NITRATE SORPTION ON ACTIVATED CARBON MODIFIED WITH CaCl2: EQUILIBRIUM, ISOTHERMS AND KINETICS

作者：Zanella Odivan^*; Tessaro Isabel Cristina; Feris Liliana Amaral

来源：Chemical Industry & Chemical Engineering Quarterly, 2015, 21(1): 23-33.

DOI：10.2298/CICEQ130830001Z

• nitrate
• isotherms
• kinetic
• activated carbon
• modified surface

In this study, nitrate removal from aqueous solutions was investigated using granular activated carbon (GAC) modified with CaCl2. Batch sorption studies were performed as a function of sorbent dose, initial nitrate concentration and pH. Sorption was maximized between pH 3 and 9. Studies on the effect of pH showed that the ion exchange mechanism might be involved in the sorption process. The percentage of nitrate removed increased with increasing sorbent concentration, and the ideal sorbent dose was found to be 20 g.L-1. Four isotherm models - Langmuir; Freundlich, Redlich-Peterson and Sibs - were used to fit the experimental data. The Redlich-Peterson isotherm model explained the sorption process well and showed the best coefficient of determination (0.9979) and Chi-square test statistic (0.0079). Using the Sibs isotherm model, the sorption capacity (q(e)) was found to be 1.93 mg nitrate per g of sorbent Kinetic experiments indicated that sorption was a fast process, reaching equilibrium within 120 min. The nitrate sorption kinetic data were successfully fitted to a pseudo-second-order kinetic model, The overall results demonstrated potential applications of modified GAC for nitrate removal from aqueous solutions.

• 出版日期2015-3