Facile one-step synthesis of graphitic carbon nitride-modified biochar for the removal of reactive red 120 through adsorption and photocatalytic degradation

Abstract

Converting waste biomass into value-added biochar has been considered as a green and sustainable strategy for resource management and pollution control. In this study, graphitic carbon nitride (g-C 3 N 4 ) modified biochars (BCs) were produced through one-pot pyrolysis of urea and hickory chips in differential ratios at 520 °C. The resulting BC/g-C 3 N 4 composites were evaluated in laboratory for their physicochemical, adsorptive, and photocatalytic properties. The characterization tests showed the successful synthesis of the BC/g-C 3 N 4 composites that introduced g-C 3 N 4 structure, N-containing surface functional groups, reduced surface area, and better thermal stability to the biochar. After modification, the BC/g-C 3 N 4 composites showed better adsorption ability to reactive red 120 (RR120) than the pristine BC, due to the strong electrostatic attrition between N-containing functional groups of g-C 3 N 4 on biochar surface and anionic RR120. The BC/g-C 3 N 4 composites also inherited g-C 3 N 4 's photocatalytic activity, which is visible light responsive to generate free radicals for RR120 degradation. In addition, the composites with higher urea modification ratios were more effective in the degradation of RR120. Overall, this study demonstrates the feasibility and promising potential of combining biochar and photocatalyst for the removal of aqueous dye. Because of the synergistic adsorption and photodegradation ability, BC/g-C 3 N 4 composites present a novel and cost-effective solution for the removal of aqueous dye and other photodegradable contaminants under natural conditions.

Efficient elimination of organic and inorganic pollutants by biochar and biochar-based materials

“…The BC/C 3 N 4 composites showed much higher adsorption capacity of reactive red 120 (RR120) than pristine biochar due to the strong electrostatic attrition between N-containing groups of C 3 N 4 and anionic RR120. The surface adsorbed RR120 was then photocatalytically degraded by the free radicals under visible light irradiation under natural conditions (Zheng et al 2019).…”

Recent Progress in Biochar-Based Photocatalysts for Wastewater Treatment: Synthesis, Mechanisms, and Applications

“…In most cases, after the combination, the S BET of the BCPs is higher than that of the original BC. However, it was found that the mesopores and micropores of BC may be clogged due to the aggregation of semiconductors, thus inducing the decrease of the S BET [62,72].…”

“…Due to the greater absorption of the visible spectrum, BC elevated the quantum efficiency, charge separation, and generation of free radicals. Zheng et al [72] synthesized BC-based g-C 3 N 4 via one-pot pyrolysis with different mass ratio. g-C 3 N 4 modification can expand biochar's capacity.…”

Biochar-Based Graphitic Carbon Nitride Adorned with Ionic Liquid Containing Acidic Polymer: A Versatile, Non-Metallic Catalyst for Acid Catalyzed Reaction

“…Preparation of biochar-based graphitic carbon nitride was carried out according to the previously reported procedure with some modification [ 75 , 76 ]. In this work, Zinnia grandiflora petals, collected from the north of Iran, were utilized for the first time as biosources.…”