Sweet-Potato-Vine-Based High-Performance Porous Carbon for Methylene Blue Adsorption

Abstract

In this study, sweet-potato-vine-based porous carbon (SPVPC) was prepared using zinc chloride as an activating and pore-forming agent. The optimised SPVPC exhibited abundant porous structures with a high specific surface area of 1397.8 m2 g−1. Moreover, SPVPC exhibited excellent adsorption characteristics for removing methylene blue (MB) from aqueous solutions. The maximum adsorption capacity for MB reached 653.6 mg g−1, and the reusability was satisfactory. The adsorption kinetics and isotherm were in good agreement with the pseudo-second-order kinetics and Langmuir models, respectively. The adsorption mechanism was summarised as the synergistic effects of the hierarchically porous structures in SPVPC and various interactions between SPVPC and MB. Considering its low cost and excellent adsorption performance, the prepared porous carbon is a promising adsorbent candidate for dye wastewater treatment.

Zanthoxylum bungeanum Waste-Derived High-Nitrogen Self-Doped Porous Carbons as Efficient Adsorbents for Methylene Blue

“…Moreover, an analysis of pore size distributions revealed the presence of abundant microporous and mesoporous structures in both NPC1 and NPC2 (inset of Figure 3a). Combined with the SEM and TEM results, it can be confirmed that the prepared porous carbons possessed rich hierarchical pore structures [6]. In addition, the BET-specific surface areas of NPC2 (1712.7 m 2 g −1 ) were higher than those of NPC1 (1492.9 m 2 g −1 ).…”

“…As the pH increased from 2 to 12, the q e of NPC1 and NPC2 for MB also increased (Figure 5a). According to the previous report, cationic species were the predominant MB species in solutions [6].…”

“…Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS) mapping were utilized to investigate the morphology, structure, and elemental compositions of NPC1 and NPC2. As shown in Figure 2a,b, the surfaces of both NPC1 and NPC2 displayed numerous macropore structures formed via the interweaving of the carbon layers [6], with NPC2 exhibiting a more abundant macropore structure. EDS patterns revealed the uniform distribution of C, N, and O atoms across the surfaces of NPC1 and NPC2 structural matrices (Figure 2c,d).…”

“…Additionally, the high-resolution N 1s spectra displayed three peaks of NPC1 at 398.7, 400.48, and 401.7 eV or NPC2 at 398.57, 400.48, and 401.4 eV, corresponding to pyridinic N, pyrrolic N and graphitic N, respectively (Figure 4c) [42]. Particularly, pyridinic N provided electrons for π, thereby enhancing charge transfer as an efficient ion-absorbing substance [27], while graphitic N contributed to greater adsorption sites owing to its high thermal stability [6]. The O 1s spectra showed peaks corresponding to C=O at 531.6 eV, O-N at 533.4 eV, and C-OH at 536.3 eV for NPC1 [9,14], and corresponding to C=O at 531.6 eV and C-O at 533.6 eV for NPC2 (Figure 4d) [5,33].…”

“…Currently, various methods, such as adsorption, photocatalysis, biodegradation, and chemical oxidation, are being employed for MB wastewater treatment [4], with adsorption being preferred owing to its cost-effectiveness, ease of regeneration, and high efficiency [5]. While a range of adsorbents, including carbon materials, hydrogels, polymers, metal nanomaterials, metal-organic frameworks and their derivatives, have been investigated for dye adsorption [6], most adsorbents encounter limitations such as low adsorption performance, potential secondary contamination, high cost, and complex manufacturing processes, which hinder their widespread application [7]. Therefore, there is a pressing need to develop efficient, eco-friendly, cost-effective, and readily available materials for MB removal.…”