共查询到19条相似文献,搜索用时 218 毫秒
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采用批处理吸附实验和柱状淋溶模拟实验,分析粉煤灰吸附重金属、处理煤矸石酸性重金属淋滤液的效果及机理。结果表明:① 粉煤灰对Pb2+、Cu2+、Cd2+ 和Zn2+的吸附等温线符合Freundlich等温模式,吸附过程符合准二级反应动力学模型,且均在30 min内达到吸附平衡,随着pH增加,4种重金属离子吸附率逐渐增加并趋于平衡(Pb、Cu、Cd、Zn分别在pH=3.5、6.0、7.5、8.0时达到平衡),在酸性环境下粉煤灰对4种金属离子具有较好的吸附性能;② 在重金属竞争性吸附中,共存离子的存在抑制了目标离子的吸附,其中Pb受共存离子的影响最小,粉煤灰吸附强弱顺序为Pb>Cu>Cd>Zn;③ 煤矸石柱状淋溶试验中,煤矸石淋滤液呈现较强酸性、较高重金属浓度的酸性矿山废水特征,而在粉煤灰处理中,淋滤液的pH值呈中性,重金属离子浓度显著下降,其主要机制为粉煤灰吸附、碱性中和、重金属与Fe共沉淀等。研究表明,实验用粉煤灰具有修复煤矸石酸性重金属淋滤液的潜力。 相似文献
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粉煤灰淋溶液对地下水污染的试验研究 总被引:2,自引:0,他引:2
介绍了粉煤灰中有害物质使 0 3m的土层对粉煤灰淋溶水中 pH值、F-、全盐量和总碱度有很强的吸附能力 ,由于贮灰场附近土层远大于 0 3m ,因此粉煤灰淋溶水不会对地下水产生污染。 相似文献
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采用两种化学组成相对含量不同,矿物组成和微观形貌差异明显的粉煤灰:即普通粉煤灰(PC灰)和固硫灰(CFB灰)补强丁苯橡胶,并对复合材料的各项性能进行了研究。试验结果表明:CFB灰补强丁苯橡胶复合材料的100%定伸应力、拉伸强度、断裂伸长率、撕裂强度性能优于PC灰。由于絮状CFB灰表面疏松多孔,相较光滑密实的球形PC灰,其与丁苯橡胶存在更多交联点,有利于提升复合材料性能。复合材料硬度随粉煤灰添加量的增加而提高。经硅烷偶联剂活化后粉煤灰具有更好的补强效果。 相似文献
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粉煤灰是一种可再资源化的工业固体废弃物,在建材、化工、农业和环保等领域都有广泛的用途。本文介绍了当前粉煤灰及其改性产品在处理含铬水溶液中的应用现状,讨论了温度、pH值、接触时间、铬离子浓度和粉煤灰用量对粉煤灰吸附性能的影响,介绍了粉煤灰对Cr(Ⅵ)和Cr(Ⅲ)的去除机理。 相似文献
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考察了粉煤灰对二价金属离子的吸附性能.结果表明,粉煤灰可有效吸附水溶液中的重金属离子.吸附由易到难次序为:Pb>Cu>Cd>Zn.随pH升高,去除率增加.吸附在约60 min内达到平衡.等温吸附数据符合Freundlich模型,但在pH=4.5时表现为单一线性区,而在pH= 6和pH=8时表现为2个线性区.粉煤灰对金属离子的吸附明显受到其它共存离子的影响,Cd与Pb之间存在较强的协同吸附作用.对实际废水的测试表明,粉煤灰可同时有效去除工业废水中多种金属离子. 相似文献
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为了强化改性粉煤灰在重金属废水处理中的吸附效果,利用微波联合碱改性的方法,研究微波温度、微波时间、微波功率等制备条件对改性粉煤灰吸附铬(Ⅵ)的影响以及吸附等温特性。结果表明,粉煤灰改性的最佳制备条件为:微波功率600 W,微波温度60℃,微波时间15 min,吸附量达到0.341 mg/g,较改性前提高50%以上。此改性条件下的粉煤灰进行吸附等温的试验研究结果表明,其对铬(Ⅵ)的吸附符合Freundlich和Langmuir等温吸附模型,此吸附过程为单分子层吸附。粉煤灰具有较高的经济性,可广泛用于含铬(Ⅵ)废水的处理。 相似文献
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A.D. Papandreou C.J. Stournaras D. Panias I. Paspaliaris 《Minerals Engineering》2011,24(13):1495-1501
In the present work the application of fly ash porous pellets as adsorbent of lead(II), zinc(II) and chromium(III) ions from aqueous solution was studied. Experiments were carried out using porous pellets developed from fly ash derived from Megalopolis, Greece coal-burning power plant. The material was shaped into spherical agglomerates, after wetting and tumbling in a laboratory scale granulator. The adsorption of heavy metals on fly ash pellets was studied as a function of the initial metal concentration, solution pH and temperature. Kinetic studies indicated that sorption follows a pseudo-second-order model. Adsorption isotherms of lead, zinc and chromium were determined for agglomerated material using the Langmuir equation. The adsorption capacity of fly ash pellets reached at 0.22 mmol Pb/g pellet, 0.27 mmol Zn/g pellet and 0.44 mmol Cr/g pellet. Furthermore adsorption from bimetallic solutions (Cr–Zn, Cr–Pb and Pb–Zn) took place in order to study presumable antagonistic effects on adsorption of heavy metals. Finally, the stabilization of metal saturated pellets was studied. The stabilization procedure took place in structures made of concrete, where 75% of cement was replaced by raw fly ash. The evaluation of the procedure through leaching tests showed excellent heavy metals stabilization in concrete blocks. 相似文献
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通过对粉煤灰进行改性处理来吸附舍磷废水中的磷,取得了良好的吸附效果.探讨了吸附接触时间、改性粉煤灰投加量、磷初始浓度、pH值和温度等因素对除磷效果的影响.结果表明,对于50mg/L的含磷废水,在室温,pH值4~10范围内.当水灰比为100:3时.吸附20min后磷的去除率可迭99%以上,净化后的污水中磷含量达国家一级排放标准的要求.吸附等温线拟合结果表明,该吸附过程可用Laagrauir吸附等温式来描述,吸附过程以化学吸附为主. 相似文献
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The basic idea in this study is to look into the possibilities of reducing the heavy metal concentrations of fly ash by means of electrostatic precipitation. The utilisation of fly ash as fertiliser is hampered by its high concentrations of heavy metals, which are highly variable. Fly ash fractionation experiments were done using electrostatic precipitators at four power plants. Based on the results, the concentrations of heavy metal are at their lowest in the first collector chamber and highest in the last chamber. The concentration of cadmium in fly ash used as fertiliser can be reduced by as much as 70% by applying electrostatic precipitation fractionation. The removal of other heavy metals is not as efficient as that of cadmium. The results show that electrostatic precipitation is an adequate method in the fractionating of fly ash to be used as a fertiliser or soil amendment. 相似文献