Phosphorus removal from aqueous solutions using a synthesized adsorbent prepared from mineralized refuse and sewage sludge.

ABSTRACT

Mineralized refuse and sewage sludge generated from solid waste from municipal landfills and sewage treatment plants were sintered as a cost-effective adsorbent for the removal of phosphorus. Compared with the Freundlich model, phosphorus adsorption on the synthesized adsorbent, zeolite and ironstone was best described by the Langmuir model. Based on the Langmuir model, the maximum adsorption capacity of the synthesized adsorbent (9718 mg kg(-1)) was 13.7 and 25.4 times greater than those of zeolite and ironstone, respectively. The desorbability of phosphorus from the synthesized adsorbent was significantly lower than that of zeolite. Moreover, phosphorus removal using the synthesized adsorbent was more tolerant to pH fluctuations than zeolite and ironstone for the removal of phosphorus from aqueous solutions. The immobilization of phosphorus onto the synthesized adsorbent was attributed to the formation of insoluble calcium, aluminium and iron phosphorus. The heavy metal ion concentrations of the leachate of the synthesized adsorbent were negligible. The synthesized adsorbent prepared from mineralized refuse and sewage sludge was cost-effective and possessed a high adsorptive capacity for phosphorus removal from aqueous solutions.