An efficient sorbent for phosphate removal from wastewater: a new application of phosphate mine wastes from Ruseifa City—Jordan

Abstract

Jordanian phosphate mine wastes (PMW) at Ruseifa City was fully characterized and tested for its PO₄ removal capacity by batch experiments using prepared phosphate solutions and domestic wastewater. PMW particles are positively charged with median particle size of 0.625 μm. Mineralogical and chemical analyses of PMW showed that it is mainly composed of calcite, fluorapatite, and quartz with high concentrations of calcium and phosphorous. The phosphate concentrations in PMW range from 11 to 24% expressed as P₂O₅. PMW as a sorbent has a very high PO₄ removal efficiency from wastewater and prepared solutions. PO₄ solutions with concentrations ranging from 5 to 5,000 mg L⁻¹ were prepared and utilized in batch experiments in the presence of PMW as a sorbent. The concentration of PO₄ in the solution phase and pH were the main parameters influencing the PMW sorption capacity of PO₄. The PO₄ removal efficiency from prepared solutions was up to 99%. Moreover, Langmuir sorption model was able to describe the observed data for PO₄ sorption by PMW. The sorption data at PO₄ concentrations >50 mg L⁻¹ were highly fitted to Langmuir model. The estimated sorption maximum capacity (b_max) of PMW was 46,620 mg kg⁻¹. On the other hand, domestic wastewater samples obtained from six Jordanian wastewater treatment plants were subjected to PO₄ removal by PMW, and the results showed that the PO₄ removal efficiency exceeded 97%. The adverse environmental impacts and human health risks associated with PMW presence are briefly discussed.

Keywords:

• Phosphate mine waste
• Phosphate removal
• Wastewater
• Natural minerals
• Sorption

Acknowledgments

The authors are highly thankful to the Testing Sector of the Royal Scientific Society of Jordan (RSS) for sponsoring this research work. The authors greatly appreciate the help received from the following persons: Dr Rafat Ahmad, executive director of the Testing Sector of RSS, Eng. Mohammad Obidat, Mr Anas Rasras, Mr Abdullah Obidat, Mr Ala’ Abu Debbes, and Mr Mahmoud Hassan from the Testing Sector of RSS. The authors would also like to express thanks to Jordan Phosphates Mines Co. Ltd for the assistance provided during the collection of samples and fieldwork.