Synthesis and Application of Hydride Silica Composites for Rapid and Facile Removal of Aqueous Mercury

The adsorption of ionic mercury(II) from aqueous solution on functionalized hydride silicon materials was investigated. The adsorbents were prepared by modification of mesoporous silica C‐120 with triethoxysilane or by converting alkoxysilane into siloxanes by reaction with acetic acid. Mercury adsorption isotherms at 20 °C are reported, and maximum mercury loadings were determined by Langmuir fitting. Adsorbents exhibited efficient and rapid removal of ionic mercury from aqueous solution, with a maximum mercury loading of approximately 0.22 and 0.43 mmol of Hg g^?1 of silica C‐120 and polyhedral oligomeric silsesquioxane (POSS) xerogel, respectively. Adsorption efficiency remained almost constant from pH 2.7 to 7. These inexpensive adsorbents exhibiting rapid assembly, low pH sensitivity, and high reactivity and capacity, are potential candidates as effective materials for mercury decontamination in natural waters and industrial effluents.     

铁基纳米材料功能化及对水中汞离子的去除

在水体重金属污染中,汞污染问题日益严峻,已成为全球性环境问题之一。近年来,纳米FeS_x、Fe₃O₄、Fe等铁基材料凭借优越的吸附性能以及比表面积优势,受到研究者的广泛关注。对铁基纳米材料进行稳定化、官能团改性之后可以增强纳米粒子的分散度,为汞离子提供更多的吸附点位,进一步加强对水中汞离子的去除效果。本文重点阐述了纳米FeS_x的稳定化、Fe₃O₄等铁基材料的巯基化（-SH）、氨基化（-NH₂）等功能化改性方法及对Hg的去除;总结了功能化铁基纳米材料对水中Hg的去除效果和影响因素;探究了功能化铁基纳米材料去除水中汞的机理;最后展望了铁基功能化纳米材料处理水体汞离子的发展方向。     

Thermal Behaviour of Silica Waste from a Geothermal Power Station and Derived Silica Ceramics

The silica waste originating from a geothermal power plant in Mexico was investigated with the aim of finding its applicability as a raw secondary material for ceramics production. The thermal behaviour of the original silica waste (containing NaCl and KCl from marine brine) and of the purified silica was characterized by means of DTA/TG, emanation thermal analysis (ETA) and thermodilatometry (TD). The reactivity of the purified silica waste mixed with CaCO₃ (1.8 mass%) was characterized by means of ETA, DTA and TG. The microstructures and phase compositions of the final products prepared by heating in air were tested by means of X-ray diffraction and of scanning electron microscopy coupled with electron probe X-ray microanalysis. The thermal analysis methods allowed determination of the optimal conditions for thermal treatment of the silica waste in order to obtain partly sintered porous materials for use as refractory bricks. This revised version was published online in August 2006 with corrections to the Cover Date.     

Biomass Novel Adsorbents for Phenol and Mercury Removal

This paper reports the use of activated carbons made from novel agriculture and industrial wastes, namely sunflower, vine shoots, and coffee endocarp, to remove two high-priority contaminants: phenol and mercury species (under different forms) from aqueous solutions. The activated carbons were used as prepared and also modified with nitric acid and triethylenediamine in order to explore additional adsorption mechanisms. The results showed an interesting potential of the materials to be used for water decontamination as indicated by the mercury uptake up to 1104 mg/g for Hg²⁺, 771 mg/g for [HgCl₄]²⁻, 966 mg/g for HgCl₂ and the maximum phenol adsorption capacity of 190 mg/g. The modification with triethylenediamine led to a significant increase in the phenol and mercury adsorption reaching an increment of 85% for phenol and 250% for Hg²⁺.     

壳聚糖及其复合物对水中汞离子的脱除

由于汞的物理化学性质和对人体的毒副作用,汞减排已成为全球共识。当前除汞方法中,吸附法为一种较有潜力的方法。壳聚糖是一种天然的汞离子（Hg²⁺）吸附剂,以物理、化学手段改性后的衍生物更具有对环境中的汞吸附容量大,吸附效率高的优点。本文综述了壳聚糖及其衍生物脱除溶液中Hg²⁺的研究近况,介绍了壳聚糖物理（冷冻干燥、静电纺丝等）、化学修饰手段（交联和接枝等）以及与新型碳材料（碳纳米管、氧化石墨烯等）复合脱汞的最新研究,分析了壳聚糖及其复合物对水中Hg²⁺的去除效果和影响因素。最后,对壳聚糖吸附剂在汞污染治理中的研究作了展望。     

疏水多孔硅制备及其对水中有机污染物的吸附

以硅酸钠为硅源,盐酸为催化剂,三甲基氯硅烷(TMCS)为表面改性剂,经溶胶-凝胶和表面改性过程制备出一种疏水性多孔硅材料.采用傅里叶变换红外(FTIR)光谱仪、接触角分析仪、氮气物理吸附仪和扫描电子显微镜(SEM)对其结构和性质进行表征.结果表明:所制备的多孔硅具有分等级孔道结构(中孔-大孔),比表面积为566m2·g-1,孔体积高达2.28cm3·g-1,多孔硅与水的接触角为156°,显示出超疏水特征.对甲苯、汽油、柴油和润滑油的吸附量均可高达自身质量的14倍,丰富的孔道使其在几分钟内即可达到饱和吸附.这种多孔硅在汽油/水混合体系中对汽油具有较高的选择性,同时具有良好的再生能力.经正己烷萃取再生后,多孔硅仍能基本保持初始吸附容量.此方法制备的多孔硅材料在吸附分离污水中的有机物和溢油处理方面具有很好的应用前景.     

Stoeber二氧化硅溶胶中氨水的去除方法

通过pH值、电导率和二氧化硅解离量的测定，研究了Stfber二氧化硅溶胶的提纯过程．发现离心水洗很难完全去除体系中的氨水并且残留的氨水会影响二氧化硅粒子的化学稳定性．对二氧化硅溶胶进行酸处理后再提纯，可以大大加速提纯过程并消除氨水对二氧化硅粒子化学稳定性的影响。     

Removal of Zinc Ions by Sol-Gel Silica Doped with Cibacron Blue

Chemically doped sol-gel silica has been developed by entrapping organic dye cibacron blue as a complexing reagent in porous silica prepared by the sol-gel method for removal of metal ions from water samples. In the doped sol-gel silica, the large reagent molecules are entrapped inside the pores while small metal ions can diffuse into the pores where they are complexed by the reagent and retained inside the pores. This new solid sorbent was tested for removal of Zn(II) from aqueous solutions. The kinetics, isotherm, and pH effect of the removal were investigated. With a loading of 0.10 mmol cibacron blue/g, the sol-gel silica sorbent had a capacity of 0.09 mmol Zn/g. It was demonstrated that the sol-gel silica sorbent could be regenerated and reused repeatedly.     

A Luminescent Hypercrosslinked Conjugated Microporous Polymer for Efficient Removal and Detection of Mercury Ions

A hypercrosslinked conjugated microporous polymer (HCMP‐1) with a robustly efficient absorption and highly specific sensitivity to mercury ions (Hg²⁺) is synthesized in a one‐step Friedel–Crafts alkylation of cost‐effective 2,4,6‐trichloro‐1,3,5‐triazine and dibenzofuran in 1,2‐dichloroethane. HCMP‐1 has a moderate Brunauer–Emmett–Teller specific surface (432 m² g⁻¹), but it displays a high adsorption affinity (604 mg g⁻¹) and excellent trace efficiency for Hg²⁺. The π–π* electronic transition among the aromatic heterocyclic rings endows HCMP‐1 a strong fluorescent property and the fluorescence is obviously weakened after Hg²⁺ uptake, which makes the hypercrosslinked conjugated microporous polymer a promising fluorescent probe for Hg²⁺ detection, owning a super‐high sensitivity (detection limit 5 × 10⁻⁸ mol L⁻¹).

     

立方介孔相含钕氧化硅的合成与表征

以十六烷基三甲基溴化铵为结构导向剂，通过水热法合成了具有立方结构的含钕Nd-MCM-48介孔分子筛材料。XRD和TEM测试表明当n_Nd/n_Si<0.05时可以获得典型的长程有序介孔立方结构相，随n_Nd/n_Si比的增加，晶胞参数的增大和红外吸收光谱(FT-IR)的变化为Nd进入介孔分子筛骨架中提供了有力证据。N₂吸附-脱附实验给出了其BET表面积为1 195 m²·g^-1，BJH平均孔径为3.6 nm。紫外-可见漫反射光谱(UV-Vis)证明钕氧形成一种八面体结构。X射线光电子能谱(XPS)进一步证明钕主要以三价形式存在于立方介孔分子筛骨架中。     

表面改性纳米SiO2复合聚合物电解质的制备及性能

通过化学方法将具有增塑效果的环状碳酸酯基团引入纳米SiO2表面,并用FTIR与TGA对改性纳米SiO2进行了表征.将改性纳米SiO2添加到以聚氧化乙烯(PEO)为基体的聚合物电解质中,制备了复合聚合物电解质.通过DSC和交流阻抗等方法对该聚合物电解质膜的热力学和电化学性能进行了研究.结果表明,掺杂改性纳米SiO2的聚合物电解质具有更高的离子电导率,室温最高离子电导率可达到1.84×10-5 S/cm;具有较高的锂离子迁移数,最高可达到0.49,且具有更好的界面稳定性.     

A Study on the Structure and Behavior of Sinter-free Material for Phosphorous Removal from Waste Water

Oyster shell and cement were taken as the major raw materials to fabricate hollow, tubular and recoverable material for phosphorous removal (P removal) from waste water without sintering. In this paper, the effects of different affecting factors on the sample P removal ratio were discussed to select optimal P removal process conditions. SEM and XRD were used to characterize the microscopic structures and composition of samples, and molybdenum blue spectrophotometry was applied to determine the P content in waste water. Results showed that at 30 ℃ for 2 d, the P removal ratio reached 93.3% when the cement content was 10 wt% and oyster shell powder was 90 wt%. SEM analysis revealed a flaky structure consisting of phosphorus-containing compound in the samples after P removal, and it piled on and maintained the porous structure. In addition, the results also suggested that raising the ambient temperature was benefit to the P removal. The P removal ratio of the material was optimal under neutral and alkali conditions.     

Role of Ceria in the Design of Composite Materials for Elemental Mercury Removal

The necessity to drastically act against mercury pollution has been emphatically addressed by the United Nations. Coal‐fired power plants contribute a great deal to the anthropogenic emissions; therefore, numerous sorbents/catalysts have been developed to remove elemental mercury (Hg⁰) from flue gases. Among them, ceria (CeO₂) has attracted significant interest, due to its reversible Ce³⁺/Ce⁴⁺ redox pair, surface‐bound defects and acid‐base properties. The removal efficiency of Hg⁰ vapor depends among others, on the flue gas composition and temperature. CeO₂ can be incorporated into known materials in such a way that the abatement process can be effective at different operating conditions. Hence, the scope of this account is to discuss the role of CeO₂ as a promoter, active phase and support in the design of composite Hg⁰ sorbents/catalysts. The elucidation of each of these roles would allow the integration of CeO₂ advantageous characteristics to such degree, that tailor‐made environmental solution to complex issues can be provided within a broader application scope. Besides, it would offer invaluable input to theoretical calculations that could enable the materials screening and engineering at a low cost and with high accuracy.     

Stber二氧化硅溶胶中氨水的去除方法

通过pH值、电导率和二氧化硅解离量的测定,研究了St ber二氧化硅溶胶的提纯过程.发现离心水洗很难完全去除体系中的氨水并且残留的氨水会影响二氧化硅粒子的化学稳定性.对二氧化硅溶胶进行酸处理后再提纯,可以大大加速提纯过程并消除氨水对二氧化硅粒子化学稳定性的影响.     

氧化硅-石墨烯气凝胶介孔复合材料的合成及其对苯的吸附性能

采用水热法快速合成了一种新型介孔氧化硅-石墨烯气凝胶复合吸附材料(MSGA)。通过X射线衍射、扫描电镜等方法对MSGA进行表征。结果表明,经过水热反应和冻干处理后的MSGA材料的介孔结构保持完好,介孔氧化硅在MSGA中的分散具有高度均一性。当介孔氧化硅的含量达到88.2(wt)%时,MSGA的比表面积可达395.5m~2/g。MSGA材料对苯蒸汽的常温常压吸附量为10.77mL/g,是石墨烯气凝胶的13倍,吸附穿透时间达到石墨烯气凝胶的34.4倍。在0.8%的环境湿度下,由于材料表面羟基的亲和性,进一步提升了对苯的吸附。得益于超低密度和丰富的内部孔隙结构,MSGA能够适应高达500mL/min的气流量。上述结果表明,该复合材料在VOCs消除领域具有广阔的应用前景。     

Synthesis,Characterization and Applications of Immobilized Iminodiacetic Acid-Modified Silica

Porous immobilized iminodiacetic acid modified silica of the general formula S—(CH₂)₃—N(CH₂COOH)₂, (where S represents [Si—O] _n siloxane network) has been prepared by replacement of the iodide in 3-iodopropyl modified silica with diethyliminodiacetate. The immobilized-diethyliminodiacetate ligand system (S-DIDA) was then hydrolyzed by hydrochloric acid to produce the immobilized iminodiacetic acid ligand system (S-IDA). The iodo functionalized modified silica (S-I) was prepared by polycondensation of Si(OEt)₄ and (MeO)₃Si(CH₂)₃I. The XPS and CP/MAS ¹³C NMR spectra showed that not all iodine atoms are replaced and that the hydrolysis of ethyl acetate groups are incomplete upon treatment with HCl. The immobilized iminodiacetic acid ligand system exhibits high potential for the uptake of various di- and trivalent metal ions such as (Mn²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺). Complexation of the iminodiacetate ligand system for the metal ions at the optimum conditions was found in the order: Cu²⁺ > Fe³⁺ > Ni²⁺ > Co²⁺ > Mn²⁺ > Zn²⁺. Stability studies of the iminodiacetate ligand system showed that a degradation of the siloxane network and leaching of some species occurred upon treatment with strong acid and base aqueous solutions.     

Study of Removal of Cationic Dye from Waste Aqua Using Chromatographic Grade Silica as Adsorbent

The adsorption of cationic dye, Basic Red 13 from aqueous solution onto silica has been studied. The time growth adsorption as a function of the amount of adsorbent, pH, initial dye concentration as well as the temperature was measured of the system. Adsorption was found to follow a first-order process. Various isotherm and thermodynamic parameters for the adsorption of dye have been calculated. Isotherms were used to identify formation of either monolayer or multilayer formation whereas thermodynamic and other parameter indicated that the dye adsorption process was physisoption as well as spontaneous and exothermic in nature.     

三维规则排列的大孔SiO2材料的制备及表征

 以聚苯乙烯微球离心后形成的三维规则排列的胶晶作模板，以正\r\n硅酸乙酯、水、乙醇和盐酸等配制的溶胶填充微球间的间隙，然后原位\r\n形成凝胶，最后通过焙烧除去微球得到三维规则排列大孔二氧化硅材料\r\n．以苯乙烯为原料，过硫酸钾为引发剂，在70℃下搅拌28h后得到含聚\r\n苯乙烯微球（直径约为600nm）的母液．将母液在900～1000r／min的转\r\n速下离心12～24h得到紧密堆积排列的胶晶．以正硅酸乙酯作为硅源，\r\n按n（Si（OEt）4）∶n（EtOH）∶n（HCl）∶n（H2O）＝1∶3．9∶0．\r\n3∶1．8制成透明的SiO2溶胶．溶胶浓度控制在0．5～1．0mol／L．滴\r\n加在胶晶上的溶胶靠毛细管的作用力填充入微球间隙．重复填充多次（\r\n一般不超过5次）．焙烧在流量为1L／min的空气中进行，升温速度控制\r\n在5℃／min以下．在300℃下恒温5h以除去聚苯乙烯微球，在570℃下焙\r\n烧5h．焙烧后的样品表面可观察到五颜六色的彩光．SEM分析结果表明\r\n，球形孔（孔径约500nm）大小均匀，排列整齐，保持了微球的紧密堆\r\n积排列结构．孔与孔之间由小孔窗相互交连，孔壁比较充实，壁厚约为\r\n130nm．     

Boron Removal from Aqueous Solutions by Adsorption on Waste Sepiolite and Activated Waste Sepiolite Using Full Factorial Design

In the present paper, boron removal from aqueous solution by adsorption was investigated and 2³ full factorial design was applied. Non activated waste sepiolite (NAWS) and HCl activated waste sepiolite (AWS) were used as adsorbents. Regression equation formulated for boron adsorption was represented as a function of response variables. The results obtained from the study on parameters showed that as pH increased and temperature decreased boron removal by adsorption increased. Adsorbed boron amount on AWS was higher than that of NAWS. Maximum boron removal was obtained at pH 10 and 20°C for both adsorbents. Adsorption data obtained from batch adsorption experiments carried out with NAWS and AWS fitted to the Langmuir equation. The batch adsorption capacities were found in mg/g: 96.15 and 178.57 for NAWS and AWS, respectively. The capacity value for column study was obtained by graphical integration as 219.01 mg/g for AWS. The Thomas and the Yoon-Nelson models were applied to experimental data to predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design.