Recovery of Aniline from Wastewater by Nitrobenzene Extraction Enhanced with Salting-Out Effect

Objective Nitrobenzene extraction enhanced by salting-out effect was employed to recover aniline from wastewater at 25 ℃. Method Batchwise experiments were conducted to elucidate the influence of various operating variables on the extracting performance, including acidity of wastewater, initial aniline concentration, ratios of solvent to wastewater, extraction stages, concentrations and different types of inorganic salts, such as NaCl, KCI, Na2SO4, CaCl2 and K29O4. Results Nitrobenzene with a concentration of 20% and a pH value of 9.1 at the temperature of 25 ℃ together with NaCl of a concentration of 14 wt.% realized nearly 100% aniline recovery at the fifth stage of wastewater treatment. Conclusions High pH values and volume ratios of nitrobenzene/wastewater are more suitable for recovery of aniline. In addition, recovery of aniline is significantly elevated with increase of the concentration of salts, whose promoting effects are in the following order: NaCI〉Na2SO4〉K2SO4〉CaC12〉KCI on the weight basis of wastewater. Furthermore, aniline in wastewater can be almost completely recovered by five-stage sequential nitrobenzene extraction, which is promoted continuously by the salting-out effect.

Salting-Out Assisted Liquid-Liquid Extraction Combined with HPLC for Quantitative Extraction of Trace Multiclass Pesticide Residues from Environmental Waters

In this study, salting-out assisted liquid-liquid extraction combined with high performance liquid chromatography diode array detector (SALLE-HPLC-DAD) method was developed and validated for simultaneous analysis of carbaryl, atrazine, propazine, chlorothalonil, dimethametryn and terbutryn in environmental water samples. Parameters affecting the extraction efficiency such as type and volume of extraction solvent, sample volume, salt type and amount, centrifugation speed and time, and sample pH were optimized. Under the optimum extraction conditions the method was linear over the range of 10 - 100 μg/L (carbaryl), 8 - 100 μg/L (atarzine), 7 - 100 μg/L (propazine) and 9 - 100 μg/L (chlorothalonil, terbutryn and dimethametryn) with correlation coefficients (R2) between 0.99 and 0.999. Limits of detection and quantification ranged from 2.0 to 2.8 μg/L and 6.7 to 9.5 μg/L, respectively. The extraction recoveries obtained for ground, lake and river waters were in a range of 75.5% to 106.6%, with the intra-day and inter-day relative standard deviation lower than 3.4% for all the target analytes. All of the target analytes were not detected in these samples. Therefore, the proposed SALLE-HPLC-DAD method is simple, rapid, cheap and environmentally friendly for the determination of the aforementioned herbicides, insecticide and fungicide residues in environmental water samples.

Ionic liquid-based salting-out extraction of bio-chemicals

Ionic liquids(ILs)are known as green solvents,and have been widely used in the dissolution and transformation of biopolymers,the extraction of bioactive compounds and metal ions,and the capture of SO2 or CO2.However,less attention was given to the separation of bio-based chemicals,such as diols and organic acids.Bio-based chemicals can be efficiently separated by organic solvent-based salting-out extraction(SOE)from fermentation broths,while organic solvents are normally unfriendly to environment and process safety in commercialized production due to their toxicity or/and flammability.In recent years,the IL-based SOE system has been explored in the separation of bio-based chemicals as an alternative of organic solvent-based SOE system.In this review,the progress of IL-based SOE of biobased chemicals has been summarized,including the effect of ILs structure on the formation of aqueous two phases,and the influences of ILs structure and concentration,temperature and pH on the partition behaviors of target products and ILs as well as removal of impurities.Most of bio-based chemicals could be distributed into the IL-rich phase with high recovery,while the partition behaviors of bio-based chemicals are sometimes different from that in organic solvent-based SOE systems.Although the results of ILbased SOE are promising,further studies are still required in the increased selectivity of target products over by-products,recovery and recycling of ILs,and the separation between ILs and bio-based chemicals.Additionally,three kinds of integrated bioprocesses would be developed on basis of utilization of ILs as extractant for SOE,catalyst for condensation reaction and solvent for pretreatment of lignocellulose.

A review of salting-out effect and sugaring-out effect:driving forces for novel liquid-liquaid extraction of biofuels and biochemicals

Biofuels and bio-based chemicals are getting more and more attention because of their sustainable and renewable properties and wide industrial applications.However,the low concentrations of the targeted products in their fermentation broths,the complicated components of the broths and the high energy-intensive separation and purification process hinder the competitiveness of biofuels and biochemicals with the petro-based ones.Hence,the production and the separation of biofuels and bio-based chemicals in energy-saving,low-cost and greenness ways become hot topics nowadays.This review introduces the separation technologies(salting-out extraction,salting-out,sugaring-out extraction,and sugaring-out)that extract biobutanol,1,3-propanediol,2,3-butanediol,acetoin,organic acids and other bio-based chemicals from fermentation broths/aqueous solutions.Salting-out/sugar-ing-out extraction and salting-out/sugaring-out technologies display the high separating efficiency and the high targeted product yields.In addition,they are easy to operate and require low cost for separating products.Hence,they are the effective and potential technologies for separating targeted products in the wide industrial applications.The successful research into the salting-out/sugaring-out and salting-out/sugaring-out extraction not only affords biofuels and biochemical but also opens a door for the development of novel separation methods.

Liquid-Liquid Equilibrium for 1-Butanol-Water-KF and 1-Butanol-Water-K_2CO_3 Systems

KF or K2CO3 was added into the 1-butanol-water system and two phases were formed： water-rich phase （water phase） and 1-butanol-rich phase （1-butanol phase）. The liquid liquid equilibrium （LLE） data for 1-butanol-water-KF and 1-butanol-water-K2CO3 systems were measured at 25℃ and showed that 1-butanol phase contained negligible salt and water phase contained negligible 1-butanol when the concentrations of KF and K2CO3 in the water phase were equal to or higher than 27.11% and 31.68% , respectively. Thus water could be separated efficiently from 1-butanol-water by adding KF or K2CO3 into the system. A theoretical calculation of LLE data was calculated by using the Pitzer theory to get water activity in the water phase, and by the models, such as the Wilson, NRTL or the UNIQUAC for the 1-butanol phase. For 1-hutanol-water-KF system, the experimental data were found in good agreement with the calculated results by using Pitzer theory and Wilson equa tion, while for 1-butanol-water-K2CO3 system, the experimental data were found in good agreement with the calculated results by using Pitzer theory and UNIQUAC eauation.

ELECTROCHEMICAL STUDIES ON THE CATHODIC REACTION OF MARINE ATMOSPHERIC CORROSION

Electrochemical studies on the cathodic reaction of marine atmospheric corrosion using Kelvin probeas reference electrode showed that the rate of cathodic reaction-oxygen reduction first increases then de-creases, with the reaction maximizing at a certain thickness as the electrolyte film decreases duringevaporation. It was indicated that with decreasing electrolyte thickness by drying, the oxygen reduction ratewas accelerated by the faster oxygen diffusion due to the thinner electrolyte layer on the metal surface. Theresults also revealed that although the oxygen salting out effect has great influence on the rate of oxygenreduction, it is not the main causative factor for the decrease in cathodic limiting current in the case of avery thin electrolyte layer.

The quasi-activity coefficients of non-electrolytes in aqueous solution with organic ions and its application on the phase splitting behaviors prediction for CO_(2) absorption

CO_(2)capture with a low energy consumption is of important application significance for reducing CO_(2)emission.The phase-change absorbent developed in recent years shows its potential for low-energy CO_(2)capture.The unclear phase-splitting rule hinders the efficient development of CO_(2)phase-change absorbents.To predict phase-splitting behaviors of mono/poly-amine-organic solvent-water system with various concentrations,a quasi-activity coefficient was developed based on Debye&Mc Aulay equation and some Density function theory descriptors.Six models based on Debye&Mc Aulay equation were developed with different ion radius,descriptors or poly-amine-CO_(2)products.The phase-splitting boundary was drawn on the model with the best predictability.This quasi-activity coefficient would provide guidance for the phase-splitting systems development,especially for polyamines.

Character of Sedimentation in the Potassium-Bearing Basin of the Gremyachinskoye Field(The Volga Monocline)

1 Introduction The Gremyachinskoye potassium salt field lies within the Safronovskaya area and is confined to the preoverthrust zone–the 20-25 kilometer band conventionally recognized in the southern termination of the Volga

羧基功能化金纳米团簇的仿生结晶及其近红外磷光性质

As an interdisciplinary product,water-soluble gold nanoclusters(AuNCs)stabilized by ligands containing carboxyl(-COOH)group have garnered significant attention from synthetic chemists and biologists due to their immense potential for biomedical applications.However,revealing the crystallographic structures of-COOH-functionalized AuNCs remains a bottleneck.Herein,we successfully applied the salting-out method to obtain a series of high-quality single crystals of-COOH-functionalized Au_(25)nanoclusters and revealed their crystallographic structures.Particularly,K_(3)Au_(25)(2-Hmna)_9(mna)_6]^(-)(Au25a)protected by 2-mercaptonicotinic acid features an unprecedented tetrameric Au_(4)(SR^(S))_(3)(SR^(S,N))_(2)staple motifs surrounding the icosahedral Au_(13)kernel,breaking the traditional perception on the structure of Au_(25)(SR)_(18).Au25a exhibits a distinct near-infrared emission at 970 nm with long lifetime of 8690 ns,which have been studied by transient absorption spectroscopy and time-dependent density functional theory.This work compensates for the research gap in the experimental structure of-COOHfunctionalized AuNCs and opens up a new avenue to explore their structure-property correlations.

Measurement of Solid-liquid Equilibria in Quaternary System Li＋, K＋//SO42-, B4O72--H2O at 288 K

In order to utilize the brine resources in China, the solid-liquid equilibria in quaternary system Li＋, K＋//SO42 , B4O72 -H2O at 288 K was studied by the isothermal solution equilibrium method. Solubilities and densities of solutions were determined experimentally. According to the experimental data, the equilibrium phase diagrams, density-composition diagram and corresponding water content diagram of the quaternary system were plotted. Double salt KLiSO4 was found in the reciprocal quaternary system Li＋, K＋//SO42-, B4O72 -H2O at 288 K. The quaternary system has three invariant points, seven univariant curves and five fields of crystallization. The five crystalliza- tion regions correspond to Li2B4O7.3H2O, LizSO4-H2O, K2B4O7-4H2O, K2SO4 and KLiSO4, respectively. The crystal- lization field of salt LizB4O7 3H20 is the largest, whereas that of Li2SO4 H2O is the smallest. The experimental results show that LizSO4 H2O has a strong salting-out effect on other salts.