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闽西北马尾松人工林营养元素的积累与分配格局 总被引:5,自引:0,他引:5
通过定位监测与取样分析,研究了41 a生马尾松人工林生态系统中的林木、林下植被、地被物及土壤等各组分营养元素含量、积累及分配特征.对林木的养分含量分析显示,除Ca元素外,针叶的养分含量最高,其次是枝、根、皮,树干的养分含量最低.林下植被层的养分含量比较高,其养分含量大小排列顺序为Ca>N>K>Mg>P;凋落物中各元素的含量与林木养分含量基本一致;土壤中K含量最高,其次是Mg,而Ca、N、P的含量则比较低.通过对林木生产力的分析表明,马尾松的养分年积累量为110.79 kg·hm-2·a-1,其中叶占34.47%,树干占22.56%,皮、枝和根分别占21.43%、10.91%和10.63%.马尾松林生态系统养分总贮量为187864.77 kg hm-2,其中土壤占98.70%,林木占1.18%,林下植被和凋落物养分元素总贮量较低,仅占总贮量的0.12%. 相似文献
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Lotaustralin from the root of Rhodiola rosea L was extracted using supercritical carbon dioxide with methanol as modifier. Response surface methodology using Box–Behnken experimental design was utilized to explore parameters for supercritical carbon dioxide extraction. The effects of various values of temperatures (50–70 °C), pressures (200--400 bar), and percentages of methanol modifier (80%–100%) on the extraction yields of lotaustralin were evaluated. Extract identification was performed using high-performance liquid chromatography. The experimental data obtained were fitted to second-order polynomial equations and assessed using analysis of variance. The highest yields predicted from the experiments were 2.05 g kg?1 lotaustralin at the optimal values, i.e. temperature 65 °C, pressure 316 bar, 88% methanol modifier at a flow rate of 0.4 mL min?1, and dynamic extraction time 90 min. 相似文献
106.
格宾护岸填料类型对河道自净能力的影响 总被引:2,自引:0,他引:2
选择花岗岩块石、卵石和废建筑砌块3种材料作为格宾填料,研究不同填料在模拟河道中对河水水质净化效果的影响。结果表明,随着实验装置运行时间的延长,各填料对N、P营养盐及有机物的去除能力均有不同程度的提高;3种填料中,卵石相较于其他2种填料对NH3-N、TOC和DOC的去除能力保持在较高的水平,运行26 d后分别达65.26%、71.06%和78.06%;3种填料在实验装置运行初期对TP都有较好的去除效果,运行12 d后,花岗岩块石、卵石、废建筑砌块对TP的去除率分别达89.20%、91.05%和94.71%;卵石表面附着的微生物脂磷含量及脱氢酶活性分别为53.43 nmol P/cm3、10.67μg TF/(h.cm3),均显著高于其他2种填料(p<0.05),其表面较高的微生物量及酶活性有利于对氮素及有机物的去除。 相似文献
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采用活性污泥曝气法降解前后COD差值的方法,进行了BOD快速检测的研究。条件实验结果表明,其适宜检测条件为:降解时间180 min;污泥量5 mL/100 mL;pH值7.0;温度25℃。模拟废水检测结果表明,该测定方法具有较高的重复性,5次测定的相对偏差小于6.5%,在BOD浓度为0~500 mg/L范围内,微生物降解前后COD差值与BOD5有良好的相关性,其相关系数达到0.98。因此,可以通过测定微生物降解前后COD值,实现快速BOD检测的目的,同时,也可实现COD和BOD一体化检测,这将是今后COD和BOD检测研究的发展方向之一。 相似文献
108.
A new strain, Pseudomonas Chlororaphis (PC), was found for dissolving gold, silver, and copper from the metallic particles of crushed waste printed circuit boards (PCBs). The optimized conditions that greatly improved the ability of producing CN? (for dissolving metals) were obtained. Dissolving experiments of pure gold, silver, and copper showed that the metals could be changed into Au+, Ag+, and Cu2+. PC cells and their secreta would adsorb metallic ions. Meanwhile, metallic ions destroyed the growth of PC. Dissolving experiments of metallic particles from crushed waste PCBs were performed by PC. The results indicated that 8.2% of the gold, 12.1% silver, and 52.3% copper were dissolved into solution. This paper contributed significance information to recovering precious metals from waste PCBs by bioleaching. 相似文献
109.
Fu Xu Zhenxing Huang Hengfeng Miao Hongyan Ren Mingxing Zhao Wenquan Ruan 《环境科学学报(英文版)》2013,25(10):2031-2040
Two identical full-scale biogas-lift reactors treating brewery wastewater were inoculated with different types of sludge to compare their operational conditions, sludge characteristics, and kinetic models at a mesophilic temperature. One reactor (R1) started up with anaerobic granular sludge in 12 weeks and obtained a continuously average organic loading rate (OLR) of 7.4 kg chemical oxygen demand (COD)/(m3.day), COD removal efficiency of 80%, and effluent COD of 450 mg/L. The other reactor (R2) started up with residual activated sludge in 30 weeks and granulation accomplished when the reactor reached an average OLR of 8.3 kg COD/(m^3·day), COD removal efficiency of 90%, and effluent COD of 240 mg/L. Differences in sludge characteristics,biogas compositions, and biogas- lift processes may be accounted for the superior efficiency of the treatment performance of R2 over R1. Grau second-order and modified StoverKincannon models based on influent and effluent concentrations as well as hydraulic retention time were successfully used to develop kinetic parameters of the experimental data with high correlation coefficients (R2 〉 0.95), which further showed that R2 had higher treatment performance than R1. These results demonstrated that residual activated sludge could be used effectively instead of anaerobic granular sludge despite the need for a longer time. 相似文献
110.
Aluminum flocculant can enhance the flocculating performance of activated sludge.However,the binding mechanism of aluminum ion(Al 3+) and extracellular polymeric substances(EPS) in activated sludge is unclear due to the complexity of EPS.In this work,threedimensional excitation emission matrix fluorescence spectroscopy(3DEEM),fluorescence quenching titration and Fourier transform infrared spectroscopy(FT-IR) were used to explore the binding behavior and mechanism between Al 3+ and EPS.The results showed that two fluorescence peaks of tyrosineand tryptophan-like substances were identified in the loosely bound-extracellular polymeric substances(LB-EPS),and three peaks of tyrosine-,tryptophanand humic-like substances were identified in the tightly boundextracellular polymeric substances(TB-EPS).It was found that these fluorescence peaks could be quenched with Al 3+ at the dosage of 3.0 mg/L,which demonstrated that strong interactions took place between the EPS and Al 3+.The conditional stability constants for Al 3+ and EPS were determined by the Stern-Volmer equation.As to the binding mechanism,the-OH,N-H,C=O,C-N groups and the sulfurand phosphorus-containing groups showed complexation action,although the groups in the LB-EPS and TB-EPS showed different behavior.The TB-EPS have stronger binding ability to Al 3+ than the LB-EPS,and TB-EPS play an important role in the interaction with Al 3+. 相似文献