Synthesis And Application Of Cationic Absorbent Of Straw In Full Utilization

Full use of stalk is a simple and low-cost technology to prepare high-value stalk derivatives. So the cationic stalk was prepared to realize the full use of com stalk and applied to remove anionic dyes from aqueous solution to evaluate the application properties and provide a feasible technology route high-value utilization of stalk.In this study, the stalk properties and structure were studied firstly. The cellulose, hemicellulose and lignin components in grains in com stalk were measured and the result was32%,26%and18%respectively. The solubility property of the com stalk was studied and its solubility in NaOH(l%) solution was0.26g. The stalk SEM images were observed, which showed that the stalk itself had pore structure and it was good absorption material.Cationic absorbent was prepared by using corn stalk as raw materials, GTA as cationic agent. The optimal synthesis condition was got:reaction time was3h, reaction temperature was70°C, GTA dose was3mol/kg stalk and NaOH dose was n(NaOH):n(GTA)=1.5:1. GTA utilization rate was53.2%, cationic group content was1.60mmol/g and the utilization rate of stalk was80%. The introduction of cationic groups was confirmed by elemental analysis and IR spectroscopy.Cationic absorbent was prepared by using corn stalk as raw materials,3-chloro-l,2-epoxypropane as crosslinking agent and GTA as cationic agent. The optimal synthesis condition was got:reaction time was4h, reaction temperature was90°C, GTA dose was3mol/kg stalk and NaOH dose was n(NaOH):n(GTA)=1:1. GTA utilization rate was51.2%, cationic group content was1.53mmol/g, and the utilization rate of stalk was95%. The introduction of cationic groups was confirmed by elemental analysis and IR spectroscopy.The cationic absorbent was applied to remove anionic dyes such as AR1, AY128and AY199from aqueous solution and the effects of adsorbent dosage, pH, time and NaCl concentration on decolorization rate were studied. The optimal absorption conditions were: when the concentrations of the there dyes above were0.1g/L, cationic straw dosage of three dyes were1.1g/L,0.9g/L,1.0g/L respectively, pH value was6and the adsorption time was4h. Under these conditions,the dye decolorization rates all reached99.9%. NaOH solution (1.0mol/L) was applied to desorb the absorbent. When the absorption-desorption was repeated5times, the removal rate of AR1waste solution(0.1g/L) droped to65%.