Degradable CO2-responsive microgels with wrinkled porous structure for enhanced, selective and recyclable removal of anionic dyes, Cr(VI) and As(V)

Abstract

Abstract Adsorbent with high and recyclable adsorption for pollutants without secondary pollution is one of great potential in water treatment. Here, degradable CO2-responsive microgels with big size and wrinkled porous structure were prepared. The microgels underwent reversible volume phase changes upon alternative stimulus of CO2 and N2, and thereby exhibited a switchable, selective, and recyclable adsorption for anionic dyes and metalloids (Cr(VI) and As(V)). The adsorption performance was improved due to the wrinkled porous structure, and the maximum adsorption capacity was up to 1537 mg g-1 for metanil yellow (MY). The competitive adsorption in binary and ternary system revealed that the affinity was in the order of MY > ponceau S (PS) > Cr(VI). Besides, the adsorbates could be desorbed by heating or treating with solution of pH 12. Microgels regenerated with CO2 trigger exhibited high adsorption ability after ten consecutive recycling trials, and could be applied to fixed-bed adsorption/desorption system. Moreover, microgels could be degraded. Thus, this kind of degradable microgels have potential applications in the treatment of complex industrial wastewaters and avoid the additional pollution caused by the accumulation of waste adsorbents.