title: Struvite-based phosphorus recovery from the concentrated bioeffluent by using HFO nanocomposite adsorption: Effect of solution chemistry.
abstract: Here we reported struvite-based phosphorous recovery from the concentrated desorption effluent of a proprietary hydrated ferric oxide (HFO) nanocomposite (HFO-201) system, and the effect of solution chemistry (alkalinity, salinity, and dissolved organic matter (DOM)) on struvite formation was particularly focused on. The optimum P recovery rate (∼97%) and high quality struvite was obtained at 25°C, pH 9.0-9.5, and the molar Mg:NH4:P ratio of 1.4:4:1. The reaction reached equilibrium within ∼30min, much faster than the reported high purity struvite formation at neutral pH (several days required). It largely relied on the absence of Ca(2+) in the desorption effluent due to the Donnon co-ion effect exerted by HFO-201. Thermodynamic modelling with Stockholm humic model revealed that the presence of salinity and DOM resulted in a lower saturation index (SI) of struvite, thus inhibiting P recovery by struvite. Nevertheless, it is favorable to form struvite of large particle size. In addition, increasing the molar Mg:NH4:P ratio from 1:1:1 to 1.4:4:1 could significantly weaken the adverse effect of the high salinity and DOM. Direct addition of Ca(2+) could also result in phosphorous recovery, but the P content of the resultant solid (∼4.4%) is much lower than the formed struvite (∼17%). The results indicated that struvite process is a very attractive option to recover P from the desorption effluent, and the effect of solution chemistry is crucial to optimize the process.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
authors.forename: Yanyang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Weixian
authors.initials: W
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China. Electronic address: bcpan@nju.edu.cn.
authors.forename: Bingcai
authors.initials: B
authors.lastname: Pan
mesh_terms: D000327:Adsorption; D005290:Ferric Compounds / Q000737:chemistry*; D017616:Magnesium Compounds / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry / Q000302:isolation & purification*; D012996:Solutions; D000069877:Struvite
chemical_list: D005290:Ferric Compounds; D017616:Magnesium Compounds; D010710:Phosphates; D012996:Solutions; C000499:ferric oxide; D010758:Phosphorus; D000069877:Struvite
keywords: Desorption effluent; HFO nanocomposite; Phosphorous recovery; Solution chemistry; Struvite