The Preliminary Study On The Degradation Of Sodium Carboxymethyl Cellulos(CMC) By Hydrodynamic Cavitation

The preparation of low viscosity carboxymethyl cellulose(CMC) research methods less in our country now, there are many drawbacks in some existing preparation methods. Such as, pollution of the environment, energy consumption,high cost, and complex post-processing problems, bring a lot of problems the preparation of low viscosity CMC. Through the chemical degradation and physical degradation discussing and studing degradation of these two new ways to prepare low-viscosity CMC. This paper be divided into four parts. Their main contents as follows:1. Experimental Research on Fenton oxidative degradation CMC solutionIn the degradation process Fenton reagent, under time, temperature, preliminary exploration of concentration, p H, and the ratio of H2O2/Fe2+ different conditions influence the effect of Fenton reagent. The degradation of detection index as the viscosity decrease rate of CMC. The experimental results showed that: the reaction time prolonged the degradation effect increased first and then decreased, the most obvious effect reaction time is 30 min, as reaction temperature the degradation effect is enhanced, when increasing the concentration of the solution the degradation effect is reduced, when the p H of the solution increases the degradation effect effect worse,V(H2O2) / V(Fe2+) from 3:1 to 5:1 the degradation effect is slowly increased.Orthogonal experimental design based on single factor experiments, the results obtained as follows: the best conditions for the degradation solution concentration is 3g/L, the temperature is 50 ℃, the p H is 3.5, the ratio of V(H2O2) and V(Fe2+) is 3:1and the the reaction time was 30 min the degradation efficiency is 65.21 %, the corresponding viscosity values of is CMC 696.91mpa·s.2. Experimental Research on Venturi tube degradation CMC solutionThe on Venturi tube degradation of indicator is based on the viscosity decrease rate of CMC. The main factors that the design of single factor experiments include the reaction time, concentration, temperature, pressure and p H. under certain conditions,the reaction time more longer the intrinsic viscosity decrease rate more obvious, but the most obvious of degradation time is 30 min. With the solution concentration increases the degradation effect weakened, concentration from 3 g/L to 7 g/L, the degradation rate of CMC has dropped by 22.88 %. When the temperature of the solution the rising degradation effect is also enhanced. When the inlet the pressure increased the degradation effect is not bright. When the p H of the solution increasingthe degradation effect decreasing. Based on this, design factors and the level of response surface, using response surface Design-expert software design program. The results obtained as follows: the solution concentration is 5 g/L, temperature is 55 ℃,The pressure is 0.27 MPa, p H was 3.51, the reaction time was 30 min, the degradation efficiency predicted values is 98.56 %. Through the experimental verification the actual degradation efficiency predictive value was 97.03 %, the corresponding viscosity values of is CMC 59.49 mpa·s.Comparing the Fenton degradation and the degradation of Venturi tube device,The experimental data show that Venturi tube device degradation is better than the method of Fenton degradation,。3. The quantitative analysis and structural characterization of degradation productsReference to National Light Industry standard 《 Food additive Sodium Carboxymethyl Cellulose 》, the after degradation CMC the degree of substitution,chloride content, viscosity, water content, p H and qualitative detection. Their structures be detected through the infrared spectroscopy and X-ray diffraction,through comparative analysis of performance changes come after degradation products. Show that the CMC structure has changed over 91.89 % of the degradation effect.4.The effect of low viscosity CMC on passion fruit juiceDesign experiments that will add degraded different viscosity CMC to passion fruit juice. Through the sensory evaluation, determination of the content of solids,Stability effects. Be analyzed the results showed that the optimal value of the viscosity of CMC 398.7 mpa ? s.