Biomass is a promising carbon source because of its low-cost and rich carbon component. Here, lotus root as self N-source was used to produce N-doped biochar via a simple carbonization after freeze-drying, showing surface areas up to 694 m2/g with partial mesopores. Applicability of biochar as adsorbent for dyes removal was explored using methyl orange (MO) as model pollutant dye. LBC-800 sample obtained at 800 °C had the largest capacity of 320 mg/g in 300 mg/L solution at 25 °C with fast equilibrium time of 60 min, and pseudo-second order model expressed better for kinetics. LBC-800 also had an unprecedented maximum capacity of 449 mg/g with superior conformity to Langmuir model. The biochar was efficient for MO removal with high capacity and fast kinetic, and significantly the sustainable feature of lotus root would allow a large-scale production of biochar as well as promising use in wastewater treatment fields.
Keywords: Biomass; Direct carbonization; Dye removal; Freeze-drying; Lotus root.
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