Study of the adsorption of methylene blue by phytoremediation-plant biomass carbon

Many kinds of plant biomass are used to prepare the plant biomass carbon (PBC) to treat printing and dyeing wastewater (PDW). However, few researchers have studied how effectively PBCs prepared from phytoremediatory plants after phytoremediation can treat the wastewater. Furthermore, whether new pollutants are introduced is an urgent issue that needs interrogation. Thus, the purposes of this study were (1) to gather data on the technical parameters, effects, and mechanism of methylene blue (MB) absorption by PBC prepared from Brassica juncea harvests containing Pb and Cd, and (2) to evaluate the environmental risks associated with the addition of Pb and Cd to PDW. PBC0 and PBC1 were both alkaline with a honeycomb porous structure and an uneven surface. The surface area of PBC1 was much larger than that of PBC0, and PBC1 had more micropores. The hydroxyl group (-OH) and the stretching vibration of C-O could interact with MB molecules by hydrogen bonding and electrostatic attraction. In addition, PBCs attracted MB molecules through 7C -7C bond formed by the aromatic C-H bending, and the surface complexation would be formed by the interaction between MB molecules and Pb/Cd-O bond in the adsorption of MB by PBC1. The best technical parameters for B. juncea PBC were a PBC quality to wastewater volume ratio of 2.5 t/1000 m3, 50 mg/L; the mode of action and adsorption time set to oscil-lation for 6 h; a pH of 5; and single use of the PBC. Furthermore, there was no environmental risk during the preparation of PBC1 and in the adsorption process within the scale of this experiment.(c) 2022 Elsevier B.V. All rights reserved.