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721.
722.
微波解吸柠檬酸盐溶液中SO2实验研究 总被引:1,自引:0,他引:1
结合微波具有的热效应、非热效应特性,利用经改装的微波反应装置,研究了微波场下柠檬酸浓度、微波作用时间、微波功率、SO2初始浓度和搅拌速率对解吸柠檬酸盐溶液中SO2的影响,得出了影响SO2解吸率的基本规律和最佳解吸条件,并进行了分析。 相似文献
723.
724.
HDTMA改性累托石对水中酸性橙Ⅱ的吸附热力学及动力学 总被引:4,自引:0,他引:4
采用HDTMA(十六烷基三甲基溴化铵)对累托石原土进行有机覆盖改性,考察了HDTMA改性累托石对水中染料酸性橙Ⅱ的吸附热力学和动力学.结果表明,与累托石原土相比,HDTMA改性累托石对水中酸性橙Ⅱ的吸附效率显著提高.在最适吸附条件下,HDTMA改性累托石对水中酸性橙Ⅱ的吸附经过60 min可达平衡.等温吸附规律可用Freun-dlich模式较好地模拟.吸附热小于零,吸附是放热反应.吸附动力学规律遵循Bangham模式,内扩散过程是吸附速度的控制步骤. 相似文献
725.
催化剂在应用过程中必须具有良好的催化活性和稳定性。优化制备的CuO/γ-Al2O3催化剂用于处理高浓度难降解的乳化液废水时具有良好的催化活性。在200℃时反应2h,TOC去除率为81.3%,比未加催化剂的湿式氧化提高了14.9%。该催化剂对分散兰废水具有更高的活性和稳定性:在220℃反应1.5h后,COD和TOC去除率分别为68.8%和56.5%,比非催化氧化分别提高了18.7%和18.9%。 相似文献
726.
Twenty-eight PM2.5 samples collected in Summer (July 2002) and Winter (November 2002) at two sites in Beijing, China were analyzed using GC/MS to investigate the impact of meteorology and coal burning on the solvent extractable organic compounds (SEOC). The characteristics and abundance of the n-alkanes, polycyclic aromatic hydrocarbons (PAHs), n-fatty acids and n-alkanols were determined. Source identification was made using organic species as molecular markers. Semi-volatile compounds of alkanes and PAHs had much higher concentrations in winter than summer because of the large difference in the temperature between the seasons. Plant wax emission was a major contributor to n-alkanes in summer, but fossil fuel residue was a major source (>80%) in winter. The seasonal differences in the distribution of pentacyclic triterpanes clearly shows the impact of coal burning for space heating in winter. The yield of PAHs in winter (148 ng m(-3) at the urban site and 277 ng m(-3) at the suburban site) was six to eight times higher than that in summer and was found to be mainly from coal burning. Higher pollutant concentrations were measured at the suburban site than the urban site in winter due to the rapid expansion of the city limit and the relocation of factories from urban to suburban areas over the last two decades. 相似文献
727.
In the present work experimental conditions were optimized for the analysis of organochlorine traces in water matrix using solid-phase microextraction (SPME) followed by gas chromatography with mass selective detector. The parameters including time of exposure of the fiber in the aqueous sample, fiber type, agitation speed, pH, ionic forces, temperature of adsorption, and time of desorption were evaluated. The best conditions to analyze organochlorine were obtained by using higher than room temperature, agitation of the sample, extraction time of 40 min, and polyacrylate fiber. 相似文献
728.
本文选择了上试-402树脂作为常温高效选择性吸附氯化甲基汞的吸附剂,改进了Cbromosorb W-SE30-HCl吸附剂管的制备方法,并同时组装了一套由微孔纤维滤膜与Chromosorb W-SE30-HCl、402树脂、螺旋银丝、镀金细砂等四种吸附管串联组成的采样系统,由小型采样机抽气采样,于常温下同时依次富集颗粒汞、氯化汞、氯化甲基汞、单质汞及二甲基汞,系统小型轻便,适于野外采样。采样后,四种吸附剂分别采用高低两种温度脱汞。上述五种形态汞均由装有高温石英原子化器的AAs定量测定。 相似文献
729.
铜的形态分布与Daphnia magna急性毒性关系 总被引:14,自引:0,他引:14
本文利用化学平衡模式MINTEAQ2研究不同酸度,碱度和有机配体存在下铜的形态分布特点,通过Daphnia magna毒性试验获得形态变化时的毒性变化规律。结果显示:无论是总量,还是游离态浓度,都不能反映出铜的毒性大小。 相似文献
730.
ABSTRACT To determine whether grafting increases cadmium (Cd) accumulation in the post-grafting generation of hyperaccumulator plants, the effects of grafting on Cd accumulation characteristics of post-grafting generations of a potential Cd-hyperaccumulator Solanum photeinocarpum were evaluated in pot and field experiments. The following four grafting combinations were examined: ungrafted (UG), self-rooted grafting involving one S. photeinocarpum seedling (SG), self-rooted grafting involving two S. photeinocarpum seedling developmental stages (DG), and grafting on wild potato rootstock (PG). Grafting did not induce genetic changes in S. photeinocarpum, and increased the shoot biomass and the amount of Cd extracted by the shoots of the first, second, and third generations of S. photeinocarpum (PG > DG > SG > UG). Additionally, enhanced superoxide dismutase, peroxidase, and catalase activities and increased soluble protein contents of the first post-grafting generation were observed for the DG and PG, whereas only enhanced superoxide dismutase and peroxidase activities were observed for the SG. Grafting increased the DNA methylation levels by inducing hypermethylation in the first post-grafting generation (PG > DG > SG > UG). Therefore, grafting can enhance the Cd accumulation (phytoremediation) ability of post-grafting generations of S. photeinocarpum by enhancing DNA methylation levels, especially when wild potato rootstock is used. 相似文献