Adsorption characteristics of arsenic from micro-polluted water by an innovative coal-based mesoporous activated carbon

An innovative coal-based mesoporous activated carbon (NCPAC) was prepared by re-agglomeration, oxidation and two-step activation using coal-blending as precursor. Adsorption capacities of As(III) and As(V) ions (<0.5 mg/L) onto NCPAC as a function of pH, adsorbent dose, initial arsenic concentrations, contact time, and adsorption isotherms at 7 °C was investigated. The innovative methods promoted total pore volume (1.087 cm3/g), mesoporosity (64.31%), iodine numbers (1104 mg/g), methylene blue (251.8 mg/g) and ash contents (15.26%). The adsorption capacities of NCPAC for As(III) and As(V) were found to be strongly dependent on pH and contact time. The optimal pH value was 6. The equilibrium time was 60 min for adsorption of As(III) and As(V) by NCPAC. The Langmuir model fitted the experimental data well for both As(III) (R2 = 0.9980) and As(V) (R2 = 0.9988). Maximum adsorption capacities of As(III) and As(V) (C0 = 0.50 mg/L) by NCPAC were 1.491 and 1.760 mg/g, respectively.