Abundant cilantro derived high surface area activated carbon (AC) for superior adsorption performances of cationic/anionic dyes and supercapacitor application

Abstract

With the growing concern about water quality requirements and the looming energy crisis, researchers all over the world have committed to the development of novel single low-cost porous materials for a variety of applications (ex: environmental and energy applications). Treatment of dye contaminants before they are released into the environment is considered as a significant challenge in the field of water treatment. Treatment of such dye contaminants remains as challenging task and evolved as the most persistent issues in the environmental remediation field. To address all these specific limitations present investigation involves the conversion of inexpensive Cilantro plants (C. sativum) into Activated Carbon (AC) which can be utilized as a fascinating alternative potential low-cost AC material for the treatment of toxic dye contaminants (environmental) and supercapacitor (energy) applications with improved performances. The fundamental physical–chemical properties of AC were confirmed by using various analytical and spectroscopic techniques. It is substantial to mention, obtained AC possesses a microporous structure and a large specific surface area of 2200 m2g−1. Further, AC was employed for the adsorption of methyl orange (MO) and rhodamine-6G (Rh-6G) dyes from aqueous solutions. The rapid adsorption process occurred within the contact time of 14 and 20 min for MO and Rh-6G. In addition, demonstrated with > 99 % removal efficiencies and an outstanding maximum adsorption capacity of 467.29 mg/g for MO and 143.47 mg/g for Rh-6G was witnessed surpassing the commercially available activated carbon material (CAC). To prove the efficacy of AC, the real-time application was evaluated by taking an industrial wastewater sample which showed 99.45 % of removal efficiency. Furthermore, a cartridge was developed and utilized for the treatment of dye solution for an on-field demonstration to assess potable water. Moreover, the synthesised AC witnessed a removal efficiency of > 80 % even up to the 4th cycle. Most importantly, to mark the waste management process the regenerated AC adsorbent and desorbed pollutants are treated effectively and can be utilized for further applications. Interestingly, the AC material obtained at 700 °C displayed optimum specific surface area (SSA), surface functionalities which help electrode wetting, surface redox reaction and pseudo-capacitance from ion diffusion and showed specific capacitance of 162.4F/g at 1 A/g (three electrode system). Notably, the AC symmetric supercapacitor provides a high-power density of 243.94 W/kg and could be reversibly cycled with very minimal capacitance loss over 5000 cycles at 10 A/g.