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101.
The competition of hydrogen and manganese ions for adsorption sites in Sitka spruce litter was investigated in a factorial design, simulated acid rain experiment, which involved leaching of litter with simulated throughfall solutions at three pH levels (5.3, 4.3 and 3.3) and three manganese concentrations (0 to 0.2 mg1-1). the throughfall solution at the lowest pH was the most efficient in removing exchangeable manganese from litter. the manganese concentration in the leachates was approximately proportional to the hydrogen ion concentration in the simulated throughfall solution. Under field conditions, throughfall manganese concentration also naturally tends to increase as a consequence of enhanced foliar leaching of manganese in response to increasing precipitation acidity. the manganese concentration in the simulated throughfall also affected manganese concentration in the leachates, however, and contributed to a buildup of exchangeable manganese in litter, thus counteracting to some extent possible adverse effects of excess leaching due to increased throughfall acidity. 相似文献
102.
天然矿物锰矿砂对苯酚的界面吸附与降解研究 总被引:26,自引:0,他引:26
研究了天然矿物锰矿砂对苯酚的界面吸附与降解,结果表明锰矿砂对苯酚具有较强的吸附作用,较高温度,低pH值,固相与苯酚的较高质量比值有利于苯酚的吸附。吸附过程遵循二级反应动力学,吸附等温线为Langmuir型。应用简化的表面络合反应模式,求得了不同条件下的条件稳定常数及吸附苯酚的表面总吸附位。 相似文献
103.
ZHAO Hongbo 《环境科学学报(英文版)》2000,12(1):120-124
IntroductionUsingcomplexphosphatetotreatmanganesewastewaterfromtitaniumdioxideplantwaspresentedinthispaper.Comparingwithother?.. 相似文献
104.
Guo Jin Ma Jun Shi Xuehua 《Frontiers of Environmental Science & Engineering in China》2007,1(2):251-256
To understand the water purification mechanism of potassium permanganate as a coagulation-aid during the preoxidation process,
the microtopography of its reductive products, the newly formed hydrous manganese dioxide and the aged hydrous manganese dioxide,
was investigated. The morphology of natural organic matter (NOM) adsorbed by the newly formed hydrous manganese dioxide was
also compared with that of NOM alone. By using the tapping mode atomic force microscopy (AFM), the observation results show
that the newly formed hydrous manganese dioxide possess a perforated sheet (with a thickness of 0–1.75 nm) as well as some
spherical particle structures compared with the hydrous manganese dioxide with 2 h aging time, which demonstrated that the
newly formed hydrous manganese dioxide had a large surface area and adsorption capacity. When 1 mmol/L newly formed hydrous
manganese dioxide was added, the microtopography of NOM molecules shifted from a loosely dispersed pancake shape (with adsorption
height of 5–8.5 nm) to a densely dispersed and uniform spherical structure. These results provide a valid proof that it is
the perfect adsorption capability of the newly formed hydrous manganese dioxide that might result in the coagulation aid effect
of potassium permanganate preoxidation.
Translated from Environmental Science, 2006, 27(5): 945–949 [译自: 环境科学] 相似文献
105.
桂北锰矿废弃地主要植物种类调查及土壤重金属污染评价 总被引:9,自引:0,他引:9
采用样方法和实地勘查法调查了桂北荔浦锰矿区废弃地自然定居和人工种植的植物,并且对8个区的主要植物及其土壤重金属含量进行了分类、测试。并采用污染指数评价法对矿区废弃地土壤重金属的污染程度进行了评价。结果表明,白茅(Imperata cylindrica)、马唐(Digitaria sanguinalis)、飞蓬(Erigeron acer)、苍耳(Xanthium sibiricum)、耳草(Hedyotisauricularia)对重金属有较强的耐性,而且能适应废弃地的不良环境,可作为锰矿废弃地生态恢复的先锋植物;用3种不同的背景值对废弃地土壤重金属污染程度的评价结果是一致的,除Pb外,5种重金属元素单项污染指数均大于2,表示被污染,其中以Mn、Zn、Cd污染最为严重。锰矿废弃地人工复垦采用典型的农业恢复模式,以种植果树和经济作物为主,果实中Cr、Cd的含量均超过食品卫生限量标准,因此矿山恢复的早期不宜直接种植果树和食用经济作物。以上研究结果可为锰矿废弃地的生态恢复和植被重建提供科学依据。 相似文献
106.
107.
以热带亚热带土壤为研究对象,用连续分级浸提法探讨了土壤中锰赋存形态与pH值的关系。结果表明:土壤中的锰处于一种动态平衡状态,各形态锰的含量及其占全锰的比例随pH的变化而变化,其中代换态锰和有机态锰随pH值升高而减少,氧化态锰、无定形铁结合态锰和晶形铁结合态锰则随pH值升高而增加,土壤中锰的生物有效性则随pH值升高而降低。 相似文献
108.
The objective was to derive predictive equations for acetic acid-extractable cobalt (A-ECo) in soils so that extensive national databases for total (T) Co in soils and stream sediments could be converted to plant available concentrations for the purpose of predicting risk of Co deficiency in grazing livestock. Data on the chemical and physical properties of 103 soils from 15 different parent materials and 54 soil series in England and Wales were used. Ranges for the mean values for parent materials were: TCo, 5.0–20.4 and A-ECo, 0.20–1.30 mg kg–1; percentage (P) A-ECo, 3.4–13.5; soil manganese (Mn) 268–1174 mg kgDM–1; pH, 3.7–8.0. There were significant effects of parent material on all parameters with Chalks, Old and New Red Sandstones particularly low in A-ECo. Multiple linear regression yielded the following equation for predicting A-ECo, which accounted for 56% of the variance with 12 outliers, including the lowest pH values, omitted:A-ECo(mg kg-1) = 1.4 - 0.0619TCo (mg kg-1) - 0.432TMn(g kg-1) - 0.171pHPrediction of PA-ECo was less precise:PA-ECo(%) = 21.1 - 4.5TMn(g kg-1) - 1.77pH(r
2 = 44.8%; 88 d.f.REML was used on the complete, unbalanced, log-transformed data set to fit a Generalised Mixed Model with parent material as random effect and soil Mn and pH as fixed effects; the effect of parent material was no longer significant. It was concluded that A-ECo can be satisfactorily predicted for most soils in England and Wales from TCo, TMn and soil pH. 相似文献
109.
水培试验结果表明,Fe(2+)、Mn(2+)对水稻锌的吸收和运转有明显的影响.高浓度Fe(2+)或Mn(2+)(5μg/g)显著降低水稻吸锌量、抑制锌由根向茎、叶的运转.稻株生物量与叶片Fe/Zn比值或Mn/Zn比值有明显的负相关关系,在叶片Fe/Zn>8或Mn/Zn>26时,水稻生物量明显降低.造成水稻缺锌的主要原因是土壤有效锌含量低,而高浓度Fe(2+)和Mn(2+)是诱发和加重水稻缺锌的重要条件.因此在生产上应重视改善缺锌低洼稻田的排水通气状况. 相似文献
110.