NOPR Collection:

Fabrication and characterization of composite (nano)polyaniline/polyimide membrane for pervaporative separation of 1-octene/benzene mixtures

2021-02-02T07:29:50Z

Title: Fabrication and characterization of composite (nano)polyaniline/polyimide membrane for pervaporative separation of 1-octene/benzene mixtures Authors: Samanta, Monalisha; Roychowdhury, Sayan; Mitra, Debarati Abstract: The variation of modern separation technology of aromatics/aliphatics mixture is membrane process and development of new membrane materials (polymeric and composite) for high efficiency. Nano-polyaniline has been prepared by bulk polymerisation method and is used for the fabrication of (nano)polyaniline/polyimide ((nano)PANI/PI) composite membrane to achieve pervaporative separation of 1-octene/benzene mixture. Benzene is carcinogenic compound in group 1 of monograph of International Agency for Research on Cancer. Transmission electron microscopy confirmed the generation of (nano)PANI (particle size 8-9 nm). Both membrane and (nano)PANI have been characterised by Fourier transmission infra-red spectroscopy, Scanning electron microscopy, X-ray diffraction and Atomic force microscopy. The swelling behaviour and mechanical properties of the composite membrane are also investigated. Incorporation of (nano) PANI in the polyimide matrix increases the polarity of the membrane, thereby increasing its selectivity towards 1-octene. The highest permeation flux and separation factor achieved are13.88 kg.m-2h-1 and 6.44 respectively at 333 K and 1 mm Hg downstream pressure. Page(s): 441-451

Inhibition of corrosion of mild steel in simulated oil well water by an aqueous extract of Andrographis paniculata

2021-02-02T07:27:53Z

Title: Inhibition of corrosion of mild steel in simulated oil well water by an aqueous extract of Andrographis paniculata Authors: Prabha, A Suriya; Kavitha, K; Shrine, H Benita; Rajendran, Susai Abstract: An aqueous extract of Andrographis paniculata has been used as corrosion inhibitor, in controlling corrosion of mild steel in simulated oil well water (SOWW). Weight loss method reveals that 10 mL of the extract offers 94% inhibition efficiency to mild steel immersed in simulated oil well water (SOWW). The mechanistic aspects of corrosion inhibition have been investigated by electrochemical studies such as polarization study and AC impedance spectra. Polarisation study reveals that the inhibitor system controls the cathodic reaction predominantly as revealed by the shift of the corrosion potential to the cathodic side in presence of the inhibitor system. The corrosion protective nature of the inhibitor is confirmed by the increase in the linear polarization resistance value and decrease in the corrosion current value. The formation of a protective film on the metal surface is confirmed by the AC impedance spectra. This is confirmed by the fact that there is increase in charge transfer resistance value and decrease in double layer capacitance value. The adsorption of the inhibitor molecule obeys Langmuir adsorption isotherm. The protective film has been analyzed FTIR spectra. It confirms that the inhibitor has coordinated with ferrous ion the metal surface through the polar atoms of the inhibitor molecule. The surface morphology of the protective film has been investigated by SEM and AFM. It is observed that in presence of inhibitor the surface of the corroded metal becomes smoother. The Vickers hardness of the metal surface before experimentation and after experimentation has been measured. It is observed that the surface becomes harder in presence of inhibitor than in the absence of inhibitor under the influence of corrosive medium, namely simulated oil well water. The findings have potential application in petroleum industry. The inhibitor extract can be added along with the simulated oil well water in the pipelines made of mild steel. Page(s): 452-460

Study on the relationship between the oxidation degree of GO and the adsorption capacity for Pb2+

2021-02-02T07:25:23Z

Title: Study on the relationship between the oxidation degree of GO and the adsorption capacity for Pb2+ Authors: Xiao, Liu; Zihang, Zhou; Qi, Lisi; Yan, Liu Abstract: In this study, four kinds of graphite oxide (GO) with different oxidation degree have been prepared by a modified Hummers method, by changing the amount of oxidation agent KM_nO₄. To investigate the relationship between the oxidation degree of GO and the adsorption capacity for heavy metal irons, Pb²⁺ solution has been selected as a model waste water. The effects of initial Pb²⁺ concentration, solution pH and contact time on the adsorption capacity of series GO have been studied. It is found that the adsorption capacity does not always increase with the increasing of oxidation degree. The adsorption process of series GO for Pb²⁺ are well described by the Langmuir isotherm model, which reveales that the adsorption process is homogeneous monolayer coverage. Page(s): 461-469

Ultrasound assisted citronella oil in water nanoemulsion and comparison with conventional methods

2021-02-02T07:22:56Z

Title: Ultrasound assisted citronella oil in water nanoemulsion and comparison with conventional methods Authors: Jadhav, A J; Deshpande, A.S; Holkar, C R; Pinjari, D V Abstract: This study involved the acoustic cavitation aided process intensification of citronella oil-based nanoemulsion with varying process parameters. A citronella oil (10 wt. %) in water emulsion was prepared at optimized parameters such as sonication time of 20 min, surfactant concentration of 7.5 wt. % of the total emulsion with (Hydrophilic-lipophilic balance) HLB value of 12 and power amplitude of 35% (of the total power of 750 W). The prepared emulsions stability was assessed over visual observation and kinetic stability of the emulsion after formulation with 7, 30 and 90 days’ time interval term as long-term stability reported as a fraction of phase separation in percentage (f (%)). The ultrasonically prepared emulsion was found to more stable with the mean droplet diameter (MDD) of 22-23 nm, whereas, conventionally prepared emulsion get separated and creamed within the day as well as formulation required more process time and energy dissipation. Page(s): 470-478