新型吸附搅拌棒被动采样器研制及应用——基于多壁碳纳米管的改性

结合传统被动采样器原理和新发展的吸附搅拌棒技术,研制了以多壁碳纳米管-聚二甲基硅氧烷(MWCTNs/PDMS)作为涂层的新型吸附搅拌棒被动采样器,并以苯酚(PhOH)、己烯雌酚(DES)和铅(Pb)作为目标污染物,考察被动采样器其吸附性能,优化其吸附条件.结果表明,与商业化PDMS涂层吸附搅拌棒被动采样器相比,含MWCTNs/PDMS涂层吸附搅拌棒被动采样器能更快达到吸附平衡时间、具有更大的饱和吸附容量.甲醇是PhOH和DES优良解吸剂,0.6mol/L HNO₃为Pb最优解吸剂.该新型被动采样器重复使用50次以上其解吸效率仍能达到70%以上,具有良好的稳定性和重复利用效果.     

多壁碳纳米管对水稻幼苗的植物毒性研究

考察了浓度为10、50和100 mg·L~(-1)的多壁碳纳米管(MWCNTs)的植物毒性,通过测量水稻生长指数、根系氧化应激反应、细胞膜损伤和生理功能的变化,探索了其具体的毒性机制。将水稻幼苗暴露于不同浓度的MWCNTs悬浮液中培养10 d后,高浓度处理组(100 mg·L~(-1))中水稻幼苗地上部分和根系鲜重分别降低至对照组的87.6%±1.1%和69.2%±7.8%。对根系深入研究发现氧化应激反应和细胞膜的损伤主要出现在高浓度处理组,此时过氧化氢酶(CAT)活性由对照组的(8.8±1.6)U·mg-1prot(protein,蛋白质)增加至(16.3±2.8)U·mg-1prot,丙二醛(MDA)含量由对照组的(8.0±0.3)μmol·g-1FW(fresh weight,鲜重)增加至(15.1±1.4)μmol·g-1FW。然而,水稻根系的生化酶活性在低浓度(10 mg·L~(-1))时就开始明显降低。通过透射电镜(TEM)观察发现,MWCNTs颗粒分布在水稻幼苗根系细胞内,从而证实了MWCNTs能被植物细胞吸收。     

G-CNTs/PVDF mixed matrix membranes with improved antifouling properties and filtration performance

A novel nanocomposite OMWCNT-A-GO was synthesized by conjugating OMWCNT and GO. The P-OMWCNT-A-GO membrane was fabricated by non-solvent induced phase inversion. The P-OMWCNT-A-GO exhibits the best water flux, BSA rejection and flux recovery. It should be due to the enhanced membrane pore size, porosity and hydrophilicity. Although carbon nanomaterials have been widely used as effective nanofillers for fabrication of mixed matrix membranes (MMMs) with outstanding performances, the reproducibility of the fabricated MMMs is still hindered by the non-homogenous dispersion of these carbon nanofillers in membrane substrate. Herein, we report an effective way to improve the compatibility of carbon-based nanomaterials with membrane matrixes. By chemically conjugating the oxidized CNTs (o-CNTs) and GO using hexanediamine as cross-linker, a novel carbon nanohybrid material (G-CNTs) was synthesized, which inherited both the advanced properties of multi-walled carbon nanotubes (CNTs) and graphene oxide (GO). The G-CNTs incorporated polyvinylidene fluoride (PVDF) MMMs (G-CNTs/PVDF) were fabricated via a non-solvent induced phase separation (NIPS) method. The filtration and antifouling performances of G-CNTs/PVDF were evaluated using distillate water and a 1 g/L bovine serum albumin (BSA) aqueous solution under 0.10 MPa. Compared to the MMMs prepared with o-CNTs, GO, the physical mixture of o-CNTs and GO and pure PVDF membrane, the G-CNTs/PVDF membrane exhibited the highest water flux up to 220 L/m²/h and a flux recovery ratio as high as 90%, as well as the best BSA rejection rate. The excellent performances should be attributed to the increased membrane pore size, porosity and hydrophilicity of the resulted membrane. The successful synthesis of the novel nanohybrid G-CNTs provides a new type of nanofillers for MMMs fabrication.     

低传质阻力渗流式纳米电极电化学反应器处理活性艳蓝X-BR

采用渗流式电化学反应器,以碳纳米管和活性碳纤维作为反应器的阳极.选取活性艳蓝X-BR模拟废水作为实验对象,计算电化学过程的传质系数,考察电压、pH值和电解质对活性艳蓝脱色的影响,在优化条件下(电压为8V,pH=2,电解质浓度为1g·l-1),对浓度为200mg·l-1活性艳蓝X-BR的脱色率可达90%以上.     

硝酸处理的碳纳米管吸附水溶液中汞离子的研究

碳纳米管是一种具有独特结构和优异性能的纳米材料。该文研究了硝酸处理的碳纳米管作为吸附剂吸附水溶液中的汞离子的吸附特性,考察了溶液pH值、吸附时间、溶液浓度以及吸附剂的量等因素对吸附行为的影响。实验结果表明:在pH值为2～5的范围内,碳纳米管对汞离子的吸附量随着pH值的增大而增大,并在pH为5时(对汞离子的吸附量)达到了最大值,在pH大于5时,pH值对吸附效果影响不大。碳纳米管吸附汞离子的量随着吸附时间的增加而增大,且在60min内达到了吸附平衡,当Hg2+浓度为20mg/L时吸附量为16.63mg/g。通过对Langmuir和Freundlich方程对吸附等温线的拟合比较,Langmuir方程更适合描述吸附特性。随着吸附剂量增加,吸附效率上升。研究结果表明,硝酸处理的碳纳米管是一种有效的水溶液中汞离子的吸附剂。     

TX100悬浮的多壁纳米碳管在土壤中运移及其对菲迁移的影响

采用柱淋溶实验研究了TX100悬浮的多壁纳米碳管在土柱中的淋溶行为及其对菲在土壤中迁移的影响,并用胶体运移的一级动力学对流-弥散模型对纳米碳管在土柱中的迁移能力进行了估算.实验结果表明,在砂土和粉砂壤土中分别有83.5%和73.4%的多壁纳米碳管能够穿透土柱,模型估算的最远迁移距离均大于200cm,说明多壁纳米碳管有向...     

Synergistic removal of aniline by carbon nanotubes and the enzymes of Delftia sp. XYJ6

Synergistic removal of aniline by carbon nanotubes and the enzymes of Delftia sp. XYJ6, a newly isolated bacterial strain for biodegrading aniline, was investigated. It showed that biodegradation rate of aniline was increased with the augment of protein concentration in cell-free extract of Delftia sp. XYJ6. The adsorption amount of aniline by multi-walled carbon nanotubes (MWCNTs) was slightly higher than that by single-walled carbon nanotubes (SWCNTs), however the adsorption amount of protein of Delftia sp. XYJ6 by MWCNTs was lower than that by SWCNTs. Much more amount of aniline could be removed by CE of Delftia sp. XYJ6 in the presence of SWCNTs than MWCNTs, which indicated that an efficient reaction between aniline and enzymes of Delftia sp. XYJ6 on the surface of SWCNTs played a key role in the rapid enzymatic biodegradation of aniline. This study is not previously reported and may be useful in basic research and the removal of aniline from wastewater.     

碳纳米管修饰玻碳电极测定邻苯二酚的研究

文章借助循环伏安法(CV)研究了邻二苯酚(CAT)在碳纳米管修饰玻碳电极(CNTs/GCE)表面的电催化氧化行为.试验结果表明:CNTs/GCE对邻二苯酚的氧化过程表现出良好的催化活性,其响应峰电流与裸GCE相比增加了10倍以上;在最佳响应条件下,在0.25～2.0 mmol/L的浓度范围内,邻苯二酚的催化氧化峰电流与...     

Photocatalytic degradation of Rhodamine B bymicrowave-assisted hydrothermal synthesized N-doped titanate nanotubes

Microwave-induced nitrogen-doped titanate nanotubes（NTNTs） were characterized by transmission electron microscopy（TEM）, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, Fourier transform infrared spectroscopy（FT-IR）, Zeta potential analysis,specific surface area（SBET）, and UV-Visible spectroscopy. TEM results indicate that NTNTs retain a tubular structure with a crystalline multiwall and have a length of several hundred nanometers after nitrogen doping. XRD findings demonstrate that the crystalline structure of NTNTs was dominated by anatase, which is favored for photocatalytic application. The Ti-O-N linkage observed in the XPS N 1s spectrum is mainly responsible for narrowing the band gap and eventually enhancing the visible light photoactivity. FT-IR results demonstrated the existence of H3O＋, which could be excited by photo-generated holes to form hydroxyl radicals and degrade environmental pollutants. After sintering at 350°C, the UV-Vis absorbance edges of NTNTs significantly shift to the visible-light region, which indicates N atom doping into the nanotubes. Photocatalytic degradation of Rhodamine B（RhB） via NTNTs show good efficiency, with pseudo first-order kinetic model rate constants of 3.7 × 10-3, 2.4 × 10-3and 8.0 × 10-4sec-1at pH 3, 7, and 11, respectively.     

石墨烯-TiO2光催化剂复合板制备及其对五氯酚的催化降解

针对基于石墨烯-TiO_2的光催化剂多为粉末状,用于处理实际淋洗液时难以有效回收这一问题,研究以氧化石墨烯和粉末TiO_2为前期物使用水热法结合类溶胶凝胶涂布法制备出了可重复使用的石墨烯-TiO_2纳米管复合板,复合板的宏观形貌均一,催化剂在板的大部分区域上以层数较少的形式负载.应用制备的复合板对土壤淋洗液体系中的五氯酚(pentachlorophenol,PCP)进行光催化降解,在太阳光照下可在30 min内完全去除污染物,比无催化剂条件下的降解速率提高5倍以上;以氙灯作为模拟太阳光源,降解速率提高10倍.复合板经长时间浸泡和重复使用后,光催化活性无明显下降,具有长期使用的潜力.复合板的制备解决了催化剂的固定化问题,有利于分离回收等后续处理.