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Adsorption behaviour of methylene blue on carbon nanoparticles

MIcRO & NANO LETTERS 2012年第10期7卷 1060-1063页

作者： Yang, Sheng-Tao Luo, Jianbin Zhou, Qinghan Wan, Jing Ma, chen Liao, Rong Southwest Univ Nationalities Coll Chem & Environm Protect Engn Chengdu 610041 Peoples R China

Nanoadsorbents have been regarded as promising materials for water treatment. The adsorption behaviour determines the applications of nanoadsorbents. In this reported work, the authors studied the adsorption behaviour of methylene blue on oxidised carbon nanoparticles (O-cNPs) in batch experiments. The adsorption data were fitted by the Freundlich model, rather than the Langmuir model. The kinetics studies indicated that it followed the pseudo-second-order model. The intraparticle diffusion model fitting suggested that the adsorption involved both intraparticle diffusion and surface diffusion. The adsorption was more effective at higher pH and lower ionic strength. The implication for the applications of O-cNPs in water treatment is discussed.

关键词： nanoparticles Surface diffusion, segregation and interfacial compound formation dyes c adsorption Langmuir model pseudo-second-order model pH Adsorption and desorption kinetics Sorption and accommodation coefficients (surface chemistry) surface diffusion evaporation and condensation intraparticle diffusion model nanoadsorbents ionic strength carbon nanoparticles water treatment Freundlich model carbon methylene blue

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Biomass-derived porous carbon-protected silver nanoflowers construction of long-term stable SERS substrate for ultrasensitive detection of organic pollution

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JOURNAL OF MATERIALS RESEARcH 2023年第2期38卷 519-531页

作者： Zhu, Sijia Wang, Qing Yang, Jinhui Li, Hongmei Gao, Ningning Zhong, Furu Fu, Jihong Tang, Jun Wang, Tao Xinjiang Univ Phys & Chem Anal Ctr Urumqi 830046 Peoples R China Xinjiang Univ Coll Phys & Technol Urumqi 830046 Peoples R China Zunyi Normal Coll Sch Phys & Elect Sci Zunyi 563006 Guizhou Peoples R China Xinjiang Univ Coll Chem Engn Urumqi 830046 Peoples R China

Biomass-derived porous carbon (Pc) loaded with precious metals have a synergistic enhancement effect on surface-enhanced Raman scattering (SERS). In this paper, Pc containing various functional groups and large specific surface area, good stability and certain biocompatibility were prepared using tomato skins and introduced into the preparation of Ag nanoflowers (NFs) SERS substrates. Rhodamine 6G (R6G) was used as the Raman probe molecule to evaluate the sensing performance of Ag NFs@Pc. The results showed that the stable dispersion and protective effect of Pc on Ag NPs significantly improved the sensitivity and long-term stability of traditional Ag NFs. In practical application, Ag NFs@Pc was further used to successfully achieve the quantitative analysis of trace methylene blue (10 ppt) and malachite green (10 ppt) in a lake water system. Therefore, SERS sensor Ag NFs@Pc is expected to become a promising candidate sensor for detecting in the field of environment and food monitoring.

关键词： Surface enhanced Raman spectroscopy (SERS) Porosity c Ag Sensor Environment

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Energetics of graphene origami and their "spatial resolution"

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MRS BULLETIN 2021年第6期46卷 481-486页

作者： Yang, Yang Zhang, Zhuhua Hu, Zhili Penev, Evgeni S. Yakobson, Boris I. Rice Univ Dept Mat Sci & NanoEngn Houston TX 77005 USA Nanjing Univ Aeronaut & Astronaut State Key Lab Mech & Control Mech Struct Key Lab Intelligent Nano Mat & Devices Minist EducInst Nano Sci Nanjing Peoples R China

The extreme thinness of graphene combined with its tensile strength made it a material appealing for discussing and even making complex cut-kirigami or folded-only origami. In the case of origami, its stability is mainly defined by the positive energy of the single- or double-fold curvature deformation counterbalanced by the energy reduction due to favorable van der Waals contacts. These opposite sign contributions also have notably different scaling with the size L of the construction, the contacts contributing in proportion to area similar to L-2, single folds as similar to L, and highly strained double-fold corners as only similar to L-0 = const. computational analysis with realistic atomistic-elastic representation of graphene allows one to quantify these energy contributions and to establish the length scale, where a single fold is favored (7 nm < L < 21 nm) or a double fold becomes sustainable (L > 21 nm), defining the size of the smallest possible complex origami designs as L >> 21 nm.

关键词： Nanostructure c Elastic properties Aid architecture

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Application of electrochemical techniques for the control of cracks and steel corrosion in concrete

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JOURNAL OF APPLIED ELEcTROcHEMISTRY 2002年第6期32卷 635-639页

作者： Ryu, JS Otsuki, N Univ Calif Berkeley Dept Civil & Environm Engn Berkeley CA 94720 USA Tokyo Inst Technol Dept Int Dev Engn Tokyo 1528552 Japan

Electrochemical techniques are becoming increasingly popular as a means of rehabilitating deteriorated reinforced concrete. In this paper we explore the possibility of using an electrodeposition technique for repairs of land-based cracked concrete structures and investigate the effect of this technique on various concrete properties. concrete specimens reinforced with steel rebars were used as test specimens in this study. The specimens were first precracked by exposing rebars to chloride-induced corrosion, and then immersed in a solution of zinc sulfate and subjected to a constant d.c. current. The current was applied between the reinforcing steel in the concrete and an external electrode immersed in the solution for eight weeks. The degree of crack closure, water permeability, condition of reinforcing steel, and chloride concentration were investigated in order to assess the effectiveness of this method as a potential rehabilitation technique. The results indicate that the formation of electrodeposits caused the closure of cracks and led to improvement of the concrete watertightness. In addition, the investigation shows that the application of the electrical current increases the passivity of steel in concrete.

关键词： corrosion d c current electrodeposition external electrode passivity reinforced concrete

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Effects of rotational restraints on the thermal buckling of carbon nanotube

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MIcRO & NANO LETTERS 2019年第2期14卷 158-162页

作者： Yayli, Mustafa Ozgur Bursa Uludag Univ Dept Civil Engn Fac Engn 16059 Gorukle Campus Bursa Turkey

The thermal buckling response of nanotubes with rotational restraints is investigated using a Timoshenko beam model with non-local elasticity theory. Two trigonometric (Fourier) series are selected to analyse the thermal buckling of the non-local Timoshenko nanotube with rotational restraints. Explicit equations are obtained for the boundary values with a coefficient matrix. In particular, the new method can be degenerated to the non-local Euler beam model by assigning proper value to the shear correction factor. The main advantage of the present technique is its capability of dealing with deformable or rigid supporting conditions. Several numerical examples are solved to asses proposed approach reliability. The results show that thermal buckling including the thermal effects are lower than those without the thermal effects when the temperature rises. The rotational restraint springs have significant effects on the buckling response of nanotubes.

关键词： carbon nanotubes buckling springs (mechanical) Fourier series carbon nanotube Timoshenko beam model nonlocal elasticity theory nonlocal Euler beam model thermal effects rotational restraint springs thermal buckling trigonometric Fourier series shear correction factor c

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Influence of carbon black with different concentration on dynamic properties and heat buildup of semi-efficient natural rubber composites

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MIcRO & NANO LETTERS 2016年第7期11卷 402-406页

作者： Zhang, Huan Zhang, Zhiyi Zhao, Guizhe Liu, Yaqing North Univ China Shanxi Key Lab Nano Funct Composite Mat Taiyuan 030051 Peoples R China North Univ China Coll Mat Sci & Engn Taiyuan 030051 Peoples R China

High abrasion furnace black (HAF) filler has long been recognised as reinforcing filler, but the impact of concentration on dynamic mechanics performance and heat buildup of vulcanisates is rarely reported. Therefore, natural rubber (NR) composites filled by N330 with different concentration were prepared. Payne effect and heat buildup of HAF/NR composites increases with an increase of HAF loadings during to that filler network structure become stronger with an increase of HAF loadings. Moreover, tensile strength, tear strength as well as modulus increase with an increase of HAF loadings is attributed to better dispersion and improved interfacial interaction between HAF and NR matrices. The results reveal that composites with 60 per hundreds of rubber (phr) of HAF exhibit better overall mechanical properties and lower heat buildup.

关键词： carbon filled polymers rubber tensile strength abrasion carbon black dynamic properties heat buildup semiefficient natural rubber composites high abrasion furnace black filler dynamic mechanics vulcanisates tensile strength tear strength tear modulus interfacial interaction mechanical properties c

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Preparation of fluorescent carbon dots from peat for Fe³⁺ sensing and cellular imaging

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MIcRO & NANO LETTERS 2020年第2期15卷 86-89页

作者： Han, Shuai Wu, Baoshuang Wang, Hong Wang, Guangshuo Yang, Jiajia He, Leqin Wei, Fangfang Qin, Shenjun Hebei Univ Engn Coll Mat Sci & Engn Handan 056038 Peoples R China Hebei Univ Engn Key Lab Resource Explorat Res Hebei Prov Handan 056038 Peoples R China First Hosp Hebei Shijiazhuang City Dept Geriatr 1 Shijiazhuang 050011 Hebei Peoples R China

Novel fluorescent carbon dots (cDs) were fabricated using the hydrothermal carbonisation method by peat, which is a very abundant and low-cost natural material in the world. The transmission electron microscopy images revealed that the peat-derived cDs (PcDs) are well-crystalline with an average size of 4 mm Fourier transform infrared and X-ray photoelectron spectra suggested large amounts of oxygenous functionality which made the synthesised PcDs water-soluble. The optical characterisations turned out that PcDs showed a stable and excellent excitation-dependent photoluminescence (PL), while the quantum yield was calculated to be 18.3%. As the PL of the PcDs could be efficiently quenched by ferric ions with a low-detection limit of 20 nM, the as-prepared PcDs could be employed as a highly fluorescent probe for ferric ions. Furthermore, the obtained PcDs have been successfully used for fluorescent imaging and Fe3+ detecting at cell level.

关键词： photoluminescence nanofabrication scanning electron microscopy solubility chemical sensors X-ray photoelectron spectra carbon radiation quenching cellular biophysics fluorescence transmission electron microscopy X-ray diffraction Fourier transform infrared spectra nanosensors nanostructured materials biosensors nanobiotechnology cellular imaging novel fluorescent carbon dots hydrothermal carbonisation method low-cost natural material transmission electron microscopy images peat-derived cDs X-ray photoelectron spectra oxygenous functionality optical characterisations excitation-dependent photoluminescence ferric ions low-detection limit as-prepared PcDs highly fluorescent probe fluorescent imaging PcDs water-soluble size 4.0 nm Fe c

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Superior lithium storage performance of polyacrylonitrile-modified NASIcON structure Na3V2(PO4)3 materials

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JOURNAL OF THE AUSTRALIAN cERAMIc SOcIETY 2020年第3期56卷 1073-1077页

作者： Jia, Maomao Su, Zhi Tian, Hualing Xinjiang Normal Univ Coll Chem & Chem Engn Urumqi 830054 Xinjiang Peoples R China

Nanoparticle Na3V2(PO4)(3)/c materials with different polyacrylonitrile contents can be successfully synthesized using precipitation method. As an energy storage material used in the production of lithium batteries which is also compared with pure of that, the Na3V2(PO4)(3)/c not only has a larger capacity, but also has a very high cycle stability. In particular, the initial discharge capacities of the Na3V2(PO4)(3)/c sample annealed at 750 degrees c containing 10 wt% of polyacrylonitrile are 130.9 and 122.2 mAh g(-1) at current densities of 0.5 and 1 c, respectively;the corresponding coulomb efficiencies are 97.3 and 99.5%. It is also worth noting that the capacity retention can reach as high as 92.7% for 500 cycles at 1 c.

关键词： cathode materials Energy conversion Energy transfer Nanomaterials Na3V2(PO4)(3) c

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Effect of preparation methods of graphene oxide on permeability of free-standing membranes against polar and nonpolar species

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SOFT MATERIALS 2021年第1期19卷 24-39页

作者： Zomorodkia, Ali Asghar Bazgir, Saeed Zaarei, Davood Gorji, Mohsen Ardjmand, Mehdi Islamic Azad Univ Sci & Res Branch Dept Chem Engn Tehran Iran Islamic Azad Univ South Tehran Branch Dept Polymer Engn Tehran Iran Amirkabir Univ Technol NTRC Tehran Iran Islamic Azad Univ South Tehran Branch Dept Chem Engn Tehran Iran

In this study, graphene oxide (GO) was synthesized using Hummers, modified Hummers and improved Hummers methods, and then freestanding membranes were prepared based on these materials. Effects of different GO preparation methods on c/O ratio and interlayer spacing of freestanding membranes were studied. Structure of these membranes was studied by X-ray diffraction, contact angle, XRF, FT-IR, and FESEM methods. Also, permeability of ammonia, dichloromethane, and water vapor was investigated through these membranes. Results showed that, the sample prepared by the Hummers method had lower c/O ratio, smoother surface and lower permeability for polar species, such as water and ammonia vapors, than nonpolar materials. Membranes prepared using Improved Hummers method showed the least permeability against nonpolar vapors such as dichloromethane.

关键词： Freestanding Membranes c O Ratio interlayer Spacing Hummers Method

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Prediction of gas product yield from packaging waste pyrolysis: support vector and Gaussian process regression models

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INTERNATIONAL JOURNAL OF ENVIRONMENTAL ScIENcE AND TEcHNOLOGY 2023年第1期20卷 461-476页

作者： Yapici, E. Akgun, H. Ozkan, K. Gunkaya, Z. Ozkan, A. Banar, M. Eskisehir Tech Univ Fac Engn Dept Environm Engn TR-26555 Eskisehir Turkey Eskisehir Osmangazi Univ Fac Engn & Architecture Dept Comp Engn Eskisehir Turkey

The pyrolysis process enables the transformation of plastic waste into products such as oil, solid residue, and gas at temperatures of around 300-900 degrees c by thermal decomposition. conversion of such waste into valuable products depends on various factors, such as raw material composition, temperature, heating rate, residence time, and catalyst. From this point of view, in this study, predictions of gas product yield based on different pyrolysis conditions including waste types (LDPE-c/LDPE), temperature (400-600-800 degrees c), heating rate (5-10-20 degrees c/min), type of catalyst (zeolite-clay-sludge) and amount of catalyst (5%, 10%, 15%, by weight) were carried out with support from the vector regression (SVR) and the Gaussian process (GPR) models using the results of experimental studies performed under various conditions. Different kernel functions were used for SVR (Linear, Quadratic, cubic, Gaussian) and GPR (Squared Exponential, Matern 5/2, Exponential, Rational Quadratic). The Gaussian Kernel Function presented a good prediction performance (89% R-2 and 0.0011 RMSE) for SVR while the Exponential Kernel Function was the most appropriate for GPR (93% R-2 and 0.0011 RMSE). On the other hand, the deviations in the SVR model with linear Kernel change over a wide range of 0.25-80.85%, and the GPR model with exponential kernel show deviations close to each other in the range of 0.06-3.91%. The present study provides new information for future studies by understanding the pyrolysis process of plastic waste and predicting product yield.

关键词： c LDPE Gaussian process regression LDPE Pyrolysis Support vector regression

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