Bismuth-Doped Nano Zerovalent Iron: A Novel Catalyst for Chloramphenicol Degradation and Hydrogen Production

In this study, we showed that doping bismuth (Bi) at the surface of Fe⁰ (Bi/Fe⁰, bimetallic iron system)-synthesized by a simple borohydride reduction method-can considerably accelerate the reductive degradation of chloramphenicol (CHP). At a reaction time of 12 min, 62, 68, 74, 95, and 82% degradation of CHP was achieved with Fe⁰, Bi/Fe⁰-1 [1% (w/w) of Bi], Bi/Fe⁰-3 [3% (w/w) of Bi], Bi/Fe⁰-5 [5% (w/w) of Bi], and Bi/Fe⁰-8 [8% (w/w) of Bi], respectively. Further improvements in the degradation efficiency of CHP were observed by combining the peroxymonosulfate (HSO₅ ^-) with Bi/Fe⁰-5 (i.e., 81% by Bi/Fe⁰-5 and 98% by the Bi/Fe⁰-5/HSO₅ ^- system at 8 min of treatment). Interestingly, both Fe⁰ and Bi/Fe⁰-5 showed effective H₂ production under dark conditions that reached 544 and 712 μM by Fe⁰ and Bi/Fe⁰-5, respectively, in 70 mL of aqueous solution containing 0.07 g (i.e., at 1 g L^-1 concentration) of the catalyst at ambient temperature.