硅胶表面上聚酰胺-胺的合成及其对Ag(I)的吸附

用硅烷偶联剂对硅胶表面进行氨基功能化,利用氨基与丙烯酸甲酯发生的Michael加成反应和乙二胺与酯进行的交换反应.在硅胶表面合成了聚酰胺-胺(PAMAM-SG)树状大分子,用红外光谱对PAMAM-SG的结构进行了表征.研究了溶液pH、浓度和吸附温度对PAMAM-SG吸附Ag(I)的影响.结果表明,溶液的最佳吸附pH值范围为4.0～7.0,吸附速率随时间的增加逐渐降低,随温度的升高有一定升高,在30℃时具有较好的吸附性能,吸附量达59.9 mg/g;各代PAMAM-SG的吸附量大小依次为2.0G>1.5G>1.0G>0.5G>0G>-0.5G;吸附容量随浓度的增大而增加,直至平衡.     

Synthesis of polyaniline nanocomposite and its application for chromium removal from aqueous solution

The aim of this research was to investigate the sorption characteristics of polyaniline coated on sawdust (PAn/SD) for the removal of Cr(VI) ions from aqueous solutions. The sorption of Cr(VI) ions was carried out by the batch method. Characterization of PAn/SD was done by FTIR and SEM. The optimum conditions of sorption were found to be a PAn/SD dose of 0.6 g in 100 mL of Cr(VI) solution (50 mg/L), a contact time of 20 min, pH 2, and a temperature of 20°C, Increased temperature had a negative effect on the removal efficiency. Three equations, that is Morris–Weber, Lagergren, and pseudo‐second‐order, were tested to track the kinetics of the removal process. The kinetic data indicated that the adsorption process was described by the Morris–Weber equation. The Langmuir, Freundlich, and Dubinin–Radushkevick models were used with sorption data to estimate sorption capacity, intensity, and energy. The data were fitted with the Freundlich model. The thermodynamic parameters ΔH, ΔS, and ΔG were evaluated. They showed that the adsorption of Cr(VI) onto PAn/SD was feasible, spontaneous, and exothermic under the studied conditions. For desorption of Cr(VI) adsorbed onto PAn/SD, aqueous NaOH was used; with it, 85% of the adsorbed Cr(VI) could be desorbed. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers     

沸石材料的改性及其对水体污染物的吸附性能

吸附法以其选择性强、操作简易、二次污染少等优势逐步成为污水处理的重要方法。天然沸石材料具有孔腔结构丰富、吸附成本低廉以及吸附性能高等优势,但存在选择吸附性差、与水相分离困难、再生成本偏高等问题。通过改性,可以为沸石吸附剂对阴离子污染物的吸附提供更多吸附活性位点。本文基于沸石材料改性制备的国内外最新研究进展,总结了不同改性材料制备复合吸附材料的研究工作,重点介绍了沸石材料改性方法及其应用,进一步回顾了改性沸石材料对水中污染物的吸附性能和影响因素。通过改性提高沸石材料的选择吸附性能及吸附后的绿色再生将是推动沸石吸附材料规模化应用发展的核心。     

Synthesis and characterization of modified ZSM-5 nanozeolite and their applications in adsorption of Acridine Orange dye from aqueous solution

In this research, a novel method was reported for the synthesis of ZSM-5 nanozeolite. The ZSM-5 nanozeolite was modified by transition metals such as nickel, copper and iron. These nanozeolites were characterized using X-ray diffraction, scanning electronic microscopy, Fourier transform infrared and Energy-dispersive X-ray techniques. The synthesized Fe-ZSM-5 nanozeolite has been smaller average particle size than the other nanozeolites. Adsorption behavior of Acridine Orange (AO) onto nanozeolites has been studied in an aqueous medium using UV–VIS technique. The modified nanozeolites have more adsorption efficiency compared to the unmodified ZSM-5 nanozeolite for AO removal. Also, Fe-ZSM-5 nanozeolite was shown higher adsorption efficiency of AO than the other synthesized nanozeolites. Adsorption isotherms were fitted with the Langmuir, Freundlich and D–R models. The kinetic data were investigated using pseudo-first order and pseudo-second order models. The adsorption kinetics of AO on Fe-ZSM-5 nanozeolitewell matched with pseudo-second order kinetic model.     

The adsorption of dyes from aqueous solution using diatomite

Raw diatomite was calcined at 450 °C for dyes removal from aqueous solution. SEM and FTIR analysis show that the raw diatomite contains organic impurities, which are removed after the calcination. The impurities removal decreases the specific surface area and increases the average pore diameter of raw diatomite, while improves its adsorption capability of dyes. The adsorption isotherm and kinetics experiments of methylene blue onto calcined diatomite were then carried out to investigate the adsorption property. It shows that the adsorption capacity of methylene blue is about 50 mg/g. The adsorption isotherm was fitted by the Langmuir, Freundlich and Redlich-Peterson models, which reveals that the Redlich-Peterson isotherm is the best one. Two kinetic models, pseudo-first order and pseudo-second order, were rearranged for expediently investigating the adsortpion mechanisms. Fitting results show that the pseudo-first-order model is better in describing the adsorption process.     

Synthesis of superabsorbent hydrogel and manganese dioxide nanowires composite for adsorption of Pb(II) from aqueous solution

The superabsorbent composite was prepared by aqueous solution polymerization, using manganese dioxide, acrylic acid, acrylic amide, 2‐acrylamide‐2‐methyl‐1‐propanesulfonic acid as raw materials, N,N′‐methylene bisacrylamide as cross‐linker, and K₂S₂O₈ as initiator. The composite was characterized by Fourier transform infrared spectrophotometer, thermogravimetric analysis and scanning electron microscopy analysis. This article also described the adsorption behavior of the superabsorbent composite with respect to Pb(II) removal from aqueous solution. The kinetic studies for Pb(II) adsorption showed that the pseudo‐second‐order adsorption mechanism was predominant. Moreover, adsorption isotherm data were reliably described by the Freundlich model. Regeneration of the adsorbent was attained by 0.1 mol L⁻¹ HCl. POLYM. COMPOS., 36:775–784, 2015. © 2014 Society of Plastics Engineers     

Synthesis,characterization and adsorption studies of h-BN crystal for efficient removal of Cd2+ from aqueous solution

In the present study, hexagonal boron nitride (h-BN) was synthesized from boric acid and melamine by thermal annealing method in a nitrogen atmosphere. The pure h-BN was used as an efficient sorbent for the uptake of Cd²⁺ ions from the solution phase. The kinetics and sorption studies of metal ions onto the h-BN were carried out in batch adsorption experiments at different temperature, time, pH, sorbent dosage, and concentration of metal ions. The optimum pH for the removal of the Cd²⁺ ions was found to be pH 7. The effect of temperature showed that the process of Cd²⁺ sorption remained endothermic in the range of 298 K–328 K. The Lagergren's first and Ho's second kinetic models were tested to interpret the adsorption kinetic data, however the present data was explained well by Ho's model for kinetics. The thermodynamic perameters ΔG, ΔS and ΔH were determined using the available adsorption data at different temperatures. The physicochemical properties of the synthesized product were also characterized before and after adsorption by different analytical techniques like FT-IR, TGA, XRD and Point of Zero Charge (PZC). The morphology of the surface was analyzed with the help of Scanning Electron Microscopy. The h-BN proved to be an efficient adsorbent for the uptake of the Cd²⁺ ions from aqueous media.     

Extracts of phenolic compounds from seeds of three wild grapevines-comparison of their antioxidant activities and the content of phenolic compounds

Phenolic compounds were extracted from three wild grapevine species: Vitis californica, V. riparia and V. amurensis seeds using 80% methanol or 80% acetone. The total content of phenolic compounds was determined utilizing the Folin-Ciocalteu’s phenol reagent while the content of tannins was assayed with the vanillin and BSA precipitation methods. Additionally, the DPPH free radical scavenging activity and the reduction power of the extracts were measured. The RP-HPLC method was applied to identify the phenolic compounds in the extracts, such as phenolic acids and catechins. The seeds contained large amounts of tannins, catechins and gallic acid and observable quantities of p-coumaric acid. The total content of phenolic compounds and tannins was similar in the extracts from V. californica and V. riparia seeds. However, the total content of total phenolic compounds and tannins in the extracts from V. californica and V. riperia seeds were about two-fold higher than that in the extracts from V. amurensis seeds. Extracts from seeds of the American species (V. californica and V. riparia) contained similarly high concentrations of tannins, whereas extracts from seeds of V. amurensis had approximately half that amount of these compounds. The content of catechin and epicatechin was similar in all extracts. The highest DPPH^• anti-radical scavenging activity was observed in the acetonic and methanolic extracts of V. californica and V. riparia seeds— while the acetonic extract from the V. californica seeds was the strongest reducing agent.     

Application of chitosan-coated quartz sand for Congo red adsorption from aqueous solution

The preparation, characterization, and environmental application of chitosan-coated quartz sand for Congo red adsorption have been investigated. The absorbent was characterized by Fourier transform infrared spectrophotometer (FTIR) and scanning electron microscope (SEM). The experiments were carried out in a batch system to optimize operation variables: contact time, Congo red concentration, absorbent dosage, temperature, and pH. The optimum conditions for Congo red adsorption were pH 5, 45°C and contact time of 4 h. An amount of 1 g of chitosan-coated quartz sand could successfully remove 96% of the dye form 50 mg/L Congo red solution. The adsorption kinetics and equilibrium isotherms showed that the sorption processes were better fitted by pseudo-second order equation and Langmuir equation, respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of CuO nanowalnuts and nanoribbons from aqueous solution and their catalytic and electrochemical properties

One dimensional copper hydroxide nanostrands, two dimensional Cu(2)(OH)(3)NO(3) nanoribbons and three dimensional CuO nanowalnuts were synthesized from the same diluted copper nitrate solution with ethanolamine at room temperature and 10 °C, respectively. The Cu(2)(OH)(3)NO(3) nanoribbons were formed by slowly hydrolyzing ethanolamine at low temperature. The CuO nanowalnuts were formed through dehydration of copper hydroxide nanostrands in aqueous solution at room temperature. Although their average size is about 500 nm, the specific surface area of the CuO nanowalnuts can be as large as 61.24 m(2) g(-1), due to their particular morphology with assembling of 8 nm grains. The Cu(2)(OH)(3)NO(3) nanoribbons were converted to CuO porous nanoribbons, keeping the shape. The catalytic performance of the CuO nanowalnuts for CO oxidation is 160 mL h(-1) g(cat)(-1) which is 23 times higher than those of the CuO porous nanoribbons and 40 nm commercial CuO nanoparticles, respectively. The electrochemical properties of the CuO nanowalnuts were also examined in a lithium-ion battery. After 30 cycles, the capacity of the as-prepared CuO nanowalnuts could sustain 67.1% (407 mA h g(-1)) of the second cycle (607 mA h g(-1)) at a rate of 0.1 C.     

Effect of the degree of template removal from mesoporous silicate materials on their adsorption of heavy oil from aqueous solution

The key aim of this study is to evaluate the adsorption of heavy oil from aqueous solutions with different oil contents over mesoporous silicate materials having different surfactant template contents. The mesoporous silicate materials have been synthesized from tetraethylorthosilicate as a silica precursor and cetyltrimethylammonium bromide as a template using the sol-gel technique. Four samples were prepared by (1) totally removing the template using the calcination process, (2) partially removing the template via ethanol extraction, (3) partially removing the template via water extraction, and (4) keeping the template as synthesized, respectively. These four samples have been characterized using X-ray diffraction, nitrogen adsorption, thermal gravimetric analysis and Fourier transformed infrared. The effect of the degree of template removal of these mesoporous materials for the oil removal has been investigated. The oil removal is inversely proportional to the surfactant content in the mesoporous material, being highest for the calcined sample but lowest for the as-synthesized sample. The kinetic of oil adsorption over the calcined material has been also studied and the data obtained fit well a second-order model.     

ACFs吸附溶液中甲基橙的性能研究

利用扫描电子显微镜(SEM)、比表面分析仪和FTIR对活性炭纤维(ACFs)进行表征,并研究了ACFs对溶液中甲基橙的吸附性能。考察了吸附动力学、pH值、吸附温度及甲基橙溶液初始浓度对吸附性能的影响。实验结果表明,平衡吸附时间选取150 min,在溶液为中性条件下,溶液中甲基橙的去除率最高,溶液pH值为6时去除率达到最大值为93.45%;溶液温度为25℃时,ACFs的吸附效果最好;甲基橙的去除率随着甲基橙初始浓度增加而增大。等温吸附数据符合Freundlich吸附等温模型,吸附反应过程符合Langergren准一级动力学方程。     

Surface modified mesoporous silica polymer nanocomposites for adsorption of dyes from aqueous solution

Functionalized mesoporous silica nanocomposites were synthesized via in situ radical polymerization of vinyl monomers (vinylcarbazole, vinyl imidazole and vinyl sulphonic acid) and characterized for adsorption of dyes from aqueous solution. Physicochemical characterization (PXRD, SEM, adsorption studies etc.) of the functionalized nanocomposites showed the presence of mesoporous nature of the nanocomposites. Different adsorption parameters such as adsorption weight, adsorption time, temperature, pH etc., were optimized for adsorption of dyes under environmental friendly conditions. The adsorption studies showed 96.8 and 80.49 % removal for cationic and anionic dyes respectively. Adsorption kinetics of the dyes on the functionalized nanocomposites can be well depicted theoretically by using pseudo-second-order kinetic model.     

Surface modified granular activated carbon for enhancement of nickel adsorption from aqueous solution

Coal-based granular activated carbon was modified with acetates of sodium, potassium and lithium at concentrations of 10 and 15% and used as adsorbents to explore the adsorption mechanism of nickel ion in aqueous solution. Acetate treatment reduced surface area and pore volume of the activated carbons, but the adsorption amount of Ni(II) on the modified activated carbons (MAC) was greater than that on the virgin activated carbon. The adsorption depended on pH of the solution with an optimum at 4.5 and the adsorbed nickel could be fully desorbed by using 0.05M HCl solution. The maximum adsorption capacity of nickel ion on Li (15 wt%) modified activated carbon was 151.3 mg/g and the adsorption isotherm follows Langmuir, Sips, and Redlich-Peterson isotherm models better than the Freundlich isotherm model. The kinetic data was better fitted by a non-linear form of the pseudo-first order than the pseudo-second order, but the difference between two kinetic models was small.     

Improved phenol adsorption from aqueous solution using electrically conducting adsorbents

The electrically conducting and partially porous graphite based adsorbent (called NyexTM 2000) was tested for its adsorption capacity and electrochemical regeneration ability for the removal of phenol from aqueous solution. Nyex? 2000 was tested in comparison with Nyex? 1000, which is currently being used for a number of industrial waste water treatment applications. Nyex? 1000 exhibited small adsorption capacity of 0.1 mg g^?1 for phenol because of having small specific surface area of 1 m² g^?1. In contrast, Nyex? 2000 with specific surface area of 17 m² g^?1 delivered an adsorption capacity of 0.8 mg g^?1, which was eight-fold higher than that of Nyex? 1000. Nyex? 2000 was successfully electrochemically regenerated by passing a current of 0.5 A, charge passed of 31 C g^?1 for a treatment time of 45 minutes. These electrochemical parameters were comparable to Nyex? 1000 for which a current of 0.5 A, charge passed of 5 C g^?1 for a treatment time of 20 minutes were applied for complete oxidation of adsorbed phenol. The comparatively high charge density was found to be required for Nyex? 2000, which is justified with its higher adsorption capacity. The FTIR results validated the mineralization of adsorbed phenol into CO₂ and H₂O except the formation of few by-products, which were in traces when compared with the concentration of phenol removed from aqueous solution. The electrical energy as required for electrochemical oxidation of phenol adsorbed onto Nyex? 1000 & 2000 was found to be 214 and 196 J mg^?1, respectively. The comparatively low energy requirement for electrochemical oxidation using Nyex? 2000 is consistent with its higher bed electrical conductivity, which is twice that of Nyex? 1000.     

酶法提取藤茶茎中二氢杨梅素工艺研究

采用酶法提取藤茶废弃物茎中的二氢杨梅素,考察温度、pH、酶添加量和料液质量体积比对二氢杨梅素提取率和纯度的影响。结果表明,最佳提取工艺条件为:温度45℃,pH为4.46,酶添加量2.0%,料液质量体积比1∶20(g/mL)。在此条件下,二氢杨梅素提取率30.65%,纯度23.4%。优于常规热提法,与醇提相比,提取率提高10%左右,纯度没有提高。     

Cu Al-LDHs/生物质炭的制备及对水中磷的去除

采用水热法制备铜铝层状双金属氢氧化物,负载在剑麻生物质炭上,得到CuAl-LDHs/生物质炭,通过SEM、BET、XRD和FTIR等对结构进行表征,考察了初始pH值、投加量、吸附时间和温度等对吸附除磷的影响,并讨论了吸附动力学与等温吸附特性。结果表明,制备的材料结晶度高、粒径小,平均孔径为4.37 nm;吸附动力学和吸附等温线分别符合准二级动力学方程和Langmuir吸附等温方程。在pH为8.0,温度25℃时,对磷的最大吸附容量可达78.56 mg/g。     

提升生物质焦液相吸附容量的焦改性方法研究进展

生物质焦是生物质热化学转化过程中的副产品,是一种潜在的物理吸附剂,能够用作水处理吸附多种污染物。通过不同的改性方式,能够改变生物质焦的物理结构和化学特性,从而改变其对污染物的吸附脱除能力。本文在详细分析液相溶液吸附影响因素的基础上,总结了针对不同种类污染物,提升其吸附容量的有效生物质焦改性方法,包含热处理、添加试剂扩孔、超声波处理以及化学修饰和生物辅助等手段,并认为除孔隙特性外,生物质焦表面含氧官能团的化学特性同样对吸附起重要作用,如酸处理可增加焦表面酸性含氧官能团,并因阳离子交换作用而利于吸附金属离子;碱处理的焦表面因离域π电子密度提高,色散力增强,从而有利于吸附脱除酚酞、染料等有机污染物;而负载原子和化合物的焦能同时提升其对有机和金属污染物的脱除能力。此外,发现微生物作用下的生物吸附有助于脱除难降解的苯酚。该文为提升生物质焦吸附容量的改性方法选择提供了有效思路。     

Synthesis of porous carbon nanomaterials and their application in tetracycline removal from aqueous solutions

The low-cost and efficient elimination of tetracycline from wastewater and to decrease the concentration in soils, sediments, rivers, underground water, or lakes are crucial to human health. Herein, threedimensional porous carbon nanomaterials were synthesized using glucose and NH₄Cl by sugarblowing process at 900℃ and then oxidized under air atmosphere for surface functional group modification. The prepared 3D porous carbon nanomaterials were applied for the removal of tetracycline f...