Self-flocculated powdered activated carbon with different oxidation methods and their influence on adsorption...

Area of Science:

• Materials Science
• Environmental Chemistry
• Polymer Science

Background:

• Powdered activated carbon (PAC) is widely used for water purification.
• Developing advanced PAC materials with improved adsorption and functionality is crucial.
• Thermoresponsive polymers offer unique properties for material modification.

Purpose of the Study:

• To selectively oxidize commercial PAC using two distinct methods.
• To functionalize oxidized PAC with thermoresponsive poly (N-isopropylacrylamide) (PNIPAM).
• To evaluate the adsorption capacity and self-flocculation behavior of the modified PAC.

Main Methods:

• Oxidation of PAC via wet oxidation with ammonium persulfate.
• Oxidation of PAC via thermal treatment after acidification with hydrochloride acid.
• Grafting of PNIPAM onto oxidized PAC in aqueous solution.
• Characterization of surface area and adsorption capacity (Langmuir Model).

Main Results:

• Oxidized PAC from thermal treatment after acidification exhibited a larger surface area (1184 m²/g) and superior bisphenol A adsorption.
• Grafted PAC derivatives maintained significant surface area and adsorption capacity (max 156 mg/g).
• Grafted PAC demonstrated temperature-responsive self-flocculation due to PNIPAM's properties.

Conclusions:

• A novel method for producing carboxyl-rich activated carbon with enhanced surface area and adsorption was developed.
• The retrievable grafted PAC exhibits excellent self-flocculation, suitable for water remediation.
• This modified PAC holds high potential for pre-heating water treatment and emergency wild water treatment.