纳米Fe2O3与纳米SiO2对石英砂表面改性的制备工艺优化研究

以普通石英砂滤料为原材料,纳米Fe2O3、纳米SiO2为改性剂,环氧树脂为粘结剂,表面负载量和附着强度为评价指标,通过正交试验与固定因素不同水平连续性试验等方法,制备了两种纳米氧化物改性石英砂(Nano-oxide coated sand,Nano-OCS).同时,研究了不同制备因素对Nano-OCS表面氧化铁负载量和附着强度的影响,并探讨Nano-OCS制备工艺的最佳优化条件.结果表明,水浴加热过程对改性剂和粘结剂进行慢速搅拌,最佳转速为50r·min-1,时间为45min,烘干时间1h,温度(120±5)℃,纳米Fe2O3(65.8g·L-1)与未改性石英砂(RQS)的最佳投加比(体积质量比,下同)为C=0.23mL·g-1,改性剂环氧树脂(99%)溶液与RQS的最佳投加比为C1=0.035mL·g-1,纳米SiO2(10g·L-1)与RQS的最佳投加比为C2=0.17mL·g-1,在最优条件下制备的样品负载量和有机物吸附率均达到92%.投加过量时,有机物吸附率明显减小.与传统的低温碱性沉积法或高温煅烧制得的Nano-OCS相比,加入了粘结剂环氧树脂,用低温水浴固化的方法所制得的Nano-OCS,负载量提高了约8倍,脱附率降低70%以上.本法采用无添加剂的粘结剂,表面改性后不会对水体产生二次污染.     

芽孢杆菌B01固态发酵及其对园林废弃物堆肥的影响

菌剂的使用是目前促进园林废弃物堆肥的有效方法,但常用的菌剂往往为液态菌剂,其制作存在无菌操作要求高、产品存在运输不便等问题,拟尝试通过固体菌剂加以克服.以芽孢杆菌（Bacillus sp.）B01为研究对象,对其固态发酵过程中的载体、保护剂、接种量、装瓶量等常见工艺参数进行优化,制成固体菌剂,并与市售常见液体菌剂——EM菌进行对比,探究其对园林废弃物堆肥过程的影响.结果表明:B01固态发酵的最优载体配比为麦麸35%、米糠45%、乳糖6%、黄豆粉6%、硅藻土8%,保护剂为5%海藻糖,接种量为15%,装瓶量为15%,料水比为1:1.在该发酵条件下,B01固态发酵物活菌体数可达到2.62×1010 CFU/g（以干质量计）,存储90 d后,25℃下的存活率为30.19%.与EM菌相比,固体菌剂——B01可使园林废弃物堆肥过程中纤维素降解率提高11.04%、木质素降解率提高15.47%、腐殖质含量提高19.91%.研究显示,通过固态发酵条件的优化成功地将B01制成固体菌剂,该固体菌剂具有较高的活菌数量和较长的保质期,还可促进园林废弃物堆肥过程中木质素、纤维素的降解以及腐殖质的合成,具有显著的应用潜力.      

CuxZn1-xS/RGO复合材料的制备及其光催化降解环丙沙星性能研究

通过一步水热法制备了光催化剂Cu_xZn_(1-x)S/RGO,实现了Cu_xZn_(1-x)S纳米颗粒的可控生长和氧化石墨烯(GO)还原的同步进行,并将所制备的Cu_xZn_(1-x)S/RGO用于环丙沙星(CIP)的催化降解研究.采用X-射线衍射(XRD)、电感耦合等离子体-原子发射光谱仪(ICP-AES)、傅立叶变换红外光谱(FTIR)、紫外可见漫反射光谱(UV-Vis)、电子显微镜(SEM)和透射电子显微镜(TEM)对复合物的组成形貌进行表征.结果表明,球状的Cu_xZn_(1-x)S颗粒成功负载在石墨烯表面.Cu~(2+)的掺杂增强了Cu_xZn_(1-x)S/RGO光催化剂在可见光范围的响应,石墨烯的引入抑制了Cu_xZn_(1-x)S纳米颗粒的团聚,提高了光催化性能.此外,Cu_(0.1)Zn_(0.9)S/RGO_(10)对CIP的降解速率分别是ZnS、Cu_(0.1)Zn_(0.9)S的8倍和4.4倍.     

Isolation and characterization of dissolved organic matter fractions from antialgal products of Microcystis aeruginosa

An antialgal bacterium, Streptomyces sp. HJC-D1, was applied for the biodegradation of cyanobacterium Microcystis aeruginosa, and the isolation and characterization of dissolved organic matter (DOM) fractions in antialgal products were studied. Results showed the the growth of M. aeruginosa was significantly inhibited by the cell-free filtrate of Streptomyces sp. HJC-D1 with the growth inhibition of 86?±?7 %. The antialgal products were divided using resin adsorbents into the hydrophilic fraction (HPI), hydrophobic acid (HPO-A), transphilic acid (TPI-A), hydrophobic neutral and transphilic neutral, and then the five fractions were analyzed by the 3-D fluorescence spectroscopy, gel permeation chromatography, and Fourier transform infrared spectroscopy. The results indicated that the HPI component was the most abundant DOM fraction in the antialgal products, and its concentration was increased with the increase of cell-free filtrate concentration. The fluorescence peak location and intensity analysis showed that the protein-, fulvic-, and humic-like substances were dominant in the HPI, HPO-A, and TPI-A fractions, and intensities of the relevant fluorescence peaks were stronger in the experimental groups than those of the control groups. It was also found that the number-average molecular weight of DOM fractions ranged from 245 to 1,452 g mol^?1, and thereinto organic acids such as HPO-A and TPI-A exhibited lower molecular weights.     

溶藻菌对受污染水源水除藻及脱氮特性研究

针对我国水源地藻类污染日趋严重等问题,利用前期分离获得的溶藻菌Streptomyces sp.HJC-D1研究固定化微生物技术强化污染水源水除藻以及脱氮性能。结果表明,对照组和试验组的水体叶绿素a平均去除率分别为（71.66±5.35）%和（80.94±4.36）%,NH4＋—N的平均去除率为（77.76±2.83）%和（72.36±3.18）%,而高锰酸盐指数（CODMn）平均去除率为（24.99±1.52）%和（18.74±1.38）%;不同曝气条件的影响研究发现,曝气/停曝时间比2：4、曝气量60 L.h-1工况下,系统CODMn和NH4＋—N去除率均有所提高,相比对照组NO3-—N积累更为明显;水力停留时间（HRT）变化对系统NH4＋—N、CODMn等的去除影响不大,但缩短HRT时叶绿素a去除率有所降低;分析反应器内填料表面微生物相发现,试验组填料表面有溶藻菌富集,推测对照组除藻主要通过填料对藻类的吸附去除,而试验组则是藻类吸附在填料表面后通过溶藻微生物实现藻类去除。     

Diagnosis of sewer pipe defects on image recognition of multi-features and support vector machine in a southern Chinese city

An image-recognition-based diagnosis system of pipe defect types was established. 1043 practical pipe images were gathered by CCTV robot in a southern Chinese city. The overall accuracy of the system is 84% and the highest accuracy is 99.3%. The accuracy shows positive correlation to the number of training samples. Closed circuit television (CCTV) systems are widely used to inspect sewer pipe conditions. During the diagnosis process, the manual diagnosis of defects is time consuming, labor intensive and error prone. To assist inspectors in diagnosing sewer pipe defects on CCTV inspection images, this paper presents an image recognition algorithm that applies features extraction and machine learning approaches. An algorithm of image recognition techniques, including Hu invariant moment, texture features, lateral Fourier transform and Daubechies (DBn) wavelet transform, was used to describe the features of defects, and support vector machines were used to classify sewer pipe defects. According to the inspection results, seven defects were defined; the diagnostic system was applied to a sewer pipe system in a southern city of China, and 28,760 m of sewer pipes were inspected. The results revealed that the classification accuracies of the different defects ranged from 51.6% to 99.3%. The overall accuracy reached 84.1%. The diagnosing accuracy depended on the number of the training samples, and four fitting curves were applied to fit the data. According to this paper, the logarithmic fitting curve presents the highest coefficient of determination of 0.882, and more than 200 images need to be used for training samples to guarantee the accuracy higher than 85%.     

我国山区城镇地质灾害易损性评价研究现状与趋势

为进一步探索城镇地质灾害易损性的评价方法,回顾了目前国内的相关研究成果,从易损性概念入手,探讨了山区城镇易损性评估的对象及其指标体系的构建,对目前主要的易损性评价方法进行了比较,对灾害易损性评估现状进行了总结,在此基础上认为易损性量化评价体系的完善和细化、时效性和空间尺度的融合以及评估模型的可靠度和适用性的提高是今后地质灾害易损性评估值得重视的发展趋向。     

Aging effect on the mobility and bioavailability of copper in soil

Aging effect on the mobility and bioavailability of copper (Cu) was investigated using a spiked soil with different incubation periods from 3 to 56 d. Wheat was planted and earthworm was cultured separately in the incubated soils. The mobility of Cu in soil was evaluated by a chemical fractionation scheme and the toxicity and bioavailability were assessed by measuring the biomass and Cu concentration in tissues. Results showed that aging had a significant effect on Cu fraction distribution, of which Cu tended to incorporate from the exchangeable into more stable fractions such as the reducible and oxidisable fractions. However, aging had little effect on Cu bioavailability to wheat and earthworms. Comparing the soil being incubated for 3 d and 56 d, Cu concentration in wheat roots decreased from 14.5 to 12.8 mg/kg, and no significant changes in Cu concentration were observed in both wheat shoots and earthworms. The Cu concentration was around 2.0 and 50 mg/kg for wheat shoots and earthworms, respectively, irrespective of soil incubation time. The CaCl2-extractable Cu had a linear relationship with Cu concentration in wheat roots (R2 = 0.65, P < 0.05), but no linear relationship can be found for wheat shoots and earthworms. Biological control may be more crucial for Cu accumulation in organism than the changes in soil Cu fraction caused by aging.     

好氧反硝化菌及其在生物处理与修复中的应用研究进展

好氧反硝化菌因其生长特性与同步异养硝化好氧反硝化功能,为环境生物脱氮提供了崭新的技术思路.综述了已分离获得的好氧反硝化菌类群及其生长特性,重点阐述了好氧反硝化菌生物脱氮性能、影响因素与好氧反硝化机理,探讨了好氧反硝化在环境生物修复领域的应用.已有研究表明,好氧反硝化菌在环境生物脱氮方面具有明显的技术优势,但有关好氧反硝化反应机理、影响因素等仍待解析,以期为好氧反硝化菌固定化、活性持留以及受污染环境水体修复等研究提供理论依据.     

The effect of SiNPs on DNA methylation of genome in mouse spermatocytes

Environmental Science and Pollution Research - Silica nanoparticles (SiNPs), which are the main inorganic components of atmospheric particulate matter, have been proved to have certain male...