Study On Preparation And Property Of Amphoteric Starch Microspheres

Water is vital substances for human survival, especially fresh water. Discharge of rawsewage and industrial waste into the rivers is not only polluting the environment, destroyingecosystems, but also resulting in waste of resources. If they are treated again, then efflux orrecycle or transport to other industrials, ecology environment can be greatly protected andresources are made full use of for the benefit of future generations. Therefore, new economicand efficient adsorbent of environmental protection has become one of the hot research topicsin recent years, which have got the attention of the industry at home and abroad.The starch microspheres were prepared by the inverse suspension polymerization withsoluble starch as raw materials, Span60as emulsifying agent, N,N′-methylene bis acrylamideas cross-linker, cyclohexane as oil phase and potassium persulfate with sodium bisulfIte asinitiator. The product was characterized by infrared red spectrum, field emission scanningelectron microscope(SEM) and laser particle analysis. Process for preparing starchmicrospheres were optimized by the single factor experiment. The effect of some factors suchas the water-oil ratio, the cross-linker dosage, the reaction temperature and reaction time onthe effect of ball forming rate of starch microspheres were investigated. The effect of somefactors such as the starch microsphere dosage, the adsorption temperature, adsorption time andpH on the effect of the decolorization rate of fluorescent yellow solution was investigated byorthogonal test method.Amphoteric starch microspheres were synthesized by one-step, instead of two-step, withself-made starch microspheres as raw material,3-chloro-2-hydroxypropyl trimethylammonium chloride as cationic etherifying agent, sodium tripolyphosphate as esterifyingagent. Conditions of preparing process of amphoteric starch microspheres were optimized bythe Box-Behnken method. The effect of some factors such as3-chloro-2-hydroxypropyltrimethyl ammonium chloride dosage, sodium tripolyphosphate dosage, water-alcohol ratio,the reaction temperature and reaction time on the effect of the decolorization rate of dyesolution was investigated.The results showed that the better condition of starch microspheres were: volume ratio ofwater/oil is1:8, cross-linker dosage0.2143g/1g(dry basis of starch), temperature30℃and reaction time2h. The volume of starch microspheres particle size ranged of300μm-600μm.Starch microsphere surface slightly rough and a large number of pores were seen visibly bySEM. The sequence of the factors on the effect of fluorescent yellow adsorption from more toless: pH, starch microsphere dosage, adsorption time, adsorption temperature.The best condition of amphoteric starch microspheres were:3-chloro-2-hydroxypropyltrimethyl ammonium chloride dosage1.14mL/1g(dry basis of starch), sodiumtripolyphosphate dosage0.84g/1g(dry basis of starch), water-alcohol ratio1, reactiontemperature55℃and reaction time3.5h.