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Contaminated soils are a challenge for implementing biotechnology in bioremediation, the recovery of Critical and Strategic Raw Materials (CRMs and SRMs), and food security. European Union (EU) Governments have established strict limits on As, Pb, Cd, and Hg in foods (Document 32023R0915) and requested the recovery of 34 CRMs within a circular economy (CE) (5th CRMs list). This study proposed a biotechnological tool for the decontamination of soil with heavy metal(loid)s by arbuscular mycorrhizal (AM)-assisted phytoextraction and the subsequent recovery of CRMs or by phytostabilization to prevent their entry into the food chain. It consisted of placing Baccharis salicifolia plants, inoculated or non-inoculated with AM fungi, into bioreactors (BRs) containing mining soil with Cd, Ni, and Cu, according to the Argentinian Patent (AR090183B1). The bioextractive potential (BP) was also estimated at the highest Technological Readiness Level (TRL) using a vegetable depuration module (VDM, TRL 6). Inoculated plants showed significantly higher aerial bioaccumulation coefficients (Cd: 68.62; P: 2.99; Ni: 2.51; Cu: 0.18) in BRs, and the BP values reached 1.16 g, 9.75 g, 2.40 g, and 213.1 g for Ni, Cd, Cu, and P, respectively. Finally, these CRMs and SRMs could be recovered from biomass through hydrometallurgy within a CE framework. [ABSTRACT FROM AUTHOR]

The electrosynthesis of H 2 O 2 via O 2 reduction was feasible employing cheap, unmodified graphite felt on top of carbon cloth as air-diffusion cathode fitted into an undivided filter-press cell. The experiments were performed in a pre-pilot plant with recirculation of 4 dm 3 of 0.05 M Na 2 SO 4 solutions at pH 3.0 upon continuous air feeding to the cathode. The H 2 O 2 electrogeneration occurred within the range −0.30 ≤  E ≤−0.01 V|SHE, being dependent on the mean linear flow velocity ( u ), which is related to the mass transport of hydronium ions. Optimum conditions achieved at E  = −0.30 V|SHE and u  = 27.4 cm s −1 yielded 100.4 mg dm −3 H 2 O 2 , with efficiency close to 100% and low energy consumption. [ABSTRACT FROM AUTHOR]