Enhanced Capture Ability of Sludge-Derived Mesoporous Biochar with a Template-like Method.

ABSTRACT

Sewage sludge-derived mesoporous biochars (SS-MBCs) were prepared by using cationic polyacrylamide (PAM+) as a template agent through a template-like method under high temperature and employed for getting rid of methylene blue (MB) from water. Textural evolution, mesostructured morphology, thermodynamic properties, and surface chemical groups of SS-MBCs were analyzed. It showed that PAM+ not only played an important role in good nucleation that brought well-developed texture and novel pore size distribution to SS-MBCs but also improved the MB adsorption capacities of SS-MBCs by increasing the specific surface area and the content of oxygen functional groups, especially the lactone. Preparation factor analysis indicated that PAM+ concentration, dosage of additive sludge, and carbonization temperature had distinct effects on material structure and adsorption performance especially above the pyrolytic temperature of 800 °C. The adsorption kinetics and isotherms were analyzed in detail, and it revealed that the kinetics and equilibrium adsorptions of SS-MBCs could be well-described by the Langmuir isotherm model and pseudo-second-order kinetics, respectively. Remarkably, the SS-MBCs showed higher removal efficiency and adsorption capacity than commercial activated carbon and most reported sludge-based adsorbents.