Fibroin/chitosan blend membranes for perstractive removal of Hg(II) from aqueous solutions

Mercury (Hg(II)) contamination of water poses a significant environmental threat due to its high toxicity and bioaccumulation. In this study, fibroin/chitosan blend membranes were developed for the efficient removal of Hg(II) from aqueous solutions via perstraction using thiourea as a stripping agent at the downstream side to enhance Hg(II) removal. A resistance-in-series model was used to quantify and analyze the contributions of the individual resistance component in the overall mass transfer process. The research findings emphasized that while the membrane imparted a significant resistance to perstractive Hg(II) removal, the external mass transfer resistances (i.e., liquid phase boundary layer resistances, interfacial mass transfer resistance for Hg(II) release from the membrane at the downstream side) were also significant. The latter aspect was especially important when a thin membrane was used. While the liquid boundary effects could be reduced by proper management of the liquid phase hydrodynamics, the use of thiourea as a stripping agent was shown effective to facilitate Hg(II) release from the membrane, thereby minimizing the mass transfer resistance to Hg(II) perstraction at the downstream side of the membrane. This work offers a sustainable eco-friendly approach to valorization of renewable biopolymers derived from biomass wastes for the treatment of Hg(II) containing wastewater. • fibroin/chitosan blend membranes for removal of Hg(II) from water via perstraction • thiourea as a striping agent to facilitate Hg(II) release from the membrane • valorization of renewable biopolymers derived from biomass wastes for wastewater treatment