Phosphorus Adsorption on Blast Furnace Slag with Different Magnetism and Its Potential for Phosphorus Recovery

Xiaoxin Wu; Rui Zhan; Lili Liu; Jinjing Lan; Ning Zhao; Zhiping Wang

doi:10.3390/w14162452

Water (Aug 2022)

Phosphorus Adsorption on Blast Furnace Slag with Different Magnetism and Its Potential for Phosphorus Recovery

Xiaoxin Wu,
Rui Zhan,
Lili Liu,
Jinjing Lan,
Ning Zhao,
Zhiping Wang

Affiliations

Xiaoxin Wu: China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 201306, China
Rui Zhan: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237, China
Lili Liu: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237, China
Jinjing Lan: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Ning Zhao: China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 201306, China
Zhiping Wang: China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 201306, China

DOI: https://doi.org/10.3390/w14162452
Journal volume & issue: Vol. 14, no. 16
p. 2452

Abstract

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Phosphorus (P) is one of the essential nutrients for all life but also is involved in the major factor of water eutrophication. This study aimed to investigate a low-cost approach for highly efficient P removal and recovery from wastewater with blast furnace slag (BFS) as the adsorbent. The adsorption characteristics were consistent with the Langmuir adsorption isotherm (q0 0.1370~0.3848 mg/g) and quasi-secondary kinetic model (R2 = 0.9986~0.9997), suggesting monomolecular-layer chemical adsorption might be the dominant pathway. According to the determination of scanning electron microscope and energy dispersive spectroscopy, P was distributed uniformly with other elements in the surface of BFS and even formed needle-like crystals. This indicated that P might be also further deposited in the surface of BFS after the initially chemical adsorption via coordination with the active sites, which led to the slow accumulation of P along with the adsorption experiments. The binding energy and atomic composition analysis of X-ray photoelectron spectroscopy revealed that phosphate mainly existed as HPO42− in the surface of BFS, especially for those non-magnetic particles with relative low Fe content (<30%), indicating the preference of P to the hydroxyl basic sites. Compared with those magnetic particles, the adsorption capacity of the non-magnetic particles was larger and could be restored more easily with the elution of sulfate acid, resulting in about two times the P recovery capability. Based on the P adsorption mechanism in the surface of BFS, the operation conditions of the BFS adsorption column for P recovery were optimized in an alkaline condition with a low phosphate concentration and long residual time. Therefore, non-magnetic BFS with small size could be used to recover P resources from rural wastewater with low P concentration and facilitated the on-site reuse of P resources in rural districts.

Published in Water

ISSN: 2073-4441 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Hydraulic engineering; Technology: Environmental technology. Sanitary engineering: Water supply for domestic and industrial purposes
Website: http://www.mdpi.com/journal/water/

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