Construction of hierarchical porous carbon with mesopores-enriched from sodium lignosulfonate by dual template strategy and their diversified applications for CO2 capture, radioactive iodine adsorption, and RhB removal

Abstract

Lignosulfonate, as the large-scale by-products from the sulfite pulping, converting them to porous carbon is an alternative potential path. However, most sodium lignosulfonate (LS-Na) derived porous carbon all belonged to the dominated microporous carbon materials, and had poor graphitization degree and low heteroatoms content. Here, a series of hierarchically porous carbon with rich and controllable mesopores were firstly prepared from LS-Na by two dual template strategies. These carbon materials showed high Brunauer-Emmett-Teller (BET) surface areas (SBET) of 230.6–1483.3 m2/g, hierarchical porous structure (mesopore content up to 84.5%), rich heteroatoms (N, O, S) doping (9.22–22.53%), and good graphitization structure. The incorporation of SBA-15 and Ni species as the nano-templates not only brought the unique micro-structure, but also enhanced mesoporous properties. SLS-C had the largest CO2 uptake (206.2 mg/g) due to the largest micropore volume (Vmicro) and ultramicropore volume (Vultra) by micropore filling mechanism. SLS-S-Ni-C possessed effective iodine capacity (∼2.2 g/g) and good recycling (∼90.9%), the adsorption process was based on the dominated physical adsorption, meanwhile, also along with the weak chemical interaction for some iodine molecules by little strong binding sites. SLS-Ni-C had the largest equilibrium capacity of RhB (350.6 mg/g) and the fast adsorption kinetic (about 50 min) due to the large SBET, suitable micro-mesopores size and proportion. This work provided a kind of hierarchical porous carbon from LS-Na by dual template routes, and matched adsorbents for the removal of targeted contaminants.