Transforming Residual Microbial Biomass into High-Value Bicomposite Material for Reactive-Dye Removal: Insights from Batch Investigations to Fluidized-Bed Reactor Applications

The development of sustainable adsorbents from industrial biowaste has become an important strategy for reducing the environmental impact of both solid waste generation and wastewater pollution. In this study, residual Saccharomyces pastorianus biomass recovered from the brewing industry was immobilized in a polymeric matrix and evaluated as a bio-composite for the removal of reactive dyes from aqueous media. Orange 16 was selected as the target molecule. Batch biosorption experiments were conducted to identify the optimum operating conditions and to determine the adsorption capacity through Langmuir isotherm analysis. The performance of the biosorbent was subsequently validated under continuous-flow conditions in a fluidized-bed reactor, where the effects of flow rate on column (3.8 and 8.5 mL/min) efficiency were investigated. Experimental breakthrough curves were analyzed using the Clark, Yan, Bohart–Adams, and Yoon–Nelson models, which adequately described the dynamic biosorption process, particularly at the lower flow rate. The best agreement was obtained at a flow rate of 3.8 mL/min, an initial dye concentration of 87 mg/L, and a biosorbent mass of 19.5 g. The developed bio-composite material exhibited efficient dye removal and stable operation, demonstrating that residual brewing biomass can be successfully transformed into a low-cost and sustainable biosorbent suitable for continuous treatment of reactive-dye-containing wastewaters.