Coffee Silver Skin: A Useful Adsorbent Substrate for Norfloxacin Removal and Photodegradation

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Antibiotic contamination in water poses a significant environmental and health risk.
• Conventional water treatment methods are often insufficient for complete antibiotic removal.
• Valorization of agricultural by-products like Coffee Silver Skin offers sustainable solutions.

Purpose of the Study:

• To investigate Coffee Silver Skin as a novel adsorbent for Norfloxacin removal from aqueous solutions.
• To explore the regeneration of Coffee Silver Skin using advanced oxidation processes.
• To evaluate the efficiency of Norfloxacin degradation and adsorbent recyclability.

Main Methods:

• Adsorption experiments to determine optimal removal conditions, focusing on electrostatic interactions.
• Desorption studies using salt solutions (NaCl, MgCl2) to recover Norfloxacin.
• Advanced oxidation processes (UV, UV/H2O2, UV/TiO2, UV/TiO2/H2O2) for Norfloxacin degradation.
• Comparative analysis with direct photodegradation in water.

Main Results:

• Electrostatic interactions were key in Norfloxacin adsorption onto Coffee Silver Skin.
• UV light/TiO2 achieved complete Norfloxacin degradation in 6 hours; H2O2 did not enhance the process.
• Simultaneous desorption and degradation in 0.1 M MgCl2 reduced degradation time to 3 hours.
• Coffee Silver Skin was successfully recycled for up to 3 cycles.

Conclusions:

• Coffee Silver Skin is a viable, sustainable adsorbent for Norfloxacin removal.
• Advanced oxidation processes, particularly UV/TiO2, are effective for degrading adsorbed Norfloxacin.
• The developed method allows for efficient adsorbent regeneration and reuse, contributing to a circular economy.