Use of beach bivalve shells located at Port Said coast (Egypt) as a green approach for methylene blue removal

•Bivalve shells were tested as a biosorbent for methylene blue removal.•The biosorbent is economical and effective for environmental remediation.•Several models were applied to study the kinetics and equilibrium parameters.•The biosorbent was successfully removed color from dyeing effluents.

Bivalve shells of Anadara uropigimelana were firstly tested as a potential biosorbent for methylene blue (MB) recovery from an aqueous solution, Scanning electron microscopy (SEM), energy dispersive X-Ray analysis (EDX), Fourier-transform infrared (FTIR) and zeta potential measurements were used to characterize bivalve shells sorbent. The influence of variables including pH, amount of sorbent, contact time, concentration of the dye and temperature on MB sorption has been investigated. Percentage removal of 93.6% were obtained under optimum conditions of variables (initial pH of 10.4, sorbent dose of 1 g L−1, initial MB concentration of 20 mg L−1, and temperature of 25 ± 1 °C). The sorption of MB dye onto the sorbent could reach equilibrium after 10 min. Equilibrium data were well fitted to the Langmuir model. Sorption isotherm results showed that the maximum sorption capacity of MB by bivalve shells was 1000 μg g−1. Thermodynamic analysis showed that the sorption of MB onto bivalve shells increased with increasing temperature from 25 to 55 °C, indicating the endothermic nature of the sorption process. Meanwhile, the positive values of ΔSo suggest the increased randomness at the solid/solution interface during the MB sorption. The sorbent was successfully tested for color removal from dyeing facility. This work shows that the bivalve shells hold promises acting as effective sorbent to remove dyes in the wastewater.

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