Solution CMC

Figure 4. Decrease in specific viscosity during the hydrolysis of CMC solution by E-3-1, E-3-2, E-3-3, E-3-4, and E-3-5. Reaction mixture consists of 3.0 mL 1% CMC, 7.0 mL 0.1M sodium acetate buffer, pH 4.0, and 2.0 mL enzyme solution containing an amount of protein equivalent to an optical density of 0.05 at 280 nm. The reaction mixture was carried out at 30°C in an Ostwald viscometer.

Figure 10. Time course of Ex-1 activity for CMC. Reaction mixture of enzyme and CMC solutions was incubated at 30°C for different reaction times, then examined for reducing sugar production. Final enzyme concentration 3.0 X 10 2%.

Figure 19. Decrease in specific viscosity during the hydrolysis of CMC solution by En-1. Reaction conditions are the same as in Figure 18 final enzyme concentration 2.2 X 10 4%.

Evaluating the Flow Curve from Experimental Data The flow rate of 3% CMC solution in water was measured in a long capillary as a function of pressure drop. Based on the results given in the following table, compute the non-Newtonian viscosity versus the shear-rate curve. 

Figure 4.12 (Measured result of 0.6 wt% aqueous CMC solution and fitted...

They found that optimal conditions of the position of the stirrer exist in the range of 0.25 < HJd < 0.75 for both turbine and propeller stirrers. Their work suggests that beyond a Reynolds number of 20,000, the power number becomes constant. An increase in solid content increases the power consumption, while an increase in gas velocity reduces the power consumption. Kurten and Zehner (1979) examined the effect of gas velocity on the power consumption for suspension of solids and found that because of simultaneous aeration, a higher power input is required for suspension in the presence of gas. This is mainly due to the reduced liquid circulation velocity in the presence of gas bubbles. Most recently, Albal et al. (1983) evaluated the effect of liquid properties on power consumption for both two- and three-phase systems. They found that power consumption per unit volume increases with solid concentration. The influence of particle size on power consumption increases with the solids concentration. For an unconventional arrangement of a stirrer, they also found different Ne-Re curves for glycerine and CMC solutions. 

Other relations have been presented by Luong and Volesky (1979), Hassan and Robinson (1977), and Oyama and Endoh (1955). Luong and Volesky (1979) and Schugerl (1981) investigated non-Newtonian CMC solutions, while Hassan and Robinson (1977) investigated electrolytic solutions. Joshi et al. (1982) recommend the use of Hughmark s correlation. A reliable correlation for the gas holdup is also reported by Hughmark (1980) as... 

In Table 3 we present the data on influence of viscosity of CMC and OSR water solutions on oil-recovery coefficient for two types of oils. Received data testify that water solutions of OSR possess higher oil-sweeping properties in comparison with CMC solutions of the same viscosity. This fact is explained by higher surface activity of OSR solutions on the interface with oil [16],... 

Sodium carboxymethyl cellulose, RceiiO-GHjCOO Na " (CMC), is another common cellulose ether. The degree of substitution (D.S.) that can be obtained for this product usually ranges between D.S. = 0.1 to D.S. = 1.2. As a by-product, sodium glycolate can be formed in the synthesis. Pure CMC is commercially available. Carboxymethyl cellulose in itself is a weak acid that can be precipitated from CMC solutions with a mineral acid. The pH of precipitation varies between 6 for low substitution values to 1 for high substitution (D.S of about 0.9). 

Here are the salient features of the process 1.21 sodium CMC solution (10 g NaCMC/litre) were mixed with 0.145 litre of Empilan AQ 100 solution (100 g contains 1007o ethylene derivative of lauric acid/litre) made up to volume of 15 litres with water are kept at 25 C. During a period of 60-70 min, introduced simultaneously, the solutions of sodium azide (108 g NaNj/litre) and lead acetate (315 g(CH3CO0)3Pb-3ll2O/liire) - 14 litres of each while stirring. The product precipitated and is washed by decantation, filtered and dried. The yield was 3.3-3.3 kg lead azide. The content of Pb(N3)j 96.3%. 

Fig. 3 Surface pressure versus molecular area for a DODAB monolayer on pure water (a), on a 5x10 5 monoMol PSS solution (b), and on a 5x 10 5 monoMol CMC solution...

Upper plot aquaeous PAA and CMC solutions from [195] middle and lowest plot Wi y) and /reffC ) for aquaeous xanthan 2.5% and PAA 1.0 and 1.5% solutions, resp. from [196]. 

Fig. 2.9 Dependences of Ne upon Co / = Re/Fr for different values of Q for a turbine stirrer with d/D — 0.3 in aqueous glycerine and CMC solutions. The middle and bottom graphs apply for aqueous PAA solution and prove the considerable influence of the stirrer type upon gas cushion formation in a viscoelastic liquid from [216).

The relationship, which is valid for turbine stirrers with d/D < 0.45, Newtonian liquids in the range of Re = 10 to 10 and Fr > 0.6 Ne x/(Q, Re = according to expression (2.25), is shown in Fig. 2.11 as a dashed curve. The plotted experimental data were those from Hocker and Langer [216, 217], obtained with water, glycerine, CMC solutions and PAA solutions as converted by Henzler [192] and were well represented by equation (2.25) in a relatively narrow range of A, otherwise they were by 15% higher. 

The m value for the above equation can be determined by bringing into coincidence the predicted and measured circulation characteristics N (Reefr) for different CMC solutions. 

The sorption characteristic for aqueous CMC solutions proposed in the evaluation framework (k aV/q)Sc°- — f P/q) in Fig. 4.8 showed a good correlation of the data. The process characteristic was as follows ... 

Fig. 4.7 Sorption characteristics for water, aqueous giucose and CMC solutions. Tank with turbine stirrer (d/D 0.3, H/D= 1) from [192],...

Fig. 4.8 Sorption characteristics for CMC solutions incorporating the Sc number. Tank with turbine stirrer (d/D = 0.25 to 0.33 H/D = 1) from [193]. For literature data given in the inset see [193].

Sorption measurements with a 1.5% CMC solution and two different stirrer types (turbine and MIG stirrer) have shown [217], that the stirrer type exerted no effect, whereas the sparger exerted a clear effect A large area three ring rose head gave the best performance. 

The process characteristic of the Sulzer SMX-L mixer is for the 5% CMC solution identical to that for the Kenics mixer for L/D> 30, see expression (8.19). The value for glycerine lies about 20% above that for PAA. The viscoelastic viscosity behavior affected heat transfer negatively. The pressure drop characteristic Cf Re — const (for Re < 1 X lO ) has been confirmed for SMX-L, the constant being about a factor of 10 higher than for an empty pipe. 

Process 1. Add to pan 1.2 liters of sodium CMC solution and 0.145 liter of Empilan AQIOO solution making up to a volume of 15 liters with water with stirring. 

The measurement of yield stress at low shear rates may be necessary for highly filled resins. Doraiswamy et al. (1991) developed the modified Cox-Merz rule and a viscosity model for concentrated suspensions and other materials that exhibit yield stresses. Barnes and Camali (1990) measured yield stress in a Carboxymethylcellulose (CMC) solution and a clay suspension via the use of a vane rheometer, which is treated as a cylindrical bob to monitor steady-shear stress as a function of shear rate. The effects of yield stresses on the rheology of filled polymer systems have been discussed in detail by Metzner (1985) and Malkin and Kulichikin (1991). The appearance of yield stresses in filled thermosets has not been studied extensively. A summary of yield-stress measurements is included in Table 4.6. 

It is, however, to be noticed that the viscosity of CMC solutions is affected by the pH value and the ionic strength of the solvent as demonstrated by Iwasaki et ah (25). Thus, the pH value and ionic strength of CMC solutions must be fixed when comparisons of cellulase activity are carried out with different CMC solutions. 

Enzyme preparations, CMC solutions, and buffers were preserved from contamination with 0.05% Merthiolate (Eli Lilly Co.). 

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