A research group led by Prof. LU Zhiyi at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of Chinese Academy of Sciences (CAS), has proposed a facile and cost-effective strategy to regenerate powdered activated carbon (PAC) by anchoring isolate Fe atoms on commercial PAC.

Water is the basis of the human being's survival. However, the increasing shortage of fresh water has become a growing concern in our daily lives, which requires effective measures, such as wastewater treatment and reuse.

Thanks to the advantages of large adsorption capacity, high specific surface area, nontoxicity, and acid/base resistance, PAC plays an irreplaceable role in drinking water purification and wastewater treatment, which serves as an efficient adsorbent for removing organic pollutants from wastewater. While the existing PAC regeneration technologies still needs upgrading due to the fairly high costs.

In the study published in Advanced Science, researchers at NIMTE constructed isolated Fe sites anchored on commercial PAC (i.e., Fe-PAC), efficiently realizing the regeneration of Fe-PAC in H₂O₂ solution treatment at a low expense.

Employing rhodamine B as a representative pollutant, the cyclic adsorption-regeneration experiment results demonstrated that the absorption capability of the synthesized Fe-PAC could be regenerated over 10 cycles within 24h.

Superior to the traditional Fenton-based regeneration technology, the synthesized Fe-PAC with a relatively low cost of ≈$0.35 kg^-1 shows higher regeneration efficiency (70.5–92.7%), lower loss rate of absorbent (≈8.25% per cycle), as well as lower H₂O₂ dosage (2.31 g g_(PAC)^-1).

In addition, the Fe-PAC based adsorption-regeneration process shows excellent general applicability, which could be extended to other simulated wastewater with contaminants like methylene blue and crystal violet.

Furthermore, the study has illuminated for the first time the vital role atomically dispersed sites play in PAC regeneration.

This promising strategy for PAC regeneration shows bright and broad application prospects in large-scale cost-effective wastewater treatment.

This work was supported by the Ningbo Yongjiang Talent Introduction Programme (Nos. 2021A-036-B), National Natural Science Foundation of China (No. 52201285), Ningbo S&T Innovation 2025 Major Special Program (Nos. 2020Z059 and 2020Z103).

Fig. The H₂O₂-based PAC adsorption/regeneration process for wastewater treatment (Image by NIMTE)

Contact
CHEN Xu
Ningbo Institute of Materials Technology and Engineering
E-mail: chenxu@nimte.ac.cn