Improved adsorption of streptomycin onto Thalia dealbata activated carbon modified by sodium thiosulfate

Sodium thiosulfate-modified activated carbon (TDAC-ST) was prepared from Thalia dealbata, and its ability to remove streptomycin (STM) from aqueous solutions was examined. The surface properties of TDAC-ST and the original carbon (TDAC) were also measured by scanning electron microscopy, N-2 adsorption/desorption isotherms, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The results indicated that modification with sodium thiosulfate slightly decreased the carbon's surface area but introduced more functional groups and improved the adsorption ability greatly as compared to the original carbon. The effects of solution pH, initial STM concentration and contact time on adsorption system were also studied. The kinetics data followed the pseudo-second-order kinetics model, and the adsorption isotherms fit the Langmuir isotherm equation quite well, and the maximum adsorption capacity of was 247.65 and 170.84 mg/g for TDAC-ST and TDAC, respectively. The results indicated that sodium thiosulfate modification could greatly enhance the adsorption of STM onto activated carbon, and TDAC-ST was a promising adsorbent for the removal of streptomycin from aqueous solutions.