| Guar gum is a kind of galactomannan polysaccharide obtained from Cyamopsis tetragonolobus seeds. At present, guar gum and its derivations are widely used in the food industry, medicine, water treatment, chemical industry, petroleum, mineral industry and so on.However, the studies on guar gum and its derivations are carried out latter than many other polysaccharides such as xanthan, chitosan and sodium alginate in our country, which lead to less knowledge in the properties and applications of guar gum and its derivations. So, it was introduced in this paper, including the developing of guar gum and its derivations; the studies on preparing of spilled oil gelling agents with guar gum by carboxymethylation, esterification and interaction with metallic ions; the studies on the synergistic interaction between the mixed gel of cationic guar(CG40)/sodium alginate, cationic guar(CG40)/xanthan; and the studies on the grafting of acrylamide(AM) onto CG40 and the application to wastewater treatment of the copolymer. The main contents are as follows:(1) There is synergistic interaction between the guar hydroxypropyltrimonium chloride (CG40) and sodium alginate, which makes them form gels. The effects of the mass ratio of them, mixed temperature, incubation time, balk salt ion concentration and pH value on gelation have been studied. It had been observed that there was a gel strength maximum when the mass ratio was 0.6, the mixed temperature was 70 ℃, the incubation time was 30 min, the salt ion concentration was 1.0 mol/L, and the optimal pH value was 8.0. That's to say, the synergistic interaction was strongest under these conditions. Interaction between molecules of these two polysaccharides was investigated by FT-IR spectrometry.(2) There is synergistic interaction between CG40 and xanthan gum which makes them form gels. The effects of the mass ratio of them, mixed temperature, incubation time, balk salt ion concentration on gelation have been studied. It had been observed that there was a gel strength maximum when the mass ratio was 20 '. 80, the mixed temperature was 60 ℃ , the incubation time was 30 min, the salt ion concentration was 1.0 mol/L. And it was showed that gel strength increased with the increasing of pH value. Interaction between molecules of these two polysaccharides was investigated by FT-IR spectrometry.(3) Using ceric ammonium nitrate (CAN) as initiator, the grafted copolymer of cationic guar gum and acrylamide(AM) was prepared by solution polymerization technique. The effects of different reaction conditions on the grafting were studied in detail. The grafting ratio was optimal under the following conditions: CG40 at 10 g/L; CAN at 3 mmol/L; AM at 0.7mol/L; temperature at 50 °C and reaction time at 4 h. FT-IR was used for the confirmation of copolymer formation. The copolymers were applied as cationic flocculations to treat municipal wastewater, and the results of the flocculation experiments showed that the copolymers had ideal flocculating properties and the performance of they was superior to that of anionic polyacrylamide. What's more, the flocculating properties were improved obviously when combined with PFS as a dual-component system.(4) Spilled oil gelling agents on seawater surface were prepared with guar gum by carboxymethylation, esterification and interaction with metallic ions. The effects of the carboxymethylated degrees, the esterificated degrees on the coagulations of the gelling agents were studied as well as the coagulations of the gelling agents to different oils. It was showed that the best coagulations was get when the carboxymethylated degree was 0.102 and the esterificated degree was 0.383. The coagulations of guar gelling agents to crude oil were better than to diesel oil and kerosene.
|
PDF Full Text Request