Recovery of antimony using biological waste and stepwise resourcization as catalysts for both polyesterification and transfer hydrogenation

The recycle and reutilization of antimony in industrial sewage is an important issue. Here, we developed a protocol for the efficient antimony adsorption and the resourcization of the waste adsorbent. Following the concept of “treat waste by waste”, the adsorbent was produced with a kind of waste, pomelo peel, which was transferred to the biochar loaded ferric oxide (Fe3O4/BC) as the adsorbent. The Fe3O4/BC exhibited a fast procedure for the adsorption of antimony, and its maximum Sb(III) adsorption capacity reached 246.19 mg g−1 at 40 °C. Next, the re-utilization of the waste adsorbents was considered to avoid the secondary pollution of the solid waste. Taking the treatment of textile printing waste water as a real application, we realized the stepwise resourcization of the waste adsorbents as catalysts. The used adsorbents, Sb(III)/Fe3O4/BC, were extracted by KOH glycol solution and the eluent was directly used in synthesizing polyethylene terephthalate (PET). The remained part of the adsorbents could be converted into the catalyst for transfer hydrogenation (CTH) of nitroarenes. This work helps to achieve the waste-free application of antimony, and delivers an overall solution of Sb-containing waste water, which follows the concept of “turning waste into treasure”.