Synthesis of recyclable powdered activated carbon with temperature responsive polymer for bisphenol A removal

• Powdered activated carbon has been grafted with poly(N-isopropylacrylamide).
• The grafted PAC has excellent self-flocculation effect.
• The mechanism of the self-flocculation effect was depicted.
• The grafted PAC has two-stage adsorption behavior and little amount of desorption.

Self-flocculated powdered activated carbon (PAC) with high recovery performance and unique adsorption performance of bisphenol A (BPA) has been synthesized. PAC was treated with acidification to increase its surface active points without influence on its surface area. The PAC after acidification was functionalized in the presence of macro-initiators and then grafted with N-isopropylacrylamide (NIPAM) in aqueous solution (PAC-PNIPAM). By controlling the grafting degrees of PNIPAM, the synthesized PAC-PNIPAM exhibited different removal efficiency of BPA, the maximum adsorption capacity simulated under Langmuir models reached 247.532 and 116.298 mg/g, respectively. Moreover, the desorption behaviors of BPA also changed significantly from two-stage desorption to minor desorption in water, suggesting the potential application of PAC-PNIPAM in removal of concerned pollutants. Additionally, PAC-PNIPAM showed a good self-flocculation effect, implying that PAC after adsorption could be easily retried and recovered to avoid the secondary pollution of the adsorbent. In all, our work demonstrated potential application of this newly synthesized PAC in water purification and micro-pollutant remediation.

We have synthesized the new recyclable powder activated carbon with self-flocculation effect (settle down with less than 60 s) of a removal percentage of higher than 99%. The new activated carbon has two-stage adsorption behavior of bisphenol A and little desorption.Figure optionsDownload as PowerPoint slide