Using density functional theory, noncovalent interactions and two mechanisms of covalent functionalization of drug carmustine with functionalized carbon nanotube（CNT） have been investigated. Quantum molecular descri...Using density functional theory, noncovalent interactions and two mechanisms of covalent functionalization of drug carmustine with functionalized carbon nanotube（CNT） have been investigated. Quantum molecular descriptors of noncovalent configurations were studied. It was specified that binding of drug carmustine with functionalized CNT is thermodynamically suitable. NTCOOH and NTCOCl can bond to the NH group of carmustine through OH（COOH mechanism） and Cl（COCl mechanism） groups, respectively. The activation energies, activation enthalpies and activation Gibbs free energies of two pathways were calculated and compared with each other. The activation parameters related to COOH mechanism are higher than those related to COCl mechanism, and therefore COCl mechanism is suitable for covalent functionalization. COOH functionalized CNT（NTCOOH） has more binding energy than COCl functionalized CNT（NTCOCl） and can act as a favorable system for carmustine drug delivery within biological and chemical systems（noncovalent）. These results could be generalized to other similar drugs.展开更多
Pristine and poly(tert-butyl acrylate) (PTBA) functionalized carbon nanotubes are continuously exposed to 2.41 eV laser irradiation while collecting Raman spectra. The loss of the intensity of the radial breathing mod...Pristine and poly(tert-butyl acrylate) (PTBA) functionalized carbon nanotubes are continuously exposed to 2.41 eV laser irradiation while collecting Raman spectra. The loss of the intensity of the radial breathing modes (RBMs) of small metallic PTBA functionalized nanotubes is less than that of pristine nanotubes. A reduction of the intensity of the G? band of pristine SWNTs occurs such that the overall shape of the G band evolves to resemble that of the PTBA functionalized sample. Complementing the measurement of the ratio of intensities of the D and G bands, the laser-in- duced spectral changes provide another way to determine the sidewall functionalization of carbon nanotubes. The laser-induced changes of the G and RBM bands are consistent with the greater sidewall reactivity of small metallic nanotubes toward functionalization with PTBA and reaction with photosensitized oxygen.展开更多
建立了羧基化碳纳米管固相萃取-液相色谱-串联质谱联用检测环境水体中四溴双酚 A 和双酚 A 的方法。比较了多壁碳纳米管、C60和羧基化多壁碳纳米管作为固相吸附剂对水体中四溴双酚 A 和双酚 A 的吸附效率。固相萃取浓缩后的样品经 Therm...建立了羧基化碳纳米管固相萃取-液相色谱-串联质谱联用检测环境水体中四溴双酚 A 和双酚 A 的方法。比较了多壁碳纳米管、C60和羧基化多壁碳纳米管作为固相吸附剂对水体中四溴双酚 A 和双酚 A 的吸附效率。固相萃取浓缩后的样品经 Thermo Scientific Hypersil C18色谱柱（150 mm±4.6 mm，3μm）分离，采用串联质谱负离子模式进行检测。结果表明，四溴双酚 A 和双酚 A 在0.02～1.0 mg / L 范围内具有良好的线性关系（ r2≥0.99），空白样品中的检出限（S / N =3）分别为0.04μg / L 和0.2μg / L。将所建立的方法应用于实际环境水体中四溴双酚 A和双酚 A 的检测，添加回收率在82％～99％之间，精密度小于5.0％，该方法可用于复杂环境样品中痕量四溴双酚 A和双酚 A 的检测。展开更多
Recently, many attempts have been made to use carbon nanotubes in analytical chemistry, especially in adsorption of heavy metal ions from water. In this study, multiwalled carbon nanotubes (MWCNTs) were functionalized...Recently, many attempts have been made to use carbon nanotubes in analytical chemistry, especially in adsorption of heavy metal ions from water. In this study, multiwalled carbon nanotubes (MWCNTs) were functionalized with tris(2-aminoethyl) amine. The functionalized nanoparticles were characterized using Fourier transform infrared (FTIR), thermal gravimetric analyzer (TGA), elemental analysis, and Raman spectroscopy. The results revealed that the functionalization reaction was successfully accomplished. Lead adsorption from water was carried out using functionalized MWCNTs and measured by flame atomic absorption spectrometry (FAAS). The effects of pH, shaking time, initial metal ion concentration, and adsorbent dosage on the adsorption process were studied via batch method. The results obtained showed that removal of lead ions strongly depended on the pH. Desorption study revealed that lead ions adsorbed on the functionalized MWCNTs could be desorbed at pH 3 due to breakage of complexes formed on the sorbent surface. Maximum adsorption capacity of the sorbent under the optimal conditions was 43 mg/g. This favorable adsorption capacity suggests that functionalized carbon nanotubes can be applied for removal of lead from water solutions. The data obtained were fitted with the Langmuir and Freundlich isotherm adsorption models and Langmuir model showed better agreement with the experimental data.展开更多
文摘Using density functional theory, noncovalent interactions and two mechanisms of covalent functionalization of drug carmustine with functionalized carbon nanotube（CNT） have been investigated. Quantum molecular descriptors of noncovalent configurations were studied. It was specified that binding of drug carmustine with functionalized CNT is thermodynamically suitable. NTCOOH and NTCOCl can bond to the NH group of carmustine through OH（COOH mechanism） and Cl（COCl mechanism） groups, respectively. The activation energies, activation enthalpies and activation Gibbs free energies of two pathways were calculated and compared with each other. The activation parameters related to COOH mechanism are higher than those related to COCl mechanism, and therefore COCl mechanism is suitable for covalent functionalization. COOH functionalized CNT（NTCOOH） has more binding energy than COCl functionalized CNT（NTCOCl） and can act as a favorable system for carmustine drug delivery within biological and chemical systems（noncovalent）. These results could be generalized to other similar drugs.
文摘Pristine and poly(tert-butyl acrylate) (PTBA) functionalized carbon nanotubes are continuously exposed to 2.41 eV laser irradiation while collecting Raman spectra. The loss of the intensity of the radial breathing modes (RBMs) of small metallic PTBA functionalized nanotubes is less than that of pristine nanotubes. A reduction of the intensity of the G? band of pristine SWNTs occurs such that the overall shape of the G band evolves to resemble that of the PTBA functionalized sample. Complementing the measurement of the ratio of intensities of the D and G bands, the laser-in- duced spectral changes provide another way to determine the sidewall functionalization of carbon nanotubes. The laser-induced changes of the G and RBM bands are consistent with the greater sidewall reactivity of small metallic nanotubes toward functionalization with PTBA and reaction with photosensitized oxygen.
文摘建立了羧基化碳纳米管固相萃取-液相色谱-串联质谱联用检测环境水体中四溴双酚 A 和双酚 A 的方法。比较了多壁碳纳米管、C60和羧基化多壁碳纳米管作为固相吸附剂对水体中四溴双酚 A 和双酚 A 的吸附效率。固相萃取浓缩后的样品经 Thermo Scientific Hypersil C18色谱柱（150 mm±4.6 mm，3μm）分离，采用串联质谱负离子模式进行检测。结果表明，四溴双酚 A 和双酚 A 在0.02～1.0 mg / L 范围内具有良好的线性关系（ r2≥0.99），空白样品中的检出限（S / N =3）分别为0.04μg / L 和0.2μg / L。将所建立的方法应用于实际环境水体中四溴双酚 A和双酚 A 的检测，添加回收率在82％～99％之间，精密度小于5.0％，该方法可用于复杂环境样品中痕量四溴双酚 A和双酚 A 的检测。
文摘Recently, many attempts have been made to use carbon nanotubes in analytical chemistry, especially in adsorption of heavy metal ions from water. In this study, multiwalled carbon nanotubes (MWCNTs) were functionalized with tris(2-aminoethyl) amine. The functionalized nanoparticles were characterized using Fourier transform infrared (FTIR), thermal gravimetric analyzer (TGA), elemental analysis, and Raman spectroscopy. The results revealed that the functionalization reaction was successfully accomplished. Lead adsorption from water was carried out using functionalized MWCNTs and measured by flame atomic absorption spectrometry (FAAS). The effects of pH, shaking time, initial metal ion concentration, and adsorbent dosage on the adsorption process were studied via batch method. The results obtained showed that removal of lead ions strongly depended on the pH. Desorption study revealed that lead ions adsorbed on the functionalized MWCNTs could be desorbed at pH 3 due to breakage of complexes formed on the sorbent surface. Maximum adsorption capacity of the sorbent under the optimal conditions was 43 mg/g. This favorable adsorption capacity suggests that functionalized carbon nanotubes can be applied for removal of lead from water solutions. The data obtained were fitted with the Langmuir and Freundlich isotherm adsorption models and Langmuir model showed better agreement with the experimental data.
