Biosorption of methylene blue from wastewater by an extraction residue of Salvia miltiorrhiza Bge.

Efforts were made in this study to using an extraction residue of Salvia mitiorrziza Bge (SM), a widely utilized traditional Chinese medicine, as an effective biosorbent of methylene blue from polluted water. Batch experiments were carried out with original and chemical modification, particle size, dosage, solution pH, contact time, and initial concentration of the dye. Experimental data fit Langmuir isotherm and pseudo-second order kinetic best compared to other models applied in the study. Characterization of adsorption was determined by FT-IR, SEM and particle surface area measurement. The maximum monolayer biosorption capacity of raw SM is 100.0mg·g(-1). The citric acid and Na2CO3 modification can significantly enhance this value up to 161.29 and 178.57mg·g(-1), respectively. This investigation provides a novel approach for reutilizing the enormous quantity of Chinese herbal medicine wastes, which is significant since these dregs have brought out big environmental and heathy problems in the present China.