不同粒径羟基磷灰石对污染土壤铜镉磷有效性和酶活性的影响

为研究不同粒径羟基磷灰石对重金属污染土壤的修复效果,采用向污染土壤添加常规磷灰石（150 μm）、微米（3 μm）和纳米（40 nm）羟基磷灰石的田间原位试验方法,考察其钝化修复5 a后对土壤铜镉磷有效性和酶活性的影响.结果表明:3种粒径羟基磷灰石均提高了土壤pH,降低了土壤交换性酸和交换性铝的含量,且微米羟基磷灰石处理效果最好.常规磷灰石、微米和纳米羟基磷灰石处理分别使w（离子交换态铜）降低了62.6%、74.3%和70.4%,w（离子交换态镉）降低了15.7%、25.3%和26.7%.3种材料均增加了土壤w（TP）,其中4.61%~17.4%和73.4%~89.8%分别转化为树脂磷和稳定态磷.微米羟基磷灰石处理分别使土壤脲酶活性和微生物量碳含量提高了4.66和0.66倍.研究显示,微米羟基磷灰石更有利于铜和镉由活性态向非活性态转化,增加土壤磷的有效性,提高土壤微生物活性,在我国南方重金属污染红壤区具有较好的应用潜力.      

原始红松林退化演替后土壤微生物功能多样性的变化

为了全面了解原始红松林退化演替为次生林后土壤生境及土壤微生物功能多样性的变化规律,以小兴安岭典型的原始阔叶红松林、退化演替后先锋阶段的白桦林及亚顶级阶段的硬阔叶林为研究对象,采用Biolog-ECO微平板检测法,分析三者0~ < 10 cm和10~20 cm表层土的土壤微生物功能多样性变化规律.结果表明:各林型土壤微生物的AWCD值（平均颜色变化率）随培养时间的延长而增加,培养初期表现为原始阔叶红松林>硬阔叶林>白桦林;培养末期表现为原始阔叶红松林>白桦林>硬阔叶林,三者的AWCD值在0~ < 10 cm土层分别为1.06、0.86、0.81,10~20 cm土层分别为0.68、0.47、0.45,原始林显著高于次生林（P < 0.05）,说明原始林土壤微生物对单一碳源的代谢活性显著高于次生林;同一林型下土壤微生物的AWCD值均表现为0~ < 10 cm土层显著高于10~20 cm土层（P < 0.05）. Shannon-Wiener多样性指数、Simpson指数、McIntosh指数和Richness丰富度指数也均表现为原始林显著高于次生林（P < 0.05）.原始林土壤微生物对各类碳源的综合利用强度均大于次生林,不同林型下土壤微生物群落的优势碳源类型存在一定的差异,碳水类、氨基酸类、羧酸类和多聚物类碳源是原始林退化演替后土壤微生物群落在碳源利用上发生变化的敏感碳源.      

Bioavailability of wastewater derived dissolved organic nitrogen to green microalgae Selenastrum capricornutum, Chlamydomonas reinhardtii, and Chlorella vulgaris with/without presence of bacteria

Effluent dissolved organic nitrogen (DON) is problematic in nutrient sensitive surface waters and needs to be reduced to meet demanding total dissolved nitrogen discharge limits. Bioavailable DON (ABDON) is a portion of DON utilized by algae or algae + bacteria,while biodegradable DON (BDON) is a portion of DON decomposable by bacteria. ABDON and BDON in a two-stage trickling filter (TF) wastewater treatment plant was evaluated using three different microalgal species, Selenastrum capricornutum, Chlamydomonas reinhardtii and Chlorella vulgaris and mixed cultured bacteria. Results showed that up to 80% of DON was bioavailable to algae or algae + bacteria inoculum while up to 60% of DON was biodegradable in all the samples. Results showed that C. reinhardtii and C. vulgaris can be used as a test species the same as S. capricornutum since there were no significant differences among these three algae species based on their ability to remove nitrogen species.     

A metal-free composite photocatalyst of graphene quantum dots deposited on red phosphorus

A simple approach to enhance the photocatalytic activity of red phosphorus(P) was developed.A mechanical ball milling method was applied to reduce the size of red P and to deposit graphene quantum dots onto red P. The product was characterized by scanning electron microscopy, transmission electron microscopy, contact angle measurements, zeta-potential measurements, X-ray diffraction and UV–vis absorption spectroscopy. The product exhibited high visible-light-driven photocatalytic performance in the photodegradation of rhodamine B.     

Determination of 15 phthalate esters in air by gas-phase and particle-phase simultaneous sampling

Based on previous research, the sampling and analysis methods for phthalate esters (PAEs) were improved by increasing the sampling flow of indoor air from 1 to 4 L/min, shortening the sampling duration from 8 to 2 hr. Meanwhile, through the optimization of chromatographic conditions, the concentrations of 9 additional PAE pollutants in indoor air were measured. The optimized chromatographic conditions required a similar amount of time for analysis as before, but gave high responsivity, the capability of simultaneously distinguishing 15 kinds of PAEs, and a high level of discrimination between individual sample peaks, as well as stable peak generation. The recovery rate of all gas-phase and particle-phase samples of the 15 kinds of PAEs ranged from 91.26% to 109.42%, meeting the quantitative analysis requirements for indoor and outdoor air sampling and analysis. For the first time, investigation of the concentration levels as well as characteristics of 15 kinds of PAEs in the indoor air from four different traffic micro-environments (private vehicles, busses, taxis and subways) was carried out, along with validation of the optimized sampling and analytical method. The results show that all the 9 additional PAEs could be detected at relatively high pollution levels in the indoor air from the four traffic micro-environments. As none of the pollution levels of the 15 kinds of PAEs in the indoor air from the 4 traffic micro-environments should be neglected, it is of great significance to increase the types of PAEs able to be detected in indoor air.     

北京市潮白河再生水补水河段水质时空变异

城市河道是城市再生水利用的主要载体,而人工湿地是城市再生水河道补水前主要的水质净化方式.为了解再生水补水与人工湿地对再生水补水段水质的影响,选取北京市潮白河再生水补水河段作为研究对象,利用聚类分析、判别分析及因子分析等方法对不同季节水体的水质情况进行分析.结果表明:研究区内水体氮磷污染严重,其中TN污染表现为NO₃--N、NO₂--N和NH₄+-N的混合型污染.聚类分析结果表明,水质在季节尺度上表现为丰水期（6-9月）和枯水期（2月、3月、5月和12月）两大类;在空间尺度上受再生水补水和湿地净化的影响表现为显著的空间差异性.判别分析结果表明,再生水补给对河道水质的影响无显著季节差异,湿地净化功能在丰水期和枯水期差异较大且丰水期湿地的净化效果最为明显.因子分析结果表明,再生水作为城市河道的补充水源,一方面对河道中的F-、Chl-a等起到稀释作用,另一方面使得水体中的N、P及离子含量增加;丰水期湿地的净化作用使水体中氮磷等有机营养物质含量及ρ（TDS）等显著降低.      

自养脱氮污泥的亚硝化活性恢复策略

为考察自养脱氮污泥亚硝化活性快速恢复的策略,在3个反应器内分别采用不同的方法对经过长期冷冻保存后的污泥进行了恢复活性的研究.其中R1为MBR(膜生物反应器),采用低ρ(DO)(0.30 mg/L)连续流恢复策略;R2为SBR(序批式反应器),采用低ρ(DO)(0.30 mg/L)间歇流恢复策略;R3为SBR,采用低ρ(NH₄+-N)预培养-高曝气-低ρ(DO)运行三阶段的恢复策略.结果表明,R1的恢复时间为46 d,NH₄+-N氧化速率达到4.99 mg/(h·g)(以N计),最终ρ(MLSS)达到5.43 g/L;R2的恢复时间为39 d,NH₄+-N氧化速率达到4.61 mg/(h·g),最终ρ(MLSS)达到4.47 g/L;R3的恢复时间为48 d,NH₄+-N氧化速率达到5.64 mg/(h·g),最终ρ(MLSS)达到5.16 g/L. 3个反应器均能长期抑制亚硝酸盐氧化细菌的活性,使亚硝化稳定运行. 3个反应器中,R3恢复所需时间最长,但污泥活性最好; R1中的污泥活性较低,但是膜组件有效截留了污泥,达到了最高的ρ(MLSS).研究显示,通过厌氧预培养后转为膜生物反应器连续流运行的策略,可有助于污泥的极大保留及污泥活性的最大恢复.      

自适应智能电磁防护材料测试方法研究

目的在强电磁场环境下研究自适应智能电磁防护材料的相变特性。方法针对自适应智能电磁防护材料相变前后电导率的变化范围大、需要强场激励状况,考虑测试系统强场生成、大动态范围、测试精度以及相应的绝缘性和较高的安全性要求,采用电容充放电原理设计强场激励测试电路,搭建绝缘环境,确保操作的安全性和测试数据的可靠性。结果利用测试系统对现有商业化电阻器进行验证试验,得到的特性曲线与理论相一致。结论测试系统能够满足自适应智能电磁防护材料相变特性试验的需求,可获取有效且可靠的测试数据。     

湖北省PM2.5与PM10比值分析及PM2.5时空分布特征研究

基于2012年-2014年湖北省大气污染物监测数据,通过数据反演方法,得到湖北省17个城市的PM2.5年均浓度.利用ArcGIS绘制出各城市不同年份的颗粒物浓度空间分布图,并对其进行分析.结果表明,2012年-2014年间,湖北省17个城市PM2.5与PM10年均浓度比值为0.66,PM2.5年均浓度超出国家二级标准,整体呈现上升趋势.城市方面,在多数城市PM2.5与PM10浓度上升的同时,仅武汉、黄冈和天门3个城市颗粒物浓度2014年较2013年有所下降,且武汉市PM2.5浓度下降率达12.8%,表明武汉市近两年来采取的政策措施具有较好的可行性和有效性.     

高原高寒地域中重型车辆进气预热起动辅助装置研究

目的解决高海拔地域中重型越野车辆的起动困难问题。方法从进气温度对车辆起动的影响因素入手,系统地研究几种典型进气预热型式的优缺点。针对中型和重型两台越野车的具体情况,设计选型集中加热的电阻型格栅式进气预热器。经设计计算和反复测试,确定两型加热器的尺寸和功率等主要参数和控制策略,计算分析与车载蓄电池的匹配关系。结果对两型进气预热器进行实车安装后,分别经过实验室试验和野外现场验证,在-30℃实验室常压环境和-27℃的高原环境条件下,两型车辆均能在3 min内顺利起动。结论在高原高寒地域,格栅式电阻进气预热器可有效解决-30℃以上温度范围的起动困难问题。该装置结构简单、安装方便、可靠性高,便于中重型车辆加装使用,为该类问题提供了有效的技术解决途径。