Green synthesized MgO combined with dielectric barrier discharge plasma enhanced phosphorus (P) recovery from livestock wastewater: A dual approach for management of wastewater and P resources.

Phosphorus (P) recovery from wastewater using integrated techniques i.e., adsorption combined with advanced oxidation technologies is a novel approach for cleaning wastewater and preventing eutrophication. This approach, however, has not been extensively studied, particularly in the context of real wastewater applications. In this study, a green biomass-based sol-gel method was developed using potato starch (PS) and MgCl·6HO to synthesize MgO (PS-MgO). The unique synthesis method resulted in PS-MgO composed predominantly of spherical particles with an average size of about 103 nm and exhibited superior P adsorption performance compared to commercial MgO materials (GH-MgO and AD-MgO). The Langmuir maximum P adsorption capacity (mg/g) of the PS-MgO was 429.4, while that of the commercial GH-MgO and AD-MgO was 341.3 and 421.7, respectively, at the solution pH 7.0. The kinetic model fitting demonstrated that the adsorption rate of PS-MgO was faster than the two commercial MgOs. Importantly, PS-MgO can maintain a high P adsorption capacity across a wide pH range (425 mg/g at pH 5.0 and 369 mg/g at pH 11.0), whereas the P adsorption capacities of GH-MgO (153 at pH 5.0 and 297 at pH 11.0) and AD-MgO (422 at pH 5.0 and 200 at pH 11.0) were more pH-dependent. In addition, PS-MgO exhibits high selectivity for P capture in solutions containing coexisting ions, and the P-loaded PS-MgO can efficiently release P through acid or base treatment, highlighting its potential for reuse as a fertilizer. To enhance P recovery from real livestock wastewater, the dielectric barrier discharge (DBD) plasma technology was combined with MgO adsorption. The P recovery capacity of MgOs from livestock wastewater increased 1.4-1.7 times after DBD plasma treatment, attributed to the degradation of aromatic proteins and microbial metabolites. These findings provide new insights into the design of efficient and environmentally friendly materials for P recovery, while also demonstrating the potential of integrating advanced oxidation technologies with adsorption processes.