Molten salt synthesis of hierarchical porous carbon from wood sawdust for supercapacitors

The IPN hydrogels possess uniform pore structure andhigh porosity (> 97%). The specific surface area and compressive strength were higher than 82 m2 g−1 and1.26 kPa, respectively. Water swelling experiments showed that the IPN hydrogels were both pH-sensitive andtemperature-sensitive. The swelling of hydrogels was limited at high temperature and in neutral medium. Therewas an increase in the swelling ratio as the NFC content increased. Adsorption kinetic and thermodynamicsstudies of Cu(II) and Pb(II) explained pseudo-second-order equation and Langmuir model (R2 > 0.99) as thebest fit. The maximum adsorption capacities of Cu(II) and Pb(II) according to Langmuir model were 217.39 mg/g and 81.96 mg/g, respectively. The good adsorption performance can be attributed to the chelation of tertiaryamine groups and the ion-exchange of carboxyl groups.