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In order to evaluate the combined effect of adsorption and biodegradation of H(2)S on activated carbon surface in biotrickling filtration, four laboratory-scale biofiltration columns were operated simultaneously for 120h to investigate the mechanisms involved in treating synthetic H(2)S streams using biological activated carbon (BAC). The first three columns (A, B, C) contained a mixture of activated carbon and glass beads, with the carbons (BAC or virgin activated carbon (VAC)) and conditions (with or without liquid medium recirculation) differentiated. The last column (D) used 100% glass beads with liquid medium recirculation. Air streams containing 45ppmv H(2)S were passed through the columns at 4s of gas retention time (GRT) and liquid flow rate was set at 0.71mlmin(-1). Column D got its breakthrough in 3min of operation, indicating a negligible contribution of glass beads to the adsorption of H(2)S. The removal efficiency (RE) of Columns B and C using VAC dropped quickly to 30% within the first 8h, and afterwards continued to drop further but slowly. Column A using BAC stayed at 25% of RE throughout the operation time. A thorough investigation of the H(2)S oxidation products, i.e., various S species in both aqueous (recirculation media) and solid phases (BAC and VAC), was conducted using ICP-OES, IC, XRF, and CHNS elemental analyzer. BAC demonstrated a better performance than columns with adsorption only. Water film was found to enhance H(2)S removal. The percentage of sulphate in the total sulphur of the BAC system improved to twice of that of VAC system, indicating sulphate is the main product of H(2)S biofiltration. The observed pH drop in BAC system double confirmed that the presence of biodegradation in the biofilm over carbon surface did profound effect on the oxidation of H(2)S, compare to the systems with adsorption only. 相似文献
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火花放电条件下CS_2转化为COS的反应 总被引:3,自引:1,他引:2
利用火花放电技术模拟研究了自然界闪电作用下CS2转化为COS的反应. 结果表明, 放电条件(电压3000 V)下CS2(初始分压为1.33×103 Pa)能与空气(25 ℃, 103 Pa)中的氧气、水蒸气作用, 转化为COS以及其他含硫含碳产物(CO、CO2、SO2等); CS2初始分压、水蒸气和放电时间等因素对COS生成量有明显的影响. 并在实验基础上结合多种理论, 探讨了相关过程的大气闪电反应机理. 这些结果可为自然界闪电条件下的硫循环、碳循环过程的研究提供重要依据. 相似文献
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介质阻挡放电常压降解哈隆的研究 总被引:5,自引:0,他引:5
本文以介质阻挡放电的方式产生低温等离子体,利用低温等离子体技术成功地降解了常压状况下的气态CF2ClBr,CF2ClBr含量为0.6%的空气在放电10s的条件下,可使CF2ClBr达到95%的降解率。本文研究了常压状况下的CF2ClBr低温等离子体空间反应机理,以及CF2ClBr初妈压力,电场强度和外加气体分别对低温等离子体降解CF2ClBr的影响。 相似文献
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等离子体技术降解茜素红水溶液的机理研究 总被引:4,自引:0,他引:4
研究了等离子体在内电极通氧条件下降解水相中茜素红的机理。研究表明:茜素红溶液的降解率与电极位置有关,且在0和22.5mm处出现2个高值。在0和22.5mm 2种电极位置时,茜素红的降解率与等离子体电压、茜素红的浓度、溶液初始pH值、处理时间的变化规律不完全相同。在0处时,茜素红溶液经等离子体放电处理后产物主要是含氧和羟基的小分子物质;在22.5mm时,产物主要是含-CO和含-OH的芳香类物质。研究认为:在内电极位置为0处时主要是高能电子的作用,而在22.5mm处时则是O2被解离产生氧原子,氧原子和高能电子与O2和H2O溶液作用产生O3、OH·、O2-和eaq-等活性物种与茜素红作用而引起其降解。这些结果为等离子体降解有机废水的实际应用提供了信息。 相似文献