Résumé

Emerging organic micropollutants (OMPs) are ubiquitous in waterbodies and not fully eliminated by wastewater treatment plants (WWTP). A proposed WWTP upgrade includes OMPs sorption by biochar rather than activated carbon (AC). Activated biochar (AB) and non-activated biochar (NAB) sorption performance towards 4 target OMPs (benzotriazole, sulfamethoxazole, carbamazepine, diclofenac) were evaluated in real-wastewater. Sorption processes are discussed in light of sorption mechanisms that depend both on OMP and on biochar physico-chemical properties. AB and AC have similar average sorption efficiency (45%), while NABs are much less efficient (<19%). OMPs sorption significantly correlates to SSA, inversely to H/C (indicating hydrophobic interaction with graphene-like structures) and to CEC or ash content (indicating H-bond or ternary surface complexation sorption mechanisms). This highlights the need to mix AB sources with different physico-chemical characteristics to sorb a large OMP spectrum within WWTPs. Production and use of ABs alleviate the negative environmental impact of ACs.

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