Degradation of Orange Ⅱ by persulfate activated with nitrogen-doped porous sludge carbon

Abstract

A nitrogen doped porous sludge biochar（NKBC） was prepared using municipal sludge as carbon source，potassium bicarbonate as activator，and urea as nitrogen source. N2 adsorption-desorption experiments，SEM，XRD and XPS were used to characterize and analyze its specific surface area and surface characteristics. The results showed that NKBC had a large specific surface area. Due to N loading in the pores of NKBC，its surface was wrinkled，with many defects and activation sites. NKBC was used to activate the degradation of Orange Ⅱ by persulfate（PDS），and the performance of the NKBC/PDS system in degrading Orange Ⅱ was investigated. The results showed that after adding PDS 20 minutes，the degradation rate of Orange Ⅱ by the NKBC/PDS system reached 99.7%. This system could function over a wide pH range （3-11） and under common anionic conditions. The results of free radical quenching experiments and EPR spectroscopy indicated that the main active species for the degradation of Orange Ⅱ in the NKBC/PDS system were ·OH，SO4·- and 1O2，with 1O2 being the main active specie. The NKBC/PDS system constructed in this research can be applied to the treatment of dye wastewater，achieving the goal of “treating waste with waste”.

Keywords

• nitrogen-doping
• sludge biochar
• persulfate
• orange ⅱ