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991.
Ji-Dong Gu Shunjuan Yang R. Welton D. Eberiel S. P. McCarthy R. A. Gross 《Journal of Polymers and the Environment》1994,2(2):129-135
Previous research in our laboratory reported a convenient laboratory-scale composting test method to study the weight loss of polymer films in aerobic thermophilic (53°C) reactors maintained at a 60% moisture content. The laboratory-scale compost reactors contained the following synthetic compost mixture (percentage on dry-weight basis): tree leaves (45.0), shredded paper (16.5), food (6.7), meat (5.8), cow manure (17.5), sawdust (1.9), aluminum and steel shavings (2.4), glass beads (1.3), urea (1.9), and a compost seed (1.0) which is designated Mix-1 in this work. To simplify the laboratory-scale compost weight loss test method and better understand how compost mixture compositions and environmental parameters affect the rate of plastic degradation, a systematic variation of the synthetic mixture composition as well as the moisture content was carried out. Cellulose acetate (CA) with a degree of substitution (DS) value of 1.7 and cellophane films were chosen as test polymer substrates for this work. The extent of CA DS-1.7 and cellophane weight loss as a function of the exposure time remained unchanged when the metal and glass components of the mixture were excluded in Mix-2. Further study showed that large variations in the mixture composition such as the replacement of tree leaves, food, meat, and sawdust with steam-exploded wood and alfalfa (forming Mix-C) could be made with little or no change in the time dependence of CA DS-1.7 film weight loss. In contrast, substituting tree leaves, food, meat, cow manure, and sawdust with steam-exploded wood in combination with either Rabbit Choice (Mix-D) or starch and urea (Mix-E) resulted in a significant time increase (from 7 to 12 days) for the complete disappearance of CA DS-1.7 films. Interestingly, in this work no direct correlation was observed between the C/N ratio (which ranged from 13.9 to 61.4) and the CA DS-1.7 film weight loss. Decreasing moisture contents of the compost Mix-2 from 60 and 50 and 40% resulted in dramatic changes in polymer degradation such that CA DS-1.7 showed an increase in the time period for a complete disappearance of polymer films from 6 to 16 and 30 days, respectively.Guest Editor: Dr. Graham Swift, Rohm & Haas.Paper presented at the Bio/Environmentally Degradable Polymer Society—Second National Meeting, August 19–21, 1993, Chicago, Illinois. 相似文献
992.
993.
江苏省城市生活垃圾特征处理现状及存在问题 总被引:1,自引:0,他引:1
在调查收集了大量资料的基础上,从地级市、县、中心镇三个层次总结了江苏省城市生活垃圾的特征、处理现状及其存在的问题。提出,江苏省城市生活垃圾产量、可燃组分、热值逐年上升,含水量基本保持稳定,容重、碴石含量呈下降趋势;目前江苏省填埋、焚烧、堆肥和综合四种处理方式中均有一些问题,且能够达到国家标准的很少;还存在管理体制不顺,缺少资金,减量化、资源化尚未引起重视,法规不健全,混合收集,废品回收率低,处理模式单一、技术落后等问题。这些都使控制垃圾产生、实现资源回收利用并确定其处理方式,以及进一步推动江苏省城市生活垃圾处理的深入研究十分必要。 相似文献
994.
利用回转窑焚烧废物简述 总被引:2,自引:0,他引:2
本文介绍了回转窑的类型、结构和及其工艺特点,并对国内外利用回转窑焚烧危险废物的实验情况进行了综述,为我国废物焚烧领域的工作者提供借鉴。 相似文献
995.
996.
定型机废气中油烟监测方法探讨 总被引:1,自引:0,他引:1
印染行业中定型机废气的主要污染物之一是其中的工业油烟,由于当前我国没有工业油烟排放监测分析的国家标准,在实际监测过程中主要参照饮食业油烟的监测方法,但是工业油烟和饮食业油烟之间存在性质等方面的较大差异,导致两者在监测过程中也存在区别。通过对定型机排放废气中油烟多次监测分析,探讨在当前条件下,符合定型机废气中油烟监测的方法。 相似文献
997.
Baseline levels of PCDD/Fs in soil and herbage samples collected in the vicinity of a new hazardous waste incinerator in Catalonia,Spain 总被引:5,自引:0,他引:5
Schuhmacher M Agramunt MC Rodriguez-Larena MC Díaz-ferrero J Domingo JL 《Chemosphere》2002,46(9-10):1343-1350
The construction in Constantí (Catalonia, Spain) of a new hazardous waste incinerator (HWI), which is the first one in Spain, finished in 1999. In order to determine the temporal variation (1996–1998) in the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in the vicinity of the new HWI, 40 soil and 40 herbage samples were collected (1998) at the same sampling points in which samples had been taken two years before (1996). Each sample was analyzed for PCDDs and PCDFs by high resolution gas chromatography/high resolution mass spectrometry. In the 1996 survey, PCDD/F concentrations in soils ranged from 0.13 to 24.20 ng I-TEQ/kg (d.m.), with median and mean values of 0.67 and 1.68 ng I-TEQ/kg (d.m.), respectively. In the present study, PCDD/F concentrations ranged from 0.12 to 17.20 ng I-TEQ/kg (d.m.), with a median value of 0.75 ng I-TEQ/kg (d.m.) and a mean value of 1.59 ng I-TEQ/kg (d.m.). In turn, in the present study PCDD/F concentrations in vegetation ranged from 0.14 to 2.01 ng I-TEQ/kg (d.m.) (median and mean values: 0.23 and 0.31 ng I-TEQ/kg, respectively), while in the 1996 survey PCDD/F concentrations ranged from 0.24 to 1.22 ng I-TEQ/kg (d.m.) (median and mean values: 0.53 and 0.61 ng I-TEQ/kg, respectively). According to the present (1998) and the previous (1996) levels of PCDD/Fs found in soils and vegetation, the area under potential influence of the new facility shows a rather low contamination by these compounds. The current results should be useful to establish the environmental impact of the HWI. 相似文献
998.
Sorption and diffusivity of iodide and pertechnetate (I- and TcO4-) on MX-80 bentonite with different hexadecylpyridinium (HDPy+) loadings were studied using equilibrium solutions of different ionic strengths. In HDPy(+)-modified bentonite, iodide and pertechnetate ions exhibited increasing sorption (characterized by the distribution ratio, Rd), while Cs+ and Sr2+ showed decreasing sorption with increasing organophilicity. In case of medium-loading levels, the simultaneous sorption of anions (I- and TcO4-) and cations (Cs+ and Sr2+) was observed. Sorption of ions was influenced by the composition of the electrolytes employed. It decreased gradually with increasing ionic strength of the electrolyte solutions. The experiments revealed the general tendency that the diffusivity (Da [cm2.s-1]) for iodide and pertechnetate decreases with increasing organophilicity and increases with increasing ionic strength of the equilibrium solutions, confirming the results of the sorption experiments. Additionally, some mineralogical and chemical investigations, like IR spectral analysis of the organo-bentonite samples and exchange behavior of HDPy+, were performed. On the basis of these analyses, it was concluded that the alkylammonium ions are sorbed as (1) HDPy+ cations, (2) HDPyCl molecules and (3) micelles with decreasing binding intensities in this order. 相似文献
999.
1000.
不同部位梧桐生物质炭对水溶液中镉吸附的机理 总被引:1,自引:0,他引:1
为了探究梧桐不同部位废弃物所制备的生物质炭(皮、枝、叶)对Cd2+的吸附效率和稳定修复的机理,以此为园林废弃物炭化利用在重金属污染修复方面的应用提供科学依据.利用实验室模拟法,通过高温煅烧法制备梧桐不同部位生物质炭,采用元素分析仪、比表面积及孔隙分析(BET)、X射线衍射仪(XRD)、扫描电镜/能谱(SEM/EDS)及衰减全反射红外光谱(ATR-IR)等技术研究不同反应时间、重金属浓度和溶液初始pH条件下生物质炭对Cd2+吸附效果的影响,并运用四步萃取法和脱附实验分析生物质炭上Cd2+的吸附形态和稳定性.3种生物质炭都在8 h左右达到吸附平衡,最终吸附量依次为树皮炭>枝条炭>叶片炭;溶液初始浓度为0.5—2 g·L-1时Cd2+的吸附量呈增长趋势,在2.5—3g·L-1时逐渐平缓;生物质炭Cd2+吸附量均随着pH的升高而升高,但在pH值为5—8时,吸附的趋势逐渐平稳;树皮炭的酸溶态和非生物利用态的稳定Cd形态要高于枝条炭和叶片炭;比表面积不是影响梧桐生物质炭吸附Cd2+的主要影响因素,吸附动力学,ATR,XRD和重金属形态萃取均证实Cd碳酸盐类矿物生成是主导吸附机理;3种生物质炭的脱附量在4 h后逐渐趋于平衡,其中脱附量最大为叶片炭,最小为树皮炭.梧桐不同部位的初始性质对生物质炭吸附Cd2+具有明显的影响,其中梧桐皮具备更高的吸附量和重金属稳定形态,并且相比其他种类生物质炭有明显优势.因此,从吸附效果和生产成本的角度,本研究建议以梧桐皮为主,枝条和叶片为辅的生物质炭对重金属Cd进行修复治理. 相似文献