Simultaneous removal of organic inorganic composite contaminants by in situ double modified biochar: Performance and mechanisms

Background In this study, double modified biochar was prepared to remove organic matter and heavy metals at the same time. It has high removal efficiency for organic matter even in actual irrigation water. Methods Tobacco stem was used as carbon-based carrier, modified with polyacrylic acid (PAA) rich in oxygen functional groups (OFGs) and transition metals (iron and cobalt) with excellent catalytic activity. After mixing them evenly, the in-situ double modified biochar (BC PAA @CFO) of OFGs and CoFe 2 O 4 (CFO) was obtained by one-step hydrothermal carbonization (HTC). Significant findings BC PAA @CFO in QNC-Pb 2+ composite system, CFO can quickly activate peroxymonosulfate (PMS), and the degradation efficiency of quinclorac (QNC) is as high as 80.7%. Free radical quenching experiments and electron paramagnetic resonance (EPR) analysis indicated that SO 4 · − , ·OH, ·O 2 − and 1 O 2 were the main active species involved in the degradation of QNC. At the same time, the rich OFGs make the adsorption efficiency of Pb 2+ reach 73.2% within 4 h. FT-IR results further confirmed that the dominant role of adsorption should be OFGs. In general, this in-situ double modified BC PAA @CFO obtained by one pot HTC is a promising purifying agent for mixed pollutants.