沸石的改性工艺及其吸附除磷特性研究

研究了组合改性沸石的最佳制备方法,以及不同改性方式和pH对改性沸石除磷效果的影响。通过吸附动力学与吸附等温线探究其吸附机理并使用扫描电镜对改性前后的沸石进行表征。结果表明,最佳的改性方案为2.0 mol/L NaOH溶液和2.0 mol/L聚合氯化铝(PAC)溶液组合改性。当废水pH=7时该改性沸石除磷效果最佳,此时除磷率为98.74%,其吸附符合准二级动力学方程和Langmuir模型。扫描电镜表征结果表明,碱改性和铝改性均可改变沸石的孔隙结构,增加吸附点位。     

沸石去除废水中磷的研究进展

沸石作为一种大储量的矿物,对废水中的各种污染物有很强的吸附作用,被广泛应用于污水处理中。文章介绍了天然及改性沸石去除水中磷的研究现状和进展,对沸石的除磷机理进行了归纳总结,对今后的应用前景进行了展望。     

沸石分子筛的磷改性方法研究及应用

沸石在工业上得到广泛的应用 ,主要是由于这类矿物晶体具有很开旷的硅氧格架 ,在晶体内部形成许多孔径均匀的孔道和内表面很大的孔穴 ,从而具有独特的吸附 ,筛分 ,阳离子交换和催化性能。对于沸石改性的研究和应用的报道很多。“改性沸石”包括的范围很广 ,从简单的离子交换到结构完全崩塌的材料都属于改性范围。改性沸石包括三大类 :一是结构改性 ,即改变沸石的SiO2 /M2 O2 (M =AL或Fe、B、Ca等 ) ,从而达到改变沸石酸性的目的 ,水热脱AL是这类改性沸石的典型方法 ;二是沸石晶体改性 ,如加入不能进入沸石孔道的大分子金属有机化合物达…     

磷改性分子筛的研究进展

综述了国内外采用磷化合物改性沸石分子筛（ZSM-5、Y、β和MCM-41等）的研究进展,重点介绍了改性后沸石分子筛的结构、催化活性,水热稳定性和表面酸性以及其催化反应等方面的变化,同时对磷改性沸石分子筛的应用前景进行了展望。     

疏水性沸石分子筛的特性及表面改性研究

介绍了疏水性沸石分子筛的疏水机理、吸附特性和表面改性技术 ,探讨了这一技术用于二氧化碳控制技术的发展前景     

改性吸附材料选择性吸附除磷研究进展

受污染水体中富含磷酸盐、硫酸盐、硝酸盐、碳酸盐等多种污染物。如何排除其他阴离子干扰,从水体中靶向性吸附磷酸盐成为了高效除磷技术的研究热点。文中综述了选择性吸附除磷的作用机制以及改性吸附材料选择除磷的研究进展,为水体高效除磷提供借鉴。     

改性沸石/聚合氯化铝造粒复合材料对水中氨氮和磷的吸附性能研究

以改性沸石（MZ）和聚合氯化铝（PAC）为原料,添加粘结剂聚乙烯醇（PVA）和造孔剂碳酸氢钠（NaHCO3）,制备出可同步脱氮除磷的复合颗粒材料（MZP）,并探究了投加量和pH等因素对氨氮和磷吸附性能的影响。结果表明,在MZP投加量为7 g/L,pH为6～8条件下,MZP对氨氮和磷的去除率均高于84%。MZP对氨氮和磷的吸附符合Freundlich吸附等温线模型,且吸附过程受液膜扩散和颗粒内扩散共同控制,符合准二级动力学模型,吸附过程MZP对氨氮和磷的最大理论吸附量分别为5.92、2.25 mg/g。共存离子对MZP吸附氨氮和磷有一定影响。经过5次吸附-解吸再生循环利用后,MZP仍能保持74%的氨氮去除率和52.6%的磷去除率。结合材料表征分析结果,MZP对氨氮的吸附主要为离子交换,对磷的吸附主要为静电吸附和配体交换。     

CTAB改性沸石对刚果红的吸附

为有效去除水溶液中的刚果红染料,采用阳离子表面活性剂十六烷基三甲基澳化铵（CRAB）对沸石进行改性。刚果红在改性沸石上的吸附量远远大于未改性沸石的吸附量。考察了吸附时间、溶液pH值、离子强度等因素对改性沸石吸附效果的影响。通过对吸附等温线进行分析,沸石对刚果红的吸附很好的符合Lansmuir吸附模型。     

松香改性阳离子表面活性剂的合成

普通松香通过丙烯酸改性,与氯化亚砜、甲醛、吡啶合成新型吡啶双季铵盐阳离子表面活性剂。确定了反应的最佳工艺条件:n(丙烯酸改性松香)∶n(甲醛)∶n(吡啶)=1∶3∶4,m(催化剂)∶m(反应物料)=0.04∶1,反应温度75～85℃,反应时间8h。用红外光谱对目标产物进行了分析,测定了目标产物的表面性质。结果表明,目标产物吡啶双季铵盐阳离子表面活性剂具有良好的表面活性,并与阴离子表面活性剂有很好的相容性。     

改性除磷絮凝剂的研究进展

絮凝剂是化学除磷的关键性物质,而传统的除磷絮凝剂或单一的絮凝剂在去除废水中的磷时具有絮凝剂用量大、价格高、效率不够高、有毒等缺点,絮凝剂的改性是解决上述除磷絮凝剂的手段。文中概述了两大类除磷絮凝剂的改性方法,分别是物理化学改性和复合絮凝剂,并且分别对两类方法的研究进展进行了总结。最后,对未来改性除磷絮凝剂的发展做出了展望。     

Effect of Cationic Surfactant on the Adsorption of Arsenites onto Akaganeite Nanocrystals

Abstract

The current research focuses on removal of arsenite ions from aqueous solutions by a new adsorbent, surfactant modified akaganeite (Ak_m), prepared after the adsorption of the cationic surfactant, hexadecyl trimethyl ammonium bromide (N‐Cetyl‐N,N,N‐Trimethylammonium Bromide) onto akaganeite. The new adsorbent was investigated with Fourier transform infrared spectra and X‐ray photoelectron spectroscopy methods for a better understanding of the effects of surface properties on arsenite adsorption. Surfactant modified akaganeite was found to be an effective adsorbent for the removal of arsenite ions from aqueous systems. It presented a significantly higher arsenite adsorption capacity than the pure nanocrystalline akaganeite. Kinetics of adsorption obeys a second‐order rate equation. The maximum adsorption capacity was found to 328.3 mg g^?1 over a wide pH range significantly higher than those of other adsorbents reported.     

Highly Efficient Adsorption of Anionic Dyes from Aqueous Solutions Using Sawdust Modified by Cationic Surfactant of Cetyltrimethylammonium Bromide

In the present study, the adsorption behavior of Congo Red (CR) dye from aqueous systems onto sawdust modified by cetyltrimethylammonium bromide, CH₃(CH₂)₁₅N(CH₃)₃Br (CTAB) was attempted. Adsorption experiments were carried out using both batch and column modes under various operating conditions. The effects of some important parameters such as solution pH, adsorbent dosage, initial dye concentration and contact time were investigated. Treatment of the equilibrium data obtained in batch experiments was carried out using Langmuir and Freundlich isotherm equations. Based on the isotherm analysis, it was found that the adsorption of CR dye onto SD fits well to the Langmuir model and the adsorption pattern on CTAB modified sawdust (CTAB/SD) followed the Freundlich isotherm which is indicative of heterogeneity of the adsorption sites on the surfactant-modified sawdust. The maximum adsorption capacity of SD and CTAB/SD were found to be 5.2 and 9.1?mg?g^?1, respectively, according to the Langmuir model. However, much higher differences in sorption capacities were observed for CTAB/SD and SD in the column system (66.73?mg?g^?1). In order to find out the possibility of the exhausted column for frequent use, a regeneration study was also carried out. It was found that the dye uploaded column can be easily regenerated with a high performance using ethanol as the washing solution.     

改性沸石制备及对其铬吸附特性的研究

为了解决天然沸石对废水中重金属吸附能力低的问题,制备出了六种改性沸石并考察了改性沸石对六价铬离子的吸附特性。在这六种改性沸石中,H2 SO4/CuSO4复合改性沸石对铬的吸附性能最佳,其对铬的吸附曲线符合Freundlich方程;其吸附强度是天然沸石的8倍;其吸附动力学曲线符合二级动力学模型,实测值十分接近理论值,这也证明在其对六价铬离子的吸附过程中离子交换起着十分重要的作用。     

Preparation of Modified Reduced Graphene Oxide nanosheet with Cationic Surfactant and its Dye Adsorption Ability from Colored Wastewater

In this paper, reduced graphene oxide (rGO) nanosheet from graphite was synthesized using the top-down approach. The surface of rGO was modified by cetyltrimethylammonium bromide (CTAB) to prepare rGO/CTAB adsorbent for anionic dye removal. The prepared rGO/CTAB was characterized by XRD, FTIR, FE-SEM and TGA. The operation parameters (surfactant concentration, adsorbent dosage, pH and initial concentration of dye solution) affecting the batch adsorption process to remove direct red 80 (DR80) and direct red 23 (DR23) were studied in detail. The dye adsorption capacity of rGO/CTAB was 213 and 79 mg/g for DR80 and DR23, respectively. In addition, dye removal followed the Langmuir isotherm with pseudo-second order reaction kinetics.     

二聚阳离子表面活性剂改性蒙脱土的制备和表征

合成了二聚阳离子表面活性剂GeminiC12,用核磁共振氢谱(1HNMR)表征了它的结构,并用它作为有机插层剂应用于蒙脱土的改性处理。红外光谱(FTIR)、热重分析(TGA)表明,GeminiC12已插层到蒙脱土片层间。X射线粉末衍射(XRD)表明,插层后蒙脱土层间距从1 19nm增加到3 8nm,是十六烷基三甲基溴化铵(CTAB)处理效果的两倍。沉降实验表明,改性后蒙脱土在苯乙烯和石蜡中形成凝胶体系,表现出很好的相容性和分散性,这种改性效果优于目前常用的CTAB处理效果,更有利于聚合物或其单体进入蒙脱土层间形成纳米复合材料。     

改性阳离子水性聚氨酯研究进展

重点介绍了改性阳离子水性聚氨酯的合成方法,总结了改性阳离子水性聚氨酯的研究现状,包括无机纳米材料改性、丙烯酸类树脂改性、有机硅改性、植物油改性、环氧树脂改性.简述了改性阳离子水性聚氨酯在织物整理剂、胶粘剂等方面的应用现状,展望了阳离子水性聚氨酯的发展方向.     

沸石研究的新进展

综述了近年来新型结构沸石的合成、研究和应用的新进展。     

改性纤维素材料对金属离子吸附研究进展

纤维素在地球上含量十分丰富,且表面含有大量的羟基,可以通过羟基一系列的衍生反应,对纤维素进行改性,将纤维素制成离子型的吸附剂。本文就纤维素改性,综述了近些年来国内外以纤维素为原料改性制得的吸附剂相关的研究进展。