Behavior of hydrophobic ionic liquids as liquid membranes on phenol removal: Experimental study and optimization

Room temperature ionic liquids show potential as an alternative to conventional organic membrane solvents mainly due to their properties of low vapor pressure, low volatility and they are often stable. In the present work, the technical feasibilities of room temperature ionic liquids as bulk liquid membranes for phenol removal were investigated experimentally. Three ionic liquids with high hydrophobicity were used and their phenol removal efficiency, membrane stability and membrane loss were studied. Besides that, the effects of several parameters, namely feed phase pH, feed concentration, NaOH concentration and stirring speeds on the performance of best ionic liquid membrane were also evaluated. Lastly, an optimization study on bulk ionic liquid membrane was conducted and the maximum phenol removal efficiency was compared with the organic liquid membranes. The preliminary study shows that high phenol extraction and stripping efficiencies of 96.21% and 98.10%, respectively can be achieved by ionic liquid membrane with a low membrane loss which offers a better choice to organic membrane solvents. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down

Emulsion stabilization using ionic liquid [BMIM](+)[NTf(2)](-) and performance evaluation on the extraction of chromium

This study focuses on the role of a hydrophobic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [BMIM](+)[NTf(2)](-) in the preparation of emulsion liquid membrane (ELM) phase containing kerosene as solvent, Span 80 as surfactant, NaOH as internal phase and TOMAC (tri-n-octylmethylammonium chloride) a second ionic liquid as carrier. The first time used [BMIM](+)[NTf(2)](-) in ELM was found to play the role of a stabilizer. The emulsion prepared using [BMIM](+) [NTf(2)](-) has a long period of stability of about 7h (at 3% (w/w) of [BMIM](+)[NTf(2)](-)) which otherwise has a brief stability up to only 7min. The stability of the emulsion increases with the increase in concentration of [BMIM](+)[NTf(2)](-) up to 3% (w/w). Nevertheless, with further increase in concentration of [BMIM](+)[NTf(2)](-), a reduction in the stability occurs. The extraction experiments were carried out after holding the ELM for 2h after the preparation and a removal efficiency of approximately 80% was obtained for Cr. The destabilization of the emulsion was studied by observing the change in the interface height. An empirical correlation for the stability of the emulsion has been proposed

A comparative study of experimental optimization and response surface optimization of Cr removal by emulsion ionic liquid membrane

A comparative study on the optimization of process parameters of an emulsion ionic liquid membrane (EILM) by experimental work and response surface methodology (RSM) has been carried out. EILM was prepared by using kerosene as solvent, Span 80 as surfactant, NaOH as internal reagent, a hydrophobic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM](+)[NTf(2)](-)) as a stabilizer and a second ionic liquid tri-n-octylmethylammonium chloride (TOMAC) as a carrier. The prepared EILM was used to separate and concentrate Cr from wastewaters. The comparison between the experimentally optimized and the RSM optimized values was accomplished by optimizing the following parameters: homogenization speed, carrier concentration, internal phase concentration, agitation speed, treat ratio, internal to membrane phase ratio, surfactant concentration and pH of the feed phase. The comparison showed that all the values were in good agreement except for the internal phase concentration and the treat ratio. It was observed that the stability provided by [BMIM](+)[NTf(2)](-) decreased as the extraction progressed due to its high density. Nevertheless, a good stability could be obtained by the combination of [BMIM](+)[NTf(2)](-) and Span 80 during extraction process

Experimental and theoretical investigation of parametric sensitivity and dynamics of a continuous stirred tank reactor for acid catalyzed hydrolysis of acetic anhydride

The continuous stirred tank reactor is a dynamic system exhibiting nonlinear behavior such as multiplicity and oscillations and, in certain range of operating conditions, may exhibit a parametric sensitivity where small changes in one or more of the input parameters lead to large changes in the output variable. In the present work, hydrolysis of acetic anhydride reaction system was used to demonstrate the existence of parametric sensitivity with respect to the input parameter, the cooling water flow rate. The applications of parametric sensitivity analysis were used for detection of parametric sensitivity in a continuous stirred tank reactor using catalyses hydrolysis of acetic anhydride reaction system. Also, theoretical investigation revealed that the effect of wall capacitance has definite influence on the dynamics of continuous stirred tank reactor. The continuous stirred tank reactor showed parametric sensitivity both in the regions of uniqueness and multiplicity, and a mathematical model was developed for the reactor. The numerically simulated results are in satisfactory agreement with the experimental data

Performance of Choline-Based Deep Eutectic Solvents in the Extraction of Tocols from Crude Palm Oil

Deep eutectic solvents are emerging green solvents that have potential in many separation processes. This study investigates the performance of choline-based deep eutectic solvents in the extraction of tocopherols and tocotrienols (collectively known as tocols) from palm oil, a major natural source of tocols. Deep eutectic solvents comprised of choline chloride salt and selected carboxylic acids as hydrogen bond donors were prepared and used in the extraction of tocols from crude palm oil by liquid-liquid extraction. Tocols concentration in the extracted product was at least double that in the control (8671 mg/kg compared to 3285 mg/kg, respectively). Increasing the amount of the deep eutectic solvents increased the tocols concentration in the extracted product up to 18,525 mg/kg, but the yields lowered from 4 % to less than 1 %. The tocols profile was significantly improved by the increase of the tocotrienols fraction in the products from 80.8 to 99.8 %. This study showed that unique interaction between the selected deep eutectic solvents with the tocols make it possible to selectively separate individual tocols in palm oil, where products with fractions rich in tocotrienols and low in tocopherols (particularly alpha-tocopherol) are favorable

Novel microwave-assisted multiwall carbon nanotubes enhancing Cu (II) adsorption capacity in water

Microwave induced multiwall carbon nanotubes (MWCNTs) synthesized use a tubular microwave chemical vapor deposition technique, using acetylene and hydrogen as the precursor gases, and ferrocene as the catalyst. The novel MWCNT samples tested for performances in terms of Cu (II) binding were synthesized and characterized using BET,HRTEM,FESEM analysis and using this sample adsorption of Cu (II) they were studied as a function of pH, initial Cu (II) concentration, MWCNTs dosage, agitation speed, and adsorption time. The effect of process parameters for the adsorption of Cu (II) such as pH, MWCNTs dosage, agitation speed, and adsorption time was optimized. The adsorption data followed both Freundlich and Langmuir isotherms. On the basis of the Langmuir model, q < inf > m < /inf > was calculated to be 99mg/g for microwave-synthesized MWCNTs. In order to investigate the dynamic behavior of MWCNTs as an adsorbent, the kinetic data were modelled using the pseudo-second-order and second-order. Different thermodynamic parameters, viz., ?H°, ?S° and ?G° have also been evaluated and it has been found that the adsorption was feasible, spontaneous and endothermic in nature. The statistical analysis reveals that the optimum conditions for the highest removal (99.9%) of Cu (II) are at pH 5.5, MWCNTs dosage 0.1 g, contact time 35min and agitation speed of 160rpm. Our results prove that microwave-assisted MWCNTs can be used as an effective Cu (II) adsorbent due to the high adsorption capacity as well as the short adsorption time needed to achieve an equilibrium

Joint Measurement of the 235^{235}U Antineutrino Spectrum by Prospect and Stereo

International audienceThe PROSPECT and STEREO collaborations present a combined measurement of the pure U235 antineutrino spectrum, without site specific corrections or detector-dependent effects. The spectral measurements of the two highest precision experiments at research reactors are found to be compatible with χ2/ndf=24.1/21, allowing a joint unfolding of the prompt energy measurements into antineutrino energy. This ν¯e energy spectrum is provided to the community, and an excess of events relative to the Huber model is found in the 5–6 MeV region. When a Gaussian bump is fitted to the excess, the data-model χ2 value is improved, corresponding to a 2.4σ significance