可还原性能是影响催化活性的主要因素，催化剂活性顺序为Co₃O₄ /SBA-15> Co₃O₄ /MCM41> Co₃O₄ /MCM-48。     

Socially facilitated egglaying behavior in Mediterranean fruit flies

We examined the behavior of individual mature female Mediterranean fruit flies (medflies), Ceratitis capitata (Wiedemann), transferred from a holding cage without fruit to a clean host kumquat fruit already occupied by another medfly female engaged in ovipositional behavior. A significantly greater proportion of transferred (=test) ovipositionally naive females initiated ovipositor boring into a fruit in the presence than in the absence of an occupying medfly. Moreover, test females commenced boring significantly sooner in the presence than in the absence of another medfly. Interestingly, similar results occurred when a test medfly was transferred to a kumquat occupied by an ovipositing female oriental fruit fly, Bactrocera dorsalis Hendel. In contrast, there was no enhancement of propensity to bore when a test medfly was transferred to a kumquat occupied by a female Biosteres arisanus (Sonan), a parasitoid attacking medfly eggs. The principal proximate stimulus giving rise to the higher tendency to oviposit of a test medfly in the presence of an occupying medfly or oriental fruit fly appeared to be wing-waving by the occupant during an encounter. We consider our findings to be good evidence of socially facilitated ovipositional behavior in ovipositionally naive medflies, and suggest that such females may benefit from acquisition of a cue demonstrating the acceptability of a host for oviposition. Received: 7 July 1997 / Accepted after revision: 30 August 1997     

生物接触氧化处理渗滤液有机物的动力学模型研究

以重庆黑石子垃圾填埋场渗滤液生物接触氧化工艺为依托,针对其处理效果的局限性,设计了强化预处理-生物接触氧化反应器,并进行生物接触氧化反应器试验及其有机物降解动力学模型研究,旨在优化运行参数,提高渗滤液处理效果.结果表明,改进后系统比原工艺处理效果好,COD、NH4 -N、TN平均去除率分别达到95.83%、97.60%、85.60%;出水水质得到大幅度提高,出水COD、NH4 -N、TN平均质量浓度分别为235、35、199 mg/L.对生物接触氧化反应器内垃圾渗滤液有机物降解生化反应过程进行量化研究,得到微生物生长动力学模型为1/θc=0.918 7q-0.002 5;根据生物接触氧化反应器内基质消耗过程的物料平衡,得到生物接触氧化反应器处理垃圾渗滤液有机物生物降解的动力学模型为q=1.09S/(10 230 S).试验结果为生物接触氧化反应器的优化控制、设计与放大提供了参考依据.     

无污泥持留序批式预处理反应器渗滤液预处理的正交试验研究

以黑石子垃圾填埋场渗滤液强化预处理-生物接触氧化为依托,针对其处理效果的局限性,研究无污泥持留序批式预处理(WSIP)反应器正交试验,旨在优化运行参数,提高低温期间渗滤液处理效果.实验表明,COD、NH 4-N、TN去除率较高,出水可生化性较好;优化碳氮质量比,为后续好氧微生物降解创造条件;曝气时间、HRT、进水磷浓度、序批周期对NH 4-N、TN去除效果影响显著;低温期间,获得较好出水水质的最佳运行参数为曝气时间9h、HRT4d、进水磷质量浓度50mg/L、序批周期6h.     

陕南秦巴山区地质灾害发育及空间分布规律

为进一步研究陕南秦巴山区地质灾害发育及空间分布规律,对区内地质灾害的数量、规模、物质组成等进行概率统计分析,结果显示:该区地质灾害以堆积层滑坡为主,岩质崩塌次之;滑坡规模以小型、浅层和等长式为主,崩塌以小型、等长式为主。地质灾害空间点密度呈"四高两低"分布,崩塌呈"三高四低"分布,泥石流呈"三高两低"分布。地质灾害、断裂、河流及道路的空间分布具有分形特征。滑坡(崩塌)面积与体积(长、宽)之间具有幂律相依性,面积与体积符合对数正态分布。结论为陕南秦巴山区移民搬迁安置选址提供技术支持。     

表观遗传学机制与空气污染的健康效应

空气污染是一个全球性的问题,并且具有深远的环境影响。暴露于空气污染会对人体健康产生许多不同的影响,理解空气污染的健康效应又是一个复杂命题,既要考虑不同类型的污染物同时也要考虑相关疾病的复杂性。然而越来越多的研究表明,表观遗传学在空气污染相关疾病的发生、发展中发挥着重要的作用。空气污染物可引起DNA甲基化、组蛋白修饰和miRNA表达等表观遗传学改变,这种改变往往发生在疾病产生的早期,因此相关研究不仅可以了解疾病的发病机制,而且还为疾病早期诊断和预防筛选可能的标志物。本文综述了表观遗传学的几种修饰方式和空气污染物造成不良健康损伤机制的一些研究进展。     

磁微球负载硝基锌卟啉光催化剂的制备及催化性能研究

以氯化血红素为原料,制备了磁负载的硝基锌卟啉光催化剂.同时,利用热重分析仪(TG)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)和振动磁强计(VSM)对催化剂进行了表征,发现制备的催化剂负载率为32.06%,催化剂为粒径均一的球形壳-核结构,具有良好的磁性.其次,研究了催化剂的催化降解性能.结果表明,磁负载硝基锌卟啉光催化剂在可见光下,对水中的双酚A(BPA)、对硝基苯酚(PNP)等均有90%以上的去除率;对于活性红染料废水的降解也取得了83.67%的降解率.自由基捕获实验证明,电子(e-)、羟基自由基(·OH)、空穴(h+)和氧自由基(O-·2)是降解反应中重要的活性物种.最后通过GC-MS等手段对降解机理进行了研究.     

中国环境基准研究重点方向探讨

环境基准是环境标准的科学依据,在国家环境质量评价和风险管理体系中处于基础地位。它主要是依据特定对象在环境介质中的暴露数据,以及与环境要素的剂量效应关系数据,通过科学判断得出的,涉及环境化学、毒理学、生态学、流行病学、生物学和风险评估等前沿学科领域。国家环境基准研究是一个长期的系统工程,本文基于环境基准研究的学科特点和国际前沿,结合国家科技需求和相关领域的研究现状,综合分析并提出了未来中国环境基准研究的重点研究方向:1)环境基准的理论与方法学;2)环境基准基础数据库;3)基准目标污染物的筛选甄别和优先排序技术;4)水体营养物基准;5)生物测试与毒性评价技术;6)人体暴露评价理论与相关技术;7)环境基准的审核和校对;8)环境基准与标准转化理论及其对环境管理支撑技术。本文从环境基准学科发展的角度,阐述了与环境基准研究紧密相关的8个重点研究方面的国内外研究进展、关键科学问题以及未来重点研究内容。同时指出,这些重要的研究方向是环境基准研究的根本,未来环境基准的长期战略发展必将是建立在各个重要方向长足发展的基础之上,环境基准研究也必带动这些方向的共同蓬勃发展,为环境地球化学、毒理学、生态学等学科领域发展注入活力。     

超高效液相色谱-串联质谱法同时分析地下水中24种内分泌干扰物

建立了基于超高效液相色谱-串联质谱法同时测定地下水中9种雌激素、5种雄激素、3种肾上腺皮质激素、4种酚类和3种非甾类激素共24种内分泌干扰物的方法。在活化后的MCX固相萃取柱中加入水样,再加入pH=5的水溶液淋洗,随后用碱化乙腈(4.5%,体积分数)洗脱。收集洗脱液并用氮气吹至近干后,用甲醇定容。采用Poroshell 120 Bonus-RP色谱柱(2.7 μm,100 mm×2.1 mm),以0.1%氨水溶液-乙腈为流动相进行梯度洗脱,实现液相分离。质谱检测采用MRM模式进行采集,通过正负离子模式切换同时进行测定,使用内标法定量。检测结果显示,目标物在线性范围内,决定系数R²均大于0.995,方法检出限为0.05~2.00 ng/L,加标回收率为68.8%~108%。该方法灵敏度高、准确度好,具有较强的实用价值。     

Microwave-assisted continuous flow phytosynthesis of silver nanoparticle/reduced graphene oxide composites and related visible light catalytic performance

The creation of an environmentally friendly synthesis method for silver nanomaterials (AgNPs) is an urgent concern for sustainable nanotechnology development. In the present study, a novel straightforward and green method for the preparation of silver nanoparticle/reduced graphene oxide (AgNP/rGO) composites was successfully developed through the combination of phytosynthesis, continuous flow synthesis and microwave-assistance. Oriental persimmon (Diospyros kaki Thunb.) extracts were used as both plant reducing and capping agents for fast online synthesis of AgNP/rGO composites. The experimental parameters were optimized and the morphologies of the prepared materials were investigated. The characterization results reveal that spherical AgNPs were quickly synthesized and uniformly dispersed on rGO sheets using the proposed online system. Fourier transform infrared spectroscopy analysis confirmed that phenols, flavonoids, and other substances in the plant extracts played a decisive role in the synthesis of AgNP/rGO composites. Using sodium borohydride (NaBH₄) degradation of p-nitrophenol (4-NP) as a model, the catalytic activity of the prepared AgNP/rGO materials was evaluated. The complete degradation of 4-NP was achieved within 12 min through the use of AgNP/rGO materials, and the composite had a much better catalytic activity than the bare AgNPs and rGO had. Compared with the conventional chemical method, our online method is facile, fast, cost-efficient, and environmentally friendly.