Green synthesis of biodegradable polyurethane and castor oil-based composite for benign transformation of methylene blue

Abstract

A series of polyurethane (PU), polyethylene glycol (PEG) and castor oil (CO) (ricin) based foams (PU-PEG, PU-PEG40/CO60, PU-PEG60/CO40 and PU-CO) were prepared and their catalytic activity for removal of methylene blue (MB) dye was evaluated. The prepared foams were characterized by FTIR, SEM and TGA analysis. The foams were porous in nature and the thermal stability was improved with CO incorporation. The PU-CO furnished promising catalytic efficiency and PU-PEG, PU-CO, PU-PEG40/CO60 and PU-PEG60/CO40 removed MB dye completely within 33, 5, 12 and 20 min. The removal of MB dye over foams followed second order kinetic model. The reusability of PU-CO showed stability up to 10 runs. Moreover, the phytotoxicity of the treated dye solution was performed, which reduced significantly after dye solution treatment with prepared foams. The prepared PU-CO also showed biodegradable nature under soil natural conditions. The prepared PU based foams showed excellent catalytic potential for the removal of MB dye along with thermal stability and recyclability, which could be a potential class of materials for the remediation of dyes in effluents.

Keywords

• Polyurethane
• Ascorbic acid
• Castor oil
• Catalytic reduction
• Methylene blue
• Kinetics