title: Phosphorus recovery from biogas fermentation liquid by Ca-Mg loaded biochar.
abstract: Shortage in phosphorus (P) resources and P wastewater pollution is considered as a serious problem worldwide. The application of modified biochar for P recovery from wastewater and reuse of recovered P as agricultural fertilizer is a preferred process. This work aims to develop a calcium and magnesium loaded biochar (Ca-Mg/biochar) application for P recovery from biogas fermentation liquid. The physico-chemical characterization, adsorption efficiency, adsorption selectivity, and postsorption availability of Ca-Mg/biochar were investigated. The synthesized Ca-Mg/biochar was rich in organic functional groups and in CaO and MgO nanoparticles. With the increase in synthesis temperature, the yield decreased, C content increased, H content decreased, N content remained the same basically, and BET surface area increased. The P adsorption of Ca-Mg/biochar could be accelerated by nano-CaO and nano-MgO particles and reached equilibrium after 360min. The process was endothermic, spontaneous, and showed an increase in the disorder of the solid-liquid interface. Moreover, it could be fitted by the Freundlich model. The maximum P adsorption amounts were 294.22, 315.33, and 326.63mg/g. The P adsorption selectivity of Ca-Mg/biochar could not be significantly influenced by the typical pH level of biogas fermentation liquid. The nano-CaO and nano-MgO particles of Ca-Mg/biochar could reduce the negative interaction effects of coexisting ions. The P releasing amounts of postsorption Ca-Mg/biochar were in the order of Ca-Mg/B600>Ca-Mg/B450>Ca-Mg/B300. Results revealed that postsorption Ca-Mg/biochar can continually release P and is more suitable for an acid environment.
authors.affiliation: Key Laboratory of Plant-Soil Interactions of Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China. Electronic address: 948376144@qq.com.
authors.forename: Ci
authors.initials: C
authors.lastname: Fang
authors.affiliation: Key Laboratory of Plant-Soil Interactions of Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China. Electronic address: taozhang@cau.edu.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Plant-Soil Interactions of Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.affiliation: Key Laboratory of Plant-Soil Interactions of Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Rongfeng
authors.initials: R
authors.lastname: Jiang
authors.affiliation: College of Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Shubiao
authors.initials: S
authors.lastname: Wu
authors.affiliation: College of Science, China Agricultural University, Beijing 100193, China.
authors.forename: Haiyu
authors.initials: H
authors.lastname: Nie
authors.affiliation: Key Laboratory of Plant-Soil Interactions of Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Yingcai
authors.initials: Y
authors.lastname: Wang
mesh_terms: D056804:Biofuels / Q000032:analysis*; D002118:Calcium / Q000737:chemistry*; D002606:Charcoal; D005285:Fermentation; D008274:Magnesium / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry*; D014865:Waste Disposal, Fluid
chemical_list: D056804:Biofuels; C540010:biochar; D002606:Charcoal; D010758:Phosphorus; D008274:Magnesium; D002118:Calcium
keywords: Biogas fermentation liquid; Ca–Mg loaded biochar; Phosphorus; Recovery