Abstract
Mg(NO3)2·6H2O-modified porous carbon derived from peanut shell (PS) (MN-PSC) was fabricated by a facile one-step approach, i.e., direct calcining the mixture of PS and Mg(NO3)2·6H2O (MN). The effects of calcination temperature, time and PS-MN ratio on the structure, texture, morphology and p-nitrophenol (pNP) adsorption of MN-PSC were investigated via characterization techniques such as XRD, TG-DSC, SEM, N2 adsorption/desorption and batch adsorption. The results show MN obviously decreased PS’s carbonization temperature. An interconnected pore structure was formed in MN-PSC with a surface area of 773.5 m2 g−1 and pore volume of 0.5310 m3 g−1 as the pyrolysis procedure is 200 °C for 1 h coupled with 750 °C for 2 h and the mass ratio of PS and MN is 1:1 (MN-PSC750–2). The formation mechanism of MN-PSC750–2 is that MN is firstly decomposed as MgO and oxidants such as NO2, O2 and HNO3 at 200 °C. These oxidants make PS cellulose carbonization in-situ form initial biochar-MgO with micropores and mesopore. MgO was blown out at 750 °C from inner biochar to form porous biochar with micro-, meso- and macro-pores. The adsorption capacity of MN-PSC750–2 for pNP is 106.95 mg g−1, which is obviously higher than those of PSCs due to the MN-PSC750–2’s well ordered porosity and the exist of functional group (C=O).