氧化石墨烯负载纳米零价铁的制备及其对亚甲基蓝的吸附

采用液相还原法制备氧化石墨烯负载纳米零价铁吸附剂(Fe0/GO),并用于吸附去除溶液中的亚甲基蓝(MB)。考察了溶液p H、吸附温度、吸附时间、初始MB质量浓度对Fe0/GO吸附MB的影响。SEM等表征结果显示:Fe0以球形或短链形负载在GO上,增加了材料的反应活性位点;Fe0/GO的比表面积为158.32 m2/g,等电点为3。实验结果表明:在溶液p H为6、吸附时间5 h、吸附温度25℃的最佳条件下,加入400 mg/L的Fe0/GO,处理初始MB质量浓度为160 mg/L的MB溶液,MB去除率为89.26%,吸附量为125.5 mg/g;Langmuir等温吸附方程和Frenudlich等温吸附方程均能较好地描述Fe0/GO对MB的吸附过程;Fe0/GO对MB的吸附行为遵循准二级动力学方程;计算得出吸附温度为25℃、初始MB质量浓度为160 mg/L时的饱和吸附量为201.2 mg/g,平衡吸附量为124.3 mg/g。     

Sulfonated tea waste: A low-cost adsorbent for purification of biodiesel

In the present work, the crude biodiesel produced from spent fish frying oil through alkaline catalyzed transesterification was purified using a low-cost adsorbent viz. sulfonated tea waste. After separating the glycerol, the crude biodiesel was purified using the suggested adsorbent. Various methods of purification using the said adsorbent were applied such as purification using adsorption column chromatography and shaking methods. The results showed that purification using adsorption column chromatography exhibited the bst result. Properties of the purified fuels were determined and found conformed to those specified by the ASTM standards. For the sake of comparison, purification using zeolite and water washing method was also investigated. The result indicated that the suggested adsorbent was more successful on purification of the crude biodiesel compared to other methods.     

Phosphorus-doped graphene supported palladium (Pd/PG) electrocatalyst for the hydrogen evolution reaction in PEM water electrolysis

PEM water electrolysis is one of the most efficient methods for the production of hydrogen because of produced high purity of the gases and environmentally friendly. In the present study, Phosphorus-doped Graphene (PG) was synthesized by thermal annealing of triphenylphosphine (TPP) and graphene oxide (GO). The PG supported palladium (Pd/PG) electrocatalysts were synthesized by chemical reduction method and used as the cathode for hydrogen evolution reaction (HER) electrode. Structural properties and electrochemical performances of the synthesized Pd/PG electrocatalyst were studied by FE-SEM, EDS, ICP, FT-IR, XRD, and Cyclic voltammetry (CV) methods, respectively. The membrane electrode assemblies (MEA’s) were fabricated using Pd/PG as cathode for HER electrode and RuO₂ as anode for OER electrode. Also, their electrochemical performances along with the corresponding hydrogen yields were evaluated in single cell PEM water electrolyzer at various experimental conditions such as different current densities from 0.1 to 2.0 A cm^?2 and temperatures (28–80°C). The synthesized Pd/PG electrocatalyst was observed a current density of 1 A cm^?2 with 1.95 V at 80°C. Further, long-term stability studies were carried out continuously up to 2000 h which showed a reasonable stability. Hence, the synthesized Pd/PG can be used as an alternative to Pt-based electrocatalysts for the HER in PEM water electrolysis.     

Determination of 2,4-Dichlorophenoxyacetic acid in food and water samples using a modified graphene oxide sorbent and high-performance liquid chromatography

Abstract

In the present work, dispersive micro-solid phase extraction (D-μ-SPE) method using magnetic graphene oxide tert-butylamine (GO/Fe₃O₄/TBA) nanocomposite, as an efficient sorbent, was applied for determining 2,4-dichlorophenoxyacetic acid (2,4-D) in water and food samples. Detection was carried out using high-performance liquid chromatography (HPLC) instrument. Influential parameters of D-μ-SPE such as sorbent and its amount, elution solvent and its volume, adsorption and desorption times and pH of sample solution were investigated and optimized. Under the optimized conditions, limit of detection and quantitation values were 0.007 and 0.02?μg/mL, respectively. Recovery data for several real samples were obtained within the range of 88.0–94.0% with a relative standard deviation (RSD) less than 7.5%. The proposed method was successfully applied to quantitative determination of 2,4-D in several vegetables and water samples.     

氧化石墨烯和多环芳烃与肺表面活性物质间的相互作用

为阐明氧化石墨烯与多环芳烃这一复合污染体系与肺表面活性物质（PS）的作用,考察了各组分之间的作用方式及效应,并对作用机制进行分析.结果表明,PS及其组分对多环芳烃有增溶作用,增溶能力依次为萘 < 苊 < 苯并（a）蒽;氧化石墨烯对多环芳烃和PS有一定的吸附作用,且多环芳烃和PS存在竞争吸附,入肺后PS及其组分占据多环芳烃的吸附位点而负载于氧化石墨烯表面;多环芳烃在PS及其组分增溶作用下在氧化石墨烯表面解析,毒性增强;DPPC由竞争吸附产生的解析效果尤为显著,当苯并（a）蒽的加入量到0.6mg/L时,DPPC于GO上吸附量减少了28.92mg/g;同时,多环芳烃和PS均会促使氧化石墨烯团聚,粒径增大3倍以上;C=C键的增多和化学键转化产生的作用力影响了氧化石墨烯的稳定性.本研究为复合污染对肺的潜在毒性效应及肺风险评估提供了一定的理论支撑.     

GO-TiO2改性PVDF复合膜去除微污染水体中氨氮

以氧化石墨烯（GO）、二氧化钛（TiO₂）和氧化石墨烯-二氧化钛（GO-TiO₂）为改性物质,借助真空过滤法对聚偏氟乙烯（PVDF）微滤膜进行改性制备复合膜.利用接触角测量仪、扫描电子显微镜、傅里叶红外变换光谱、X射线粉末衍射仪等手段探究了复合膜的结构和亲水性.同时选用腐殖酸（HA）作为水中微污染物的代表考察了复合膜的抗污染性能.选择常州滆湖支浜水样作为原水,研究了复合膜在黑暗及紫外光条件下对氨氮的去除效果.结果表明,GO、TiO₂和GO-TiO₂（GT）复合膜均具有优于PVDF膜的亲水性和抗污染性能,黑暗条件下,GO浓度为1mg/mL的GO复合膜氨氮去除率最高,达到26.4%;紫外光条件下,GO和TiO₂间存在协同作用,GO-TiO₂浓度为1mg/mL、GO/TiO₂=3：1的GT复合膜氨氮去除效率达到最佳（58.2%）.     

Fe3O4/GO对水溶液中Cd(II)去除的影响因素

为探索高效且快速去除水溶液中Cd （Ⅱ）污染方法,采用自制磁性四氧化三铁负载氧化石墨烯（Fe₃O₄/GO）纳米复合材料对水溶液中Cd （Ⅱ）进行去除,利用单因素实验确定影响因素水平范围（初始Cd （Ⅱ）浓度、温度、反应时间、初始pH值）,并采用响应面法（RSM）及人工神经网络-遗传算法（ANN-GA）对去除水溶液中Cd （Ⅱ）的影响因素（4因素3水平）进行优化,利用等温吸附、动力学及热力学参数研究吸附剂性能.通过扫描电子显微镜（SEM）、X射线衍射仪及超导量子干涉器件（SQUID）对复合材料表征.结果表明,平均粒径为30.9nm的磁性Fe₃O₄/GO纳米复合材料被成功制备.RSM用于磁性Fe₃O₄/GO纳米复合材料对水溶液中Cd （Ⅱ）去除条件优化,预测去除率达到86.451%,验证试验为82.220%,对应条件：温度为20.14℃,反应时间为57.78min,初始pH值为6.41和初始Cd （Ⅱ）浓度为11.18mg/L; ANN-GA优化条件后的预测去除率为89.722%,验证试验为87.723%,相应条件：温度为29.96℃,pH值为5.49,初始Cd （Ⅱ）浓度为28.36mg/L,反应时间为65.78min.根据模型R²值,预测的最大去除率及验证试验,ANN-GA模型性能及预测能力均高于RSM.RSM方差分析表明4个因素对磁性Fe₃O₄/GO纳米复合材料去除水溶液中Cd （Ⅱ）的影响大小为：初始Cd （Ⅱ）浓度>温度>反应时间>pH值.吸附机理分析结果显示,Fe₃O₄/GO纳米复合材料对Cd （Ⅱ）吸附过程同时存在着物理吸附和化学吸附.结合ANN-GA优化,利用磁铁实现且快速分离,磁性Fe₃O₄/GO纳米复合材料用于去除Cd （Ⅱ）是可行的.关键字：Cd （Ⅱ）;四氧化三铁负载氧化石墨烯;单因素实验;响应面法;人工神经网络-遗传算法中图分类号：X53     

碳纳米材料在环境中的转化

碳纳米材料主要包括富勒烯、碳纳米管和石墨烯.随着碳纳米材料的研究和应用范围不断扩大,其对环境的影响和在环境中的行为也逐渐受到关注,而在环境中的转化是环境行为的一个重要方面.首先,环境转化会改变碳纳米材料的性质,从而影响其它行为如聚集沉降和生态毒性.同时,作为一种以碳为骨架的材料,能否被自然界转化、从而进入碳循环是评价碳纳米材料长期环境影响的必要信息.因此,本文重点总结了碳纳米材料在自然环境条件和水处理条件下可能发生的生物或非生物转化,并分析影响碳纳米材料转化的因素,和转化过程对其环境行为的影响.     

聚砜-磺化聚砜共混超滤膜的研究

本文以聚砜和磺化聚砜为原料,制备了低截留分子量的共混超滤膜,此种膜具有适中透水量,对分子量3000的PEG截留率在90％以上。对膜的制备参数,如聚合物浓度、不同溶剂、不同添加剂和凝胶介质对膜性能的影响进行了较详细的研究。     

膜萃取和CaO-MgO乳状液反萃取法由醋酸废水生产醋酸钙镁盐

采用磺化聚醚砜中空纤维膜萃取醋酸废水,再用CaO—MgO乳状液反萃取制备醋酸钙镁盐。考察了膜萃取和反萃取的最佳实验条件。单级膜萃取醋酸废水（醋酸质量分数2％）的最佳条件为：水相走管程有机相走壳程（水外油内）逆流、有机相流量与水相流量比1．3、水相流量0．23mL/min,在此条件下萃取率可达74％;采用二级萃取,总萃取率可达95％。反萃取的最佳条件为：采用质量浓度100g／L的CaO—MgO乳状液作反萃取剂,CaO—MgO与醋酸摩尔比1．0：2．0,投料钙与镁摩尔比2．9：7．0,反萃取时间30min,室温,在此条件下反萃取率高于97％。