Evaluation of bound water in flocculated systems of pumice using DSC Experiments

摘要

Differential Scanning Calorimetry (DSC) was performed to characterize the water present in flocculated and non-flocculated systems of pumice. Pumice was found to flocculate in polymer solutions of carbopol (0.5% w/v), sodium alginate (3% w/v) and gelatin (0.25% w/v) with a pumice concentration of 10% w/w. The polymer concentration used was the optimum concentration for each to produce flocculation. The sample for the non-flocculated system was collected from a mixture of pumice (10% w/w) in water. The adsorption peak showed three peaks for carbopol and two for the sodium alginate and gelatin flocculated systems. The enthalpy values for each of the peaks, namely, crystallization, fusion and adsorption was found to be more for the all three flocculated samples in comparison to the non-flocculated pumice sample. Relative percent bound water was calculated for each of the flocculated systems with respect to the non-flocculated system, giving the. latter a unit value for ratio of enthalpy. The relative bound water thus calculated was 36% for gelatin, 63% for carbopol and 131 and 115% for sodium alginate, flocculated samples. The relative percent was concluded to be a function of the concentration of the polymer.