共查询到17条相似文献,搜索用时 62 毫秒
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微生物矿化修复重金属污染土场地可同步实现控制污染物与提高土体强度的双重目标。采用巴氏芽孢杆菌对铅污染粉土进行注浆固化和稳定化试验,以胶结液浓度、铅污染浓度为影响变量,分析污染粉土的固化强度特性,以及铅污染物的稳定化形态与浸出特性。结果表明:微生物固化500 mg/kg铅污染粉土的强度能够达到793 kPa,可交换态铅含量降至94.8 mg/kg;浓度为0.50~0.75 mol/L胶结液比更高浓度的胶结液有利于控制顶出液中铅污染物的流失;微生物固化和稳定化粉土中可交换态铅和碳酸盐结合态铅含量呈负相关关系。对于铅污染浓度低于500 mg/kg的粉土,在酸性浸提液下的毒性淋滤试验(TCLP)铅离子浸出浓度能够降至5 mg/L的限值内。方解石和铅-钙碳酸盐共沉淀形成的无定形团聚体是固化铅污染粉土的主要胶结物,铅污染物通过碳酸盐共沉淀、直接吸附、碳酸钙包裹等形式实现稳定化。物理破碎能够使部分包裹稳定化的铅污染物二次释放。微生物注浆处理能够有效提高铅污染粉土的强度,大幅降低污染粉土中可交换态铅的占比,对铅污染物有良好的稳定效果。 相似文献
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为响应我国建设无废城市号召建设海绵城市,以垃圾焚烧飞灰替代部分胶凝材料与矿渣、偏高岭土、脱硫石膏与钢渣、碎石为骨料采用冷固法制备了环保透水砖,分析了粗细骨料体积比、颗粒级配、水胶比、飞灰参量等因素对透水砖性能的影响。结果表明:最佳的工艺参数为粗细骨料体积比为1.4、颗粒级配为DP3(钢渣细骨料2.36~4.75 mm、粗骨料粒径4.75~9.5 mm)、水胶比为0.26、飞灰参量为20%在4 MPa压力下成型其透水系数3.93 cm2/s、抗压强度32.53 MPa、抗折强度可达4.01 MPa,满足相关标准要求,将飞灰替代部分水泥制备透水砖,不仅可以减少资源浪费,还能降低环境污染。 相似文献
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以TG固化剂、水泥、石灰3种固化材料为影响因素,它们的剂量为因素水平,7d无侧限抗压强度为考核指标,对稳定土进行正交试验设计,并对试验结果进行极差和方差分析。结果表明:TG固化剂、水泥、石灰均是7 d无侧限抗压强度的显著性因素,可靠度达95%。在保证强度并考虑经济的情况下,对稳定土的配比方案进行优化,最终确定最优方案为TG固化剂∶石灰∶水泥为0.02%∶4%∶4%。同时,对最优配比下的稳定土进行微观结构的观察和固化剂机理的分析得出,当3种固化材料同时加入时,固化效果较好,能形成致密、稳定和高强的胶凝结构,而只加入水泥和石灰时,虽然能够形成团状骨架大颗粒,有一定强度和稳定性,但结构不够致密,不能形成胶凝状结构。 相似文献
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为探究水泥固化路基填料在季节性冻土区的特性,通过试验,针对其在冻融损伤条件下的养生时间、水泥占比等情况进行探究,分析水泥固化路基在季节性冻土区条件下的冻融损伤规律,为相关区域的工程建设开展提供有效信息支持。 相似文献
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微生物固化粉土坡面能够提高粉土边坡的抗侵蚀能力,微生物固化防护层的物理力学特性以及植物的适生性是影响该技术应用的重要因素。采用巴氏芽孢杆菌以及胶结液对粉土进行表层喷洒固化处理,研究高羊茅和披碱草在微生物固化表层的粉土中的出苗生长情况。试验结果显示,提高胶结液浓度能够获得更高的粉土表层固化层强度。采用高浓度胶结液的固化层水稳定性更好。粉土表层经微生物固化后高羊茅和披碱草的出苗率随着固化层贯入阻力的提高而降低,出苗时间延迟4~5 d。固化层贯入阻力低于280 k Pa时,出苗率可达到80%以上。采用菌液和浓度为0.75~1.00 mol/L、喷洒量0.06 m L/cm2的胶结液喷洒3遍处理,可以保证粉土坡面既具有一定防护强度,又能够保证高羊茅正常生长。粉土经微生物固化表层后不适于披碱草的生长。研究结果表明,微生物固化粉土坡面对草本植物具有一定的适生性;植物种类及固化层强度是影响出苗率和出苗速率指数的重要因素。将微生物坡面防护与植物防护相结合的粉土坡面防护技术有良好的发展潜力。 相似文献
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应用病毒复合微生物杀虫剂防治美国白蛾试验 总被引:1,自引:0,他引:1
应用病毒复合微生物杀虫剂进行防治美国白蛾幼虫药效试验,筛选出了防治不同虫龄的最佳体积浓度和最佳施药时间.幼虫1~2龄为1∶800倍液,3~4龄为1∶400倍液,5龄为1∶200倍液;最佳施药时间宜在晴天的8时以前和16时以后或阴天的全天,杀虫效果均在95%以上,既可节约防治费用,又能达到防治效果. 相似文献
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通过一个实例,分析介绍了生活垃圾焚烧炉渣分选处理的一种工艺。实践证明:综合利用破碎、筛分、磁力分选、跳汰分选、摇床分选等固废处理技术,对炉渣进行分选预处理,可有效回收利用Fe、Cu、Al等废旧金属,有效分离收集未燃尽的剩余垃圾,并妥善处理,从而使炉渣的性质满足资源化利用的技术要求,变废为宝。 相似文献
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Preparation and properties of waste tea leaves particleboard 总被引:4,自引:0,他引:4
Shi Jin-shu Li Jian-zhang Fan Yong-ming Ma Hong-xia 《中国林学(英文版)》2006,8(1):41-45
Urea-formaldehyde (UF) adhesive is the main source of formaldehyde emission from UF-bonded boards. The components in waste tea leaves can react with formaldehyde to serve as a raw material in the production of low formaldehyde emission boards. In our study, waste tea leaves and UF adhesive were employed in the preparation of waste tea leaves particleboard (WTLB). An orthogonal experimental method was applied to investigate the effects of process parameters on formaldehyde emission and mechanical properties of WTLB. The results indicated that: 1) waste tea leaves had the ability to abate formaldehyde emission from boards; and 2) density of the WTLB was a significant factor affecting its modulus of rupture (MOR), modulus of elasticity (MOE) and internal bonding (IB). 相似文献
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Hermann Pleschberger Alfred Teischinger Ulrich Müller Christian Hansmann 《Wood material science & engineering》2014,9(2):92-101
Effects of different thermal treatments (maximum treatment temperatures of 200, 210 and 220°C for 2.5 hours) on solid spruce (Picea abies L. Karst.) and ash (Fraxinus excelsior L.) were investigated in this study. The fracture behaviour in radial/longitudinal as well as in tangential/longitudinal and the change of the wood colour (CIEL*a*b* colour space) on all principal anatomical surfaces (cross sectional, radial and tangential) were analysed. The specific fracture energy and the maximum breaking load decreased almost significantly after all thermally treated samples in comparison to the untreated (standard dried) sample. The wood colour changed also significantly, in particular the lightness decreased with increasing intensity of thermal treatment on all investigated surfaces. A comparison of the percentage loss of the different fracture and colour values has shown a strong correlation between the maximum breaking load and the lightness after several thermal treatments, in both investigated crack propagation systems, on all measured surfaces and for both analysed species. 相似文献
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Yongyuth Theapparat Sunisa Khongthong Prawit Rodjan Kowit Lertwittayanon Damrongsak Faroongsarng 《林业研究》2019,(3):1139-1148
Physicochemical characteristics and in vitro antioxidant activities of four pyroligneous acids carbonized from the wastes of wood species including Mangosteen (Garcinia mangostana Linn.), Durian (Durio zibethinus L.), Rambutan (Nephelium lappaceum L.), and Langsat (Lansium domesticum Serr.) were assessed. Appearing as transparent liquors with pH 3.9–4.2, the pyroligneous acid samples under test possessed acetic acid (23.22–25.46%) as the dominant component. The total soluble tar, total acid, and water content were 0.15 - 0.28 wt%, 99–192 mg KOH/g and 84.5–93.5 wt%, respectively. Phenolic compounds namely: 2,6-dimethoxyphenol (6.88–9.69%),phenol (2.97–5.88%), 4-methylsyringol (3.10–3.56%), guaiacol (2.36–3.55%), and 2-methoxy-4-methylphenol (1.08–1.28%) were found. All had in vitro antioxidant activities especially mangosteen pyroligneous acid, which showed activity roughly similar to BHT (P>0.05) against anti-lipid peroxidation. Nitric oxide scavenging capacities of all pyroligneous acids were significantly higher than BHT (P<0.05). Our results suggest that pyroligneous acids from the four types of branch waste could be used as sources of beneficial natural antioxidants, possibly as food or feed additives to protect against lipid peroxidation, and potentially also in veterinary medicine in anti-inflammatory products. 相似文献