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实验表明蒙脱石吸附氟的能力与溶液的PH值呈显著的负相关关系：在较低PH值条件下，蒙脱石的吸氟量较大，具有显著的降氟作用；而对中性—碱性溶液来说，蒙脱石对氟的吸附能力则大大降低，基本不具吸氟能力。蒙脱石的吸氟量还与其用量及含氟溶液的浓度有关。吸附原因一方面是由于体系PH值降低，导致其表面带正电荷而吸附F^-；另一方面，随着NaF浓度升高，蒙脱石的双电层变薄，体系ξ电势减少，发生絮凝作用，并携带F^-沉淀下来。另外，F^-与OH^-的离子交换作用也是酸性条件下蒙脱石吸氟的一个重要原因。 相似文献
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用固相反应法和sol-gel法合成了不同类型的磷灰石（AP），并采用TEM、XRD、IR、BET比表面积法及静、动态吸附等方法研究了不同AP的比表面积、结晶度、晶胞参数、结晶尺寸、晶格缺陷度、Ca/P摩尔比和煅烧温度等与吸氟能力的关系，结果表明：结晶度高、晶粒大的AP有较小的吸氟量，属表面单分子层化学络合吸附机理；酸活化的AP有较大的吸氟量，属溶解-沉淀与沉淀物表面纳米尺寸效应吸附的复合去氟机理；具纳米尺寸的HAP在常温、常压、无二次污染、小于11mg/L的低含氟浓度废水中且不酸化情况下有较大吸氟量，属纳米尺寸效应吸附机理。 相似文献
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地下水样品采自印度Andhra Pradesh，Anantapur地区。该地区主要地层为太古代半岛片麻岩。本文分析了该水样的F^-和其他化学参数。结果表明，该区氟源主要来自围岩，这个地区的F^-紧紧地吸附在包含粘土的矿物质土壤中。F^-与成岩的钠之间很强的正相关性反映出了风化侵蚀作用。正是这种相关性导致了F^-拘滤出，而半干旱气候和强灌溉也是F^-产生的原因。研究区循环水的碱性环境使土壤更容易滤出F^-，也导致地下水中的F^-含量高。高蒸发率引起的水在含水层中的滞留时间长和风化带水力传导系数低，将促使含氟矿物的溶解，这是另一个地下水中氟含量进一步增加的因素。提出了提高地下水质量的建议，从而改善居民的健康状况。 相似文献
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合成ＰｂＳ和ＺｎＳ对Ａｇ２＋、Ｃｕ２＋、Ｃｄ２＋、Ｆｅ２＋、Ｍｎ２＋、Ｍｇ２＋、Ｓｂ２＋和Ｂｉ３＋等离子吸附量与温度关系的实验研究表明，其遵从Ｋｅｌｖｉｎ公式：在Ａ类吸附，即抗衡离子交换型吸附中，温度上升，其吸附量升降由反应热决定，本实验中Ａ类吸附多为上升型；而大部分Ｂ和Ｃ类吸附，即朗谬尔型及反朗谬尔型的吸附量则随温度上升呈指数下降。例外的仅有ＰｂＳ对Ｂｉ３＋离子的吸附，其吸附量随温度上升有微弱的上升。这可能与Ｂｉ３＋离子和吸附剂ＰｂＳ之间共晶反应和铅的铋硫盐的形成有关。Ａ类吸附的吸附量受介质条件变化影响很少。但对Ｂ和Ｃ类吸附，吸附量受ｐＨ和离子强度变化影响取决于三个因素：①吸附剂ＰｂＳ、ＺｎＳ表面电荷特性；②溶液介质条件变化时吸附离子在溶液中离子态的分布与变化；③被吸附离子在吸附剂中扩散和形成化合物或共晶的能力。因此，当ｐＨ增加时，Ｐｂｓ和ＺｎＳ对金属离子吸附量的变化表现出多样性：增加的有ＰｂＳ对Ｆｅ２＋离子的吸附；下降的有ＰｂＳ对Ｓｂ３＋离子的吸附和ＺｎＳ对Ｆｅ２＋、Ｍｎ２＋离子的吸附；不变的有ＰｂＳ对Ｂｉ３＋、Ｚｎ２＋离子的吸附和ＺｎＳ对Ｍｇ２＋离子的吸附。当溶液中离子强度增加时，由于溶液中自由态离子 相似文献
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氟与聚合羟基铝-蒙脱石复合体相互作用机理及土壤环境意义 总被引：5，自引：1，他引：4
在一定条件下利用钠基蒙脱石 (Na- Mt)合成了 OH/Al比为 1.6的聚合羟基铝-蒙脱石 (HyAl- Mt)复合体,并研究了弱酸性和强酸化条件下 HyAl- Mt与氟之间的相互作用及土壤环境意义.结果表明, pH在 5.0～ 9.0之间时, HyAl- Mt对氟的吸附受 pH影响小;当 pH < 4.5时,吸附能力随 pH减小迅速增大. pH 6.62时, HyAl- Mt对氟的吸附主要是络合交换机制,而 pH 3.02及高氟浓度条件下是表面吸附、矿物溶解及共沉淀-卷扫等协同作用机制,并使 HyAl- Mt具有异常高的氟去除能力.与蒙脱石粘土相比, HyAl- Mt的氟吸附能力明显提高,土壤中的 HyAl- Mt组分可有效地降低氟污染土壤中氟的迁移性并减少其生物有效性.在酸性氟污染的土壤中,氟与 HyAl- Mt相互作用还可一定程度抑制土壤的酸化.土壤酸度越大,这种抑制作用越明显.施用合成的 HyAl- Mt 可作为酸性氟污染土壤修复并控制土壤酸化的有效途经之一. 相似文献
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高氟地下水混凝沉淀降氟试验研究 总被引：5，自引：0，他引：5
本文开展了山西运城地区高氟地下水的降氟试验，对聚铁、硫酸铝和明矾等不同混凝剂降氟效果进行对比，探讨了地下水硬度对混凝沉淀除氟效果的影响。实验结果表明：明矾混凝沉降效果优于其它混凝剂，0．3g／L的明矾溶液可使含氟浓度4．0mg／L的地下水降低到浓度1．0mg／L以下；地下水的硬度对明矾混凝降氟效果没有明显影响。 相似文献
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A. A. Al-Bedoor A. E. Al-Rawajfeh D. M. M. Jaradat Y. Al-Jaradeen A. Al-Obeidein 《International Journal of Environmental Science and Technology》2017,14(7):1551-1558
Fluoride ion (F?) removal technologies from water (defluoridation) suffer from cost and/or efficiency drawbacks. The hugely available low-cost calcined gypsum (plaster of paris) represents a material of choice, especially in the developing countries. Partially soluble calcined gypsum introduces Ca2+ and SO4 2? into the water. In this work, the influence of tartaric acid, paracetamol, polyvinyl alcohol and Zn/Al layered double hydroxide additives (either retarders or accelerators) on defluoridation of water by calcined gypsum was studied. These additives act as retarders to the calcined gypsum setting and, hence, delay or disturb the crystallization of gypsum, offering the time for the crystallization of fluoro-compounds containing calcium, fluoride, phosphate and silicate. The more retarded the setting time, the more the Ca2+ is introduced in the solution, and hence, the more efficient the defluoridation process. The values of ΔG 0 are negative for all additives, indicating the spontaneity of the fluoride removal process. The results of X-ray diffraction, Fourier transform infrared and scanning electron microscopy of the produced gypsum supported this interpretation. 相似文献
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Carlos Bandeira Luiz Antonio Trindade 《中国地球化学学报》2006,25(B08):59-59
The Brazilian Society of Geochemistry--SBGq founded in 1985, is located at Rio de Janeiro, Brazil, having more than 300 affiliates that represent most of the principal Brazilian universities. The main SBGq way of divulgation is an international magazine-Geochimica Brasiliensis and a site： www.sbgq.org.br/. Regular meeting of SBGq is realized in each two years in odd years The last meeting it has been realized together the Geochemistry of Portuguese Language Countries and Geochemistry Symposium of the MERCOSUL countries （Argentina, Brazil, Paraguay and Uruguay）. During the even years are realized specific meeting as Environmental Geochemistry in Tropical Countries. The SBGq is associated with other Brazilian scientific societies as Latin American Association of Organic Geochemistry--ALAGO. During its existence the SBGq has published approximately 3000 papers related to the environment, lithogeochemistry, isotopes, surface geochemistry, organic geochemistry, coastal environmental geochemistry, secondary environments, hydrogeochemistry, exploration geochemistry, magmatic geochemistry, rare earth geochemistry, geochemistry of carbonations, biogeochemistry, mineral geochemistry, geochemistry vs. geochronology and geochemistry of precious metals. 相似文献
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The adsorption of fluoride ions on ground fired clay pot has been investigated. The maximum efficiency of the adsorbent for defluoridating 1–2 litres of water was found to be 200 mg fluoride kg−1 adsorbent. The investigation showed that 5–20 mg l−1 fluoride, from 1 litre of water, could be reduced to less than 1.5 mg l−1 using 120–240 g of the adsorbing medium. The effects of the dose of the medium, the pH, the contact time and the initial fluoride content were studied in relation to defluoridation efficiency. Comparison of fluoride removal capacity of the adsorbent was also made with those of fired brick, clay soil and red ash. The latter exhibited practically no adsorption. A packed column of the same ground clay pot was saturated with 285 mg fluoride kg−1 of adsorbent when 20 litres of water containing 10 mg l−1 F was allowed to pass through it. This column defluoridated 6 litres of tap water containing 10 ppm F− to below 1.5 mg l−1. 相似文献
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Amer A. Al-Rawas Yahia E-A. Mohamedzein Abdulaziz S. Al-Shabibi Salem Al-Katheiri 《Geotechnical and Geological Engineering》2006,24(5):1365-1383
Absrtract This paper investigates the potential use of sand–attapulgite (palygorskite) mixtures as a landfill liner. The sand and attapulgite
clay used in this study were brought from Wahiba (eastern Oman) and Al-Shuwamiyah (southern Oman), respectively. Initially
the basic properties of the sand and clay were determined. Then the attapulgite clay was added to the sand at 5, 10, 20 and
30% by dry weight of the sand. The sand–attapulgite clay mixtures were subjected to mineralogical, chemical, microfabric and
geotechnical analyses. The X-ray diffraction (XRD) qualitative analysis showed that attapulgite is the major clay mineral.
The chemical compounds, exchangeable cations and cation exchange capacity (CEC) for the␣samples were determined. The CEC for
the sand–clay mixtures is low but increases with the increase in clay content. The scanning electron microscope (SEM) examination
showed that the addition of clay developed coating between and around the sand grains which results in filling the voids and
reducing the hydraulic conductivity of the sand–clay mixtures. The hydraulic conductivity values for the pure clay and sand
+ 30% clay mixture prepared at 2% above optimum water content are slightly higher than hydraulic conductivity requirements
for landfill liners but can be acceptable. The geotechnical study which included grain size distribution, Atterberg limits,
specific gravity, compaction, hydraulic conductivity and shear strength tests showed that the sand+30% clay mixture prepared
at 2% above optimum water content can be considered to satisfy the requirements for landfill liners. For all sand–clay mixtures
no swelling was recorded and the addition of clay to the sand improved the shear strength. 相似文献
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苏皖沉积型凹凸棒石粘土矿床沉积环境探讨 总被引：3，自引：0，他引：3
本文对苏皖沉积型凹凸棒石粘土矿床形成时的沉积环境特征、水介质的ｐＨ值、氧化还原条件、温度及盐度进行了讨论。研究表明凹凸棒石粘土矿床形成于碱性、还原、低盐度的浅水湖相环境。与火山作用有关的热水溶液参与了成矿作用。 相似文献
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This paper deals with mineral and thermomineral water occurrences of the Bujanovac valley in south eastern part of Serbia related to granitoides of the Bujanovac massif along both the margin and the floor of the valley. In past decades (1966–2010) numerous hydrogeological, hydrogeochemical and geophysical explorations were carried out. One of results of these explorations is the completion of test holes and exploratory—production wells. They provide groundwater for three water bottling factories: “Heba”, “Bivoda”, “Prohor” as well as the “Vrelo Bujanovac Banja Spa Centre” for rehabilitation, treatment, and prevention. All stated consumers use the same mineral water aquifer. The content of fluoride in the majority of examined mineral waters is higher than 4 mg/1, whereby they are singled out as typical fluoride waters. The content of calcium ions in them amounts 80 mg/1, and the values of the saturation index in relation to calcium fluoride (SI) range from 0.4 to 0.7 mg/1, which points to mineral waters saturated in relation to fluorite. However, in the study area, there are mineral water occurrences with the content of fluoride significantly lower than in the majority of analysed waters representing hydrochemical anomalies. These waters occur as hydrochemical anomalies in marl and sandstone wherein Secondary mineral water aquifers, originating from cracked granite of the Bujanovac massif, are formed. When mineral waters from granite (with the increased content of fluoride) reach these secondary aquifers, the content of fluoride ions lowers to about 1 mg/1, which is of great significance from the point of view of mineral water utilisation as table bottled water. In this paper, it is proved that, in addition to the presence of some minerals as basic fluorine bearers, the role of the lithological environment where the natural process of defluoridation occurs is significant, which is confirmed by the revitalization of the A-4 well. The paper deals with mineral water deposits of the Bujanovac valley, and the natural way of lowering of fluorine content in the given waters. 相似文献
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介绍了膨润土、沸石、硅藻土、海泡石、凹凸棒石等非金属矿物材料的结构和性质,对其在环境保护领域的应用现状进行了综述.提出应加强非金属矿物基础研究和应用研究,并加强开发生产非金属矿物环境材料. 相似文献