Adsorptive characteristics of the polyurethane-immobilized Corynebacterium glutamicum biosorbent for removal of Reactive Yellow 2 from aqueous solution

Polyurethane (PU) was evaluated for its possibility as an immobilization matrix for the raw biomass of Corynebacterium glutamicum. Initially, different blending ratios of the raw biomass to PU weight were tested, and the ratio of 7: 3 was identified as the optimal condition. PU-immobilized biosorbent (PUIB) with a particle size ranging from 0.425 to 0.18mm was selected for the adsorption of Reactive Yellow 2 (RY2). The uptake of RY2 on the PUIB was favorable at acidic pH, especially below 3. According to the Langmuir model, the maximum RY2 uptakes were estimated to be 104.0, 93.3, and 87.3mg/g at pH 2, 3, and 4, respectively. The pseudo-first-order and pseudo-secondorder models were applied to fit the biosorption kinetic data; the latter model fitted the data well with a high coefficient of determination (R²) and low average percentage error (ε) values. The RY2-sorbed PUIB was able to be regenerated and reused for five cycles of the adsorption and desorption processes.