Adsorption/ion-exchange behavior between a water-insoluble cationic starch and 2-chlorophenol in aqueous solutions

✍ Scribed by Wu-Chung Chan; Tzu-Ping Fu

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 184 KB
• Volume: 67
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19980207)67:6<1085::aid-app16>3.0.co;2-#

✦ Synopsis

An investigation was undertaken regarding the removal of 2-chlorophenol from solutions using highly crosslinked cationic starch containing a tertiary amine group. The mechanism of removed 2-chlorophenol is affected by the pH of the aqueous phase. The nonionized and ionized species are removed by the adsorption and ionexchange process, respectively. It has been found that the adsorption process predominated over the initial pH ranging from 2 to 6, the ion-exchange process predominated at initial pH 12, and both processes coexist over the initial pH ranging from 8 to 10. A method is suggested to determine the contribution of the nonionized and ionized species to remove 2-chlorophenol over the test pH range. The adsorption process is initially pH-independent, and the ion-exchange process is initially pH-dependent. The adsorption and ion-exchange processes are concentration-dependent, endothermic, and follow the Langumir isothermal adsorption. The DH is 2.504 kcal/mol for the adsorption process and 3.580 kcal/mol for the ion-exchange process. The ion-exchange capacity is larger than the adsorption capacity.