Sludge-based mesoporous activated carbon: the effect of hydrothermal pretreatment on material preparation and adsorption of bisphenol A

Background The excess sludge produced by sewage treatment plants contains a large number of pollutants, which is of huge environmental risk. Transforming this kind of solid waste into adsorption materials is an effective approach to realize the resource utilization of sludge. Combined with hydrothermal pretreatment and chemical activation, the synthesis of sludge-based mesoporous carbon is used to remove bisphenol A (BPA) in wastewater. Results A resource recycling measure to prepare mesoporous activated carbons (MACs) from sewage sludge was developed via the combination of hydrothermal pretreatment and chemical activation using sewage sludge and sulfuric acid as carbon precursor and activating agent, respectively. The combination of hydrothermal pretreatment and chemical activation not only can make efficient use of the activating agents but also facilitate the deep pyrolysis of the sludge. The resultant MAC obtained using the hydrothermal pretreatment possessed a larger total surface area, less crystalline phase and a narrower pore size distribution compared to other samples. Meanwhile, the MAC obtained from hydrothermal pretreatment presented the highest amount of adsorption of BPA and achieved a better capture than the reference commercial activated carbons. In addition, a possible adsorption mechanism has been proposed to further analyze the enhanced adsorption performance. Conclusions The yield and mesoporous content of the obtained MAC is 59.19% and 31.51%, respectively. The maximum adsorption capacity for BPA is 137.87 mg g(-1). Microporosity, hydrogen bonding and pi-pi effect introduced by the hydrothermal pretreatment play an important role in BPA adsorption. (c) 2020 Society of Chemical Industry