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701.
Waste plastics recycling by an entrained-flow gasifier 总被引:1,自引:0,他引:1
Takatoshi Shoji Kenjiro Shindoh Hironori Ozaki Atsushi Sodeyama 《Journal of Material Cycles and Waste Management》2001,3(2):75-81
We studied an entrained-flow gasification process which efficiently converts waste plastics to energy at a high energy recovery
rate. Waste plastics, after being shredded to <8 mm or <14 mm, were fed into an entrained-flow gasifier with air and oxygen.
In the gasifier, organic substances were pyrolyzed, partially combusted, and then converted into synthetic gas (CO, H2) at a high temperature (over 1600 K). The clarified gasification characteristics were that the lower heat value (LHV) of
the product gas was over 4.2 MJ/Nm3 and the cold gas efficiency was approximately 60%. Other inert substances in the wastes such as ashes and metals were melted
into slag and condensed on bag filters. The bag filters and a water scrubber removed impurities such as dusts, heavy metals,
and hydrogen halides from the product gases. Solid hydrocarbons, which include char and soot, were removed at a hot cyclone
and on the bag filters.
Received: July 19, 2000 / Accepted: October 3, 2000 相似文献
702.
运河(杭州段)底质有机质与重金属元素相关性的探讨 总被引:7,自引:0,他引:7
通过对京杭大运河 (杭州段 )底质的监测 ,探讨了底质有机质与 8种重金属元素的相关性 ,并对其成因作出了解释 ,得出了 8种重金属在运河 (杭州段 )底质中易积累的顺序。 相似文献
703.
The aim of this study was to evaluate the possible toxicity of the leachate produced by the residues generated in the process of recycling lead from waste batteries. These residues are slag, which once formed, is characterised by its content in ferrous sulphide, sodium carbonate as well as residual coke from the process. It also contains, as minor components, lead and other heavy metals. The slag was stored and watered periodically over a period of 6 months, its composition changing until finally becoming inert, with no exothermal activity. The slag was leached, and its ecotoxicity was determined by means of the bioluminescence test, along with its content in heavy metals. The results obtained indicate a greater degree of toxicity in the residues with a shorter storage period than the established one, and which were therefore still in the phase of decomposition. However, in the samples taken on completing 6 months of storage, the EC50 value of the leachate was found to be higher than 3000 mg/l. Hence, a storage period under suitable environmental conditions which leads to inactivity of the residue as well as a decrease in its ecotoxicity, is considered absolutely essential. At the same time, a direct relationship was observed between the lead content and the ecotoxicity value. 相似文献
704.
705.
Acidic bioleaching of heavy metals from sewage sludge 总被引:2,自引:0,他引:2
The overall objective of this study was to evaluate the use of controlled bio-acidification prior to land application as a
decontamination process to remove heavy metals from sludge. The sulfur-oxidizing bacteria were naturally available in the
sludge samples and were activated by providing sulfur and aeration at 28°C–30°C. Activation resulted in bio-acidification
to pH 2 within 5–11 days. Successive inoculation of fresh sludges with 5% acidified samples reduced the acidification time
to 2–3 days in most samples. Bio-acidification resulted in dissolving significant quantities of heavy metals from all sludge
types tested. The maximum solubilization results were: 86%–97% for Ni; 48%–98% for Pb; 26%–71% for Cr; 18%–91% for Zn; 16%–90%
for Cu; 7%–60% for Cd. Limited metal solubilization results were observed in the various control samples that accompanied
the bio-acidified samples. The leaching results in the control samples were limited to 2%–19% for Ni, 0%–7% for Pb, 0%–5%
for Cr, 0.3%–4% for Zn, 0.2%–4% for Cu and 0%–3% for Cd. The results confirmed that Ni and Pb were the easiest metals to dissolve
from the various sludge types. On the other hand, the lowest solubilization results were observed for Cu and Cd, and moderate
solubilization results were achieved for Cr. The bio-acidification process resulted in moderate gains in terms of improving
the suitability of tested sludges for land application.
Received: April 19, 1999 / Accepted: November 4, 1999 相似文献
706.
采用流动法催化反应装置测定了蜂窝陶瓷负载催化剂同时催化氧化丙烷 ( C3H8)、丙烯 ( c3H6)和 CO的活性 ,考察活性组分 Pd和非贵金属氧化物、La改性、反应空速对起燃温度、热稳定性和动力学转化特征的影响 .结果显示 ,含 Pd催化剂上 C3H6和 CO的起燃温度比 C3H8低 ,1150℃高温老化对 C3H8氧化性能的影响比对 C3H6和 CO的小 .含稀土非贵金属氧化物的活性、热稳定性及动力学转化性能都比单 Pd催化剂低 ,添加 La能提高 2类催化剂的初活性和高温热稳定性 . 相似文献
707.
重金属污染土壤修复中杂草资源的利用 总被引:30,自引:0,他引:30
对重金属污染土壤植物修复基本原理、作用方式及亟待解决的问题进行了论述,认为现有修复植物均不同程度存在一些弱点,还难以大规模应用于修复实践。杂草具有抗逆境能力强、生长迅速、繁殖能力强以及在环境条件适宜情况下生物量能够急剧提高等特点,可以弥补现有修复植物的缺点和不足,是较理想的植物修复资源。结合笔者的研究情况,对杂草资源在重金属污染土壤植物修复中的利用方式、修复植物筛选方法进行了论述,而且在植物修复生物量处理方面也进行了讨论,试图为重金属污染土壤植物修复进一步发展提供科学依据。 相似文献
708.
709.
上海市苏州河支流--桃浦河底泥重金属的污染特征 总被引:4,自引:1,他引:3
对桃浦河底泥15个柱样(75个样品)测试分析了8种金属元素.结果表明,这些金属元素的平均含量都比较高,超标顺序为Zn>Cu>Cd>Hg>Pb>As>Ni>Cr,均高于苏州河的浓度.除As、Hg与其他元素的相关性较小外,Pb、Cd、Cu、Zn、Ni、Cr等之间均具有较为显著的相关性,相关系数介于0.616~0.890间.沿河各段重金属污染程度不同,上游和下游污染最严重.底泥金属的垂直分布与其底质沉积特征相对应.这在底泥疏浚时应具体考虑. 相似文献
710.
针铁矿及腐残质对水体重金属离子的吸附作用 总被引:7,自引:2,他引:5
采用针铁矿、腐殖质,针铁矿-腐殖复合微粒对重合微粒对重金属离子进行了吸附-解吸实验。结果表明它们对Cu^2 ,Zn^2 有强烈的吸附作用。针铁矿对Cu^2 和Zn^2 的吸附边界pH值分别为4.3和5.8,且吸附率可达95%以上。腐殖质对Cu^2 和Zn^2 的吸附边界pH值分别为4.1和5.6,且在pH值为8时,吸附率可达96%以上。针铁矿与腐殖形成的稳定复合微粒不仅对重金属离子具有良好的吸附作用,还具有均匀性好和沉降稳定的特点,可用于土壤修复和含重金属离子的污水的处理。 相似文献