The characteristics of pharmaceutical sludge-derived biochar and its application for the adsorption of tetracycline

In this study, the specific surface area, pore structure, surface functional groups and microstructure of the biochar derived from the pyrolysis of pharmaceutical sludge are analyzed. The results showed that the pyrolysis temperature had a great influence on the properties of sludge-based biochar (SBB), and the specific surface area of the SBB first increased and then decreased with an increase in the pyrolysis temperature. The maximum specific surface area was 214.97 m2/g at 600 °C, while the pore volume increased with an increase in the pyrolysis temperature. The pickling process removed impurities in the SBB and increased the specific surface area of the material (319.80 m2/g). The effects of pyrolysis temperature, pH, adsorption time, and initial pollutant concentration on the adsorption process were also studied. The results showed that the adsorbents had good pH adaptability, and biochar produced at 600 °C had the best adsorption capacity (94.69 mg/g). Pickling increased the adsorption capacity to 157.38 mg/g. The results showed that pharmaceutical sludge has great potential as a raw material for the preparation of adsorbent. These benefits can compensate for the cost of sludge pyrolysis treatment.