Production of magnetic sewage sludge biochar: investigation of the activation mechanism and effect of the activating agent and temperature

Abstract Sewage sludge-based porous materials were prepared through an integrated and energy-saving procedure that combines chemical activation with alkali (NaOH or K 2 CO 3 ) physical in a single step. The study was conducted wide temperature range (600–1000 °C), using higher temperatures than those commonly used. From the standpoint of textural properties, impregnation results decrease optimum temperature: 800 °C for untreated samples, 600–700 impregnated samples. increases amount –OH –NH functional groups, it also leads to generation new oxygen- and/or nitrogen-containing functionalities (above whole NaOH). treatment favors development magnetic properties on biochars, which is advantage its reuse wastewater treatment, since removal anionic surfactants heavy metals such as lead, copper, zinc, manganese. uptake phenol methylene blue (MB) maximized combination (with NaOH MB) use moderate (600–700 °C). values represent increase 87% 152% MB phenol, respectively, compared highest value non-impregnated samples (activated at lower required. Graphical abstract