Insight into mechanism, Box-Behnken design, and artificial neural network of cationic dye biosorption by marine macroalgae Fucus spiralis

In this study, an efficient adsorbent prepared from Fucus spiralis (FSB) macroalgae was used in the removal of methylene blue (MB) as a hazardous dye from aqueous solution. The estimated specific surface area of FSB using MB method was 1820 m2/g. Kinetics and isotherm modeling revealed that the experimental data fit well with pseudo-second-order and Langmuir models and a significant adsorption capacity of approximately 854 mg/g was calculated. The thermodynamic study suggested the spontaneity and endothermic nature of the process. The adsorption mechanism of MB dye onto FSB involved electrostatic, pi-pi, and hydrogen bonding interactions. Dye removal was optimized using response surface methodology (RSM) based on Box Behnken design, and five variables were investigated, namely FSB dose (10-100 mg), contact time (10-240 min), MB concentration (50-1000), pH (2-12) and temperature (25-35 degrees C). The accuracy of RSM in predicting the removal of MB was compared with that of artificial neural network method (ANN). ANN and RSM approaches showed adequate and comparable predictions, with R2 of 0.98 and 0.96, respectively. The findings indicated that Fucus spiralis-based adsorbent could be a potential solution for colored wastewater depollution.