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Keywords:

  • Adsorption mechanism;
  • Drinking water;
  • 2-Isobutyl-3-methoxy pyrazine;
  • 2-Isopropyl-3-methoxy pyrazine

Abstract

Granular activated carbon (GAC) adsorption of two representative taste and odor (T & O) compounds, 2-isopropyl-3-methoxy pyrazine (IPMP), and 2-isobutyl-3-methoxy pyrazine (IBMP), in drinking water was investigated. Results show that the modified Freundlich equation best fit the experimental data during the adsorption isotherm tests, and the pseudo first-order kinetics and intra-particle diffusion kinetics well described the adsorption kinetics pattern. The calculated thermodynamic parameters (ΔH0, ΔS0, and ΔG0) indicated a spontaneous and endothermic adsorption process. Factors affecting the treatment efficiency were carefully evaluated. Acidic and alkaline conditions both favored GAC adsorption of IPMP and IBMP, especially the former. With the GAC dosage increasing, the first order adsorption rates increased, while the intra-particle adsorption rates decreased. Within 12 h, 200 mg/L GAC could remove >90% of 150 µg/L IPMP and IBMP via adsorption at pH 3–11. Therefore, GAC is a promising treatment technology to control the T & O compounds associated water pollution.