Application Of ⁶⁰Coγ Radiation To Prepare The Cationic Absorbent With Rice Straw

In this work, the rice straw through a series of treatments to prepare a ne w kind of cationic adsorbent. The treatments are consist of two steps:(1) Use ultrasonic and lime co-pretreatment to remove lignin effectively and destroy th e structure of rice straw. (2)Modified rice straw was prepared by the graft cop olymerization of dimethyl diallyl ammonium chloride(DMDAAC) onto the pretr eatment rice straw by radiation. Its adsorption capacity for the anionic dyes an d ability to reuse were investigated.1. Effect of ultrasonic and lime co-pretreatment on percentage of cellulose was investigated. After 120min of lime pretreatment processing, the percentage of cellulose was 51.10%, compare to only use lime pretreatment, through 120 min of ultrasonic and lime co-pretreatment processing, the percentage of cellulo se risen to 58.89%.2. Orthogonal design were used to investigate ultrasonic and lime co-pretre atment on percentage of cellulose. It found that the factor affecting grafting yie Id ranked from high to low was ultrasonic power, ultrasonic time, the concentr ation of Ca(OH)2 The optimal conditions was Ca(OH)2 at concentration of 15%, ultrasonic time at 150min, ultrasonic power at 450W, and the highest percentag e of cellulose was 61.27%.3. Orthogonal design were used to investigate graft copolymerization of di methyl diallyl ammonium chloride(DMDAAC) onto the pretreatment rice straw by radiation. It found that the factor affecting grafting yield ranked from high to low was the proportion of DMDAAC, the dosage of radiation, the volume of water. The optimal conditions was water volume is 40mL, the dosage of ra diation was 7kGy, the proportion of DMDAAC was 5:1, graft ratio was 16.08 %.4. The characteristics of modified rice straw was investigated by FTIR spe ctroscopy, SEM and Elemental analyzer, indicated that the structure of rice stra w has been destroyed and DMDAAC has been grafted on cellulose. The Nitro gen content of rice straw from 0.138% risen to 1.240%5. The solution pH presented influence on the absorption of anionic dyes. And the adsorption equilibrium data of the cationic absorbent all well fitted wi th the Langmuir model and Pseudo-second order model, it showed the adsorpti on was a monolayer adsorption also ion-exchange adsorption.The maximum ads orption capacity of cationic adsorbent for COD was 73mg/g.