聚苯乙烯接枝胶粉对改性沥青性能的影响

采用苯乙烯对废轮胎胶粉进行表面接枝聚合改性,并将接枝改性胶粉用于制备湿法胶粉改性沥青。接枝改性后,废轮胎胶粉的X射线光电子能谱和13C固体核磁检测结果表明,苯乙烯链段成功接枝到废轮胎胶粉表面,同时系统研究了苯乙烯接枝率对胶粉改性沥青25℃针入度、软化点和5℃延度的影响规律。实验结果表明,当苯乙烯接枝率小于36%时,随着苯乙烯接枝率的提高,胶粉改性沥青的25℃针入度和5℃延度增大,软化点下降,说明胶粉表面苯乙烯链段的接枝,能够显著提高胶粉-沥青的界面相容性;当苯乙烯接枝率为36%时,胶粉改性沥青的5℃延度达到11.0 cm,相比于普通胶粉改性沥青(7.0 cm)提高了57%;但当苯乙烯接枝率大于36%时,随着苯乙烯接枝率的提高,胶粉改性沥青的25℃针入度和5℃延度下降,软化点升高,表明胶粉-沥青界面层中过量的聚苯乙烯链段,使胶粉改性沥青的低温延展性有所降低。通过分析可知,在胶粉表面接枝适当比例的聚苯乙烯能够显著改善胶粉改性沥青的低温延展性能。     

次氯酸钠氧化废轮胎胶粉对改性沥青性能的影响

采用次氯酸钠对废轮胎胶粉进行表面氧化改性,并将所得胶粉用于湿法制备胶粉改性沥青,通过设计3因素3水平正交实验,研究氧化剂用量、氧化温度及氧化时间对胶粉改性沥青的25℃针入度、软化点和5℃延度的影响规律。氧化前后废轮胎胶粉的XPS表征结果表明,次氯酸钠氧化能够使胶粉表面的C—O键和O—C=O键的含量显著增加。次氯酸钠对废轮胎胶粉的表面氧化,能够有效增强胶粉与沥青之间的界面结合强度,使胶粉改性沥青的软化点显著提高。通过对实验结果的极差分析和方差分析,提出了以软化点为主要考核指标时胶粉氧化改性的最佳反应条件,即次氯酸钠用量40 m L,氧化温度40℃,氧化时间3.0 h。该条件下制备的氧化胶粉改性沥青,软化点能够达到73.3℃,改性沥青的高温稳定性显著增强。     

孤岛落地油泥制备改性沥青及其性能

以油田油泥与基质沥青为实验原材料,采用高速剪切方法制备油田油泥改性沥青,通过针入度、软化点、延度、运动黏度和离析软化点差等表征方法,研究孤岛落地油泥对沥青高低温性能、加工性能和储存稳定性的影响。结果表明:活性中间体与苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)添加量(质量分数)分别为15%与4%时,孤岛落地油泥改性沥青的针入度比基质沥青降低0.4 mm,软化点比基质沥青提高24℃,运动黏度为0.28 Pa·s,离析软化点差(165℃,48 h)为0.3℃,其各项指标均同时满足橡胶沥青评价指标要求和SBS沥青评价指标要求;加入适量的油泥可提高沥青的低温抗裂性能,改善加工性能,而对沥青储存稳定性无明显影响。     

响应面法优化废聚乙烯农膜制备聚乙烯蜡的工艺研究

采用响应面法对废聚乙烯(PE)农膜催化裂解制备聚乙烯蜡(PEW)的工艺参数进行优化。在单因素试验的基础上,运用Box-Bechken中心组合试验设计,建立了PEW收率与4个因素的二次回归方程,分析了各因素的显著性及交互作用,并对PEW产品进行结构表征和性能测试。结果表明,筛选HZSM-5和重芳烃油分别为废PE农膜催化裂解制备PEW的催化剂和溶剂,此时得到的PEW的滴熔点为104℃,针入度为1.21mm,黏均相对分子质量为1 687;各因素对PEW收率影响为催化剂用量裂解温度裂解时间溶剂用量;催化剂用量和溶剂用量、催化剂用量和裂解温度对PEW收率交互影响较大。以PEW收率最大、性能最佳为目标,获得最佳工艺条件:在100g废PE农膜中,加入0.35g HZSM-5作催化剂、17.00mL重芳烃油作溶剂,在385℃左右下裂解4.10h后,可得浅黄色的PEW,收率平均为98.45%。     

复合胶凝剂和废玻璃钢纤维改性半水脱硫石膏

以工业副产物脱硫建筑石膏为原料,采用超细钢渣-矿渣-电石渣(SGC)复合胶凝剂和废玻璃钢纤维对其进行改性研究,得到适宜的改性条件为:复合胶凝剂适宜掺量为20%~25%,废玻璃钢纤维最佳长度为10~15 mm,适宜掺量为1.0%,且经过EDTA溶液浸泡处理的废玻璃钢纤维对石膏基体的改性效果较好。改性后石膏制品的软化系数提高到0.91,抗折强度为7.6 MPa,抗压强度为23.4 MPa,耐水性与力学强度显著提高,实现了不同工业废弃物的协同处置和脱硫石膏的高质化利用,也为难以处置的玻璃钢废弃物找到一种有效利用途径。     

含滑石粉的环保型聚乙烯包装材料的可环境消纳性能研究

借助人工加速老化、自然土壤填埋等实验方法 ,采用力学性能测试、扫描电镜 (SEM)、热重 -红外联用仪 (TG IR)等测试方法 ,对所研制的含滑石粉的环保型聚乙烯 (PE)塑料包装材料的可环境消纳性能进行探讨。实验结果表明 ,以PE为主材料 ,添加不易分解的滑石粉、生物活性剂、FeSt3 MnSt2 复合光敏剂 ,研制出的高填充可降解的PE塑料薄膜 ,具有良好的光 -生物降解性能 ,且可适用于焚烧处理。     

挤压法制备Fe-Al-Ce复合氧化物颗粒除氟性能及地下水处理应用

利用粘结挤压法将Fe-Al-Ce复合氧化物粉末材料制备成颗粒材料(GFAC),进行表征、静态和动态吸附除氟性能评价和现场应用.结果显示,优选GFAC颗粒直径为1.6 mm,具有较高的压缩破坏强度33.80 N和除氟性能.GFAC颗粒对氟的吸附过程符合准二级反应动力学方程,吸附速率受膜扩散和内扩散共同控制;在pH 7.0±0.2条件下,GFAC颗粒对氟的饱和吸附容量达到51.28 mg/g(25℃,Langmuir等温吸附模型).不同空间流速(SV)下动态实验出水穿透(1mg/L)时对氟的累积吸附量分别为5.69mg/g (SV=1 h-1)、5.61mg/g (SV=2h-1)、2.83 mg/g (SV=5 h-1),高于常见活性氧化铝除氟剂(AA,1.77 mg/g,SV=1 h-1)及其他报道的颗粒除氟剂.GFAC颗粒在河北现场成功用于实际高氟地下水的处理,在原水氟浓度(3.7±0.3)mg/L和pH 8.0±0.2条件下,对氟的累计吸附量为3.16 mg/g,明显高于AA(0.83mg/g),具有较好的应用前景.     

Zr掺杂对SBA-15上负载胺分散性及CO_2吸附特性的影响

针对胺改性复合吸附剂稳定性差、负载胺分散性欠佳的问题,对介孔SBA-15进行原位Zr掺杂改性,考察了载体材料表面酸性对胺分散状态及其CO_22吸附性能的影响。研究表明:载体表面酸性的增强可改善聚合胺在其孔道结构中的空间分散构型,使其暴露出更多的活性位点,由此低PEI负载量下复合吸附剂(30PEI/ZrSBA-15)对CO_2的吸附容量均在99 mg.g~(-1)以上,超过50PEI/SBA-15在优选温度75℃下的吸附容量89.8 mg·g~(-1);且表面酸性位与端位氨基间的结合也增进了复合吸附剂的热稳定性与循环稳定性,3次循环测试后样品的CO_2吸附容量没有下降。     

废润滑油絮凝脱色试验研究

废润滑油的回收再生利用不仅可以节约石油资源,而且是防治废润滑油污染、保护环境的主要措施.针对有污染的传统酸-白土废润滑油再生工艺,提出了以絮凝为主的无污染再生新技术,重点考察了影响废润滑油脱色再生效率的各种因素.结果表明,在絮凝剂用量为1.2%(体积分数)、搅拌时间为5 min、反应温度为75℃、沉降温度为80℃、沉降时间为2.0 h的条件下,废润滑油絮凝脱色效果最佳.废润滑油经过絮凝脱色和白土精制后理化指标得到了较大改善,基本接近该级别新油SC40的标准.     

流化床结晶软化高硬度地下水及其晶体生长动力学

采用流化床结晶软化的方法对北京市城区某地下水进行软化处理,研究考察了软化药剂投加量、诱晶颗粒粒径、诱晶颗粒填料高度、入水流速、碳酸钙过饱和度等参数对水质硬度去除的影响。研究发现,当药剂投加量为220 mg·L~(-1)时,出水钙硬度去除率可达90%以上,总硬度去除率达到60%,出水总硬度可达300 mg·L~(-1)左右。使用石英砂颗粒作为诱晶材料,粒径为0.21~0.43 mm。当诱晶材料填料高度为40 cm,入水流速控制在40~70 m·h-1时,均可得到较好的出水水质。优化反应参数,可控制处理后的出水总硬度在300 mg·L~(-1)左右,即去除235 mg·L~(-1)的暂时硬度,煮沸的水不再浑浊,无水垢生成,并且出水pH可控制在8.5以下。此外,探究了多相流化过程中诱晶颗粒的线性增长速率以及床层增长速率与过饱和度、颗粒粒径、入水流速的关系,通过计算得到晶体线性增长速率相关表达式。     

Chloroaromatic pollutants in mussels incubated in two finnish watercourses polluted by industry

Concentrations of different chlorinated compounds were measured in mussels incubated in two polluted watercourses, a river (the River Kymijoki) and a lake (Lake Vanaja) for four weeks in summer 1995. The sum concentrations of polychlorinated phenols (PCP) and biphenyls (PCB) were both about 1 μg/g lipid weight (lw) in Lake Vanaja mussels, while in the River Kymijoki mussels PCPs were non-detectable and PCBs were measured 120 ng/g lIw. The concentrations of toxic polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners ranged between <17 and 370 pg/g Iw in Lake Vanaja mussels and between <38 and 11,000 pg/g lw in the River Kymijoki mussels. Polychlorinated diphenyl ethers (PCDE) were detected in the mussels incubated in the River Kymijoki (0.4–1.1 ng/g Iw), but not in those incubated in Lake Vanaja. Polychlorinated phenoxyanisoles (PCPA) were measured 33 ng/g lw and polychlorinated phenoxyphenols (PCPP) 300 ng/g lw in the mussels incubated in the River Kymijoki. PCPAs were also detected in reference samples, which were sediment and pike from the River Kymijoki and Baltic salmon, seal and white-tailed sea eagle.     

Book review

The Pesticide Manual ‐ A World Compendium, 8th Edition, C.R. Worthing, Editor and S.B. Walker, Assistant Editor, British Crop Protection Council, BCPC Publications Sales, Bear Farm, Binfield, Bracknell, Berkshire RG12 5QE, England. 1987, 1100 pp., UK £50; Overseas £56. ISBN 0–948404–01–9.     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

The chemical stability of formulations of some hydrolyzable insecticides in aqueous mixtures with hydrolysis catalysts

Abstract

The active ingredients in commercial formulations of malathion, oxamyl, carbaryl, diazinon, and chlorpyrifos diluted to “spray tank”; concentrations with buffered distilled or natural water of pH 4–9 were stable for at least 24 hr. Formulations of trichlorfon were not stable at pH 7 or above but disappearance rates were slower than for the pure chemical in homogeneous solution. Cupric ion was observed to be an effective catalyst for the hydrolysis of a variety of pure organophosphorus insecticides but did not catalyze hydrolysis of the active ingredients of the formulations examined. Increasing the dilution of the formulation increased the susceptibility of malathion, oxamyl, and carbaryl to hydrolysis.     

Organochlorine compounds in a three-step terrestrial food chain

The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.     

Radionuclides and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

Radionuclides in pinon pine (Pinus edulis) nuts from los alamos national laboratory lands and the dose from consumption

Abstract

One of the dominant tree species growing within and around the eastern portion of Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis). Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food—the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of ³H, ¹³⁷Cs, ⁹⁰Sr, ^totU, ²³⁸Pu, ^{239, 240}Pu, and²⁴¹ Am in soils (0‐ to 12‐in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (3) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of ³H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 μSv); this is far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem (1000 μSv). Soil‐to‐nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.     

Degradation and sorption of imidacloprid in dissimilar surface and subsurface soils

Degradation and sorption/desorption are important processes affecting the leaching of pesticides through soil. This research characterized the degradation and sorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine) in Drummer (silty clay loam) and Exeter (sandy loam) surface soils and their corresponding subsurface soils using sequential extraction methods over 400 days. By the end of the incubation, approximately 55% of imidacloprid applied at a rate of 1.0 mg kg^?1 degraded in the Exeter sandy loam surface and subsurface soils, compared to 40% of applied imidacloprid within 300 days in Drummer surface and subsurface soils. At the 0.1 mg kg^?1 application rate, dissipation was slower for all four soils. Water-extractable imidacloprid in Exeter surface soil decreased from 98% of applied at day 1 to > 70% of the imidacloprid remaining after 400 d, as compared to 55% in the Drummer surface soil at day 1 and 12% at day 400. These data suggest that imidacloprid was bioavailable to degrading soil microorganisms and sorption/desorption was not the limiting factor for biodegradation. In subsurface soils > 40% of ¹⁴C-benzoic acid was mineralized over 21 days, demonstrating an active microbial community. In contrast, cumulative ¹⁴CO₂ was less than 1.5% of applied ¹⁴C-imidacloprid in all soils over 400 d. Qualitative differences in the microbial communities appear to limit the degradation of imidacloprid in the subsurface soils.     

Biochemical interaction of six op delayed neurotoxicants with several neurotargets

Abstract

Five organophosphorous insecticides: Leptophos, EPN, Cyano‐fenphos, trichloronate and salithion proved to cause irreversible ataxia not only to chicken but also to mice and sheep. TOCP was included as a reference. Cyanofenphos blocked the catecholamine B‐receptor binding activity with ³H‐norepinephrine at a level similar to that of the specific inhibitor propranolol in the mouse heart preparation. In the lamb heart preparation, the B‐receptor was more sensitive to Leptophos, salithion and TOCP than to propranolol. The six compounds and their oxons were screened for their in‐vitro inhibition to monamine oxidase (MAO), acetyl cholinesterase (AChE) and neurotoxic esterase (NTE) in the brain of either mouse, lamb or chicken. It is believed that their AChE inhibition stands for their acute toxicity, while NTE inhibition is responsible for their paralytic ataxia.