N, P, O-codoped biochar from phytoremediation residues: a promising cathode material for Li-S batteries.

Environment and energy are two key issues in today's society. In terms of environmental protection, the treatment of phytoremediation residues has become a key problem to be solved urgently, while for energy storage, it tends to utilize low-cost and high specific energy storage materials (i.e. porous carbon). In this study, the phytoremediation residues is applied to the storage materials with low-cost and high specific capacity. Firstly, the phosphorous acid assisted pyrolysis of oilseed rape stems from phytoremediation is effective in the removal of Zn, Cu, Cd and Cr from the derived biochar. Moreover, the derived biochar from phytoremediation residues shows abundant porous structure and polar groups (-O/-P/-N), and it can deliver 650 mAh g-1with 3.0 mg cm-2sulfur, and keeps 80% capacity after 200 cycles when employing it as a sulfur host for lithium-sulfur (Li-S) batteries. Hence, phosphorous acid assisted pyrolysis and application in Li-S battery is a promising approach for the disposal of phytoremediation residues, which is contributed to the environmental protection as well as energy storage.

Cobalt (0/II) incorporated N-doped porous carbon as effective heterogeneous peroxymonosulfate catalyst for quinclorac degradation.

A cobalt(0/II)-incorporated N-doped porous carbon (Co/NC) catalyst was prepared via one-step thermal decomposition of ethylene-diamine tetra-acetic acid and a Co salt. Fine Co nanoparticles composed of metallic and oxidized Co species were formed and well dispersed in the graphene-like film-type N-doped carbon support. The Co species played a dominant role in peroxymonosulfate (PMS) activation to generate sulfate and hydroxyl radicals. The N-doped porous carbon synergistically affected the catalytic performance by enhancing electronic transfer. The resulting Co/NC was a highly efficient heterogeneous catalyst for PMS activation and enabled considerably enhanced quinclorac (QNC) degradation. Typically, 93% QNC (50 mg L-1) removal was achieved with 0.08 g L-1 Co/NC and 20 mmol L-1 PMS. The QNC degradation kinetic data fitted a pseudo-first-order kinetic model well, with a correlation coefficient (R2) higher than 0.99. Investigation of the reaction mechanism suggested that hydroxyl (HO) and sulfate (SO4-) radicals were the predominant active species in the Co/NCPMS system and QNC degradation mainly involved dehydroxylation and substitution of OH for COOH. This Co/NC catalyst is promising for use in advanced oxidation processes for the removal of persistent organic pollutants.