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721.
722.
Effect of spent mushroom substrate applied to vineyard soil on the behaviour of copper-based fungicide residues 总被引:1,自引:0,他引:1
Herrero-Hernández E Andrades MS Rodríguez-Cruz MS Sánchez-Martín MJ 《Journal of environmental management》2011,92(7):1849-1857
The effect of the addition of spent mushroom substrate (SMS) to the soil as an amendment on the distribution and/or fate of copper from a copper-based fungicide applied to a vineyard soil in La Rioja (N. Spain) was studied. The study was carried out on experimental plots amended or not with SMS at rates of 40 and 100 t ha(-1). The variation in total Cu content in the topsoil (0-10 cm) and in the soil profile (0-50 cm), and the distribution of Cu in different fractions of the topsoil were studied as a function of the dose of Cu added (5 and 10 kg ha(-1)) and of the time elapsed since application (0-12 months). In addition, the changes in the chemical properties (solid organic carbon (OC), dissolved organic carbon (DOC) and pH) of the soils were studied. A greater capacity for Cu retention by the amended soils than by the unamended one was observed only when the fungicide was applied at the high dose. No effect of the amendment rate was noted on this retention capacity. The metal content in the topsoil decreased over time in step with the disappearance of the OC in the amended soil due to its oxidation, mineralization and/or leaching. This decrease in total Cu content was possibly due to the formation of soluble Cu complexes with the DOC, which facilitated its transport through the soil. A re-distribution of Cu in the different soil fractions was also observed over time, mainly from the organic to the residual fraction. The results obtained indicate that the increase in OC due to the application of SMS at the rates used does not lead to any significant increase in the persistence of Cu in the soil over time. Of greater interest would be the assessment of the risk for groundwater quality, owing to possible leaching of the fungicide enhanced by the SMS when SMS and Cu-based fungicides are jointly applied to vineyard soils. 相似文献
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724.
Spent mushroom compost (SMC) is a co-product of edible mushroom which contains abundant nutrients including organics, nitrogen (N) and phosphorous (P). This study is related to the release potential of nitrogen, phosphate and organic matter from SMC amended soil in column-based experiments. Results showed that due to SMC application, NH4+–N and NO3−–N concentrations in leachate decreased by 92.5% and 76.3%, respectively, while EC and CODCr concentrations increased by 84.2% and 481.9%, respectively, as compared to chemical fertilizers. Moreover, a minor loss of TNcum (65%) and TPcum (almost equal value) exhibited good nutrient retention capacity. Leaching test results demonstrated that the mixed application of SMC and chemical fertilizers could alleviate excessive CODCr level in SMC leachate. The release process of nutrients in SMC amended soil could be described by first/first order mixed model, indicating that nutrients leached from SMC follow a two-stage pattern. 相似文献
725.
强化SCR脱硝催化剂转化零价汞的初步研究 总被引:1,自引:0,他引:1
常规的选择性还原脱硝(SCR)催化剂对烟气中的零价汞具有一定的催化氧化作用,从而有利于提高下游的除汞效率。但在烟气HCl浓度较低时,SCR催化剂对燃煤烟气中的零价汞催化氧化效果较差。为了提高SCR催化剂对零价汞的催化氧化效果,在现有SCR催化剂基础上,通过负载其它金属元素的方法,对其进行改性掺杂。结果发现,负载锰氧化物的Mn/SCR催化剂,对零价汞的催化氧化作用明显提高,而将其再掺杂Mo后,其催化氧化性能得到更进一步提高。在反应温度350℃的条件下,加入7.5 mg/m3HCl,Mo-Mn/SCR对零价汞的催化氧化效率接近90%,而常规SCR催化剂只有35%左右。另外,Mo只有在与Mn结合使用,其促进作用才能较显著地体现出来。对改性后的SCR催化剂的脱硝性能研究表明,掺杂Mo-Mn元素对于SCR的脱硝性能无明显影响。 相似文献
726.
727.
Electroreductive dechlorination of chlorophenols with Pd catalyst supported on solidelectrode was studied. As solid electrodes, carbon cloth (CC), carbon felt (CF) and titanium mesh were used, and palladium was plated on solid electrodes by either electrolytic or electroless method. On each electrode with Pd, chlorophenols were qualitatively dechlorinated to phenol, while they were entirely intact on electrodes without Pd. Moreover, neither base electrode nor plating method significantly affected the activity of Pd as far as it was sufficiently loaded on the electrode. Based on the results in the experiments using one electrode repeatedly, Pd catalyst proved to possess a satisfactory duarability under the present condition. It was suggested that the reactive species responsinble for the dechlorination of chlorophenols could be formed during preliminary electrolysis. Thus, (Pd)x-H resulting from the adsorption of electrogenerated hydrogen on metallic Pd might be assumed most probable. 相似文献
728.
基于燃煤烟气SO3生成与排放给电厂运行及大气环境带来的严重影响,研究了一种在役典型商用蜂窝型V/W/Ti系脱硝催化剂表面的SO3生成反应动力学及反应机理.结果表明,反应温度与SO2浓度是影响催化剂表面SO3生成的关键因素.在SO2浓度为400×10-6时,当反应温度从300℃升至360℃,SO2-SO3转化率从0.2%提高至0.65%,温度达到400℃后,催化剂表面V2O5活性增加更为显著,SO2-SO3转化率从0.65%增2.3%,SO3生成反应的表观速率常数增加近3倍.SO3在催化剂表面的生成路径为:SO2与V5+-OH反应生成中间产物VOSO4与HSO4-,随后进一步反应生成SO3.SO2主要通过其在催化剂表面的吸附、转化过程影响SO3的生成,其本征动力学反应级数为0.52.O2的本征动力学反应级数为0,SO3生成反应可以在无O2条件下进行,O2存在会促进反应进行,但不会改变反应路径. 相似文献
729.
730.
选择性催化还原(SCR)是目前控制氮氧化物排放的主要技术。本文介绍了锅炉炉后脱硝系统的布置位置及工艺条件、已经工业化的氨选择性高温还原钒催化剂的特点,以及近年来低温脱硝催化剂的研究现状。指出我国脱硝催化剂应提高还原剂的选择性,开发新型低温催化剂应重点考察烟气中的水、二氧化硫及硫酸氢铵等对催化剂的影响。 相似文献