Adsorption-electrochemical mediated precipitation for phosphorus recovery from sludge filter wastewater with a lanthanum-modified cellulose sponge filter

Shuoxun Dong; Xiaolin Li; Siying Wang; Daxin Zhang; Yuchi Chen; Feng Xiao; Yili Wang

doi:10.1016/j.scitotenv.2023.165545

Adsorption-electrochemical mediated precipitation for phosphorus recovery from sludge filter wastewater with a lanthanum-modified cellulose sponge filter

Sci Total Environ. 2023 Nov 10:898:165545. doi: 10.1016/j.scitotenv.2023.165545. Epub 2023 Jul 14.

Authors

Shuoxun Dong¹, Xiaolin Li², Siying Wang², Daxin Zhang², Yuchi Chen³, Feng Xiao⁴, Yili Wang²

Affiliations

¹ School of Water Resources and Hydropower Engineering, North China Electric Power University, Beijing 102206, China.
² College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China.
³ Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
⁴ School of Water Resources and Hydropower Engineering, North China Electric Power University, Beijing 102206, China. Electronic address: xiaofeng@ncepu.edu.cn.

PMID: 37454846
DOI: 10.1016/j.scitotenv.2023.165545

Abstract

In this study, the sludge filter wastewater is confirmed to investigate the effects of adsorption-electrochemical mediated precipitation (EMP) driven phosphorus recovery on the basis of lanthanum-modified cellulose sponge filter (LCLM) material. The adsorption-EMP method relies on in situ recovery phosphate (P) from the used desorption agent (NaOH-NaCl binary solution) via the formation of Ca₅(PO₄)₃OH all while preserving the alkalinity of the desorption agents which benefited long-term application. The lanthanum content of LCLM was 9.0 mg/g, and the adsorption capacity reached 226.1 ± 15.2 mg P/g La at an equilibrium concentration of 3.9 mg P/L. After adsorption, 55.7 % of P was recovered, and the corresponding alkalinity increased from 1.9 mmol/L to 2.2 mmol/L. Adsorption mechanism analysis revealed that the high lanthanum usage of LCLM was attributed to the synergistic effect of the lattice oxygen of LaO and LaPO₄·0.5H₂O crystallite formation. Additionally, the Ca₅(PO₄)₃OH was found precipitated in the precipitation in the cathode chamber (P-CC) rather than on the surface/section of cation exchange membrane (CEM) and cathode indicating that the P recovery process was controlled by the saturation of CaP species in the EMP system and the electromigration effect. These findings present a new strategy to promote the effective utilization of rare earth elements for P adsorption and demonstrate the potential application of adsorption-EMP systems in dephosphorization for wastewater treatment.

Keywords: Adsorption; Calcium phosphate; Electrochemical mediated precipitation; Lanthanum; Phosphate recovery.