铈改性活性炭对苯酚的吸附行为研究

采用浸渍法制备铈改性活性炭(Ce/AC),研究活性炭改性前后对苯酚的去除率,考察pH值及Ce/AC投加量对苯酚去除率的影响,采用吸附等温线模型、热力学模型及动力学模型对Ce/AC吸附苯酚过程进行拟合,研究其吸附特性及机理。结果表明,同等条件下,Ce/AC对苯酚的吸附量为56.9mg/g,是改性前的4倍;在25℃,不调节pH值,Ce/AC的投加量为6g/L时,Ce/AC对苯酚去除率达到95.4%;Langmuir吸附等温线可较好地描述Ce/AC吸附苯酚过程,热力学计算结果表明,Ce/AC吸附苯酚过程为自发吸热熵值增大的过程,吸附动力学符合拟二级动力学模型,Ce/AC吸附苯酚过程存在亲(疏)水作用、氢键作用及软硬酸碱作用。     

Fe2O3/CNT催化湿法H2O2氧化苯酚

通过化学沉积法和热处理得到多壁碳纳米管负载Fe2O3催化剂 Fe2O3/CNT, Fe2O3的负载质量分数约为15.1%,XRD表征显示,负载的Fe2O3存在α和γ这2种晶型。考察了Fe2O3/CNT催化湿式H2O2氧化去除废水中苯酚催化性能,通过苯酚的去除率及反应过程中催化剂活性组分的溶出总量,研究了催化剂制备过程中添加聚乙烯醇对催化剂性能的影响。在苯酚和H2O2初始浓度分别为350和1 500 mg/L、催化剂投加量为1.0 g/L、温度80 ℃条件下,经过240 min的反应,苯酚去除率达100％,COD去除率为86.1％。     

镀铜铁屑-H_2O_2催化氧化降解含酚废水

采用镀铜铁屑代替传统Fenton体系中的FeSO4作为催化剂,通过改变H2O2与镀铜铁屑的投加量、溶液的pH值、反应温度、反应时间等条件,研究了该体系对处理苯酚废水的影响。结果表明,常温下处理实际含酚印染废水,在pH值为4~6,30%H2O2 12mL/L,镀铜铁屑5g/L,反应时间为45min时,COD去除率可达96%,其CODCr从5827mg/L降至419mg/L,色度从2000降至30,符合国家三级排放标准。     

三维电极系统电化学氧化三唑酮

以三唑酮(TDF)为目标污染物,以钛基钌铱电极和不锈钢板作阳极、阴极,颗粒活性炭(GAC)为粒子电极构建三维电极系统,通过搅拌实现粒子电极呈流化状态。研究电流密度、TDF初始浓度、GAC投加量、初始pH对三维电极系统的TDF去除效率的影响。研究结果表明:增大电流密度有助于提高TDF去除效率;TDF去除率随初始pH的增大呈现逐渐增大的趋势,碱性条件有助于TDF的去除;当GAC投加量为1～4 g/L时,增大GAC投加量有助于TDF的降解;增大TDF初始浓度会导致去除率的降低。当TDF初始浓度为200μg/L、电流密度为8m A/cm2、初始pH=11、GAC投加量为4 g/L时,电化学氧化10 min时TDF去除率达到99.95%。三维电极系统的传质效率高于二维电极系统,三维电极电化学氧化系统是一种适用于降解TDF的高级氧化技术。     

邻硝基苯甲醚生产废水预处理工艺的研究

采用"酸化-树脂吸附"法对邻硝基苯甲醚生产废水进行预处理研究。比较了XAD-4、NDA-88、NDA-99、NDA-150几种树脂对酸化后废水中邻硝基苯酚的静态吸附行为,并选用吸附量较大的NDA-150树脂对该废水进行了吸附及脱附研究。结果表明,pH为4时,NDA-150树脂的平衡吸附量4.38mmol/g。动态吸附处理量为40BV(树脂体积)时,酚去除率95%,以8%NaOH为脱附剂,温度333K,脱附率98%。该工艺CODCr总去除率92%,邻硝基苯酚总去除率99%,每升废水可回收邻硝基苯酚10.8g,纯度大于97%。     

亚临界水萃取-高效液相色谱法测定聚碳酸酯水杯中双酚A和苯酚的迁移量

建立了亚临界水萃取-高效液相色谱同时测定聚碳酸酯(PC)水杯中双酚A和苯酚迁移量的方法。选择萃取温度120 ℃、萃取压力6.89 MPa(1000 psi)、静态萃取时间1 h、萃取1次对11种样品进行测定。双酚A的迁移量为6.81～11.16 μg/g。5种样品中未检出苯酚,其余样品中苯酚迁移量为3.25～6.08 μg/g。在优化的测定条件下,双酚A和苯酚在8 min内达到基线分离。双酚A和苯酚分别在0.05～20 mg/L和0.02～20 mg/L范围内线性关系良好,相关系数(r)均大于0.9997,检出限分别为7.6 μg/L和2.0 μg/L。日内及日间的重复性(以RSD计)分别小于5.21%及11.63%。传统的浸提法结果表明长时间浸提会使PC材料发生微弱水解。相比传统的浸提法,该方法的萃取效率提高了49～106倍。该方法简便、快速、环保,可用来测定PC水杯中双酚A和苯酚的迁移量。     

氮氯共掺杂多孔碳活化过一硫酸盐降解苯酚的性能及机理研究

杂原子共掺杂碳材料在过硫酸盐活化领域具有广阔的应用前景. 本工作通过两步煅烧法合成了氮氯共掺杂ZIF-8衍生多孔碳材料(NClC), 并以苯酚为目标污染物, 考察其活化过一硫酸盐(PMS)的催化性能, 结果表明, 30 min内, 0.04 g/L NClC900活化0.3 g/L PMS可去除水中97.7%的苯酚(50 mg/L), 且总有机碳去除率可达72.4%; NClC900/PMS体系具备优异的酸碱耐受性(pH=3~9)和抗干扰能力, 无机阴离子和腐植酸对其影响较小, 且该体系还可有效去除水中的染料、抗生素、酚类及农药等有机污染物; 循环实验结果表明, NClC900在重复使用4次后其苯酚去除率可达72.1%; 猝灭实验、电子顺磁共振和电化学分析表明¹O₂和表面结合SO₄^•-是导致苯酚降解的主要活性物种, 而NClC900中的石墨N、C—Cl是产生¹O₂和表面结合SO₄^•-的关键活性位点.     

基于脂肪酸的漂浮液滴固化分散液液微萃取-高效液相色谱法联用测定酒类样品中的4-乙基苯酚和4-乙基愈创木酚

建立了基于脂肪酸的漂浮液滴固化分散液液微萃取（FA-DLLME-SFO）方法,与高效液相色谱联用检测了酒类样品中的4-乙基苯酚和4-乙基愈创木酚。该方法萃取时间仅需4 min,仅需脂肪酸、氨水和硫酸3种对环境友好的试剂。对影响方法萃取效率的因素（包括样品的体积、萃取剂的种类和用量、氨水和硫酸的体积以及盐的加入量）进行了详细的考察。在最佳萃取条件下（10 mL样品,100 μL辛酸萃取剂,110 μL 25%～28%（质量分数）的氨水,0.8 mL 98%（质量分数）的浓硫酸,3.0 g NaCl）,4-乙基苯酚和4-乙基愈创木酚在0.02～1.0 mg/L范围内呈良好的线性关系,相关系数分别为0.9997和0.9999,相对标准偏差（n=3）分别为6.2%和3.5%,检出限分别为6.33和5.81 μg/L,富集倍数分别为79和86。在啤酒和白葡萄酒样品中,加标回收率为81.4%～108.7%,相对标准偏差（n=3）小于8.9%。该方法简单、对环境友好,可用于酒类样品中4-乙基苯酚和4-乙基愈创木酚的检测。     

纳米级Pd/Fe双金属体系对水中2,4-二氯苯酚脱氯的催化作用

 利用化学沉淀法制备了纳米级Fe和纳米级Pd/Fe双金属催化剂,研究了它们对2,4-二氯苯酚(2,4-DCP)还原脱氯的催化性能. 结果表明,纳米级颗粒具有较高的比表面积和表面反应活性,其BET比表面积可达12.4 m2/g,当Pd/Fe用量为6 g/L时,2,4-DCP脱氯率达到90%以上. 脱氯效率与pH值、温度、钯含量和Pd/Fe投加量等因素有关. 2,4-DCP在脱氯过程中先生成2-氯苯酚和4-氯苯酚,最终生成苯酚,而少量的2,4-DCP可直接降解成苯酚.     

微波辅助纳米CeO_2/H_2O_2体系催化氧化苯酚的研究

以Ce(NO3)3·6H2O和NH3·H2O为原料,采用沉淀法制备Ce O2粉体,采用X射线衍射仪、扫描电子显微镜对催化剂的晶相结构和表面形貌进行表征。在微波加热作用下,以苯酚为模拟含酚废水对催化剂的催化性能进行了测定,并探讨了原料投加量、搅拌时间、微波加热时间等对苯酚去除率的影响。结果表明:所制备的Ce O2纳米材料为高度结晶的立方萤石型结构,平均粒径为36.5 nm。在微波辅助Ce O2/H2O2体系催化降解苯酚实验中,当苯酚初始浓度500 mg·L-1,投加纳米Ce O20.4 g,10%H2O20.6 m L,室温下搅拌60 min,微波反应器中以100℃反应40 min,苯酚的去除率达到87%以上。     

Preparation of bio‐based keratin‐derived magnetic molecularly imprinted polymer nanoparticles for the facile and selective separation of bisphenol A from water

In this study, new bio‐based magnetic molecularly imprinted polymer nanoparticles (∼23 nm) were synthesized from keratin extracted from chicken feathers and methacrylate‐functionalized Fe₃O₄ nanoparticles for its potential application in separation and removal of bisphenol A from water. The prepared magnetic molecularly imprinted polymer was characterized by Fourier‐transform infrared spectroscopy, field‐emission scanning electron microscopy, thermogravimetric analysis, alternative gradient field magnetometry, and energy‐dispersive X‐ray spectroscopy. The sorption of bisphenol A was investigated by changing the influencing factors such as pH, immersion time, Fe₃O₄ nanoparticles dosage, and the initial concentration of bisphenol A. Results illustrated that sorption was very fast and efficient (Q_m = 600 mg/g) having a removal efficiency of ∼98% in 40 min of immersion. The adsorption process showed better conformity with the Weber−Morris kinetics and the Freundlich isotherm model. The selectivity of bisphenol A by adsorbent was checked in the presence of hydroquinone, phenol, tetrabromobisphenol, and 4,4′‐biphenol as interferences.     

Core-shell magnetic porous organic polymer for magnetic solid-phase extraction of fluoroquinolone antibiotics in honey samples followed by high-performance liquid chromatography with fluorescence detection

By monomer-mediated in-situ growth synthesis strategy, with hydroquinone and 1,3,5-tris(4-aminophenyl)benzene as monomers, a core-shell magnetic porous organic polymer was synthesized through a simple azo reaction. Based on this, a magnetic solid-phase extraction–high-performance liquid chromatography–fluorescence detection method was proposed for the analysis of fluoroquinolones in a honey sample. With ofloxacin, ciprofloxacin, enrofloxacin, lomefloxacin, and difloxacin as target analytes, factors affecting the extraction efficiency had been optimized. The LODs were 1.5–5.4 ng/L (corresponding to 0.23–0.81 μg/kg in honey). The linear range was 0.005–20 μg/L for difloxacin, 0.01–20 μg/L for ofloxacin, ciprofloxacin and lomefloxacin, and 0.02–20 μg/L for enrofloxacin. The enrichment factor was 84.4–91.7-fold with a high extraction efficiency of 84.4–91.7%. The method was assessed by the analysis of target fluoroquinolones in honey samples, and the recoveries for the spiked samples were 79.3–95.8%. The results indicated that the established magnetic solid-phase extraction–high-performance liquid chromatography–fluorescence detection method is efficient for the analysis of trace fluoroquinolones in honey.     

Simple magnetization of Fe3O4/MIL‐53(Al)‐NH2 for a rapid vortex‐assisted dispersive magnetic solid‐phase extraction of phenol residues in water samples

The present work describes a simple route to magnetize MIL‐53(Al)‐NH₂ sorbent for rapid extraction of phenol residues from environmental samples. To extend the applications and performances of the metal‐organic frameworks in the field of adsorption materials, we combined the properties of metal‐organic frameworks and magnetite to decrease the extraction time and simplify the extraction process as well. In this study, a simple and quick vortex‐assisted dispersive magnetic solid phase extraction method for the extraction of ten United States Environmental Protection Agency's priority phenols from water samples prior to analysis by high‐performance liquid chromatography with photodiode array detection was proposed. The developed method exhibits a rapid enrichment of the target analytes within 10 s for extraction and 10 s for desorption. Low detection limits of 1.8‐41.7 µg/L and quantitation limits of 6.0‐139.0 µg/L with the relative standard deviations for intra‐ and interday analyses less than 12% were achieved. Satisfactory recoveries in the range of 80‐111% with the relative standard deviations less than 11% demonstrated that Fe₃O₄/MIL‐53(Al)‐NH₂ is promising sorbent in the field of magnetic solid‐phase extraction for environmental samples.     

Fe3O4/reduced graphene oxide‐carbon nanotubes composite for the magnetic solid‐phase extraction and HPLC determination of sulfonamides in milk

A novel magnetic adsorbent Fe₃O₄/reduced graphene oxide‐carbon nanotubes, was prepared by one‐pot solvothermal synthesis method. It was characterized by scanning electron microscopy, X‐ray powder diffraction and vibrating sample magnetometry. The diameter of Fe₃O₄ microparticles was about 350 nm, which were covered by carbon nanotubes and reduced graphene oxide sheets, while carbon nanotubes inserted between the reduced graphene oxide sheets effectively prevented their aggregation. The composite had large surface area and good magnetic property, suiting for magnetic solid‐phase extraction and the determination of sulfonamides, by coupling with high‐performance liquid chromatography. Under the optimized conditions (including extraction time, amount of adsorbent, solution pH, ionic strength and desorption conditions), a good linear was achieved in the concentration range of 5–500 μg/L and the low limits of detection and low limits of quantification were 0.35–1.32 and 1.16–4.40 μg/L, respectively. The enrichment factors were estimated to be 24.72 to 30.15 fold. The proposed method was applied for the detection of sulfonamides in milk sample and the recoveries were 88.4–105.9%, with relative standard deviations of 0.74–5.38%.     

Synthesis of Fe3O4@poly(methylmethacrylate-co-divinylbenzene) magnetic porous microspheres and their application in the separation of phenol from aqueous solutions

A simple strategy to fabricate magnetic porous microspheres of Fe(3)O(4)@poly(methylmethacrylate-co-divinylbenzene) was demonstrated. The magnetic microspheres, consisting of polymer-coated iron oxide nanoparticles, were synthesized by the modified suspension polymerization of methacrylate and divinylbenzene in the presence of a magnetic fluid. The morphology and the properties of the magnetic porous microspheres were examined by scanning electron microscopy, transmission electron microscopy, superconducting quantum interference device, Fourier transform infrared spectroscopy, thermogravimetry, and X-ray powder diffraction. The pore size distribution and the specific surface area of the microspheres were measured by nitrogen sorption and mercury porosimetry technique. As predicted from the previous knowledge, the magnetic porous microspheres possessed a high specific surface area using n-hexane as a porogen. It was further found that the amounts of divinylbenzene and methacrylate, the ratio of porogens, and the dosage of ferrofluids affect the specific surface area of the microspheres. Furthermore, the microspheres were applied to remove phenol from aqueous solutions. The results showed that the microspheres had a high adsorption capacity for phenol and a high separation efficiency due to their porous structure, polar groups, and superparamagnetic characteristic.     

Microwave‐assisted preparation of magnetic nanoparticles modified with graphene oxide for the extraction and analysis of phenolic compounds

Here in, magnetic nanoparticles combined with graphene oxide adsorbent were fabricated via a microwave‐assisted synthesis method, and used in the solid‐phase extraction of three phenolic compounds (phenol, 4‐nitrophenol, and m‐methylphenol) in environmental water samples. Various instrumental methods were employed to characterize the magnetic nanoparticles modified with graphene oxide. The influence of experimental parameters, such as desorption conditions, amount of adsorbent, extraction time, and pH, on the extraction efficiency was investigated. Owing to the high surface area and excellent adsorption capacity of the prepared material, satisfactory extraction was achieved. Under optimum conditions, a linear response was observed in the concentration range of 1.000–100.0 μg/L for phenol, 0.996–99.6 μg/L for 4‐nitrophenol, and 0.975–97.5 μg/L for m‐methylphenol, with correlation coefficients in the range of 0.9995–0.9997. The limit of detection (signal‐to‐noise ratio of 3) of the method varied between 0.5 and 0.8 μg/L. The relative standard deviations were <5.2%. The recovery percentages of the method were in the range of 89.1–104.3%. The results indicate that the graphene oxide‐modified magnetic nanoparticles possess high adsorptive abilities toward phenolic compounds in environmental water samples.     

环糊精改性Fe_3O_4磁性液体的制备与感应加热特性

采用两步法制备β-环糊精改性纳米四氧化三铁磁性液体,探讨了pH值、改性剂用量、改性温度对改性效果的影响.改性水基磁性液体性能稳定,饱和磁化强度可达1.78emμ/g.在高频交变磁场下,磁性液体升温超过41℃,可用于肿瘤的磁热疗研究.     

基于介孔Fe3O4@mSiO2@Cu2+磁性纳米粒子的固相萃取-高效液相色谱法测定水中微囊藻毒素

通过水热合成和常温合成的方法制备了介孔Fe₃O₄@mSiO₂@Cu²⁺磁性复合纳米粒子(NPs),其具有均匀的尺寸大小、良好的磁性能和特异的选择性。本研究将合成的NPs用作磁性固相萃取(MSPE)介质,结合高效液相色谱(HPLC)发展了一种测定水样品中痕量微囊藻毒素MC-LR的方法。在优化MSPE和HPLC条件后,该方法在0.1~15 μg/L范围内呈现良好的线性,线性相关系数(r)为0.9994,检出限为0.025 μg/L,定量限为0.082 μg/L。进一步将该方法用于水样中痕量藻毒素分析,结果发现回收率达到78%。这一结果表明:制得的磁性纳米粒子具有良好的萃取性能,可有效用于水样中痕量藻毒素的测定。     

磁性石墨烯纳米粒子固相萃取与气相色谱-质谱相结合测定环境水样中的三嗪类除草剂

将磁性石墨烯作为磁性固相萃取的吸附剂与气相色谱-质谱(GC-MS)相结合建立了环境水样中7种三嗪类除草剂残留的测定新方法。对影响萃取效率的一些因素如吸附剂用量、萃取时间、样品溶液的pH值、离子强度和解吸条件等进行了优化。在优化的实验条件下,7种三嗪类除草剂的富集倍数在574~968之间。测定西玛津、扑灭津、嗪草酮、西草净、氰草津的线性范围为0.01~10.0 μg/L,莠去津的线性范围为0.05~10.0 μg/L,扑灭净的线性范围为0.01~8.0 μg/L。线性相关系数为0.9968~0.9998,检出限(S/N=3)为1.0~5.0 ng/L。将本方法应用于井水、自来水和湖水等实际水样的分析,在0.5 μg/L和2.0 μg/L下的加标回收率为79.8%~118.3%,相对标准偏差为3.6%~10.5%。该法操作简单、富集倍数高,可满足水样中三嗪类除草剂残留的检测要求。     

Fe3O4纳米粒子修饰多壁碳纳米管的制备及在水和蜂蜜样品中痕量菊酯类农药分析中的应用

通过化学共沉淀法使Fe₃O₄纳米粒子负载于酸化多壁碳纳米管(AMWNTs)表面,得到Fe₃O₄/AMWNTs磁性纳米材料。该材料具有很好的磁响应度和分散性,将其用于富集痕量拟除虫菊酯类农药残留,结果证明该复合材料对菊酯类农药的吸附性能良好。通过对影响萃取性能的几种因素如离子强度、萃取时间和解吸时间依次进行优化,在最优条件下,建立了Fe₃O₄/AMWNTs磁性分散固相萃取-气相色谱测定6种菊酯类农药残留的分析方法。线性范围在0.5~50 μg/L之间,相关系数(R²)大于0.990,检出限为0.07~0.20 μg/L,精密度为3.8%~8.1%。该方法用于河水、鱼塘水和两种市售蜂蜜中菊酯类农药的残留分析,回收率高于78.4%。该方法操作简便、灵敏度高,能够满足环境水样及蜂蜜样品中痕量菊酯农药残留的分析需求。