High efficiency removal of Pb(Ⅱ) by modified spent compost of Hypsizygus marmoreus in a fixed-bed column

摘要

The spent compost of Hypsizygus marmoreus (SCHM) modified by NaOH solution was used as a novel biosorbent (MSCHM) to remove Pb(II) ions from aqueous solution in this study. Batch adsorption experiments revealed that the uptake capacity increased from 54.8 mg/g by SCHM to 72.5 mg/g by MSCHM and the adsorption efficiency improved regardless of the initial Pb(II) concentration. In the fixed-bed column experiments, the breakthrough and exhaustion time were extended/shorten about 2-11 times with the flow rate, bed depth and initial concentration changing from 20 mL/min, 12 cm and 45 mg/L to 40 mL/min, 28 cm and 145 mg/L, respectively. The adsorption process was predicted and described well by Thomas model indicating the external and internal diffusions were not the bottleneck of the process. The regeneration experiments were conducted to validate the reuse effectiveness of MSCHM, and the final regeneration efficiency achieved to 73%. Furthermore, the preliminary adsorption mechanisms of Pb(II) onto MSCHM were investigated by Brunauer-Emmett-Teller method, scanning electron microscope and Fourier transform infrared (FT-IR) spectrometer, and carboxyl, hydroxyl and amide might be important functional groups adsorbing Pb(II) ions.