Sulfamethoxazole Removal from Drinking Water by Activated Carbon: Kinetics and Diffusion Process

Area of Science:

• Environmental Chemistry
• Water Treatment Technologies
• Adsorption Science

Background:

• Sulfamethoxazole (SMX) is a persistent pharmaceutical residue found in aquatic environments and drinking water.
• Conventional water treatment methods show limited effectiveness in removing SMX due to its low biodegradability.
• Understanding SMX removal mechanisms is crucial for ensuring water safety.

Purpose of the Study:

• To evaluate the kinetic reactivity and performance of activated carbon powder (ACP) for sulfamethoxazole (SMX) removal from tap water.
• To investigate the adsorption mechanisms and influencing factors under industrially relevant conditions.
• To assess the efficiency of ACP in purifying slightly polluted drinking water.

Main Methods:

• Experimental investigation of SMX adsorption onto ACP at varying concentrations (2 µg/L and 2 mg/L SMX to 10 mg/L ACP).
• Application of four kinetic models and two monosolute equilibrium models to analyze adsorption data.
• Characterization of adsorption mechanisms, including physical interactions and bridging phenomena.

Main Results:

• Complete removal of SMX at low concentrations (2 µg/L) was achieved.
• Adsorption exhibited energetic heterogeneity and rapid kinetics suitable for industrial processes.
• Intraparticle diffusion significantly affected the adsorption kinetics.
• Proposed adsorption mechanisms involve π-π dispersion and electrostatic interactions.

Conclusions:

• Activated carbon powder (ACP) is highly efficient for removing low levels of sulfamethoxazole (SMX) from tap water.
• The adsorption process is rapid and compatible with industrial water treatment timescales.
• ACP presents a viable solution for purifying drinking water contaminated with pharmaceutical residues.