Porcine acute liver failure model established by two-phase surgery and treated with hollow fiber bioartificial liver support system

AIM： To establish a highly reproducible animal model of acute liver failure （ALF）, for assessing the effect of bioartificial liver support system （BALSS）. METHODS： A two-phase complete liver devascularization procedure was performed in eight Ioco-hybrid pigs. Blood biochemical index and liver biopsy were studied every 2 h after surgery, and survival time was recorded. The BALSS constructed with high volume recirculating technique was a hollow fiber circulating system consisting of a hepatocyte reactor-hollow fiber module inoculated with microcarrieradhering hepatocytes, and a double pump, heparinized, thermostabilized, micro-capsulized activated carbonadsorbing plasmapheresis system. Twelve pigs undergoing two-phase surgery were randomized into： control group （perfused without hepatocytes, n = 6） and treatment group （perfused with hepatocytes, n = 6）. Intergroup liver biochemical indexes, survival time, and liver pathological changes were analyzed at regular intervals. RESULTS： Two-phase surgery was performed in all the experimental pigs, and there was no obvious difference between their biochemical indexes. After 3 h of phase II surgery, ammonia （Amm） increased to （269＋37）μmol/L. After 5 h of the surgery, fibrinogen （Fib） decreased to （1.5±0.2） g/L. After 7 h of the surgery, ALT, AST, Tbil and PT were （7.6±1.8） nka/L, （40±5） nka/L, （55±8）μmol/L and （17.5±1.7） nka/L respectively. After 9 h of surgery, ALB and Cr were （27±4） g/L and （87±9）μmol/L. After 13 h of surgery, BUN was （3.5±0.9） μmol/L. All the above values were different from those determined before surgery. Survival time of pigs averaged 13.5±1.4 h. ALF pigs in the other group were treated with BALSS. The comparison analysis between the treated and control animals showed the changes of Tbil, PT, AIb, BUN, Cr, Fib, and Amm （P〈0.01）, but there was no change of ALT and AST. The survival time was statistically different （P〈0.01）, and there was no significant difference in histological changes.CONCLUSION： The porcine ALF model established by two-phase devascularized surgery is valid and reproducible. The hollow fiber BALSS can meet the needs of life support and is effective in treating ALF.

Characterization of P-nitrophenol Adsorption Kinetic Properties in Batch and Fixed Bed Adsorbers

P-nitrophenol（PNP） adsorption in batch and fixed bed adsorbers was studied. The homogeneous surface diffusion model（HSDM） based on external mass transfer and intraparticle surface diffusion was used to describe the adsorption kinetics for PNP in stirred batch adsorber at various initial concentrations and activated carbon dosages. The fixed bed model considering both external and internal mass transfer resistances as well as axial dispersion with non-linear isotherm was utilized to predict the fixed bed breakthrough curves for PNP adsorption under the conditions of different flow rates and inlet concentrations. The equilibrium parameters and surface diffusivity（Ds） were obtained from separate experiments in batch adsorber. The obtained value of Ds is 4.187×1012 m2/s. The external film mass transfer coefficient（kf） and axial dispersion coefficient（DL） were estimated by the correlations of Goeuret and Wike-Chang. The Biot number determined by HSDM indicated that the adsorption rate of PNP onto activated carbon in stirred batch was controlled by intraparticle diffusion and film mass transfer. A sensitivity analysis was carried out and showed that the fixed bed model calculations were sensitive to Ds and kf, but insensitive to DL. The sensitivity analysis and Biot number both confirm that intraparticle diffusion and film mass transfer are the controlling mass transfer mechanism in fixed bed adsorption system.

Effect of rare earth addition on Cu-Fe/AC adsorbents for phosphine adsorption from yellow phosphorous tail gas

Phosphine(PH3) is a highly toxic air pollutant,commonly produced in phosphorous chemical industry.But it has received less research attention due to its handling difficultly.CO is the main content of the phosphorous chemical industry tail gas,the concentration of which is always more than 80 vol.%,and it can be the feed gas to produce various valuable products such as formate,oxalate,and methanol and so on.But,PH3 is one of the important barriers,which is harmful to the following chemical process.In order to make use of the tail gas,PH3 should be removed firstly,and CO should be covered in the whole purified procedure at the same time.In this work,the modified activated carbon(MAC) was used as the adsorbent to separate PH3 from the mixture tail gas.Series of MAC adsorbents were prepared for the adsorption of PH3,which loaded Cu-Fe and Ce(La),or separately.The PH3 adsorption capacities,chemical and physical properties of MAC were all investigated.The results showed that over 99% PH3 adsorption efficiency was achieved when used MAC adsorbents.The removal efficiency and PH3 adsorption capacity of the Cu-Fe-Ce/AC(20:1:0.4) were both much higher than those modified activated carbons.The maximum PH3 adsorption capacity was 71 mg of PH3/g of MAC on the Cu-Fe-Ce/AC,which were much higher than literature data using CuO only for adsorbing hydride gases.