多形貌聚醚砜纤维毡吸附双酚A的特性

以四氢呋喃和N,N–二甲基甲酰胺作溶剂,将一定浓度的聚醚砜(PES)通过静电纺丝获得具有串珠结构的纳米纤维毡,并且发现通过提高制备过程中空气相对湿度可进一步获得形貌均一且无串珠结构的纳米纤维。采用比表面积与孔隙度分析仪,扫描电镜与水接触角测量仪等对PES纤维毡的形貌和物理特性进行了系统表征。在相对湿度(RH)为0.20 g/mL时获得串珠状PES纳米纤维,其具有不同的珠长径比。当RH值增加到60%时,获得均匀的无珠子纳米纤维毡。此外,在此条件下,随着PES浓度的增加,纤维的平均直径,比表面积和累积孔容均逐渐增加。通过紫外分光光度计测定了不同PES纤维毡样品对双酚A(BPA)的吸附量及吸附速率,发现具有更大比表面积和更好亲水性能的PES纳米纤维毡能够吸附更多的BPA,在RH=60%时,PES浓度为0.22 g/mL的比表面积为31.33 m^2/g,水接触角为108°,对BPA的吸附量可达8.28 mg/g,且吸附过程均符合准二级动力学模型。     

疏水性MCM-41介孔分子筛对水溶液中双酚A的吸附研究

双酚A(BPA)作为一种环境内分泌干扰物严重威胁到人类的身体健康.吸附法作为一种有效的方法广泛应用于BPA的去除研究中.分别以十六烷基三甲基溴化铵(CTAB)作为模板剂常温一步合成的未煅烧介孔分子筛(MCM-41-dry)和通过煅烧去除模板剂的介孔分子筛(MCM-41-cal)作为吸附剂吸附水溶液中的BPA.结果表明,MCM-41-dry的吸附效果远高于MCM-41-cal,这归因于含有表面模板剂的MCM-41-dry具有较强的疏水性.同时发现当3 ＜pH＜10时,MCM-41-dry的吸附效果没有发生明显的改变,说明该材料在较大的pH范围内能保持稳定的吸附效能,但是当pH＞ 10时,吸附容量迅速下降.BPA在MCM-41-dry上的吸附过程符合Langmuir吸附模型,25℃时的最大吸附容量高达405 mg·g-1.     

静电喷雾法制备聚醚砜多孔微球孔隙率的控制研究

采用静电喷雾法制备了聚醚砜(PES)多孔微球,通过加入亲水性聚合物聚乙烯醇(PEG)和聚乙二醇(PVA)来调控PES多孔微球的孔隙率,利用扫描电子显微镜和热失重法分析仪表征了PES多孔微球的形貌和孔隙率。结果表明,加入亲水性聚合物PEG和PVA均能显著提高PES多孔微球的孔隙率,且随着其添加量的增多,孔隙率呈先增大后减小的趋势;PVA对PES多孔微球孔隙率的调控效果优于PEG,当PVA添加量为3%(质量分数,下同)时,PES多孔微球孔隙率达到最高值91.35%。     

PVA/PES/MWNT杂化膜制备与性能研究

采用溶液相转化法制备了聚乙烯醇/聚醚砜(PVA/PES)非对称膜。将碳纳米管(MWNT)引入共混体系,制备了PVA/PES/MWNT杂化膜。通过SEM、溶胀吸附性能测试、力学性能测试等手段对膜进行了结构表征和性能测试。结果表明,当凝固浴为异丙醇时,PVA/PES膜的断面结构由近似指状孔结构向海绵孔过度,随着PVA含量的增加,膜溶胀度逐渐下降。加入碳纳米管后,PVA/PES/MWNT杂化膜的结构中出现了一定的"通道",膜的溶胀度和渗透通量有很大增加,但断裂强度有所降低。     

Sol-gel法制备多孔氧化铝及其对甲醛的吸附研究

采用溶胶凝胶法制备出多孔活性氧化铝,采用XRD、热分析等表征手段进行分析,并且研究了造孔剂添加量对氧化铝吸附性能的影响.用静态吸附法研究了不同工艺方法制备的氧化铝对于甲醛的吸附性能,并与高锰酸钾处理的氧化铝进行了比较,结果表明实验制得的活性氧化铝对甲醛吸附性能较好,添加20%造孔剂制备的多孔氧化铝的吸附性能最好.聚乙烯醇(PVA)作为造孔剂能够起到提高多孔活性氧化铝的吸附性能的作用.     

聚乙烯醇基多孔复合材料研究进展

综述了聚乙烯醇（PVA）基多孔复合材料成型方法中乳液模板法、超临界二氧化碳法、静电纺丝法、冷冻干燥法、致孔法和相分离法等对孔结构及性能的影响。重点介绍了PVA基多孔复合材料在吸附领域的应用,详细阐述了其用于油水分离、无机盐吸附及染料吸附等方面的研究工作及最新进展,展望了通过交联改性赋予其功能化的发展趋势。     

木质素改性多孔酚醛树脂微球的制备研究

本文以苯酚和甲醛为反应单体,采用聚乙烯醇(PVA1788)作分散剂,三乙胺(TEA)作碱催化剂,六次甲基四胺(HMTA)作交联剂,利用水相悬浮缩聚法制备了球形酚醛树脂。在稳定悬浮缩聚体系引入致孔剂,制备多孔的酚醛树脂微球,并对木质素部分替代苯酚制备多孔酚醛树脂微球进行初步探讨。通过实验确定了水相悬浮缩聚法制备酚醛树脂珠体基本合成工艺:先将苯酚、甲醛、三乙胺加入到一定浓度的PVA水溶液,在95～97℃反应40 min后,加入HMTA,继续反应4 h,再用1 mol/L的盐酸溶液调节pH值至2,固化反应1 h,可得到形态规整的珠体;并发现PVA浓度对酚醛树脂珠体粒度影响很大,粒度分布较宽。甲苯致孔得到多孔球形酚醛树脂微球,粒径分布较无致孔剂时窄,孔径在2μ以上;甲苯用量5 g,PVA浓度为0.375%时,得到的粒径在20～80目间的粒子数量达90%;提高甲苯量能增大多孔球形酚醛树脂微球比表面积,但加宽粒径分布;且高甲苯添加量时,PVA浓度对缩聚产物形态影响非常显著,低PVA浓度下易结块,高PVA浓度下得细粉(粒径小于200目)。邻苯二甲酸二丁酯致孔得到外表面光滑内表面多孔的酚醛树脂中空微球,粒径分布也窄,粒径在20～80目间粒子数量占80%以上。木质素替代苯酚制备多孔球形酚醛树脂,木质素能参与反应成球,但球形度稍差,孔径也更小。     

单分散大粒径介孔二氧化硅微球的制备及表征

以正硅酸四乙酯(TEOS)为硅源、N,N-二甲基甲酰胺(DMF)为乳化致孔剂,采用酸催化法得到部分缩合的聚硅酸乙酯(PES),再经碱进一步催化得到介孔二氧化硅微球。分析了酸催化剂用量、旋蒸温度对PES粘度及聚合程度的影响以及PES粘度对二氧化硅微球粒径的影响,并研究了氨水用量、乳化致孔剂种类、乳化致孔剂用量以及搅拌速度和后处理方式对二氧化硅微球性质的影响。利用扫描电子显微镜、旋转粘度计、氮吹吸附仪、傅里叶变换红外光谱仪等对所得微球进行表征。结果表明,所制备的介孔二氧化硅微球球形完整,粒径分布均匀,纯度高,微球平均孔径为10.164 4 nm,孔体积为1.023 023 cm³/g,比表面积为396.528 1 m²/g。     

PAN多孔纳米纤维的制备及其吸附性能研究

以聚丙烯腈(PAN)为原料,以聚乙二醇(PEG)为造孔剂,通过静电纺丝制成PAN/PEG复合纳米纤维,再经水洗去除纤维中的PEG成分制备出PAN多孔纳米纤维。采用傅里叶变换红外光谱仪、扫描电子显微镜、比表面孔径测定仪、分光光度计分别对PAN多孔纳米纤维的结构、形貌、比表面积及吸附性能进行了表征。结果表明:PAN/PEG复合纳米纤维中两组分呈微观相分离状态,通过水洗可去除PEG组分制得PAN多孔纳米纤维;PAN多孔纳米纤维的直径随PEG含量及相对分子质量的增加而减小,而比表面积、孔体积以及吸附能力随PEG含量及相对分子质量的增加而增大。     

直接电纺制备多孔γ-Al2O3纤维研究

本文以羟基氯化铝为原料,去离子水为溶剂,PVA为助纺剂,采用静电纺丝技术制备出多孔γ-Al2O3纤维.通过XRD和SEM分析纤维的物相组成与显微结构,利用比表面积分析仪表征纤维的孔结构参数.结果表明:采用静电纺丝可直接制备出多孔氧化铝纤维,物相组成为γ-Al2O3,纤维直径约为500?nm,表面存在一定量的孔结构,平均...     

Porous Electrospun PES/PEG Ultrafine Fibers for the Removal of Endocrine Disruptors

In this work, porous polyethersulfone (PES)/polyethylene glycol (PEG) ultrafine fibers were prepared via electrospinning technique, and then were used to removing endocrine disrupters from their aqueous solutions. The surface and the internal structures of PES/PEG ultrafine fibers were characterized by scanning electron microscopy (SEM) and the result showed that they were both porous. The porous electrospun PES/PEG ultrafine fibers can remove endocrine disrupters such as biphenyl A (BPA) and biphenyl (BP) effectively. Compared with pure PES ultrafine fibers, PES/PEG ultrafine fibers showed larger adsorption capacity and faster kinetics of uptaking target species. The hydrophilic properties and the porosity of porous PES/PEG ultrafine fibers can be controlled by adding hydrophilic materials such as polyethylene glycol (PEG), which can improve the adsorption properties of porous PES/PEG ultrafine fibers significantly. The results showed that porous electrospun PES/PEG ultrafine fibers had the potential to be used in environmental application and water treatment.     

Adsorption of methylene blue on hemicellulose‐based stimuli‐responsive porous hydrogel

A stimuli‐responsive porous hydrogel was synthesized from wheat straw hemicellulose using CaCO₃ as the porogen, and its application for the removal of methylene blue was studied. The porous structure of the prepared hydrogel was confirmed by SEM analysis. The effects of pH and polyelectrolyte on the swelling of the hydrogels were discussed, and the porous hydrogels showed excellent sensitivity to pH and salt. The deswelling kinetic study indicated that the hydrogels exhibited rapid shrinking in NaCl aqueous solutions. The methylene blue adsorption on the hydrogels was investigated, and the obtained adsorption data was fitted to the pseudo‐first‐order, pseudo‐second‐order and intra‐particle diffusion kinetics models, and the pseudo‐first‐order kinetic model could describe the adsorption process, and the adsorption process of methylene blue on the hydrogels was controlled by external film diffusion. This study reported that the hemicellulose‐based porous hydrogel is promising for water treatment. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41606.     

Adsorption behavior of Cd(II) ions on humic acid-immobilized sodium alginate and hydroxyl ethyl cellulose blending porous composite membrane adsorbent

A novel porous composite adsorbent was prepared by using sodium alginate and hydroxyl ethyl cellulose blending as an immobilization matrix for humic acid, then crosslinked by glutaraldehyde. The adsorbent was prepared using polyethylene glycol (PEG) as porogen and used to remove Cd(II) ions from aqueous solution. The physico-chemistry properties of adsorbent before and after adsorption were investigated by FT-IR, SEM and EDX methods. Batch adsorption experiments were carried out to investigate the effects of the amount of PEG adding to the adsorbent, solution pH, dosage of adsorbent, initial Cd(II) ions concentration and contact time. The prepared adsorbent exhibited the maximum uptake of 148.9 mg/g under the optimal adsorption condition. Kinetics experiments indicated that the pseudo-first-order model displayed the best correlation with adsorption kinetics data. The Crank model showed that the intraparticle solute diffusion was the rate-controlling adsorption step. Besides, experimental data could be better described by the Freundlich isotherm model. Dubinin–Radushkevich isotherm indicated that the adsorption was mainly an ion exchange process. The results suggested that the prepared adsorbent is promising for using as an effective and economical adsorbent for Cd(II) ions removal.     

Dielectric loss in porous TiO2

The dielectric loss behavior of TiO₂ was characterized on samples of variable porosity and variable pore size. Pores were formed by two methods: varying the sintering temperature and by the addition of a spherical carbon porogen. Porosities varied from 5.9% to 59.3%. Dielectric loss increased with increasing pore volume in each case. However, dielectric loss increased at a slower rate for porogen induced pores. At equivalent pore volumes, pore surface area volumes were higher than those induced using the porogen. Dielectric loss behavior was shown to vary linearly with pore surface area. Our work demonstrates that large pores reduce free surface area and decrease dielectric loss when compared to similar samples with smaller pores. A new model of porous dielectric loss is proposed that characterizes materials based on generalized free surface area instead of porosity alone. Based on this model, we show that the relative loss of porous dielectrics depends critically on the pore surface area and the loss tangent of the parent dielectric.     

硼碳氮多孔材料的制备及其吸附再生性能研究

硼碳氮(BCN)多孔材料因其具有高的比表面积、优异的化学稳定性而被认为是一种优异的吸附材料。本文以废弃椰壳、硼酸(H₃BO₃)和尿素(CO(NH₂)₂)为原料,采用冷冻干燥法制备多孔生胚,并在NH₃气氛下通过高温固相反应法在不同的反应温度下合成BCN多孔材料。结果表明,随着反应温度的升高,BCN多孔材料孔径逐渐变大,当反应温度为950 ℃时平均孔径为2.1 nm。将BCN多孔材料用于吸附水中孔雀石绿(MG)有机染料,其最大吸附量可达1 239.8 mg·g^-1,5次循环再生后吸附量平均值仍高达1 138.6 mg·g^-1,说明BCN多孔材料具有优异的循环吸附性能。采用Langmuir和Freundlich等温吸附模型、准一级和准二级吸附动力学模型研究了浓度、吸附时间和平衡吸附量之间的关系。结果表明,BCN多孔材料的吸附与准二级吸附动力学模型吻合,其对MG的吸附属于均匀表面单层分子的Langmuir等温吸附。BCN多孔材料展现出优异的吸附能力,是一种非常有应用前景的新型吸附剂。     

磺化聚醚醚酮纳米纤维膜的制备及其吸附性能

通过静电纺丝法制备了不同磺化度的磺化聚醚醚酮(SPEEK)纳米纤维膜,运用扫描电镜、热重分析仪分别对纤维的形貌和热性能进行了分析,并利用紫外-可见分光光度计研究了纤维膜对亚甲基蓝染料的吸附行为。结果表明:随着磺化度的增加,纺丝束流的稳定性得到改善,纤维直径减小;纤维膜对亚甲基蓝具有良好的吸附能力,在p H值=7时其对亚甲基蓝的去除率最大,平衡吸附时间约为90min;热力学分析表明,使用Freundlich模型描述SPEEK纳米纤维膜对亚甲基蓝的吸附行为更加合理;动力学分析表明,SPEEK纳米纤维膜对亚甲基蓝的吸附遵循准二级动力学模型。     

Comparison of the effect of pore architecture and bead size on the extent of plasmachemical amine functionalisation of poly(styrene-co-divinylbenzene) permanently porous resins

Poly(styrene-co-divinylbenzene) (PS/DVB) permanently porous resins suitable for plasmachemical modification with allylamine were prepared by suspension polymerisation. Experimental design methods were employed to investigate simultaneously the influence of crosslinker content, porogen type and porogen level on the surface area, pore volume and pore diameter of the resins. From this, it was found that the porogen has a greater influence than the crosslinker. Variation of porogen type and level while keeping crosslinker level constant then lead to the maximisation of each parameter of interest, resulting in a set of samples with a wide range of values. Six samples were then chosen, representing high and low values of each property, and were subjected to plasmachemical modification with allylamine. It was found that pore volume had the greatest influence on the extent of modification. However, subsequent experiments indicated that the extent of modification is much greater for smaller beads. It is concluded that plasmachemical functionalisation occurs mainly on the external surface of the beads.     

Adsorption thermodynamics and kinetics of disperse dye on poly(p-phenylene benzobisoxazole) fiber pretreated with polyphosphoric acid

Adsorption thermodynamic and kinetic studies of C. I. disperse dye 60 on PBO fiber pretreated with polyphosphoric acid (PPA) were carried out under the conditions of pH 6.0±0.2, initial dye concentration 0.05–1.0 g/L and liquor ratio 2,000: 1. The results showed that the equilibrium adsorption isotherm of the disperse dye on the pretreated PBO fiber was a Langmuir-Nernst mixed Model and the saturated adsorption capacity of the turning point was 1.046 mg/g. The thermodynamic parameters were calculated by the equilibrium adsorption isotherm, such as standard affinity, enthalpy change and entropy change, which indicated that the adsorption of disperse dye on the pretreated PBO fiber was an exothermic process. Based on the thermodynamic and kinetic data, the adsorption of the dye on the pretreated PBO fiber was a kinetics controlled process, and the disperse dye could only diffuse into the surface layer of pretreated PBO fiber. Meanwhile, the adsorption kinetics of disperse dye on pretreated PBO fiber well agreed with a pseudo-first-order kinetic model.     

绿色法制备多孔球状镧铁复合物及其吸附磷性能研究

利用水热法和碱刻蚀法制备多孔球状镧铁复合物（LFA-C）。通过扫描电镜（SEM）、红外光谱仪（FTIR）、X射线衍射仪（XRD）和比表面及微孔物理吸附仪对复合物材料进行表征分析,并考察其作为吸附剂对磷酸盐的吸附性能。结果表明,LFA-C材料表面形貌粗糙多孔,碱刻蚀过程促进氢氧化镧在LFA-C的表面生成,同时LFA-C的比表面积增加有利于获得更多的吸附活性位点。吸附动力学研究表明,LFA-C的吸附过程符合准二级动力学模型。热力学研究发现Langmiur模型能更好地拟合吸附等温线,拟合饱和吸附量为159.08 mg/g。在共存离子条件下,LFA-C吸附磷酸盐的抗干扰能力强,同时LFA-C通过吸附-解析过程展现出良好的循环性能。LFA-C作为高效去磷、抑制富营养化的环境功能材料,具有广阔的应用前景。     

多孔壳聚糖膜的制备表征及其吸附性能研究

以琼胶固体颗粒为致孔剂,通过热致相转移法制备了的多孔壳聚糖膜,并通过FT-IR和SEM对其进行了表征,也考察了其对有机染料二甲苯蓝FF的吸附性能。结果表明,以琼胶作为制孔剂可以制备出性能良好的多孔壳聚糖膜,在吸附有机染料方面,多孔壳聚糖膜PCS-2对二甲苯蓝FF的吸附量是壳聚糖膜的1.3倍。另外,作为对比,本文也制备和表征了琼胶-壳聚糖共混薄膜。