膨润土深加工制备P型沸石

以廉价的膨润土为原料,分别进行了氢氧化钠水溶液高温活化和氢氧化钠碱熔活化制备P型沸石的实验,合成了两种结构不同的P型沸石,并对合成产品作了表征和物化性能测试.结果表明:碱法工艺具有资源利用率高,无废液排放等优点.合成的P型沸石性能比4A沸石优越,是理想的洗涤助剂替代品.     

Adsorption of humic acid onto pillared bentonite

Pillared bentonite, a clean and cost-effective adsorbent with high specific areas of 111.3 m²/g and high basalspacing of 1.98 nm, was prepared for the removal of humic acid from water. It is effective for the removal of humic acid with a high adsorption capacity of 537 mg/g, and adsorption is favored under acid conditions. Adsorption is dependent on ionic strength and dissolved NaCl enhanced adsorption. Over 97% removal was observed under natural pH conditions from humic acid solutions containing 10 mg/L Ca²⁺ or Mg²⁺, which suggests that pillared bentonite can be an effective adsorbent for the removal of humic acid for drinking water purification. Pillared bentonite can be regenerated with NaOH, and the regeneration efficiency reaches 83% and 85% when the concentration of NaOH reaches 0.025 and 0.05 mol/L. The mechanism for adsorption of humic acid to pillared bentonite is discussed.     

改性膨润土对废水中染料的吸附

简述了膨润土的基本结构,概括了膨润土的主要改性方法,即活化改性法和添加改性剂改性法;分析了改性方法的主要优点,总结了改性膨润土对废水中染料的吸附效果.结果表明,改性膨润土对染料的吸附效果较好,染料去除率最大可达99.7％.另外,探讨了改性膨润土的吸附机理、影响因素和吸附等温式,并展望了改性膨润土的应用前景.     

Adsorption behaviour of Cu and Cd onto natural bentonite

The adsorption behaviour of Cu²⁺ and Cd²⁺ onto bentonite was studied as a function of temperature under optimized conditions of amount of adsorbent, particle size, pH, concentration of metals, and shaking time. The adsorption patterns of metal ions onto followed the Langmuir, Freundlich and Dubinin-Radushkevich isotherms. This included adsorption isotherms of single-metal solutions at 298-333 K by batch experiments. The thermodynamic parameters such as variation of enthalpy ΔH, variation of entropy ΔS and variation of Gibbs free energy ΔG were calculated from the slope and intercept of lnK_o vs. 1 / T plots. The adsorptions were endothermic reactions. The results suggested that natural bentonite was suitable as sorbent material for the recovery and adsorption of metal ions from aqueous solutions.     

膨润土碱熔活化水热合成NaP沸石分子筛

为利用膨润土合成NaP沸石分子筛,研究了膨润土的成分,该膨润土的主要成分为蒙脱石和石英。采用向膨润土中加碱在850 ℃碱熔1 h的方法,活化了膨润土中的蒙脱石和石英,获得了高活性的原料。采用水热合成的方法,通过正交实验,确定了合成NaP沸石分子筛的优化条件：二氧化硅与三氧化二铝物质的量比为5、氧化钠与二氧化硅物质的量比为1.6、水与氧化钠物质的量比为50、50 ℃老化2 h、95 ℃晶化9 h。X射线衍射和扫描电镜分析结果表明,所得产物为纯净的NaP沸石分子筛,平均粒径为1 μm,干沸石的钙离子交换量（以碳酸钙计）为315 mg/g。     

Adsorption of phosphates using transition metals-modified bentonite clay

ABSTRACT

Phosphorus is a micronutrient but when it exists in abundance, it can have detrimental environmental impact. Bentonite (Bent) modified with Fe, Co and Ni salts were synthesized and evaluated for adsorption of phosphate ions from water. Results indicated that metal-modified bentonite have lower crystallinity compared to the native bentonite. Batch adsorption experiments showed maximum adsorption capacities of 20.88, 46.95, 29.07 and 6.57 mg/g for Fe-Bent, Co-Bent, Ni-Bent and Bent, respectively. The pseudo-second-order kinetic model provided a better fit for all adsorbents. The competition effect of coexisting anions were not significant for Fe and Ni modified bentonite.     

四乙烯五胺接枝膨润土对酸性大红GR的吸附性能

在膨润土（Bent）表面接枝四乙烯五胺（TEPA）制备四乙烯五胺改性膨润土（TEPA/Bent）,利用FTIR（红外光谱仪）、XRD（X射线衍射仪）、EA（元素分析）、SEM（扫描电镜）和EDS（能谱仪）对其进行表征分析,并考察对水体中阴离子染料酸性大红GR的吸附性能。结果表明：TEPA成功接枝于膨润土表面,提高了膨润土对酸性大红GR的吸附量;pH对TEPA/Bent表面电位和吸附量影响较大;随着初始pH的增大,TEPA/Bent的zeta电位由正变为负,对酸性大红GR吸附量减少;在pH=3,染料初始质量浓度为100mg/L条件下,TEPA/Bent对酸性大红GR的吸附量可达44.63mg/g;TEPA/Bent对酸性大红GR的吸附动力学符合准二级动力学模型;吸附等温线符合Langmuir吸附等温模型,为单分子层吸附;吸附热力学表明该吸附为自发吸热过程。吸附剂经过5次再生后,吸附量仍保持为初始80%以上。研究表明,TEPA/Bent是从水溶液中去除阴离子染料的潜在有效吸附剂。     

有机磁性膨润土对环丙沙星和四环素的吸附性能

为了提高磁性膨润土（magnetic bentonite,MB）的磁分离性能,达到高效去除抗生素的目的,本文采用羧甲基纤维素（sodium carboxymethyl cellulose,CMC）和壳聚糖（chitosan,CS）相互作用所生成的有机共聚膜（chitosan/sodium carboxymethyl cellulose copolymer film,CC）对MB进行联合修饰,制得双有机修饰的有机磁性膨润土（magnetic bentonite/carboxymethyl cellulose-chitosen composite,MB-CC）,同时进行了MB-CC对环丙沙星（ciprofloxacin,CIP）和四环素（tetracyclines,TC）的吸附性能研究。表征结果表明,磁性Fe₃O₄纳米粒子和有机共聚膜CC成功地固定在MB上;经过CC改性,提高了Fe₃O₄的稳定性和对CIP及TC的去除性能。吸附结果表明,在pH为5、温度为25℃的条件下,MB-CC对CIP和TC的吸附容量（182mg/g和189mg/g）高于MB对CIP和TC的吸附容量（147mg/g和136mg/g）。经过5次循环,MB-CC对CIP和TC的去除率仍然保持在90%以上。与Freundlich模型相比较而言,CIP和TC在MB和MB-CC上的吸附行为更加符合Langmuir模型;吸附过程可由准二级动力学模型描述,说明吸附速率主要由化学吸附控制。MB-CC对CIP和TC的吸附机理主要包括孔扩散、阳离子交换和静电吸引作用。综上所述,MB-CC具有合成简单、高效等优点,是一种很有前途的抗生素废水去除方法。     

改性膨润土对苯胺与苯酚混合液的吸附性能

研究酸活化膨润土和有机改性膨润土对苯胺和苯酚混合溶液的吸附性能,结果表明,酸活化膨润土对苯胺的吸附效果明显优于苯酚,具有较强的吸附选择性;有机膨润土对苯胺和苯酚的吸附无明显差别。吸附动力学研究表明,酸活化膨润土与有机改性膨润土对苯胺的吸附均符合准二级吸附动力学模型,相关系数分别为R²=0.999 8和R²=0.997 9。酸活化膨润土对苯胺的吸附符合Freundlich等温线模型,有机膨润土对苯胺的吸附数据对Freundlich等温线模型与Langmuir等温线模型均有较好的拟合。     

酸改性膨润土对［BMIM］Cl离子液体的吸附

利用酸改性膨润土对低浓度［BMIM］Cl离子液体水溶液的吸附性能进行研究;考察了吸附温度、吸附时间、溶液pH值等吸附条件对离子液体的吸附率的影响。结果表明;酸改性膨润土对［BMIM］Cl的阳离子具有良好的吸附作用。在中性溶液中;酸改性膨润土对离子液体具有最大的吸附率。酸改性膨润土对离子液体的吸附过程是放热过程且属于Langmuir等温吸附;同时;得到膨润土上离子液体吸附的Langmuir等温方程且相关系数大于0.99。     

碱金属离子在树脂上的动态吸附行为

选取4种Na型树脂（D001、D113、Ls-1000、Ls-5000）为吸附剂,通过动态吸附法研究其对碱金属混合溶液的动态吸附行为,重点考察了其中铷、铯的分离性能,并考察了溶液pH、溶液组成、流速及树脂类型等对分离性能的影响。研究发现,中性条件下对铷、铯的吸附量顺序为离子交换树脂>螯合树脂。强酸性树脂D001对碱金属离子的亲和顺序为Cs+>Rb+>K+>Li+,其余3种树脂均为Cs+相似文献   

Aqueous Phase Adsorption of Cephalexin onto Bentonite and Activated Carbon

The adsorption of cephalexin in aqueous solution has been investigated using bentonite and activated carbon as the adsorbents. Batch kinetics and isotherm studies were carried out to evaluate the effect of contact time, adsorbent dosage, pH, particle size, and temperature. Adsorption equilibrium data were well represented by the Langmuir and Freundlich isotherm models. The adsorption intensity was found to be increased as the aqueous phase pH increased, and had a maximum at pH = 6.1. The pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models were used to describe the kinetic data. The experimental data fitted very well with the pseudo-second-order kinetic model and also followed the simple external and intraparticle model.     

改性膨润土对废水中Cd(II)的吸附特征及吸附动力学研究

为探讨改性膨润土对Cd(II)的吸附特征及吸附动力学机制,通过吸附实验探讨了pH值、初始浓度和吸附时间对改性膨润土吸附Cd(II)的影响。结果表明,盐酸改性膨润土对Cd(II)的去除率表现为随溶液pH值升高而升高,而氢氧化钠改性膨润土、膨润土与十二烷基磺酸钠改性膨润土的去除率分别在pH=6和7时达到最大值。膨润土及改性膨润土对Cd(II)的去除率随初始浓度的增加而降低,吸附量随平衡浓度增加而增大,并趋向平稳,吸附符合Langmuir方程,吸附为单分子层吸附。膨润土及改性膨润土的吸附反应在240 min内基本达到平衡,吸附动力学分析表明吸附过程更符合准二级动力学模型,吸附过程以化学吸附为主,膨润土及改性膨润土的吸附速率大小依次为K2HCl-B＞K2NaOH-B＞K2B＞K2SDS-B,液膜扩散与颗粒内扩散过程均为控速步骤。该研究可为改性膨润土处理含镉废水和修复镉污染土壤提供参考。     

Adsorption of cadmium and zinc from aqueous solution on natural and activated bentonite

The adsorption of cadmium and zinc ions on natural bentonite heat-treated at 110°C or at 200°C and on bentonite acid-treated with H₂SO₄ (concentrations: 0·5 mol dm^?3 and 2·5 mol dm^?3), from aqueous solution at 30°C has been studied. The adsorption isotherms corresponding to cadmium and zinc may be classified respectively as H and L types of the Giles classification which suggests the samples have respectively a high and a medium affinity for cadmium and zinc ions. The experimental data points have been fitted to the Langmuir equation in order to calcualte the adsorption capacities (X_m) and the apparent equilibrium constants (K_a) of the samples; X_m and K_a values range respectively for 4·11 mg g^?1 and 1·90 dm³ g^?1 for the sample acid-treated with 2·5 mol dm^?3 H₂SO₄ [(B)-A(2·5)] up to 16·50 mg g^?1 and 30·67 dm³ g^?1 for the natural sample heat-treated at 200°C [B-N-200], for the adsorption process of cadmium, and from 2·39 mg g^?1 and 0·07 dm³ g^?1, also for B-A(2·5), up to 4·54 mg g^?1 and 0·45 dm³ g^?1 [B-N-200], for the adsorption process of zinc. X_m and K_a values for the heat-treated natural samples were higher than those corresponding to the acid-treated ones. The removal efficiency (R) has also been calculated for every sample; R values ranging respectively from 65·9% and 8·2% [B-A(2·5)] up to 100% and 19·9% [B-N-200], for adsorption of cadmium and zinc.     

聚乙烯亚胺改性磁性膨润土对Pb2 和Cu2 的吸附性能

在磁性膨润土(MBent)表面接枝聚乙烯亚胺(PEI)制备了聚乙烯亚胺改性磁性膨润土(PEI/KH560/MBent),采用FTIR、VSM、XRD、TGA、EA、SEM和EDS对其进行了表征,考察了其对水溶液中Pb2+和Cu2+的吸附性能.结果表明,聚乙烯亚胺已成功接枝于磁性膨润土表面,并有效提高了其对Pb2+和Cu2+的吸附量;溶液初始pH对吸附量影响较大,随着pH的增大,吸附量增加.在pH=5,溶液初始质量浓度为300 mg/L,PEI/KH560/MBent对Pb2+和Cu2+吸附量分别为96.21和61.08 mg/g;吸附过程符合准二级动力学模型,吸附行为符合Langmuir吸附等温模型.热力学研究表明,吸附为自发吸热过程.经过5次循环利用后,其吸附容量仍保持初始的60％以上,表明PEI/KH560/MBent具有一定的重复利用性.     

Adsorption of lead and copper on bentonite and grapeseed activated carbon in single- and binary-ion systems

In this study, bentonite originating from Turkey (Eski?ehir province) and activated carbon obtained from grapeseed were used as adsorbents for the removal of lead (Pb²⁺) and copper (Cu²⁺) ions from aqueous solutions. Experiments were performed in single- and binary-ion systems at constant temperature of 298 K and pH value of 5. In order to describe the adsorption mechanism Langmuir, Freundlich and Temkin isotherms were used. The total adsorption capacity values of adsorbents were compared. It was observed that the total adsorption capacity values were changed depending on the type of adsorbent used, type of metal ion and interaction between metal ions.     

膨润土吸附水中Cr(Ⅵ)的实验研究

研究了钠化膨润土对Cr6 的吸附行为,考察了溶液中Cr6 的初始质量浓度、吸附剂用量、pH、搅拌时间、温度、粒度等因素对膨润土吸附的影响.结果表明,钠化膨润土对于Cr6 的吸附在1h基本达到吸附平衡,吸附量随溶液pH的增大、温度的升高、膨润土粒度的增加以及溶液中Cr6 的初始质量浓度的增高而降低.在混合体系中,共存离子的存在影响金属离子的吸附效率,共存离子的质量浓度与Cr6 相近时,对Cr6 的吸附效果影响很大,其中,Zn2 的影响大于Pb2 ;共存离子的质量浓度远大于Cr6 时,Zn2 基本没有影响,Pb2 却能提高对Cr6 的吸附效率.     

膨润土对核素的吸附行为研究

介绍了内蒙古高庙子膨润土的EDXRF分析,得到了内蒙古高庙子膨润土的元素构成,并论述了近几年膨润土对核素的吸附行为研究,主要影响因素包括:pH值、吸附时间、温度、离子强度、无机离子、腐殖酸等。并对每种影响因素对不同核素的影响效果进行了总结。     

膨润土合成有机膨润土的研究

本文以辽宁抚顺膨润土为原料,对有机膨润土的合成进行了研究,并对所得产品进行了XRD、SEM、IR和DAT／TG等表征。