共查询到19条相似文献,搜索用时 171 毫秒
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吉林露水河硅藻土质量评价 总被引:1,自引:0,他引:1
露水河硅藻土矿是第四纪形成的沉积矿床,具有直链硅藻土和圆环硅藻土两种类型矿层。硅藻土矿的物质组成以硅藻为主,可含少量粘土矿物。SiO2主要由硅藻贡献。Al2O3主要由粘物贡献,Fe主要以Fe2O3形成被吸附在粘土矿物颗粒表面和粒间。直链硅藻土矿层厚度稳定,主要是Ⅱ级土,含Fe较高;圆环硅藻土矿层厚度有变化,大多为Ⅰ级土,含Fe低,但局部见硅藻严重破碎现象。利用SiO2-密度相关图解,可适时监测硅藻土品质。 相似文献
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重金属离子在胡敏酸-高岭石复合体上的吸附 总被引:6,自引:0,他引:6
本文研究了胡敏酸存在下高岭石对重金属离子的吸附行为。实验结果表明:①胡敏酸和Cu2 溶液按先后顺序或同时加入高岭石中反应,在Cu2 平衡浓度<10mg/L时,3种加入顺序对Cu2 的吸附量基本相同,当Cu2 平衡浓度>10mg/L时,(K Cu) HA和(K Cu HA)两种加入顺序对Cu2 的吸附量比(K HA) Cu的略大。②在pH=5时,胡敏酸-高岭石复合体对Cu2 的吸附量明显大于纯高岭石。这是由于胡敏酸含有大量的羧基和酚羟基等活性基团,吸附在高岭石上的胡敏酸增加了其表面吸附位,在复合体表面形成了S—HA—Cu三元配合物,且Cu2 的吸附量与复合体中胡敏酸的含量在一定范围内成正相关;③溶液pH值在4~7之间变化可调控复合体对Cu2 的吸附机制。④在Cu2 和Cd2 共存时,随着金属离子初始浓度的增大,Cu2 的吸附量呈直线上升,而Cd2 的吸附量增加缓慢,表明复合体对Cu2 的吸附能力比对Cd2 强。 相似文献
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考察酸性条件特别是在近中性 pH范围内胡敏酸对高岭石吸附铜离子的强化作用。研究表明 ,胡敏酸的加入可以提高高岭石对铜离子的吸附率 ,甚至在pH 5~ 6附近高岭石对铜离子的吸附率也从约 5 0 %提高到约 6 5 %。当 pH <4时 ,由于高岭石表面铝的高溶出或胡敏酸阴离子基团离解程度降低等因素 ,使其表面对胡敏酸的吸附率有所降低 ,但与高岭石样品相比 ,胡敏酸高岭石复合体对铜离子的吸附仍然有明显的增加。胡敏酸对高岭石吸附铜离子的强化机制是 ,高岭石端面形成了Al—HA—Cu三元配合物 (B型 ) ,与传统的诸如pH、离子强度与离子初始浓度等介质条件影响不同。在 pH >7时高岭石端面及腐殖质基团去质子化增强 ,因而静电排斥降低了高岭石对胡敏酸的吸附 ,从而使得胡敏酸对铜离子在高岭石表面上的吸附作用有所减弱 ,此时可能出现胡敏酸铜及氢氧化铜的沉淀 ,铜离子的表观吸附率可能不会有明显变化 相似文献
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水井酸处理用酸量和用酸浓度的探讨 总被引:1,自引:0,他引:1
针对水井酸处理中用酸量和最佳用酸浓度问题,通过理论分析和数学推导,提出了一套水井酸处理用酸量的确定方法,即通过被处理碳酸盐岩含水层张开裂隙数目来计算用酸量;研究表明,用酸浓度越低,水井酸处理的效果越差;对华中科技大学供水井分别注2.4mol/L盐酸4t,4.8mol/L的4t,9.5mol/L的3.7t,进行了3次酸处理,井的涌水量分别增加0%,20%,100%,说明水井酸处理应尽量用浓酸。 相似文献
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高纯度石英的酸浸实验研究 总被引:14,自引:4,他引:14
针对脉石英矿中含有大量云母及长石等伴生矿的特点,通过调整溶液浓度及温度等手段,强化矿物的酸浸效果。根据石英与杂质矿物在酸浸过程中的差异,探索消除石英中杂质矿物的方法。研究表明石英原料粉在温度为120℃、HF酸与水的比为0.4~0.5的溶液中酸浸适当时间后,其纯度可达到中高档石英玻璃的技术要求。 相似文献
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采用阳离子表面活性剂(十六烷基三甲基溴化铵)对硅藻土进行改性, 并以优选的改性方案为基础, 研究了该有机硅藻土对水中有机氯农药DDTs(p, p'-DDT、p, p'-DDE和p, p'-DDD)的吸附过程及增强机理.结果表明, 十六烷基三甲基溴化铵能有效改变硅藻土的Zeta电位、比表面积和表面疏水性质, 从而提高硅藻土吸附有机氯农药的能力.改性硅藻土对水中3种有机氯农药的吸附能力依次为: p, p'-DDT>p, p'-DDE>p, p'-DDD.基于模型的准确性(R2值)考虑, Redlich-Peterson方程能更好地用于拟合DDTs在改性硅藻土上的等温吸附曲线. 相似文献
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《矿产与地质》2017,(2)
阳离子表面活性剂十六烷基三甲基溴化铵可以有效对天然硅藻土进行有机改性,获得有机改性硅藻土。有机改性硅藻土对富含甲基橙、酸性绿溶液的吸附实验研究结果表明,在相同条件下,改性硅藻土对甲基橙的吸附效果比较好,对酸性绿的吸附效果不是很理想,但也远远高于硅藻土原土对这两种阴离子的吸附效果。在室温条件下,当甲基橙溶液的浓度为20mg/L时,改性硅藻土投加量为0.2g、pH值为4、吸附时间为80min,改性硅藻土对其的吸附效果较好;在室温条件下,当染料酸性绿溶液的浓度为20mg/L时,改性硅藻土投加量为0.15g、pH值为4、吸附时间为80min,改性硅藻土对其的吸附效果较好;两种阴离子的吸附过程均符合Freundlich模型。基于n值对比分析,改性硅藻土对甲基橙的吸附属于优惠吸附,而对酸性绿的吸附属于非优惠吸附。 相似文献
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《矿物学报》2013,(Z1)
Diatomite, a type of biogenic mineral, is sourced from deposition and accumulation of diatom shell. Diatom shells are mainly composed of amorphous hydrated silica, which is categorized as non-crystalline opal-A according to the mineralogical classification. Diatomite has a characteristic macro/mesoporous structure and unique physical and chemical capabilities, such as high thermal stability, strong acid resistance, and high adsorption capacity, and thus is widely used as the filter aid, catalytic support, and adsorbent. However, the low surface area of diatomite shows disadvantage in adsorption. Moreover, the hydrophilic surface which contains abundant silanols is usually covered by adsorbed water, resulting in that the adsorption sites of diatomite were occupied and the adsorption capacity of hydrophobic guests decreased. In previous reports, zeolitization was employed to increase the specific surface area (SBET) and porosity of diatomite. However, the hydrophilic property of diatomite was not changed after zeolitization. It is due to that the zeolite formed on the surface area of diatomite contained some aluminum in its structure, which was highly hydrophilic. Therefore, it is significantly interesting to prepare the zeolitized diatomite with both large SBET and high hydrophobicity. 相似文献
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粤西徐闻九亩硅藻土表面多孔,除含有蛋白石外,还含有少量的蒙脱石等粘土矿物;其对水体中的Zn^2+具有修复能力,且对Zn^2+的吸附效率较高;宜在弱酸性-中性的pH值条件下修复Zn^2+;在低Zn^2+浓度下,硅藻土可以有效地去除Zn^2+,而对硅藻土进行改性后将有利于对较高浓度的Zn^2+进行修复;评价硅藻土对水体中Zn^2+的修复效果应该综合考虑去除率与负载量,在Zn^2+初始浓度为20mg/L时,徐闻九亩硅藻土吸附剂的用量应以10g/L为宜。 相似文献
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Effects of process parameters such as concentrations of FeCl2, NaOH, and drying temperature on the formation mechanism and chemical characteristics of ferrihydrite-modified diatomite
are studied by using X-ray absorption near-edge structure spectroscopy. The spectra were recorded in total electron yield
mode and/or fluorescence yield mode to investigate the chemical nature of Fe and Si on the surface and/or in the bulk of ferrihydrite-modified
diatomite, respectively. It was found that only the surface SiO2 was partially dissolved in the NaOH solution with stirring and heating, whereas the bulk of diatomite seemed to be preserved.
The dissolved Si was incorporated into the structure of ferrihydrite to form the 2-line Si-containing ferrihydrite on the
surface of diatomite. The crystalline degree of ferrihydrite increased with the increasing FeCl2 concentration and the Brunauer–Emmett–Teller specific surface area of ferrihydrite-modified diatomite decreased with the
increasing FeCl2 concentration. The crystalline degree of ferrihydrite decreased with the increase of NaOH concentration. The high temperature
calcination caused an energy shift in the Si L-edge spectra to the high energy side and a transformation of Si-containing
ferrihydrite to crystallized hematite might occur when ferrihydrite-modified diatomite is calcined at 900°C. In this study,
the optimal synthesis conditions for the ferrihydrite-modified diatomite with the least crystalline Si-containing ferrihydrite
and the highest surface area were found to be as the follows: 0.5 M FeCl2 solution, 6 M NaOH solution and drying temperature of 50°C. 相似文献
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煤系共伴生非金属矿产开发及综合利用难度大。本文针对先锋褐煤共伴生硅藻土高有机质、高铁的特点,提出硅藻土原矿经提纯处理后,在N2作为保护气氛下,高温煅烧形成硅藻土-无定形碳-氧化铁三元复合材料,在类Fenton体系下,去除TNT污染物的开发利用技术路线。本文考察了硅藻土处理条件、反应时间、H2O2浓度、三元复合硅藻土投加量、pH值等因素对TNT降解效能的影响。研究表明三元复合硅藻土对TNT吸附降解的最佳工艺条件为:硅藻土用量为2 g/L,H2O2(30%)4 m L/L,pH值1,反应时间2.5 h。该工艺条件下,50 mg/L TNT去除率为98%。 相似文献
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硅藻土在一些高附加值产品中的应用及其基础研究 总被引:12,自引:0,他引:12
硅藻土是重要的非金属矿物材料。本文综述了它在具有高附加值的功能材料领域,包括助滤剂、吸附剂、载体中的应用,并从这些产品对原料的要求的角度,探讨了有关硅藻土的成分、结构、表面酸性、羟基结构、界面反应性,以及提纯处理的研究现状。 相似文献
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腾冲地区分布的粘土质硅藻土是一种特殊性的岩土体,具有孔隙大、密度低、含水量高,富含膨胀性粘土矿物、结构性强等特点。近年来已发生一系列与粘土质硅藻土相关的滑坡等地质灾害,造成了较大损失。在粘土质硅藻土工程地质特性测试分析的基础上,对腾冲地区粘土质硅藻土滑坡的分布特征和形成机理进行了研究,认为粘土质硅藻土滑坡以中小型滑坡为主,受公路切坡、采矿、降雨等因素影响较大;公路边坡滑坡多发生在坡体的中部和后部,在牵引作用下部分滑坡可发生大范围滑动。粘土质硅藻土具有膨胀性和极强的结构性,其边坡稳定性较差。以新修建腾泸公路边坡滑坡为例,对S238省道冯家大山滑坡的形成机理进行了探讨,认为受粘土质硅藻土膨胀性、结构性等的影响,人类工程扰动、降雨等引起边坡表部土体出现强度分层、膨胀性增强和力学强度降低,从而导致原支护结构破坏;在此基础上,对冯家大山边坡进行了优化设计和数值模拟分析,提出了综合防治建议。 相似文献
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《矿物学报》2013,(Z1)
Porous carbons are extensively applied in gas separation, water purification, catalytic reaction, and electrochemical processing, attributing to their high specific surface area, large pore volume, chemical inertness, and good mechanical and thermal stability. The templating method is widely used to synthesize porous carbons with the controlled pore structure. Among them, preparation of diatomite-templated carbons attracts increasing attention because the obtained carbon has unique developed macropores and exhibits the promising application in adsorption and support of large-sized molecules. Macroporous diatomite-templated carbons are prepared by using additive or inherent solid acid sites of diatomite as the catalyst. The obtained carbons showed tubular and pillared macroporous structures, and had a few mesopores and micropores. However, the carbons possessed the small specific surface area and micropore volume, and thus showed the low adsorption capacity of small-sized molecules, such as methylene blue (MB). In this case, enhancement of porosity, especially microporosity, is necessary. 相似文献
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Purification of diatomite powder by acid leaching for use in fabrication of porous ceramics 总被引:1,自引:0,他引:1
This study presents an investigation of the purification of a raw diatomite by acid leaching conducted in hot solution (75 °C and 5 M HCl) for long periods up to 240 h, evaluates the use of these purified powders in the fabrication of porous materials, and examines their porosities. The treatment for 1 h increased the specific surface area of diatomite from 189 m2/g to 222 m2/g, but the SiO2 content of 78.66% was still low. Material leached for a relatively short time shows an amorphous phase with quartz and plagioclase phases and the plagioclase is removable at longer leaching times during which no disruptive effect on the fine microscopic pores of the particles was observed. Thus, the diatomite based powders have potential use in the fabrication of porous coating as a membrane-separating layer: sintering at a relatively high temperature (1300 °C) still showed a significantly high apparent porosity of 48%. 相似文献