Characterization of alcohol/salt aqueous two-phase system for optimal separation of gallic acids

Gallic acid (GA) is a hydrophilic polyphenol which is noteworthy for strong antioxidant capacity. The drawbacks of conventional extraction approaches such as time-consuming and high processing cost are often viewed as a hurdle to extract GA from plant sources in industrial scale. Aqueous two-phase system (ATPS) is a separation approach which can be employed as an alternative to the conventional approaches. The partition behaviour of GA in an alcohol/salt ATPS was investigated in this study to aid the development of industrial scale ATPS to extract GA from natural sources. The separation of GA was characterized by determining the types of alcohol and salt, phase composition, sample load, pH of the system and addition of adjuvants applied in the alcohol/salt ATPS construction. The hydrophilic GA was targeted to the salt-rich phase of the alcohol/salt ATPS with a partition coefficient (K_GA) of 25.00 ± 0.00. The optimum condition of ATPS for the maximum partition of GA was achieved in ATPS comprised of 24% (w/w) 1-propanol and 22% (w/w) phosphate salt at pH 8 with 5% (w/w) of 1 mg/mL sample loading and 2% (w/w) NaCl addition. The findings suggest that ATPS can be applied for separation of GA from various natural sources.

Elucidation of 2, 4-Dichlorophenol degradation by Bacillus licheniformis strain SL10

2,4-Dichlorophenol (2,4-DCP) is a priority pollutant according to US Environmental Protection Agency. Its use in various chemical industries and its presence in the effluent necessitate effective removal studies. The present study focuses on degradation of 2,4-DCP by phenol adapted bacteria Bacillus licheniformis strain SL10 (MTCC 25059) at a relatively faster rate. The organism exhibited tolerance to 150 ppm of 2,4-DCP and showed a linear relationship between the growth and substrate concentration (µ_max 0.022/h) and the inhibitory concentration was 55.74 mg/L. The degradation efficiency of the organism was 74% under optimum conditions but increased to 97% when the growth medium containing nil sodium chloride. The degradation of 2,4-DCP was effected by the action of extracellular cocktail enzyme containing Catechol 2, 3 dioxygenase (C23DO), phenol hydroxylase and Catechol, 1,2 dioxygenase (C12DO). In vitro enzymatic degradation studies exhibit 98% degradation of 50 ppm of 2,4-DCP within 2 h. Analyses of degradation products infer that the chosen organism followed a meta-cleavage pathway while degrading 2,4-DCP. In conclusion, the bacteria Bacillus licheniformis strain SL10 finds potential application in the remediation of 2,4-DCP.

Removal of Fluorine from Wet-Process Phosphoric Acid Using a Solvent Extraction Technique with Tributyl Phosphate and Silicon Oil

The deep removal of fluorine from wet-process phosphoric acid is currently a very serious issue. In this paper, an efficient liquid-liquid separation method based on a bubble membrane was developed to solve this problem. Tributyl phosphate (TBP) and silicon oil (SIO) were used as the organic phase. The effects of the component proportion in the organic phase (TBP/SIO v/v), organic to aqueous phase ratio (O/A), pH, temperature, and reaction time on the extraction ratio were investigated. The extraction ratio of fluorine was 98.4% when using only one stage with the following conditions: 90 °C, pH -0.46, volume ratio (TBP/SIO v/v) of 7:3, phase ratio (O/A) of 1:5, stirring speed of 200 rpm, and reaction time of 50 min. Fourier-transform infrared spectroscopy and inverted fluorescence microscopy were used to investigate the reaction mechanism and reaction kinetics. In addition, the scrubbing and stripping process was investigated. When a 2 mol/L sodium hydroxide solution ([NaOH]) was used as the stripping agent with a phase ratio (O/A) of 1:10, a stirring speed of 200 rpm, and a reaction time of 30 min, a maximum stripping ratio of 90.1% was obtained.