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21.
After adding either organic or inorganic ligands, sulfidated nano-zero-valent iron (SnZVI) was used for aerobic degradation of phenol, and the effect of the ligand species on oxidation performance was investigated. We found that SnZVI hardly degraded phenol in the absence of ligand addition. Ligands initiated and promoted the degradation of pollutants by SnZVI. The data herein show that a characteristic inorganic ligand, tripolyphosphate (TPP), is more effective in enhancing oxidation than a characteristic organic ligand oxalate. In addition to the scavenging of reactive oxidants by the organic ligand, more ferrous ion (Fe(II)) dissolution from SnZVI in the TPP system is another cause for the superior enhancement by the inorganic ligand. In the oxalate system, as the sulfur content of SnZVI increased, the oxidation efficiency increased because FeS shell promoted the transfer of electrons to produce more reactive oxygen species (ROS). In TPP system, the effect of sulfur content on oxidation performance is more complex. The SnZVI with low sulfur content showed poor oxidation performance compared with that of nZVI. Further experiments proved that sulfidation might weaken the complexation of TPP with surface bound Fe, which would slow down the ionic Fe(II) dissolution rate. Therefore, sulfidation has the dual effects of enhancing electron transfer and inhibiting the complexation of inorganic ligands. In addition, the mechanisms of ROS generation in different ligand systems were investigated herein. Results showed that the critical ROS in both the oxalate and TPP systems are hydroxyl radicals, and that they are produced via one-electron activation of O2. 相似文献
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采用排放因子法建立郑州市分县区2017年大气氨排放清单,并实现1 km×1 km空间网格分配,同时进行2007~2017年氨排放趋势及1989~2017年氨排放驱动力相关性分析.结果表明,郑州市2017年氨排放量为18 143.3 t,排放强度为2.4t·km-2,农业源为主要排放源(63.4%),逸散源次之(11.3%);农业源中畜禽养殖氨排放主要来自蛋禽、肉猪和奶牛养殖;排放量前三的区县为登封市、荥阳市和新密市,分别占总量的19.3%、16.5%和15.6%;空间上郑州市南部及中西部地区排放量较高,东北部地区排放量较小; 2007~2017年各区县氨排放整体呈下降趋势,1989~2017年郑州市氨排放呈类似环境库兹涅茨曲线趋势,即氨排放整体上随着人均GDP和城镇化率上升而先增加再下降. 相似文献
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建立了层间隔震结构双质点系简化计算模型,研究了简化模型的动力特性及地震响应对模型质量比、周期比的敏感性,推导了模型参数的简化算式,提出了基于非比例阻尼的层间隔震结构的简化计算方法,并用实例验证了方法的可靠性和实用性。结果表明:层间隔震结构的动力特性与上下部结构质量比及周期比密切相关,并且可以反映层间隔震的高阶振型特点。利用本文提出的简化计算方法,可快速估计层间隔震结构的地震响应,方法概念清晰、计算简单且具有一定精度。 相似文献
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Dinh Hieu Vu Kuen-Sheng Wang Jung-Hsing Chen Bui Xuan Nam Bui Hoang Bac 《Waste management (New York, N.Y.)》2012,32(12):2306-2314
Along with the gradually increasing yield of the residues, appropriate management and treatment of the residues have become an urgent environmental protection problem. This work investigated the preparation of a glass–ceramic from a mixture of bottom ash and fly ash by petrurgic method. The nucleation and crystallization kinetics of the new glass–ceramic can be obtained by melting the mixture of 80% bottom ash and 20% fly ash at 950 °C, which was then cooled in the furnace for 1 h. Major minerals forming in the glass–ceramics mainly are gehlenite (Ca2Al2SiO7) & akermanite (Ca2MgSiO7) and wollastonite (CaSiO3). In addition, regarding chemical/mechanical properties, the chemical resistance showing durability, and the leaching concentration of heavy metals confirmed the possibility of engineering and construction applications of the most superior glass–ceramic product. Finally, petrurgic method of a mixture of bottom ash and fly ash at 950 °C represents a simple, inexpensive, and energy saving method compared with the conventional heat treatment. 相似文献
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试验以干鸡粪、米糠、堆肥返料作调理剂,同时加入不同含量的磷矿粉,对木薯渣进行好氧堆肥,研究木薯渣堆肥过程中堆肥理化性质的变化及木薯渣堆肥对难溶性磷的活化作用。试验设置磷矿粉加入量10%(T1)、15%(T2)、20%(T3)和不加磷矿粉(CK)四个处理,干鸡粪、米糠、堆肥返料的添加量均为10%、15%和20%。在堆肥过程中,四个处理均在55℃以上高温持续了25d,超过了国家规定的标准。在堆肥结束时,各处理水分含量均降至30%左右,pH升高至弱碱性,淀粉降解率均在90%以上,水溶性碳(DOC)含量均降至10g.kg。以下,达到了基本腐熟的标准。证明木薯渣通过堆肥能达到稳定无害化状态。在堆肥结束时,T1、T2、T3有效磷增加量分别为12.58、12.81、12.96g.kg-1,对磷矿粉的活化率分别为23.53%、17.07%、14.50%,T1活化效果最好。研究结果表明木薯渣堆肥对难溶性磷有一定的活化作用,可为解决堆肥资源化产品中植物可利用磷含量偏低的难题开拓一条生物学途径: 相似文献
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Yongtao LV Xuan CHEN Lei WANG Kai JU Xiaoqiang CHEN Rui MIAO Xudong WANG 《Frontiers of Environmental Science & Engineering》2016,10(2):390
Microsensor measurements and fluorescence in situ hybridization (FISH) analysis were combined to investigate the microbial populations and activities in a laboratory-scale sequencing batch reactor (SBR) for completely autotrophic nitrogen removal over nitrite (CANON). Fed with synthetic wastewater rich in ammonia, the SBR removed 82.5±5.4% of influent nitrogen and a maximum nitrogen-removal rate of 0.52 kgN·m−3·d−1 was achieved. The FISH analysis revealed that aerobic ammonium-oxidizing bacteria (AerAOB) Nitrosomonas and anaerobic ammonium-oxidizing bacteria (AnAOB) dominated the community. To quantify the microbial activities inside the sludge aggregates, microprofiles were measured using pH, dissolved oxygen (DO), NH 4 + , N O 2 − and N O 3 − microelectrodes. In the outer layer of sludge aggregates (0–700 μm), nitrite-oxidizing bacteria (NOB) showed high activity with 4.1 μmol·cm−3·h−1 of maximum nitrate production rate under the condition of DO concentration higher than 3.3 mg·L−1. Maximum AerAOB activity was detected in the middle layer (depths around 1700 μm) where DO concentration was 1.1 mg·L−1. In the inner layer (2200–3500 μm), where DO concentration was below 0.9 mg·L−1, AnAOB activity was detected. We thus showed that information obtained from microscopic views can be helpful in optimizing the SBR performance. 相似文献
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为研究施用餐厨垃圾调理剂对土壤有机碳组分的影响,以果园土壤为研究对象,从时间、空间维度解析长期施用餐厨垃圾调理剂对土壤有机碳积累、组成及其分布规律的影响,结合CPMI(碳库管理指数)和相关性分析,揭示施用餐厨垃圾调理剂对土壤碳汇的影响机制.结果表明,施用餐厨垃圾调理剂可显著提高土壤中w(TOC)(TOC为总有机碳),并随施用时间的增加逐渐向深层土壤迁移,改善TOC分布状况.随着施用餐厨垃圾调理剂时间的增加,0~20 cm土壤层中w(NOC)(NOC为非活性有机碳)和30~40 cm土壤层中w(AOC)(AOC为活性有机碳)呈增加趋势,AOC分配比例低于NOC分配比例.随着施用时间的增长,0~30 cm土壤层中w(POC)(POC为颗粒有机碳)显著提高,最大值为42.94 mg/g,MOC(矿质结合态有机碳)分配比例与POC分配比例呈相反变化趋势,有利于提高土壤碳稳定性.各土壤层中CPMI均大于空白对照组,最大值为154.437,表明施用餐厨垃圾调理剂有利于提升土壤肥力.相关性分析表明,w(POC)与pH呈负相关,与含水率、EC(电导率)、w(OM)(OM为有机质)呈正相关,其中与含水率相关性最高(R=0.91).可见,长期施用餐厨垃圾调理剂对提高果园土壤碳汇、改善土壤肥力具有重要意义,研究结果有助于进一步提升土壤碳汇的新型土壤调理剂的研发与应用. 相似文献