Effect of high hydrostatic pressure-assisted pectinase modification on the Pb adsorption capacity of pectin isolated from sweet potato residue.

Novel pectin derived from sweet potato residue was modified by high hydrostatic pressure (HHP)-assisted pectinase and then used for Pb removal from aqueous solutions. The removal characteristics and mechanisms were also investigated. Results showed that modified sweet potato pectin exhibited greater adsorption performances for Pb than that of natural ones, and showed excellent eco-friendly properties and good potential for adsorption of some other heavy metals (such as Cu). The adsorption curves were much more conformed to Langmuir model, and the highest capacity for Pb adsorption was 263.15 mg/g with 1.00% pectin at pH 7. Chemical adsorption process of pectin for Pb absorption involved O-containing functional groups (O-H, COO-), cation exchange, and along with electrostatic interactions. Overall, the results in this study indicated that sweet potato pectin modified with HHP-assisted pectinase had the potential to become an environmentally friendly coagulant-flocculant agent for the heavy metal adsorption, especially for Pb.