Adsorption Thermodynamics and Kinetics of Enramycin on XAD-16 Macroporous Resin / 中国药学杂志

OBJECTIVE: To investigate the adsorption thermodynamics and kinetics of enramycin on XAD-16 macroporous resin. METHODS: Series of static adsorption experiments were carried out. The adsorption equilibrium data were fitted to Langmuir and Freundlich isotherm equations, which could describe the adsorption behavior of enramycin on XAD-16 macroporous resin. The thermodynamic properties were described by thermodynamic parameters. Then, pseudo-first-order model and pseudo-second-order model were applied to describe the kinetics of adsorption process. RESULTS: The adsorption equilibrium data were agreed with Langmuir isotherm well. Thermodynamic analysis suggested ΔH<0, and ΔG<0, which indicated the adsortion procedure was a spontaneously exothermic reaction with entropy decrease. The adsorption of enramycin on XAD-16 macroporous resin could be described well by Pseudo-second-order model. CONCLUSION: The adsorption thermodynamics and kinetics of enramycin on XAD-16 macroporous resin can supply the theory for the separation and purification of enramycin on XAD-16 macroporous resin.

Evaluation of polymeric adsorbent resins for efficient detoxification of liquor generated during acid pretreatment of lignocellulosic biomass.

Production of fuel ethanol from lignocellulosic biomass conventionally includes biomass pretreatment, hydrolysis, and fermentation. The liquor generated during dilute acid pretreatment of biomass contains considerable quantities of pentose sugars as well as various degradation products of sugars and lignin, like furfural, hydroxymethyl furfural (HMF), organic acids, aldehydes and others, which are known to be inhibitory for microbial growth. This pentose rich liquor is a potent resource which can be used to produce alcohol or other value added metabolites by microbial fermentation. However, the presence of these inhibitory compounds is a major hindrance and their removal is essential for efficient utilization of this byproduct stream. In the present work, the polymeric adsorbent resins, XAD-4, XAD-7 and XAD-16 were evaluated for their ability to adsorb fermentation inhibitors like furfural and HMF from the acid pretreated liquor. These resins could remove 55-75% of furfural and 100% of HMF and more than 90% sugar remained un-adsorbed in the pretreated liquor. Desorption of furfural from stationary phase was evaluated by using ethanol and hot water. The results suggest that these polymeric resins may be used for detoxification of acid pretreatment liquor with selective removal of sugar degradation products without affecting the sugar content in the solution.

Simultaneous determination of Pb and Cd in seafood by ICP OES with on-line pre-concentration by solid phase extraction with amberlite XAD-4 after complex formation with DDTP

An on-line method for Cd and Pb pre-concentration and simultaneous determination in acid digested seafood by inductively coupled plasma optical emission spectrometry (ICP OES) was developed. The on-line pre-concentration was based on the complex formation of the analytes with the ammonium salt of O,O-diethyldithiophosphate (DDTP) and using the Amberlite XAD-4 resin as a solid support in a homemade column. Different conditions of the flow injection system, such as solutions flow rates, nebulizer pressure and eluent concentration were optimized. Three certified reference materials of lobster hepatopancreas, dogfish liver and fish protein, three samples of fish muscle and three samples of shrimp were digested with HNO3, H2O2 and H2SO4 in a microwave system under reflux. DDTP was added in the solutions obtained, and the mixture was injected in the FI system. Calibration curves for Cd and Pb were obtained using the standard solutions in the concentration range 0.05-0.5 µg mL-1 in the digestion medium, submitted to the same pre-concentration procedure. The quantification limits (3.3 x LOD) for 5 min of pre-concentration time were 0.005 mg kg-1 Cd2+ and 0.1 mg kg-1 Pb2+ in the sample of fish or shrimp in natura, considering 1.0 g of the sample in a final volume of 50 mL. The agreement of the obtained concentrations with the certified ones (Student t-test, 95% confidence) and the recoveries of spiked real samples, from 90 to 120%, demonstrated good accuracy. Precision was also adequate, with relative standard deviations from 2 to 13%. The method was accurate, precise and certainly could be applied to the digested samples of different natures.

Comparison of the protective effect of circulating TNF-?removal between immunoadsorption and Amberlite XAD-7 absorption on endotoxin shock / 中华肾脏病杂志

To estimate the protective effect of removing circulatory TNF-a immunoadsorpnon or Amberlite XAD-7 absorption respectively on endotoxin shock. Methods New Zealand white rabbits injected with lethal dose of endotoxin underwent hemoper-fusion through immunoadsorbent or Amberh'te XAD-7 respectively. Plasma TNF-a levels were detected, and the sorbent efficiency and survival rate were observed. Results After 2 hours hemoperfusion through immunoadsorbent or Amberlite XAD-7 respectively, plasma TNF levels were significandy lower than those in die control group, especially, die sorbent efficiency of immunoadsorp-tion was higher dian dial of Amberlite XAD-7 adsorption. Conclusion Compared widi die nonspecific Amberlite XAD-7 adsorption, immunoadsorption might be a specific and more effective therapy of endotoxin shock.

STUDY ON WATERBONE ORGANIC COMPOUNDS AS THE CAUSE OF KASHIN-BECK DISEASE-ASSAY OF ORGANIC COMPOUNDS FROM DRINKING WATER IN AN ENDEMIC VILLAGE(1) / 西安交通大学学报(医学版)

The study on the etiology of Kashin-Beck disease showed that organic residues in the large volume of water samples were concentrated onto XAD resin columns. The extracts were partioned and analyzed by GC/MS. The water samples from the endemic area of Kashin-Beck disease were collected from the Tian Tang river, deep well and cellar well which arc located in Tian Tang village, Linyou County, Shaanxi province. The control water sample was collected from a deep well on the campus of Xi'an Medical University which is the source of the University tap water. Forty, thirty one, nineteen and ten kinds of organic compounds, which were respectively found to embody twenty five, nineteen, eight and four kinds of aromatic compounds, were respectively discovered in the Tian Tang river, deep well, cellar well and control water. Alkenes, ketens, ketones, naphthalenes and thazoles were found only in the river, deep well and cellar well water. Indenes were merely found only in the river and deep well water. The results suggest that above six compounds may be important etiological factors of Kashin-Beck disease, which have never been reported. However, its real etiologcal and epidemiological signicance needs further study.