Transforming waste into worth: Procambarus clarkii carapace as a high-performance biosorbent for methyl red dye.

Low-cost and sustainable biosorbents for the treatment of dye-containing wastewater are an area that needs to be addressed in the near future. In the present study, waste from the Procambarus clarkii, an invasive crayfish, was used as a potential biosorbent to remove methyl red dye from aqueous solutions. The waste was found to have a high adsorption capacity, with a maximum capacity of 14.39 mg/g under optimum conditions. The noteworthy aspect was that the biosorbent, with a relatively low surface area (19.13 m²/g), was able to remove 97% of the dye at pH 7 in 2 h, thus proving the importance of surface functional groups in the removal of the dye. The kinetics revealed that the adsorption followed a pseudo-second-order equation. The thermodynamic parameters revealed that the adsorption was a spontaneous and exothermic process. Regeneration experiments revealed that the Procambarus clarkii biosorbent retained about 70% and 50% of the original adsorption capacity after the second and third cycles, respectively. In conclusion, this study has shown that the carapace of P. clarkii is an environmentally friendly and economically viable biosorbent, which has the dual advantage of wastewater treatment and biological waste utilization.