Disposal of blue algae (BA) and corn gluten (CG) wastes and simultaneous recovery of the abundant phosphorus (P) and nitrogen (N) by pyrolysis to obtain biochars with high fertility is a promising strategy. However, pyrolysis of BA or CG alone by a conventional reactor cannot reach the target. Herein, we propose a novel MgO-enhanced N and P recovery method by designing a two-zone staged pyrolysis reactor to highly efficiently recover N and P with easily available plant forms in BA and CG. The results show that a 94.58% TP retention rate was achieved by means of the special two-zone staged pyrolysis method, in which the effective P (Mg2PO4(OH) and R-NH-P) accounted for 52.9% of TP, while the total nitrogen (TN) reached 4.1 wt%. In this process, stable P was formed first at 400 ℃ to avoid rapid volatilization and then to form hydroxyl P at 800 ℃.

Herein, we propose a novel method to enhance the photoreactivity of an MOF catalyst by grafting isocyanate bonds (−N=C=O) and sulfhydryl-complexed copper (−SCu) onto ZIF-8 (NIF-SCu). The grafting process intercalated interlayer bands between the conduction and valence bands of ZIF-8, thereby providing a “ladder” for facile electron transition. The extreme improvement in the photoreactivity of NIF-SCu could be attributed to the enhancement in light responses in the range of 350–450 nm by −N=C=O groups and the widening of the visible light range of the MOF by −SCu groups. The formation of staggered energy levels in NIF-SCu could also narrow the band gap, lower the resistance, and facilitate the transfer of photogenerated carriers, thereby generating electrons with strong reduction potential in the −SCu conduction band. This study provides a new strategy for improving or even endowing the photoactivity of environmental functional materials with wide bandgaps.