abstract
In this study, novel walnut shell biochar-nano zero-valent iron nanocomposites (WSBC-nZVI) were synthesized using a combined pyrolysis/reduction process. WSBC-nZVI displayed a high removal efficiency (86 %) for car-bamazepine (CBZ) compared with walnut shell biochar (70 %) and nano zero-valent iron (76 %) in the presence of persulfate (PS) (0.5 g/L catalyst, 10 mg/L CBZ, 1 mM persulfate). Subsequently, WSBC-nZVI was applied for the fabrication of the membrane using a phase inversion method. The membrane demonstrated an excellent removal efficiency of 91 % for CBZ in a dead-end system (2 mg/L CBZ, 1 mM persulfate). In addition, the effect of various operating conditions on the degradation efficiency in the membrane/persulfate system was investigated. The optimum pH was close to neutral, and an increase in CBZ concentration from 1 mg/L to 10 mg/L led to a drop in removal efficiency from 100 % to 24 %. The degradation mechanisms indicated that oxidative species, including 1O2, & BULL;OH, SO4 & BULL;-, and O2 & BULL;-, all contribute to the degradation of CBZ, while the role of 1O2 is highlighted. The CBZ degradation products were also investigated, and the possible pathways and the predicted toxicity of intermediates were proposed. Furthermore, the practical use of the membrane was validated by the treatment of real wastewater.
keywords
PERFORMANCE; KINETICS; REMOVAL
subject category
Environmental Sciences & Ecology
authors
Xue, YT; Kamali, M; Liyakat, A; Bruggeman, M; Muhammad, Z; Rossi, B; Costa, MEV; Appels, L; Dewil, R
our authors
Maria Elisabete Jorge Vieira Costa
Collaborator
Mohammadreza Kamali
PhD Studentacknowledgements
Yongtao Xue would like to acknowledge the China Scholarship Council (CSC) of the Ministry of Education, P. R. China (CSC NO. 202009505003) . The research was supported by the Research Founda- tion Flanders (FWO) under grant number V422823N.