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采用十二烷基磺酸钠对膨润土进行改性,制得阴离子有机改性膨润土.通过静态吸附法探讨了改性膨润土对染料废水中甲基紫的吸附等温式和吸附热力学规律.结果表明,随着温度的升高,平衡吸附量增加;随着平衡浓度的增加,平衡吸附量不断增大,并趋于饱和.不同温度下吸附等温式与Langmuir方程拟合较好,热力学分析表明,吸附过程吸热,吸附... 相似文献
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阴离子有机改性膨润土吸附废水中甲基紫的热力学规律研究 总被引:1,自引:0,他引:1
采用十二烷基磺酸钠对膨润土进行改性,制得阴离子有机改性膨润土。通过静态吸附法探讨了改性膨润土对染料废水中甲基紫的吸附等温式和吸附热力学规律。结果表明,随着温度的升高,平衡吸附量增加;随着平衡浓度的增加,平衡吸附量不断增大,并趋于饱和。不同温度下吸附等温式与Langmuir方程拟合较好,热力学分析表明,吸附过程吸热,吸附焓变和熵变均为正值,吸附自由能变为负值。 相似文献
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重金属离子对人体有害,在废水中很难处理,利用廉价吸附剂有效处理重金属离子,既经济又环保。膨润土价廉易得,比表面积大,吸附性好,是一种天然的矿物质吸附剂。文章总结了膨润土吸附重金属离子的机理,并分析了改性膨润土在吸附重金属离子方面的研究进展及存在问题,并提出了解决办法。 相似文献
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考察了pH值、催化剂用量、酸性大红(GR)染料初始浓度、曝气量对染料去除率的影响,确定了GR染料去除的较佳反应条件:pH值为3,催化剂投加量为0.6 mg/L,GR染料进水浓度为20mg/L,曝气量为60mL/min.在较佳反应条件下,对光催化工艺、好氧生物降解工艺和光催化-好氧生物降解组合工艺处理单一染料废水效果进行了比较,并考察了组合工艺处理混合染料废水的效果,结果表明:反应5 h时,组合工艺对单一染料废水中活性墨绿(B-4BLN)和GR染料的去除率分别为85.66%和76.93%,去除效果明显高于单一工艺;组合工艺对混合染料废水中B-4BLN和GR染料的去除率分别为83.76%和71.84%. 相似文献
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土-膨润土竖向隔离墙广泛应用于阻滞污染物在地下水中的运移。通过一维压缩固结试验和变水头渗透试验,研究砂土-钙基膨润土以及砂土-黏性土-钙基膨润土竖向隔离墙材料的压缩及渗透特性。试样含水率采用膨润土掺量为10%的膨润土浆调节,通过迷你锥坍落筒的坍落度试验确定满足施工要求的试样初始含水率。试验结果表明,钙基膨润土掺量为8.3%时能够满足抗渗性能要求(渗透系数小于10-9m/s),黏性土掺量对钙基膨润土系竖向隔离墙的压缩指数和渗透系数无显著影响。采用变水头渗透试验所测定渗透系数与通过太沙基一维固结理论所确定渗透系数结果差别较小,相同有效竖向应力下两者结果比值介于1/3至3。采用有效竖向应力为1 k Pa时的孔隙比、膨润土孔隙比和液限等物理性质指标进一步评价和预测钙基膨润土系竖向隔离墙的压缩和渗透特性。 相似文献
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探讨了水解酸化脱溶和铁盐混凝工艺处理印染废水的基本原理和反应机理,阐述了该工艺在印染废水治理中的应用。从实际应用看,水解酸化脱溶—铁盐混凝工艺具有适应范围广、处理效果好、成本低廉等优点。作为印染废水预处理工序,可以使后续生化和物化工序处于更合适的浓度范围而获得更理想的处理效果。 相似文献
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采用纳米SiO2和碳酸钙晶须制备水泥基材料,利用SEM、XRD和TG-DSC等技术手段对水泥基材料的水化产物、微观结构和热稳定性等进行有效表征,并试验研究了双掺0%、1%、2%、3%、5%、10%的碳酸钙晶须和1%纳米SiO2保温水泥砂浆的力学性能和导热性能。研究结果表明:纳米-毫米两种尺度材料掺入水泥浆内部后,纳米SiO2与水泥水化产物Ca(OH)2晶体发生二次水化反应,生成C-S-H凝胶体,有效地填充水泥基体孔隙、细化水泥基内部孔径尺寸,碳酸钙晶须具备纤维和微粒双重作用,可以在水泥基中产生纤维的桥联效应,两者材料结合起来,可在水泥基内部形成密实网状絮凝结构;纳米SiO2和碳酸钙晶须掺入后可以提高砂浆的强度,3%碳酸钙晶须和1%纳米SiO2配制的保温水泥砂浆抗压和抗折强度分别为25.6 MPa和6.19 MPa,导热系数为0.456 7 W/(m·K),强度和导热性能兼顾。 相似文献
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酸对云冈石窟砂岩的劣化作用试验研究 总被引:1,自引:0,他引:1
云冈石窟所处的山西省大同市是我国重要的产煤区和煤化工基地,空气污染导致窟区内SO2浓度超标。云冈石窟砂岩主要成分中的长石及钙质胶结物,对酸的作用极其敏感。为模拟硫酸对云冈石窟洞窟岩石的劣化作用,设计了硫酸浸泡劣化试验。通过测量不同pH值硫酸溶液浸泡的砂岩岩样的质量、波速以及溶液的pH值,并对比腐蚀前后岩样的抗压强度、物质结构,来研究硫酸对石窟岩石的破坏机理及其规律。结果表明:酸对此类钙质胶结砂岩的破坏非常迅速,且主要破坏岩石的钙质胶结物;随着反应次数的增加,波速明显降低;酸对岩样表层的作用特别严重;随着胶结物的丧失,岩石强度降低明显。 相似文献
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依托上海软黏土地层的某大尺寸三角形深基坑工程,通过开展现场试验,对基坑施工过程中的地下连续墙的侧向变形、地表沉降进行了监测,并对监测数据进行了系统分析。监测结果分析表明:不同于矩形基坑,大尺寸三角形基坑连续墙顶部的水平位移约为其最大水平位移的40% ~70%;深基坑开挖结束后,拆除混凝土支撑产生的附加水平位移约为基坑开挖引起的墙体水平位移的30% ~40%;三角形深基坑开挖引起的最大连续墙水平位移介于0.05%H~0.35%H(开挖深度)之间,大于矩形和圆形深基坑引起的连续墙变形。这主要是因为三角形基坑的内支撑不能同时垂直于支撑两端的地下连续墙。深基坑的端部约束效应导致地下连续墙呈现出明显的三维变形特性,基坑中部墙体的水平位移明显大于两端位移。 相似文献
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利用VisualMODFLOW软件,模拟河流基流的减少、河流入渗的增加两个过程在抽水期间和抽水后期的地下水位场变化,直观的揭示了开采地下水对河道径流量的影响.得出:开采是导致研究区下游地下径流排泄量呈现逐年减小的趋势.从整体水均衡来看,模拟区含水层2001年至2004年都处于负均衡状态,说明该区地下水已出现超采现象. 相似文献
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平面闸门滑动行走支承的几种型式在现阶段的应用都有各自的特点及适用条件,因而,在实际设计时,应根据具体情况选择出最佳的支承型式。 相似文献
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Recycling of sludge with the Aqua Reci process. 总被引:3,自引:0,他引:3
Supercritical Water Oxidation (SCWO) is an innovative and effective destruction method for organics in sewage sludge. The SCWO process leaves a slurry of inorganic ash in a pure water phase free from organic contaminants, which opens possibilities for a simple process to recover components like phosphates and/or coagulants from the sewage sludge, a process marketed as the Aqua Reci. In a continuous pilot plant for the SCWO process digested sludge has been treated. The ash has been extracted in lab- and pilot scale with both caustic and acids in order to recover phosphates and coagulants. The particle size of the inorganic contaminants in the water after the SCWO process is between 1-10 microm, which means that it is very reactive. The phosphate, and partly the aluminium, can be extracted with caustic as iron and heavy metals are completely insoluble in caustic. This is a method to separate the phosphates from the rest of the contaminants. However, high calcium content will bind the phosphate as calcium phosphate insoluble in caustic. In most cases the calcium content is too high and the best solution is to dissolve phosphates and all metals with sulphuric acid. From this solution first iron phosphate can be separated and thereafter in a second step aluminium and finally heavy metals in a third step. Iron can be separated from the phosphate, either by leaching the phosphate with caustic off to sodium phosphate leaving a precipitate consisting of iron hydroxide, or the iron phosphate can be dissolved in hydrochloric acid followed by a liquid extraction process where ferric chloride can be separated leaving a phosphoric acid. By the acid dissolving process it is possible to recover phosphate, iron, aluminium, and heavy metals from the inorganic since the Aqua Reci process only leaves a silica residue representing about 10% of the DS content in the original sludge. 相似文献
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A three-phase (aqueous/gas/solid) mixed weak acid/base chemistry kinetic model is applied to evaluate the processes operative in the aeration treatment of swine wastewater (SWW) and sewage sludge anaerobic digester liquor (ADL). In both applications, with a single set of constants (except for the aeration rates which are situation specific), close correlation could be obtained between predicted and measured data, except for the Ca concentration-time profile in the SWW. For this wastewater, the model application highlighted an inconsistency in the measured Ca data which could not be resolved; this illustrates the value of a mass balance-based model in evaluating experimental data. From the model applications, in both wastewaters the dominant minerals precipitating are struvite and amorphous calcium phosphate (ACP), which precipitate simultaneously competing for the same species, P. The absolute and relative masses of the two precipitants are governed by the initial solution state (e.g. total inorganic C (C(T)), Mg, Ca and P concentrations), their relative precipitation rates (struvite > ACP) and the system conditions imposed (aeration rates and time applied). It is concluded that the kinetic model is able to predict correctly the time-dependent weak acid/base chemistry reactions and final equilibrium state for situations where multiple minerals competing for the same species precipitate simultaneously or sequentially, a deficiency in traditional equilibrium chemistry-based algebraic models. 相似文献
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为了评估侵蚀性水环境下混凝土的钙溶蚀规律,依据软水和硝酸环境下混凝土钙溶蚀机理,建立了侵蚀性水环境作用下混凝土二维钙溶蚀模型。模型考虑了混凝土中孔隙的曲折度和阻塞率,以及混凝土界面过渡区(ITZ)对孔隙率的影响。利用COMSOL软件对理论模型进行求解,并将数值分析结果与试验值进行对比,验证了理论模型的可靠性。对混凝土二维钙溶蚀规律的分析结果表明:混凝土在软水及硝酸环境中的钙溶蚀深度都与时间的平方根成正比。 相似文献
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The conversion of steelmaking slag (a waste product of the steelmaking process) to calcium carbonate (CaCO(3)) was tested using hydrochloric acid, ammonium hydroxide and carbon dioxide via a pH-swing process. Batch reactors were used to assess the technical feasibility of calcium carbonate recovery and its use for pre-treatment of acid mine drainage (AMD) from coal mines. The effects of key process parameters, such as the amount of acid (HCl/calcium molar ratio), the pH and the CO(2) flow rate were considered. It was observed that calcium extraction from steelmaking slag significantly increased with an increase in the amount of hydrochloric acid. The CO(2) flow rate also had a positive effect on the carbonation reaction rate but did not affect the morphology of the calcium carbonate produced for values less than 2 L/min. The CaCO(3) recovered from the bench scale batch reactor demonstrated effective neutralization ability during AMD pre-treatment compared with the commercial laboratory grade CaCO(3). 相似文献