Circular utilization of Co(II) adsorbed composites for efficient organic pollutants degradation by transforming into Co/N-doped carbonaceous catalyst

Abstract Resource recovery and environmental remediation serve to meet the scientific and technical challenges of cost-effective and sustainable strategy, especially for circular utilization of valuable metal and treatment of various wastewater (toxic metal ions, organics, etc. ). Encouragingly, the research on circular utilization of recovered valuable metals in peroxymonosulfate (PMS) activation for pollutants degradation is currently in blank; herein, a multistage utilization process for preparing Co/N-doped carbonaceous catalyst is plausibly proposed for the first time. Namely, by using a cheap and abundant alginate as a self-generating 3D network precursor, the interior/exterior modified aerogel beads (denoted as Ca–Me/SA@0.75PEI) are fabricated via a simple sol-gel assembly for toxic metals removal or valuable metals recovery, following that Co 2+ adsorbed composite (denoted as Ca–Me/SA@0.75PEI-Co) are converted into Co/N-doped carbonaceous catalyst (denoted as Ca-NC@0.75PEI-Co-700) by carbonization. Increased surface chelating sites and polarity with abundant functional components (N = 15.68%) bring strong affinity to metal ions via ion-exchange, complexation and electrostatic interactions. Detailed isotherms, kinetics and dynamic studies illuminate the high adsorption capacity (698.62 mg/g), fast adsorption rate and long-term operation stability of Ca–Me/SA@0.75PEI adsorbent toward Co 2+ , respectively. Of particular interest of is that, the catalyst evolved from Co 2+ adsorbed composite exhibits relatively-superior catalytic ability towards utilizing PMS oxidant to degrade organic pollutants. Animatingly, the simulation of real water system makes it potential for the multistage utilization of composites in actual industrial wastewater treatment. The coupling of watermelon-like structure and Co/N co-doping endows the adsorptive catalyst sustainable utilization capacity in heterogeneous catalysis based on the concept of “utilizing waste treating waste” circular economy, avoiding the problem of insufficient stability of ion adsorbed aerogel catalyst in PMS homogeneous catalysis.