The Assembly And Study Of Acid Absorption Of Layered Double Hydraoxides

Polyolefin plastic such as polyethylene (PE), polypropylene (PP) is the most common polymer materials, which is widely used in industrial production and daily life. Ziegler-Natta catalyst that used in polyolefin production process will left a certain amount of chlorine ion in the presence of acidic impurities in the product. The remaining chlorine ion will cause corrosion of downstream processing equipment and affect the life of the product. Adding an acid absorbing agent can prevent the formation of gel resin by absorbing free chlorine ions.Layered double hydroxides (LDHs) are anionic clays consisting of positively charged metal hydroxide layers with anions such as CO32-located in the interlayer space for charge compensation of the cationic layers. The basic chemical properties makes LDHs effectively neutralizes acid, and the interlayer anion exchange ability makes LDHs absorbs chlorine ion. CO3-LDHs is difficult to deintercalate carbonate carbonate ions and convert into other LDHs with anion-exchangeability.Treating with acids decomposes carbonate ions into carbon dioxide, and it makes CO3-LDHs convert into other LDHs. the chlorine ion absorption performance of LDHs. This phenomenon makes CO3-LDHs can be an effective chlorine ions scavenger in acid environment.In this paper, a series of LDHs were prepared in the laboratory, and research how initial pH, the concentration of chlorine ions, and the addition of LDHs influences the performance of chorline absorption. The XRD and IR patterns of sample showed the absorption mechanism is surface absorption in neutral and basic conditions, and ion-exchange occurs in acid condition. But strong acid will destroy the layered structure of LDHs, and causes the weight loss of LDHs. This paper also studied how the type and ratio of metal ions influence the performance of chlorine absorption. The results showed that compared to Mg-Al-LDHs and Zn-Al-LDHs, Ca-Al-LDHs shows a better performance chlorine absorption, and NH3-TPD results indicate the strength and quantity of acid site effect the chlorine absorption.