Adsorption properties of modified eggshell on phosphorus in water

Abstract

Modified eggshell adsorbent was prepared with 5% potassium permanganate solution to adsorb phosphorus in simulated wastewater. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to clarify their phosphorus removal mechanisms. Isothermal and kinetic equations were fitted to explain the mechanism of phosphorus adsorption. The results showed that the optimum conditions were as follows: phosphorus concentration of 5 mg·L-1, wastewater pH of 2, adsorbent dosage of 3.5 g, adsorption time of 350 min, phosphorus adsorption rate of modified eggshell was 90.81%, and the experimental results were relatively stable. According to the characterization, the eggshell adsorbent has good crystallinity, irregular surface structure and abundant pore channels，and the main functional groups on the surface are hydroxyl (-OH) and C-H groups, which enhanced the adsorption effect.