改性膨润土处理染料废水的实验研究

对产自辽宁某地的钙基膨润土通过不同程度的改性处理,用于处理染料废水,比较了不同改性后的膨润土处理染料废水的效果。处理效果最佳的是柱撑酸化膨润土,其对染料废水COD的去除率可达80%以上,色度去除率可达95%以上。     

镧改性、钠基和钙基膨润土净化污染河水中磷的效果

研究镧改性、钠基和钙基三种膨润土对河水中磷的去除效果.将1.6 g的镧改性、钠基、钙基膨润土分别投入到800 mL的清河河水中,清河水水质为劣Ⅴ类.试验结果表明镧改性膨润土的磷去除效果优于其他两种,对河水中总磷的平均去除率为77.41%,磷含量在第7天达到Ⅳ类水水质标准.同时镧改性膨润土对氮和含碳有机物也有一定的去除效果,在第7天对总氮的去除率达到最高值50.78%,在第3天对含碳有机物的去除率为18.34%.     

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

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...     

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

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。     

无机柱撑膨润土对有机锡废水COD的吸附研究

利用原土、羟基铁膨润土和羟基铁铝柱撑膨润土,进行了吸附有机锡废水中CODcr的试验.研究了膨润土投加量、吸附pH、时间和等温线的变化规律.结果表明,达到吸附平衡的时间为2 h;随着吸附pH由小到大的变化,CODCr的吸附去除率在一定范围内波动;膨润土的投加量宜大于4 g/L;吸附符合Henry等温式;膨润土的层间距、吸附位的数量及活性是决定对吸附性能的关键因素;吸附容量的大小和吸附作用的强弱顺序为:羟基铁铝膨润土＞羟基铁膨润土＞原土.     

改性膨润土处理重金属离子废水的研究进展

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。     

光催化-好氧生物降解处理染料废水试验研究

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%.     

三段接触氧化—水解酸化工艺处理高浓度感光废水

通过对传统活性污泥法、两级接触氧化、多段接触氧化-水解酸化三种工艺进行对比后采用多段接触氧化-水解酸化工艺的处理高浓度感光废水,处理水量300 L/d,废水经该工艺处理后,CODcr去除率可达66.36%,工艺处理效果稳定,耐冲击负荷,监测并分析了运行过程中容积负荷、温度、pH值、生物相等因素的变化规律,对高浓度感光废水的处理提供了一定的数据参考.     

钙基膨润系土竖向隔离墙材料压缩及渗透特性试验研究

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。     

水解酸化脱溶—铁盐混凝预处理印染废水的研究

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。     

纳米SiO2和碳酸钙晶须制备水泥基材料性能试验

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。     

酸对云冈石窟砂岩的劣化作用试验研究

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。     

大尺寸三角形基坑变形特性的现场试验研究

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。     

应用数值技术揭示开采地下水对河道径流量的影响

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.     

平面闸门滑动行走支承的几种型式

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。     

Recycling of sludge with the Aqua Reci process.

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.     

Integrated chemical--physical processes kinetic modelling of multiple mineral precipitation problems.

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.     

侵蚀性水作用下混凝土的钙溶蚀模型

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。     

Recovery of calcium carbonate from steelmaking slag and utilization for acid mine drainage pre-treatment

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).     

预应力加固技术应用于空腹重力坝中的断裂力学分析

通过分析空腹重力坝的优缺点,以断裂力学理沧为基础,应用有限单元法探讨了预应力大小对空腹重力坝坝踵裂缝尖端应力强度因子的影响。预应力加固技术可以很好地弥补空腹重力坝所存在的缺陷,对设计空腹重力坝有一定的参考价值。