Utilization of phosphorus loaded alkaline residue to immobilize lead in a shooting range soil

• Published in: Chemosphere (Oxford) 2016-11, Vol.162, p.315-323
• Main Authors: Yan, Yubo, Qi, Fangjie, Seshadri, Balaji, Xu, Yilu, Hou, Jiexi, Ok, Yong Sik, Dong, Xiaoli, Li, Qiao, Sun, Xiuyun, Wang, Lianjun, Bolan, Nanthi
• Format: Article
• Language: English
• Subjects: Alkaline residue; Bioavailability; Firearms; Lead - chemistry; Lead - isolation & purification; Pb immobilization; Phosphorus (P); Phosphorus - chemistry; Shooting range soil; Soil - chemistry; Soil Pollutants - analysis; Soil Pollutants - chemistry; Triticum aestivum; Waste Management - methods; X-Ray Diffraction
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2016.07.068

The alkaline residue generated from the production of soda ash using the ammonia-soda method has been successfully used in removing phosphorus (P) from aqueous solution. But the accumulation of P-containing solid after P removal is an undesirable menace to the environment. To achieve the goal of recycling, this study explored the feasibility of reusing the P loaded alkaline residue as an amendment for immobilization of lead (Pb) in a shooting range soil. The main crystalline phase and micromorphology of amendments were determined using X-ray diffraction (XRD) and scanning electron microscopy-electron dispersion spectroscopy (SEM-EDS) methods. The toxicity characteristic leaching procedure (TCLP), sequential extraction procedure, and physiologically based extraction test (PBET) were employed to evaluate the effectiveness of Pb immobilization in soil after 45 d incubation. Treatment with P loaded alkaline residue was significantly effective in reducing the TCLP and PBET extractable Pb concentrations in contrast to the untreated soil. Moreover, a positive change in the distribution of Pb fractions was observed in the treated soil, i.e., more than 60% of soil-Pb was transformed to the residual fraction compared to the original soil. On the other hand, P loaded amendments also resulted in a drastic reduction in phytoavailable Pb to the winter wheat and a mild release of P as a nutrient in treated soil, which also confirmed the improvement of soil quality. [Display omitted] •Alkaline residue collected from phosphorus adsorption process was further reused to immobilize Pb in a small shooting range soil.•Phosphorus loaded alkaline residue significantly reduced leachability, bioaccessibility, and phytoavailability of Pb in studied soil.•Phosphorus loaded alkaline residue mildly released P as a nutrient in treated soil.•Phosphorus loaded alkaline residue can be considered as a low cost and efficient amendment for the remediation of Pb contaminated soils.