The effect of various thermochemical methods on the production of biochar and removal of 2‐naphthol orange from wastewater

Abstract

AbstractBACKGROUNDThermochemical conversion methods are essential processes frequently used in the production of biochar and the type chosen affects the properties of biochar. In this study, 2‐naphthol orange was removed from synthetic wastewater using biochar adsorbents produced from pelletized furniture sawdust by thermochemical techniques (torrefaction, pyrolysis and gasification) at various durations (0.5–5 h) and temperatures (200–900 °C).RESULTSThe adsorbent produced via torrefaction at 200 °C in 1 h exhibited the best removal performance. For furniture waste biochar (FWB), the optimum conditions for 2‐naphthol orange options were initial concentration 35 mg L−1, pH 2.0, contact duration 2 h, agitation speed 200 rpm, temperature 30 °C, 1.0 g L−1 of biochar and ‐ 50‐mesh biochar size. The Langmuir isotherm and Pseudo‐second‐order models showed the highest coefficients of determination (R2 = 0.9947 and 0.9978, respectively). The terms of qm (mg g−1) and KL were found to be 230.45 and 0.28, respectively, from the Langmuir isotherm. Conversely, the terms of qe (mg g−1) and k2 [g (mg.min)−1] were found to be 29.27 and 0.00486, respectively, from the pseudo‐second‐order model. According to the long‐stability experiment, the selected adsorbent of 200–1 (biochar from torrefaction) remained more stable after 10 cycles of adsorption.CONCLUSIONIt was found that the torrefaction process provides significant advantages owing to the removal efficiencies of 2‐naphthol orange dye and the fact that biochar production is easier and more economical at low temperatures. © 2023 Society of Chemical Industry.