聚醚砜氨基化氧化石墨烯杂化膜的制备及其在吸附铜的研究

以聚醚砜(PES)为原料,以氯甲基乙醚为氯甲基化试剂,3-氨丙基三甲氧基硅烷为氨基化剂,制备了氨基化氧化石墨烯杂化膜,用于铜离子的吸附。考察了吸附时间、原液浓度、pH值和吸附温度对膜吸附量的影响,并研究了膜的重复吸附性能。结果表明:随着吸附时间的延长、氧化石墨烯含量的增加、原液浓度的上升以及pH值的增加,膜的吸附量逐渐增加。在吸附温度低于35℃时,膜的吸附量较高,吸附温度超过35℃,膜的吸附量有所下降。经过3次吸附脱附后,膜的吸附量仍然可以达到54 mg/g以上,表明该膜具有良好的使用性能。     

聚乙烯吡啶钯接枝聚醚砜膜催化还原对硝基苯酚

以聚醚砜(PES)为原料、氯甲基乙醚为氯甲基化试剂,制备了氯甲基化聚醚砜膜,该膜经碱处理后,采用乙烯基三甲氧基硅烷进行改性,得到聚4-乙烯吡啶接枝聚醚砜膜。再将该接枝膜与氯化钯反应,制成聚乙烯吡啶钯接枝膜。将该膜应用于对硝基苯酚的催化还原反应,考察了催化膜用量、反应温度对对硝基苯酚还原反应的影响,并研究了催化膜的重复使用性能。结果表明:增加催化膜用量以及提高反应温度均能使对硝基苯酚的还原反应速率加快。     

碳纳米管/聚醚砜复合纳滤膜的制备及性能研究

以聚醚砜(PES)为膜材料,羧基化多壁碳纳米管(MWCNT)为添加剂,通过相转化法制备碳纳米管/聚醚砜复合纳滤膜,并将其用于染料的去除和花青素的浓缩。考察了不同操作压力、染料浓度和溶液pH条件下膜对染料分离性能的影响。通过改变花青素溶液的温度和pH找到合适的浓缩条件。纯水通量和水接触角测试结果表明,羧基化多壁碳纳米管提高了膜的亲水性,当碳纳米管质量分数为0. 04%时,膜的分离性能最佳。     

水处理用聚醚砜膜的亲水改性方法研究进展

聚醚砜（PES）膜是一类综合性能优良的高分子聚合物膜材料,在水处理方面有着广泛的应用。然而由于本身的疏水亲油性,使PES膜在水中容易受到污染,造成膜渗透性能下降、使用寿命缩短。为增强其抗污染性能,可以对其进行亲水改性。本文介绍了3种常见的亲水改性方法,分别为表面涂覆改性法、表面接枝改性法和共混改性法。其中,共混改性法因改性效果显著、简单方便等,在水处理方面的应用最具优势。希望此文为聚醚砜膜的进一步改性研究提供参考。     

薄膜扩散梯度系数的研究

薄膜扩散梯度技术是一种新型的原位采集并测量重金属有效态或生物可给性的方法。本实验研究的是不同pH对同种聚醚砜膜的扩散系数的影响以及重复使用次数对同一种聚醚砜膜扩散系数的影响。不同pH对膜扩散系数影响的研究可以看出这种聚醚砜膜的使用范围在pH=2~9,在强碱性条件下会严重影响膜的性能。同一张聚醚砜膜不同实验次数的研究说明此种聚醚砜膜的合理使用次数为1次,重复使用会影响它的扩散性能。     

氯化银/聚醚砜复合膜原位合成及对溴离子的吸附研究

制备了用于吸附水中溴离子的复合材料,即将一定质量的硝酸银加入聚醚砜中制成铸膜液,利用原位合成法制备了氯化银/聚醚砜复合膜。通过比表面积测定（BET）、扫描电镜分析（SEM）、X射线粉末衍射分析（XRD）及拉伸性能测试等对复合膜的结构进行了表征及分析研究。通过静态吸附实验探究了氯化银添加量、吸附时间、吸附温度、溶液初始pH等对复合膜吸附去除水中溴离子的影响。通过实验得到复合膜吸附溴离子的优化条件：氯化银与聚醚砜的质量比为0.10、吸附时间为7 h、吸附温度为25 ℃、溶液初始pH为9。在25 ℃条件下溴离子在复合膜上的吸附过程符合Langmuir线性吸附等温模型和准二级动力学模型,当氯化银与聚醚砜的质量比为0.10时,制备的复合膜对溴离子的最大理论吸附量为83.31 mg/g。     

马来酸酐改性聚乙烯醇对水体中Pb2+的吸附行为

通过羟基的酯化反应并采用浓硫酸进行碳化处理,制备了马来酸酐改性聚乙烯醇,通过FTIR对其化学结构进行了表征,并研究了改性聚乙烯醇对水体中Pb^2+的吸附行为及重复使用性能。研究结果表明,改性后的聚乙烯醇表面基团结构发生了变化,成功引入了大量的—COOH;另外,其结构上呈现出大量的孔洞结构和更大的比表面积,使其与金属离子具有更多吸附位点和更强的络合能力。静态吸附结果表明,在吸附时间为60 min、pH为5.0、改性聚乙烯醇用量为0.10 g的条件下,改性聚乙烯醇对Pb^2+的饱和吸附量为287.3 mg/g,符合Langmuir等温吸附模型。通过吸附-脱附实验发现,马来酸酐改性聚乙烯醇吸附Pb2+时,具有良好的重复使用性能。     

氧化还原引发接枝—填充聚合制备pH响应型分离膜

由全反射红外光谱和场发射电子显微镜证实,利用氧化还原可成功地引发甲基丙烯酸在酚酞型聚醚砜膜表面的接枝聚合.继而,接枝膜在不同pH下的水通量测定实验表明.该接枝膜膜孔径的变化具有着显著、快速、可逆的pH响应性.     

氧化石墨烯材料在污水处理中的应用研究进展

氧化石墨烯材料具有巨大的比表面积、良好的亲水性和优异的吸附性能,在污水处理方面具有广阔的应用前景。综述了氧化石墨烯在污水处理方面的研究进展,重点分析了氧化石墨烯材料对污水中有机物、重金属和染料的吸附机理和吸附效果;氧化石墨烯作为吸附材料时其效果和成本都优于普通吸附材料;着重阐述了氧化石墨烯对水体污染物吸附性能的影响因素,如初始pH、氧化石墨烯投加量、污染物初始浓度、溶液温度等。总结了氧化石墨烯应用于污水处理时的适宜环境和条件,为未来氧化石墨烯在污水处理方面的应用提供一些思路。     

亚氨基二乙酸螯合膜的制备及对铜离子的吸附性能研究

在低密度聚乙烯薄膜上接枝亚氨基二乙酸制备氨基羧酸型吸附材料(LDPE-g-IDA)。用衰减全反射红外光谱(ATR-FTIR)表征了结构,并探讨了室温下其对Cu2+的吸附性能。结果表明:该膜材对Cu2+具有很强的吸附能力,其饱和吸附量为99.20mg/g;在pH值2～6范围内,平衡吸附量随pH值的升高而增大,其平衡吸附过程可用Langmuir模型描述,为单分子层吸附,且属于优惠吸附过程;吸附动力学符合Lagergren准一级动力学模型,反应速率受Cu2+扩散步骤的控制;吸附平衡后的膜材在0.1mol/L的HNO3溶液中120s的解吸附效率接近90%,表明该膜材具有很强的再生能力,可以循环使用。     

Radiation synthesis of graphene oxide/composite hydrogels and their ability for potential dye adsorption from wastewater

A high yield of graphene oxide (GO) was chemically synthesized from graphite powder utilizing adjusted Hummer's method. The contents of acidic functional groups in GO were determined using potentiometric titration. Composite hydrogels dependent on graphene oxide/poly(2-acrylamido-2-methylpropanesulfonic acid)/polyvinyl alcohol (GO/PAMPS/PVA) were synthesized utilizing a ⁶⁰Co gamma irradiation source at different doses. The synthesized graphene oxide and composite hydrogels were portrayed via X-ray diffraction, thermogravimetric analysis, and Fourier transform infrared analysis. The morphology of composite hydrogels was characterized by scanning electron microscope. The gel % and swelling % for the prepared hydrogel demonstrated that the swelling % of hydrogel increased with raising AMPS content. Whereas the increment of GO and increasing the irradiation dose lead to a reduction in the swelling %. The influences of pH, GO percentage, initial dye concentration, the adsorbent dosage, contact time, and temperature on the adsorption of basic blue 3 dye were evaluated and the adsorption capacity was 194.6 mg/g at optimum conditions; pH = 6, GO/PAMPS/PVA composite hydrogels with 5 wt% of GO, initial dye concentration = 200 mg/L, adsorbent dose = 0.1 g, solution volume = 50 mL after 360 min at room temperature (25°C). The adsorption of dye onto the GO/PAMPS/PVA composite hydrogels follows Pseudo-second-order adsorption kinetics, fits the Freundlich adsorption isotherm model.     

Enhanced removal of nickel(II) ions from aqueous solutions by SDS-functionalized graphene oxide

In this paper, a one-pot and easy-to-handle method at room temperature without additional chemicals for the modification of graphene oxide (GO) with surfactant is found. Removal of nickel (II) ions from aqueous solutions by GO and surfactant (sodium dodecyl sulphate) modified graphene oxide (SDS-GO) was studied spectrophotometrically at room temperature as a function of time, initial concentration and pH. Adsorption capacity of the adsorbent was increased dramatically (from 20.19 to 55.16 mg/g found by Langmuir model) due to the functionalization of the surface by SDS. The driving force of the adsorption of Ni(II) ions is electrostatic attraction and Ni(II) ions adsorbed on the GO surface chemically besides ion exchange.     

超声辅助合成磁性四氧化三铁/氧化石墨烯复合物及其在染料去除中的应用（英文）

A simple ultrasound-assisted co-precipitation method was developed to prepare ferroferric oxide/graphene oxide magnetic nanoparticles (Fe3O4/GO MNPs). The hysteresis loop of Fe3O4/GO MNPs demonstrated that the sample was typical of superparamagnetic material. The samples were characterized by transmission electron microscope, and it is found that the particles are of small size. The Fe3O4/GO MNPs were further used as an adsorbent to remove Rhodamine B. The effects of initial pH of the solution, the dosage of adsorbent, temperature, contact time and the presence of interfering dyes on adsorption performance were investigated as well. The adsorption equilibrium and kinetics data were fitted well with the Freundlich isotherm and the pseudo-second-order kinetic model respectively. The adsorption process followed intra-particle diffusion model with more than one process affecting the adsorption of Rhodamine B. And the adsorption process was endothermic in nature. Furthermore, the magnetic composite with a high adsorption capacity of Rhodamine B could be effectively and simply separated using an external magnetic field. And the used particles could be regenerated and recycled easily. The magnetic composite could find potential applications for the removal of dye pollutants.     

Synthesis of graphene oxide decorated with strontium oxide (SrO/GO) as an efficient nanocomposite for removal of hazardous ammonia from wastewater

ABSTRACT

In this research, graphene oxide decorated with strontium oxide (SrO/GO) is introduced as a new adsorbent material for the efficient removal of ammonia from industrial wastewater. The new adsorbent was thoroughly studied in terms of morphology, crystallography and chemical composition using characterization techniques such as Fourier transform infrared (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and zeta potential analysis. Several parameters such as pH, adsorbent dosage, contact time, and ammonia initial concentration were investigated and optimized. Ammonia adsorption onto SrO/GO was validated with kinetics and adsorption isotherms by adopting different models. The results revealed that ammonia adsorption kinetic was of pseudo-second order (R² = 0.999) implying that chemisorption behavior and the equilibrium isotherm follows Langmuir model. This behavior shows a high maximum monolayer sorption capacity of 90.1 mg g^?1 at pH equal to 7 and contact time of 120 min pointing out the synergism advantageous effect. The abundant oxygen functional groups on the graphene oxide surface and the integrated Sr-O nanoparticles could efficiently interact with ammonia species creating a surface for more favorable and efficient removal of ammonia.     

Facile fabrication of graphene oxide-polyethylenimine composite and its application for the Cr(VI) removal

A binary composite consisting of graphene oxide (GO) and polyethylenimine (PEI) was fabricated by a facile physical mixing. Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM), thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Zeta potential were used to characterize the prepared graphene oxide-polyethylenimine composite (GOPC). A series of experiments were carried out to investigate the effects of some important parameters, such as molecular weight of PEI, pH, time and temperature, on the adsorption efficiency of GOPC. Due to the high amine density of GOPC, its adsorption for Cr(VI) occurred more easily at lower pH mainly via electrostatic interaction. The adsorption process matched well with the Langmuir isotherm model and the pseudo-second-order kinetic model. The maximum adsorption capacity from the Langmuir model was 370.37 mg/g at pH 2.0 and 45°C for GOPC. Thermodynamic parameters revealed spontaneous and endothermic nature of the Cr(VI) adsorption onto GOPC. The main adsorption mechanism of GOPC toward Cr(VI) was electrostatic interaction. The adsorption-desorption experiments suggested GOPC was easily recycled and its stable adsorption capacity endowed it great potential as an adsorbent of Cr(VI) from wastewater.     

Application of graphene-based adsorbents in the treatment of dye-contaminated wastewater; kinetic and isotherm studies

The adsorption of methylene blue (MB) on graphene-based adsorbents was tested through the batch experimental method. Two types of graphene-based adsorbents as graphene oxide (GO) and reduced graphene oxide (RGO) were compared to investigate the best adsorbent for MB removal. So that optimizing the MB removal for the selected type of graphene-based adsorbent, the diverse experimental factors, as pH (2–10), contact time (0–1440 min), adsorbent dosage (0.5–2 g/L), and initial MB concentration (25–400 mg/L) were analyzed. The conclusions indicated that the MB removal rised with an increase in the initial concentration of the MB and so rises in the amount of adsorbent used and initial pH. Maximum dye removal was calculated as 99.11% at optimal conditions after 240 min. Adsorption data were compiled by the Langmuir isotherm (R²: 0.999) and pseudo-second-order kinetic models (R²: 0.999). The Langmuir isotherm model accepted that the homogeneous surface of the GO adsorbent covering with a single layer. And the adsorption energy was calculated as 9.38 kJ mol⁻¹ according to the D-R model indicating the chemical adsorption occurred. The results show that GO could be utilized for the treatment of dye-contaminated aqueous solutions effectively.     

Adsorption behavior of crystal violet from aqueous solutions with chitosan–graphite oxide modified polyurethane as an adsorbent

A series of chitosan (Ch)–graphite oxide (GO)‐modified polyurethane foam (PUF) materials as adsorbents were synthesized by a foaming technique. The adsorbent was characterized through IR spectroscopy, scanning electron microscopy, and thermogravimetric analysis (TGA). Batch adsorption experiments of the cationic dye crystal violet (CV) were carried out as a function of the Ch–GO content (1.0–8.0 wt %), solution pH (2–10), dye concentration (100–300 mg/L), adsorbent dosage (10–60 mg/mL), and temperature (20–45°C). At a lower pH value, the surface of Ch–GO/PUF acquired positive charge by absorbing H⁺ ions; this resulted in a decreasing adsorption of the cationic CV dye because of electrostatic repulsion. As the pH of the aqueous system increased, the numbers of negatively charged sites increased by absorbing OH⁻ ions, and a significantly high electrostatic attraction existed between the negatively charged surface of Ch–GO/PUF and the cationic dye (CV) molecules. This led to maximum dye adsorption. The kinetics, thermodynamics, and equilibrium of CV adsorption onto Ch–GO/PUF were investigated. The equilibrium data for CV adsorption fit the Langmuir equation, with a maximum adsorption capacity of 64.935 mg/g. The adsorption kinetics process followed the pseudo‐second‐order kinetics model. Thermodynamic parameters analysis revealed that the adsorption of CV from an aqueous solution by a Ch–GO modified PUF material was a spontaneous and endothermic process. We concluded that Ch–GO/PUF is a promising adsorbent for the removal of CV from aqueous solutions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41828.     

聚丙烯酸/氧化石墨烯复合水凝胶制备及对亚甲基蓝吸附

以丙烯酸(AA)为原料,二丙烯酸酯(Pul DA)分散的氧化石墨烯(GO)纳米胶粒(GO-Pul DA)为增强剂,N,N'-亚甲基双丙烯酰胺(BIS)为交联剂,通过自由基共聚合制备了一系列结构均一的聚丙烯酸/氧化石墨烯复合水凝胶(PAA/GO-Pul DA)。考察了BIS质量浓度、GO质量浓度以及溶液pH值对复合水凝胶力学性能、吸水性和亚甲基蓝(MB)吸附量的影响。结果表明,当GO质量浓度从0.1 g/L增加至1.0 g/L时,复合水凝胶拉伸强度从5.0 k Pa增加至10.4 k Pa,断裂伸长率高于100%,当GO的质量浓度为0.3 g/L时,复合水凝胶的断裂伸长率最高为151%;复合水凝胶表现出pH敏感的高吸湿性,pH从3.0增加至6.8时,平衡溶胀比(SRe)变化可达386 g/g,pH=6.8时最大SRe高达490 g/g。当溶液pH值从3.0增加至11.0时,PAA/GO-Pul D对MB的平衡吸附量(qe)可增加1 400~1 500 mg/g,pH=11.0时最大的qe高达1 789 mg/g。复合水凝胶对MB的吸附行为符合准一级动力学模型。5次吸附-解吸附循环后,相对于首次吸附,PAA/GO-Pul D对MB的吸附能力仍保持高达60%,解吸附效率高于90%。     

Defluoridation of Water by Graphene Oxide Supported Needle-Like Complex Adsorbents

The dicarboxylic acids like oxalic acid, malonic acid and succinic acid mediated graphene oxide–zirconium needle like complexes were synthesized and used to remove fluoride from simulated fluoride contaminated water. The adsorption of fluoride by dicarboxylic acids mediated graphene oxide–zirconium complexes were by both electrostatic interaction at acidic pH and ion-exchange mechanism at neutral pH. The maximum defluoridation capacity observed was 9.70 mg/g at the minimum contact time of 18 min at room temperature. Various batch equilibrium parameters like pH studies, contact time, common ion interference and temperature studies were optimized. The synthesized graphene oxide and graphene oxide supported complexes were characterized using UV–vis, FTIR, XRD and SEM with EDAX analysis to establish the mechanism of fluoride adsorption. The removal of fluoride was described by the pseudo-second-order reaction kinetics, Freundlich isotherm model and thermodynamic studies which indicates the nature of adsorption was endothermic and spontaneous. Regeneration studies depict that the dicarboxylic acid mediated graphene oxide–zirconium complex can be used as an effective adsorbent for the removal of fluoride ions from wastewater. Also, the field applicability of the material has been verified with field samples collected from nearby fluoride endemic villages.