The dewatering performance of streptomycin mycelial residue promoted by the Fenton process synergistic with biochar.

In this study, the performance and mechanism of streptomycin mycelial residue (SMR) dewatered by the Fenton process coupled with biochar was investigated. The optimal dosages of Fe2+, H2O2, and biochar were determined based on the response surface method (RSM), and the corresponding prediction equation was proposed. The walnut shell biochar prepared at 300 °C (WS300) exhibited the best dewatering performance due to its rough surface and large pore size. At the dosage of 0.3 g/g dry solids (DS) for WS300, the combination with Fenton process decreased the specific resistance to filtration of SMR and the water content (WC) of the filter cake by 93.9% and 27.8%, respectively. The RSM results suggested that the interaction between Fe2+ and H2O2 had significant influence on the dewatering properties compared to the other factor combinations. The optimum dosages of Fe2+, H2O2, and WS300 were 56.5 mg/g DS, 63.2 mg/g DS and 0.28 g/g DS, respectively. The strong oxidation of Fenton's reagents increased the zeta potential and reduced the particle size of SMR flocs, which promoted the release of bound water. In addition, the biochar worked as skeleton builder was conducive to construct hydrophobic channels and reduce the hydrophilicity of proteins and polysaccharides.