http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Mantsopa Koena Selatile,Suprakas Sinha Ray,Vincent Ojijo,Rotimi Sadiku 한국섬유공학회 2019 Fibers and polymers Vol.20 No.1
In this study, the tensile properties of systematically optimised, biodegradable polylactide (PLA) electrospum fibres are investigated in order to illuminate the influences of the factors that affect their mechanical properties such as fibre diameter, alignment, inter-fibre bonding, mat porosity, and packing density. The effect of fibre diameter was studied by varying the PLA concentration. The effect of fibre-fibre interaction enhancement was also investigated. The extent of anisotropy on the mechanical properties of the mats was evaluated as a function of the collector drum speed in the rotational (0 o), transverse (90 o), and diagonal (45 o) directions. The results demonstrate a strong correlation between the fibre diameter and the mechanical properties. Thinner fibres exhibit better mechanical properties, which are then further enhanced by fibre fusion and alignment. Other mat characteristics have minimal effects on the mechanical properties. The fibres produced atdrum speeds of <250 rpm, exhibit isotropic character. Fibre alignment is observed beyond this speed, with strong enhancement of properties in the direction of drum rotation. In summary, randomly oriented fibres with isotropic responses to mechanical properties may be used in applications such as air filtration.
E. Fosso-Kankeu,Hemant Mittal,F. Waanders,Suprakas Sinha Ray 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.48 No.-
This research paper reports on the utilization of the hydrogel of gelatine (GL) and its hybridnanocomposite with clinoptilolite for the adsorption of Cd2+ ions from an aqueous solution and multimetalions from mine effluents. The hydrogel was synthesized using the graft co-polymerization ofacrylamide (AAm) onto GL and the hybrid hydrogel nanocomposite was prepared by incorporatingclinoptilolite within the hydrogel matrix. The synthesized polymers were characterized using differentcharacterization techniques such as FTIR, XRD, SEM and TGA. The adsorption behaviour of thesynthesized adsorbents for the adsorption of Cd2+ was studied using different adsorption parameterssuch as pH, temperature and adsorbent dosage. Adsorption kinetics followed the pseudo-second-orderrate equation, whereas, the adsorption isotherm followed both the Freundlich and Langmuir isothermmodels. The thermodynamics studies revealed that the adsorption processes were spontaneous andendothermic in nature. Moreover, the synthesized adsorbents were also successfully utilized for theadsorption of different metal ions from the mine effluents.
Kumar Neeraj,Setshedi Katlego,Masukume Mike,Ray Suprakas Sinha 한국탄소학회 2022 Carbon Letters Vol.32 No.4
As frontier materials, graphene oxide (GO) and graphene have penetrated almost all research areas and advanced numerous technologies in sensing, electronics, energy storage, catalysis, water treatment, advanced composites, biomedical, and more. However, the affordable large-scale synthesis of high-quality GO and graphene remains a significant challenge that negatively affects its commercialisation. In this article, firstly, a simple, scalable approach was demonstrated to synthesise high-quality, high yield GO by modifying the improved Hummers method. The advantages of the optimised process are reduced oxidation time, straightforward washing steps without using coagulation step, reduction in cost as eliminating the use of phosphoric acid, use of minimum chemical reagents, and increased production of GO per batch (~ 62 g). Subsequently, the produced GO was reduced to reduced graphene oxide (rGO) using three different approaches: green reduction using ascorbic acid, hydrothermal and thermal reduction techniques. The GO and rGO samples were characterised using various microscopy and spectroscopy techniques such as XRD, Raman, SEM, TEM, XPS and TGA. The rGO prepared using different methods were compared thoroughly, and it was noticed that rGO produced by ascorbic acid reduction has high quality and high yield. Furthermore, surface (surface wettability, zeta potential and surface area) and electrical properties of GO and different rGO were evaluated. The presented synthesis processes might be potentially scaled up for large-scale production of GO and rGO.
Nthambeleni Mukwevho,Rashi Gusain,Elvis Fosso-Kankeu,Neeraj Kumar,Frans Waanders,Suprakas Sinha Ray 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.81 No.-
In this study, a ZnO/Ag/GO nanocomposite was synthesised and used as photocatalyst for effectivephotodegradation of naphthalene from simulated wastewater under visible light. Chemical andmorphological characterisation were successfully done using XRD, PL, UV–vis, FTIR, XPS, FESEM andHRTEM analytical tools. Photocatalytic degradation experiments werefirst carried out under darkconditions and then under visible-light irradiation. Adsorption study of naphthalene prior tophotocatalysis using synthesised material was thoroughly done by studying the kinetics and adsorptionisotherm models. All as-synthesised materials (ZnO nanoparticles, binary ZnO/Ag, and ternary ZnO/Ag/GO nanocomposites) followed pseudo-second-order kinetics and the Freundlich adsorption isotherm,confirming the adsorption on hetero-structural surface. ZnO/Ag/GO could successfully adsorb 80%naphthalene in 20 min, with 500 mg.g 1 adsorption capacity. High adsorption of naphthalene moleculeson ZnO/Ag/GO surfaces trigger improved photodegradation efficiency upon light irradiation. Incorporationof plasmonic Ag nanoparticles and 2D graphene oxide (GO) to ZnO semiconductor improved thephotocatalytic degradation efficiency of naphthalene, achieving up to 92% degradation in 50 min. Thephotodegradation of naphthalene follows the Langmuir-Hinshelwood kinetics model and was foundacceptable to express the photodegradation rate. Furthermore, the ZnO/Ag/GO photocatalyst could easilybe recycled and reused forfive cycles, maintaining up to 85% of its photodegradation efficiency.