EDS analysis of Portland ash cement degradation in an aggressive environment

The behaviour of Portland cement with and without 30% fly ash addition in aggressive solutions was studied. This paper considers the sulphate corrosion of the hardened cement paste. The cement paste test samples were prepared, cured in water for 21 day and then exposed to the influence of aggressive environment (10% (NH₄SO₄ solution). The measurements of several properties were carried out and the results were analyzed.

The image of the surface composition and morphology of the cement paste test samples was made by scanning electron microscopy (SEM). Concentration gradient of sulphate ions in cement paste depth was obtained by energy‐dispersive analysis (EDS).     

Review of strobilurin fungicide chemicals

Strobilurins are natural products isolated and identified from specific fungi. Natural strobilurins were named in the order of their discovery as strobilurin-A followed by strobilurin-B, C, D etc. Their discovery opened the door for new chemistry of synthetic fungicides. Applying Quantitative Structural Activity Relationship (QSAR) on the structures of the natural strobilurins, many pesticide companies were able to discover many synthetic analogues that are more efficacious and more stable fungicides. At present there are about eight synthetic strobilurins in the fungicides worldwide market. Some of these products are worldwide registered for use as agrochemical and some are in the process of registration. This class of fungicides is relatively new, as crop protection products and information about them is still fairly scarce. In this review, syntheses and chemistry of natural and synthetic strobilurins are discussed. Also, the mode of action, efficacy, biotic/abiotic degradation, analytical methods, and agricultural uses are discussed.     

己酸菌富集及其利用餐厨垃圾产己酸的研究

采用批式发酵的方式,考察3种不同电子供体(乙醇、乳酸、乙醇和乳酸)对己酸菌的富集情况,进而选取产己酸最优的混合菌,探究在不外加电子供体情况下,餐厨垃圾厌氧发酵产己酸的性能.结果表明:当以乙醇和乳酸共同作为电子供体时,己酸浓度可达(2303.06±499.56) mgCOD/L,产己酸效果最佳,并显著富集到了3种碳链延长菌:Clostridium_sensu_stricto_12(16.04%±0.16%),Caproiciproducens(28.78%±0.15%),Oscillibacter(2.32%±0.03%);将产己酸最优的混合菌接种于餐厨垃圾进行厌氧发酵,己酸浓度最高可达(8657.36±996.21) mg COD/L,己酸产率为(230.05±26.47) mg COD/gVS,己酸选择度为27.74%±3.19%.以上结果验证了以乙醇和乳酸共同作为电子供体时对己酸菌具有明显的富集作用,富集到的混合菌可有效用于餐厨垃圾的产己酸发酵,为餐厨垃圾的资源化利用提供了理论支撑.     

多元多相光催化氧化反应器及其对水中2,4-二硝基苯酚有机污染物降解的研究

利用多元多相光催化氧化反应器 ,可更换不同氧化剂、光源、金属氧化物半导体催化膜、电子捕获器 ,进行化学氧化、光氧化、光化学氧化、光催化氧化和光化学催化氧化等 5种类型多种组合试验 ,处理水中难降解有机物效果明显。设备具有持久性、灵活性、捕电性、简易性 ,适用于科研、工程试验中 ,亦可作教学设备     

电子供体刺激下厌氧微生物对1, 2-二氯乙烷的降解效果

通过添加电子供体进行原位生物刺激可有效降解地下水中的氯代烃,目前国内外常采用接种高效微生物的方法强化这一降解过程,鲜见仅利用实际污染场地含水层土著菌开展的生物降解试验.从北京市某氯代烃污染场地采集地下水样品,仅接种场地含水层沉积物,利用微宇宙实验体系,初步探讨了添加不同种类和质量浓度的电子供体对地下水中1,2-二氯乙烷的去除效果影响.结果表明:①同时添加初级生长基质和电子供体对反应体系进行生物刺激可显著降解地下水中的1,2-二氯乙烷.60 d后,添加1 g/L醋酸钠的反应体系中1,2-二氯乙烷的去除率最高,可达93.9%;添加1 g/L的乳酸钠反应体系次之,去除率为82.2%;添加1 g/L的乳酸的反应体系去除率最低,为61.8%.并且添加醋酸钠的试验体系可长时间维持中性pH及较低的氧化还原电位.②相同条件下,对同种电子供体来说,添加量为1 g/L的试验组中1,2-二氯乙烷的降解效果优于添加量为2 g/L的试验组,推测较高质量浓度的电子供体可对微生物的生命活动产生抑制.③对反应体系中间产物进行监测,仅监测到了乙烯的产生,表明在试验周期内无明显毒副产物积累,1,2-二氯乙烷的降解较为彻底.研究显示,醋酸钠为该试验体系中最适电子供体,添加适宜质量浓度醋酸钠对土著菌进行生物刺激可实现对1,2-二氯乙烷的绿色降解.      

某石油污染含水层降解能力地球化学评估

含水层降解能力是石油类污染场地监控自然衰减需获取的重要参数.通过测定某石油污染场地地下水电子供体（苯系物、化学耗氧量）和电子受体/产物（DO、NO₃^-、Mn²⁺、Fe²⁺、SO₄^2-和HCO₃^-）等地球化学指标,分析了电子供受体分布规律,确定了电子受体背景值,采用传统地球化学评估法,计算了所有单井降解能力;在此基础上,引入累积概率曲线法,更科学的评估了场地含水层降解能力,结合地下水更新能力,估算了污染物降解速率;同时,划分了含水层降解能力强弱区.结果显示：该场地单井降解能力为36.49~70.05mg/L,其累积概率拟合曲线符合F（x）=0.008e^0.07x指数模型,以此评估含水层降解能力为57.83mg/L.以径流量132m³/d估算地下水更新能力,估算污染物降解速率为2790kg/a;强降解能力区位于下游源区,面积约为5100m²,占场地总面积的5.3%;地下水中硫酸盐、硝酸盐消耗严重,强化硫酸盐还原和反硝化作用可能是该场地管理修复的一个有效方法.     

The colorful chemistry of nanoscale zero-valent iron (nZVI)

正Nanoscale zero-valent iron(nZVI)possesses unique chemistry and capability for the separation and transformation of a growing number of environmental contaminants.A n ZVI particle consists of two nanoscale components,an iron(oxyhydr)oxides shell and a metallic iron core.This classical"core-shell"structure offers n ZVI with unique and multifaceted     

Development of a novel myconanomining approach for the recovery of agriculturally important elements from jarosite waste

In this study, an ecofriendly and economically viable waste management approach have been attempted towards the biosynthesis of agriculturally important nanoparticles from jarosite waste. Aspergillus terreus strain J4 isolated from jarosite(waste from Debari Zinc Smelter,Udaipur, India), showed good leaching efficiency along with nanoparticles(NPs) formation under ambient conditions. Fourier-transform infrared spectroscopy(FT-IR) and transmission electron microscopy(TEM) confirmed the formation of NPs. Energy dispersive X-ray spectroscopy(EDX analysis) showed strong signals for zinc, iron, calcium and magnesium,with these materials being leached out. TEM analysis and high resolution transmission electron microscopy(HRTEM) showed semi-quasi spherical particles having average size of 10‐50 nm. Thus, a novel biomethodology was developed using fungal cell-free extract for bioleaching and subsequently nanoconversion of the waste materials into nanostructured form. These biosynthesized nanoparticles were tested for their efficacy on seed emergence activity of wheat(Triticum aestivum) seeds and showed enhanced growth at concentration of 20 ppm. These nanomaterials are expected to enhance plant growth properties and being targeted as additives in soil fertility and crop productivity enhancement.     

大同市某医院放疗装置环境辐射调查

大同市环境监察支队对大同市某医院医用电子直线加速器及近距离遥控后装机工作场所及其周围环境辐射水平进行了调查。表明，加速器及近距离遥控后装机室内X、γ辐射剂量率，在关机或开机状态下监测结果变化不明显，基本在本底范围内。加速器及近距离遥控后装机室外X、γ辐射剂量率范围接近1987年“全国放射性水平调查”的天然贯穿辐射剂量平均值；屋顶X、γ辐射剂量率监测结果也居正常本底水平。     

Study of Aging Characteristics of Ternary Blends of Polyethylenes—II

Six film samples of low-density polypropylene (LDPE)/linear LDPE (LLDPE)/high-density polypropylene (HDPE) with varying ratios of LDPE (20–45 ... wt%) and LLDPE (25–50 wt%) having a fixed amount of HDPE at 30 wt% were prepared by blown film extrusion technique. The samples were aged at four different temperatures, 55°, 70°, 85°, and 100°C, for four different time periods in the interval of between 150 hours and up to 600 hours. The change in the structure of various constituents and the formation of various oxygenated (peroxy and hydroperoxy) and unsaturated groups during thermo-oxidative degradation was discussed by infrared spectroscopy. The visiosity-average molecular weight was found to have decreased slowly in the initial aging hours and temperatures, whereas it decreased by 10% with its previous value tensile strength that is, 100°C when aged for 600 hours. The tensile strength of the sample first increased by 67% at 55°C and 89% at 70°C up to 450 hours, whereas the values increased by 52.5% at 85°C and 33.9% at 100°C when aged for 150 hours and then decreased. The percentage elongation at break increased by 2.7% at 55°C and 10.7% at 70°C for 150 and 300 hours of aging, respectively, whereas the percentage decreased when aged at 85°C and 100°C for up to 600 hours of aging. The values of gel content (percent) increased and initial degradation temperature decreased with aging time and temperature.