Adsorption Behavior of Acid Bordeaux B from Aqueous Solution onto Waste Biomass of Enteromorpha prolifera

Enteromorpha prolifera green algae is the main species that causes green tide in China's Yellow Sea. To effectively realize the resourceful utilization of this biomass, batch experiments were carried out to investigate factors that impact the Acid Bordeaux B (ABB) absorption of E. prolifera powder, such as exposure time, pH, adsorbent dose, and oscillation frequency. The dye adsorption onto adsorbent was confirmed by Fourier transform infrared spectroscopy (FUR). Results showed that amide, hydroxy, carboxylate, and C-O groups were involved in the adsorption process. The treatment conditions for dye concentration of 100 mg.L-1 were optimized: contact time 60 min, pH value 4 to 9, water temperature 303 to 313 K, adsorbent dosage 0.25 g-L-1 and oscillation frequency 150 rpm. Equilibrium data were analyzed by using the Freundlich and Langmuir models. The data fit well in both models. The maximum equilibrium adsorption capacity calculated by the Langmuir equation was 1,111.11-3,333.33 mg.g(-1). To clarify the sorption kinetic, the fitness of the Pseudo-first-order model, the Pseudo-second-order model, and the intra-particle diffusion model were tested, showing that the pseudo-second order model was suitable to describe the adsorption process. The sorption process was complex, and both the boundary of liquid film and intra-particle diffusion contributed to the rate-determining step. Thermodynamic parameters (e.g. Delta G degrees, Delta H degrees, and Delta S degrees) were calculated, which implied the exothermic and spontaneous nature of biosorption as well as the type of adsorption (physisorption). Results illustrate that the removal ratio from the wastewater with 100 mg.L-1 ABB reached 90.86%, indicating that E. prolifera could be a potential biosorbent used for the removal of ABB from industrial effluents.