膨润土的改性及其对废水中磷吸附效果的研究

[目的]研究改性膨润土对废水中磷吸附的影响.[方法]采用盐酸和煅烧两种方法对鹏润土分别进行酸改性和热改性,研究了不同浓度酸改性及不同温度热改性时膨润土磷吸附的影响,并探讨了热改性膨润土的最佳温度及pH值.[结果]在废水浓度20 mg/L、膨润土投加量2%(重量比)时,对磷的吸附效果随着酸用量的增加而增加,9%盐酸改性后磷去除率由18.14%提高到45.59%;热改性后磷去除率上升为41.17%,最佳热改性温度为500℃,在弱酸及弱碱性条件下有利于500℃热改性膨润土吸附除磷,pH=9时,10 mg/L磷溶液中磷的去除率可达92.77%,磷剩余浓度为0.47 mg/L,达到国家城镇污水处理厂一级A排放标准.[结论j酸改性和热改性均可显著提高膨润土的磷吸附效果.     

壳聚糖改性膨润土对含磷废水的处理研究

本文利用壳聚糖对膨润土原土样进行改性,对比了改性膨润土和原土样膨润土对废水中磷酸盐的去除能力,壳聚糖改性膨润土复合吸附剂的吸附能力明显优于原土样钠基膨润土。通过单因素实验,对改性膨润土去除磷元素实验条件进行优化,依次确定了膨润土上壳聚糖的最佳负载量为0.045g/g、改性膨润土投加量为60g/L、搅拌速率为120r/min、pH=6.0、搅拌时间为25min,考察了壳聚糖改性膨润土吸附含磷废水的最佳去除率为79.59%。同时根据Freundlich等温吸附方程式和Langmuir等温吸附方程式拟合得到回归曲线y=13.661x+6.0389,最终确定壳聚糖改性膨润土在固相中对磷的最大吸附量为0.1656mg/g。     

膨润土基重金属脱除剂处理钢铁工业废水的实验研究

通过实验制备新型膨润土基重金属脱除剂,用于钢铁工业废水重金属的处理。首先比较了改性的钠基膨润土和钙基膨润土的处理效果。结果表明钠基膨润土效果明显优于钙基膨润土。以钠基膨润土和助凝剂PAM为原料制备重金属脱除剂,考察脱除剂中组分比例对重金属脱除效率的影响。结果表明,重金属脱除剂配方的最佳组成为99.992%的改性钠基膨润土和0.008%助凝剂PAM。通过实验得到重金属脱除剂的合适处理条件为:处理时间50min,pH值8、废水中重金属脱除剂加入量25g/L。经处理后钢铁废水中锌、镉、铅的脱除率分别达到89.7%、78.5%、93.1%。     

废水中常见离子对载铁改性膨润土吸附Cr(Ⅵ)的影响

研究了废水中几种常见离子对载铁改性膨润土吸附Cr(Ⅵ)的影响。试验结果表明:废水中的Ca~(2+)、Mg~(2+)、CO_3~(2-)、HCO_3~-等在酸性环境中会抑制改性膨润土对Cr(Ⅵ)的吸附,在碱性环境中反而会促进改性膨润土对Cr(Ⅵ)的吸附;废水中的NH+4对改性膨润土吸附Cr(Ⅵ)的影响甚微,可忽略不计。     

改性钠基膨润土在造球工艺中的试验研究

为提高球团矿品位 ,进行了以配加防爆剂改性钠基膨润土替代钙基膨润土的造球试验研究。结果表明 ,在 1#竖炉的原料条件下 ,添加 1.5 %的钠基膨润土和 0 .5 %防爆剂 ,生球性质与添加 5 %钙基膨润土相当 ,且爆裂温度大于 80 0℃。     

宣（化）钢竖炉球团用含有机粘结剂改性膨润土的试验

在宣钢８ｍ＾２球团竖炉上采用含有机粘结剂的改性钠基膨润土替代普通钙基膨润土进行了工业试验。结果表明：改性钠基膨润土具有比普通钙基土更优良的性能,能明显提高生球的落下强度。     

低品位膨润土改性及其在球团中的应用研究

为了更好地利用低品位钙基膨润土用于球团生产,本文采用半干法对此类膨润土进行改性并进行造球试验.结果表明:膨润土经最佳半干法钠化后,2 h吸水率和膨胀容由161.1％和3.1 mL/g分别提高至349.03％和18.1 mL/g;经钠化改性和复合改性后,当配比均为1.6％时,生球落下强度由原土的3.9次/(0.5 m)分...     

吸附法脱除硫酸锰溶液中残余有机物

探讨粉煤灰、活性炭和膨润土等吸附剂对硫酸锰溶液中残余少量有机物的吸附效果,并以膨润土为吸附剂进行单因素试验,考察了膨润土用量、吸附时间、pH和温度对吸附效果的影响。结果表明,使用膨润土吸附剂,在溶液pH为7.0,25℃,吸附时间30min,膨润土用量10.0g的条件下,硫酸锰溶液的COD去除率可达32.4%;改性膨润土较未改性原土脱除溶液中有机物的效果更好,且酸化改性膨润土优于热化改性膨润土,COD去除率达到40.8%。     

STAC改性有机膨润土去除水体中U(Ⅵ)试验

为探究膨润土对含铀废水的吸附性能,对膨润土进行钠化预改性,然后用十八烷基三甲基氯化铵(STAC)对钠化膨润土进行有机改性,探究模拟含铀废水pH、固液比、反应时间、反应温度、初始浓度对STAC有机改性膨润土吸附U(Ⅵ)的影响,并探究了膨润土吸附动力学和吸附等温曲线。结果表明,当pH=7.04、固液比4.0 g/L、反应时间480 min、反应温度318.15 K、含铀废水初始浓度<10 mg/L时,该吸附材料处理含铀模拟废水的效果最佳,最高吸附率达到99.52%。准二级动力学方程和Langmuir等温吸附模型更适于阐明STAC有机改性膨润土吸附U(Ⅵ)的过程,反应主要是化学吸附和单层吸附。Langmuir拟合吸附容量最高为198.73 mg/g。     

用有机膨润土-活性炭联合净化的石油废酸浸出碳酸锰矿石

研究了用碳酸钠、十六烷基三甲基溴化铵改性膨润土制备有机膨润土,并将有机膨润土与活性炭联合用于吸附净化废硫酸,再用净化后的废硫酸浸出碳酸锰矿石。通过单因素试验及响应面试验确定最佳工艺条件,探讨吸附净化机制。结果表明:相关因素中,对废硫酸中COD去除率影响的次序为有机膨润土投加量吸附时间吸附温度搅拌速度;对于初始浓度11.12 mol/L的废硫酸,用粒径96μm有机膨润土5.8 g,在29℃、搅拌速度90 r/min条件下吸附时间49 min,然后再用活性炭4.0 g、在74℃下吸附34 min,废硫酸中COD去除率达91.07%;吸附机制可能是离子交换。     

均苯四甲酸二酐改性甘蔗渣及其对冶金废水中铅的吸附性能研究

以经碱和醇预处理过的甘蔗渣为原料,采用戊二醛为交联剂,均苯四甲酸二酐(PMDA)为改性剂,对甘蔗渣纤维进行羧基化改性,并用于冶金废水中铅的吸附。结果表明,甘蔗渣改性最佳工艺条件为:戊二醛浓度1%、PMDA添加量5%、液固比8∶1、改性温度60℃。红外光谱分析表明甘蔗渣中引入了苯环和羧基基团,戊二醛和PMDA成功改性甘蔗渣。SEM发现改性后的甘蔗渣形成了交联状,表面积增大。最佳吸附条件:吸附时间2.0h、吸附温度20℃、溶液pH=4,溶液中Pb的初始浓度70mg/L,Pb吸附率可达到98.8%。     

石墨烯改性有机膨润土吸附性能及其动力学

为提高有机膨润土的吸附性能,采用微波合成法,以石墨烯对有机膨润土进行改性,制备一种吸附效果好且回收效率高的新型石墨烯改性有机膨润土复合材料,研究其结构和吸附性能,探讨新吸附材料的作用机理。通过扫描电镜、红外光谱和X射线衍射对有机膨润土及石墨烯改性有机膨润土进行表征,并将其用于水中腐殖酸的吸附。结果表明:石墨烯与有机膨润土均匀复合,有机膨润土的层间距由1.37 nm增大至2.68 nm;当温度为25℃、p H值为6、吸附剂的用量为5 g·L^-1及吸附时间为1 h时,溶液中腐殖酸的去除率达到95.52%;石墨烯改性有机膨润土对腐殖酸的吸附等温线符合Langmuir模型和准二级动力学模型,最大理论吸附量为52.08 mg·g^-1,且为放热反应。利用0.1 mol·L^-1Na OH溶液对石墨烯改性有机膨润土进行解吸再生,5次再生后其对腐殖酸的去除率为86.3%。     

Use of Dubinin–Astakhov Equation to Describe Preloading Effect of Natural Organic Matter

This note presents a simple model to quantify the preloading effect of naturally occurring organic matter (NOM) in water on the adsorption capacity of activated carbon for a trace synthetic organic chemical (SOC). The model was developed from the Dubinin–Astakhov (DA) equation based on the assumption that the NOM preloading irreversibly reduced the limiting adsorption pore volume for the target SOC. Given that the DA-n value equal to one, the model reduces to a form similar to the one obtained by modifying the Freundlich equation directly. By assuming that the reduction of the limiting adsorption pore volume was proportional to the volume of NOM adsorbed, the NOM preloading effect was correlated directly to the amount of total organic carbon preloaded on the carbon. The resulting model was then compared with the experimental data in the literature. This simple model may be useful for certain practical applications that require only the estimation of the NOM preloading effect on the adsorption capacity of a target SOC from natural water.     

Competition of Cd, Cu, and Pb Adsorption on Goethite

Competition of copper, lead, and cadmium adsorption on goethite was studied and found to be dependent on metal ion and oxide surface characteristics. In adsorption edges, ionic strength effects suggested copper, lead, and cadmium are specifically adsorbed on goethite. Metal capacity on the goethite surface was found to increase with metal electronegativity: Cu > Pb > Cd. On the other hand, the equilibrium constant for lead was greater than that of copper, which is in agreement with their hydrated radii (Pb < Cu < Cd). Modeling revealed that the single-site Langmuir isotherm described the Cu-Cd and Pb-Cd adsorption and competition results within the error of the model. Furthermore, although the model provided a good fit for Pb and Cd data in the Pb-Cu and Pb-Cu-Cd systems, it underpredicted copper adsorption. The difference in site densities between copper and lead revealed a set of sites not available for competition. Using this approach where copper affinity is equivalent for both sites, the model provided a good fit for copper adsorption and competition. This study confirms that adsorption competition plays a crucial role in contaminant mobility in the environment.     

纳米TiO2改性彩色涂层钢板的涂层老化性能

 采用超声预分散结合湿球磨法和分散剂复配方式对纳米TiO2进行表面改性处理,研制了均匀稳定分散的纳米TiO2分散液,表征了纳米TiO2改性后的彩涂板涂料及涂层性能。结果表明：纳米TiO2在分散液中的粒径集中分布在60~100 nm范围,可完全吸收330 nm左右的紫外线,对长波紫外线的散射吸收作用强于对短波紫外线的散射吸收。纳米TiO2改性彩涂板涂料用量为w(TiO2)=20%~30%。纳米TiO2改性处理可提高涂层柔韧性和附着力,减少涂层色差变化,降低失光率。涂层抗紫外老化性能优于同类传统彩涂板涂料涂层。     

Modeling Volatile Organic Compound Sorption in Activated Carbon. I: Dynamics and Single-Component Equilibrium

Design and development of new sorption technologies for control of volatile organic compound (VOC) laden air discharges from industrial sources require characterization of proposed novel processes and systems. Extensive capital, labor, and time are needed to obtain multicomponent adsorption characteristic data through laboratory experiments. As a substitute for laboratory characterization experiments, this paper presents steps for computationally predicting VOC sorption equilibrium and nonequilibrium processes in activated carbon. The method of predicting sorption equilibrium has been described in detail, since it is critical for modeling even nonequilibrium sorption dynamic processes that are constructed as successions of equilibria steps. An accurate single-component “thermal equation of equilibrium adsorption” (TEEA) is presented by modifying the Dubinin–Astakhov (DA) adsorption isotherm. DA-TEEA is capable of accurately predicting thermodynamics of single-component vapor adsorption in ultra- and supernanoporous adsorbents. The adsorption affinity factor, determined from dispersion interaction theory, enables the DA-TEEA to predict adsorption equilibrium characteristics of VOCs from adsorption equilibrium data of only one similar reference adsorbate.     

壳聚糖希夫碱制备及对Pb^2＋吸附的研究

为了解决污水中铅离子的去除问题,制备了壳聚糖香草醛希夫碱（CTSV）、壳聚糖水杨醛希夫碱（CTSS）,又以戊二醛为交联剂,合成其交联产物CTSV—G、CTSS—G,并对4种壳聚糖希夫碱（CTS—x）进行了红外、X射线衍射和扫描电镜表征。以CTS—X为吸附剂,对比研究了4种物质对Pb^2＋的吸附,其中CTSV—G效果最好,吸附率可达73．88％。对吸附过程的动力学研究表明,吸附过程符合多孔结构的吸附特征,方程拟合结果符合二级反应动力学。     

Field-cycling NMR relaxometry of molecules undergoing Lévy walks at the surface of fine particles and porous glass

Slow surface dynamics of solvents confined in the pore space of porous glass and fineparticles was studied by proton field-cycling relaxometry. Molecular reorientations mediated by translational displacements are shown to be an important low-frequency T1-relaxation mechanism in porous media at low nuclear magnetic resonance (NMR) frequencies in the strong adsorption limit. This is revealed by the pronounced T1-dispersion in this case while a flat one is observed for weak adsorption. The following nanoporous materials were examined in this respect: fineparticles of ZnO,-TiO2, porous glass. Silanized surfaces lead to a somewhat steeper T1-dispersion of non-polar cyclohexane than the native, i.e. polar, surfaces. On the other hand, there is no strong influence of the surface groups on the T1(omega) slope of (polar) acetone. The results are discussed with reorientations mediated by translational displacements enhanced by Lévy walks on the surface.     

Influence of Al_2O_3/CeZrAl composition on the catalytic behavior of Pd/Rh catalyst

Al2O3 and Ce-Zr mixed oxides are important components of the automobile three-way catalyst.Various contents modifying A12O3(GAL) was physically introduced into Ce-Zr-Al mixed oxides(CZA) to form series of GAL/CZA composition.The Pd/Rh catalyst samples were prepared by different GAL/CZA support loading Pd/Rh,then aged at 950 oC for 6 h.The catalytic behavior of different Pd/Rh catalyst samples was studied.Surface area,oxygen storage capacity(OSC) and H2 adsorption capacity(TPR) of fresh and aged samples were...     

从铅阳极泥中富集回收碲的工艺研究与生产实践

叙述了从铅阳极泥中富集回收碲的工艺研究与生产实践,通过工艺改进及设备改造,生产出含碲20%左右的高品位碲渣,其经济效益显著。