RR2 dye adsorption to Hymenaea courbaril L. bark activated carbon associated with biofilm

This study addressed the removal performance of RR2 from aqueous solutions in adsorption columns experiments by comparing the potential of activated carbon alone (ACA) and microbially inoculated (MIAC), prepared from barks of a largely available tree in Brazilian Cerrado biome, Hymenaea courbaril L. or "Jatobá," presenting the kinetics, isotherms, breakthrough curves, and dissolved organic carbon removal. ACA presented strong interaction to RR2 dye, evidenced at the first 20 min when absorbance already attained 66.4%. The removal percentage gradually increased with time and the equilibrium occurred around 91.7% within 120 min. Langmuir model best fitted the isotherm data, indicating a maximum adsorption capacity of 4.068 mg g^-1 for the amount of 0.5 g of adsorbent. The Langmuir's model parameters K_L, R_L, and R² corresponded to 0.0234 L mg^-1, 0.4159, and 0.9663, respectively, indicating a favorable adsorption process (0 < R_L < 1). The experiments in adsorption columns revealed maximum adsorption capacities of 14.38 and 11.43 mg g^-1 for MIAC and ACA, respectively, where the microbial activity favorably retarded the adsorption breakpoint in approximately 20 min and enhanced the RR2 consumption in 25.8%. Effectiveness of DOC removal attained above 90% for both ACA and MIAC, reducing the content from 86.1 to 7.84 mg L^-1 and 4.82 mg L^-1, respectively.