Development of novel in situ nickel-doped, phenolic resin-based micro–nano-activated carbon adsorbents for the removal of vitamin B-12

Activated carbon spheres (ACSs) and carbon micro–nanoparticles derived from nickel (Ni)-doped phenolic beads (∼0.8 mm) were synthesized as efficient adsorbents for vitamin B-12 (VB12). Ni was incorporated in an intermediate step during a suspension polymerization. ACSs were synthesized by the carbonization and activation of Ni-doped polymeric beads. Carbon micro–nanoparticles (average size ∼200 nm) were synthesized by milling polymeric beads followed by carbonization and activation. Adsorption tests were carried out under both batch and dynamic (flow) conditions. The latter tests were carried out in a specially designed and fabricated micro-column packed with carbon micro–nanoparticles. The adsorption loading of VB12 on the adsorbents was determined to be ∼300 mg/g, corresponding to an aqueous phase concentration of 500 ppm, which is comparable to or larger than the literature data. The method of in situ synthesis of metal incorporated carbon micro–nanoadsorbents and their use in a micro-column under the flow conditions has much potential for bio- and pharmaceutical separation and purification applications.

Graphical abstractA specially designed packed column was developed for applying micro–nanoparticles based adsorbents to the aqueous flow without entrainment or channeling in the column. The breakthrough analysis revealed that the VB12 uptake in the bed was comparable to the equilibrium adsorption data obtained from the batch study. This indicates an effective bed design allowing a uniform flow distribution and minimal particle entrainment and loss by flow. The simple methodology for developing micro–nanoparticles based adsorbents and applying them in the column under dynamic conditions has potential for a wide range of bio-separation and bio-purification applications.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of Ni-doped activated carbon spheres and carbon micro–nanoparticles. ► Synthesized materials used as efficient adsorbents for vitamin B-12. ► A specially designed column for breakthrough study on micro–nanoparticles.