Sorghum-Waste-Derived High-Surface Area KOH-Activated Porous Carbon for Highly Efficient Methylene Blue and Pb(II) Removal

Abstract

With the development of the environment and human society, the removal of metal ions and dyes in wastewater treatment remains an urgent problem to solve. In this work, two biomass carbon adsorbents were synthesized by a KOH activation and carbonization route using sorghum stem and root as carbon precursors. In comparison with the samples without KOH activation, the pore structure of the KOH-activated carbon has been dramatically improved. The findings show that the specific surface areas of the adsorbents by sorghum stem (S 1 ) and sorghum root (R 1 ) were 948.6 and 168.1 m 2 g −1 , respectively. Meanwhile, the abundant OH − and COO − groups on the surface of these adsorbents endow them with negative polarity, thereby exhibiting excellent adsorption performance for removing methylene blue (MB) and Pb(II) from wastewater. The adsorption amount and removal rate of S 1 were 98.1 mg g −1 and 98.08%, respectively, for MB, whereas those of R 1 were 197.6 mg g −1 and 98.82% for the Pb(II) ion, respectively. Our findings offer an invaluable insight into designing and synthesizing a highly efficient sustainable adsorbent to remove MB and Pb(II) based on biomass agricultural waste.

Improved Gas-Sensitive Properties by a Heterojunction of Hollow Porous Carbon Microtubes Derived from Sycamore Fibers

“…SVFs showed two characteristic peaks at 16.1° and 21.9°, and the strong peak at 21.9° indicated the hydrogen bond interaction between the cellulose chains. The CMTs and ZnO/CMT exhibited a broad diffraction peak at 22.4°, which corresponds to the (002) graphite plane. , Remarkably, the diffraction peak at 22.4° of CMTs was wider than that of ZnO/CMT, indicating that the degree of graphitization of CMTs was lower . The diffraction peaks of ZnO/CMT appearing at 31.77°, 34.42°, 36.25°, 47.54°, 56.60°, and 62.86° correspond to the (100), (002), (101), (102), (110), and (103) planes, respectively, which matched the wurtzite phases of hexagonal ZnO .…”

“…A peak at 2841 cm –1 was identified as the 2D band, and the appearance of 2D peaks was expected to make CMTs and ZnO/CMT have good electrical conductivity. ,, The relative intensity ratio of I D / I G revealed the degree of graphitization, and the I D / I G values of CMTs and ZnO/CMT were 0.72 and 0.69, respectively. This indicated that the graphitization degree of ZnO/CMT was higher. , As shown by the FTIR spectra in Figure i, the intensity of the peak at 3442 cm –1 corresponding to the stretching vibration of O–H is strongest for the SVFs, indicating a great number of O–H groups on the SVFs. This is consistent with the fact that the SVFs are made of cellulose with rich hydroxy groups.…”

“…This indicated that the graphitization degree of ZnO/CMT was higher. 39,45 As shown by the FTIR spectra in Figure 3i, the intensity of the peak at 3442 cm −1 corresponding to the stretching vibration of O−H is strongest for the SVFs, indicating a great number of O−H groups on the SVFs. This is consistent with the fact that the SVFs are made of cellulose with rich hydroxy groups.…”

“…37,38 Remarkably, the diffraction peak at 22.4°of CMTs was wider than that of ZnO/ CMT, indicating that the degree of graphitization of CMTs was lower. 39 The diffraction peaks of ZnO/CMT appearing at 31.77°, 34.42°, 36.25°, 47.54°, 56.60°, and 62.86°correspond to the (100), (002), (101), (102), (110), and (103) planes, respectively, which matched the wurtzite phases of hexagonal ZnO. 40 This result was consistent with the SEM (inset image Figure 2i) and TEM (Figure 3f) analyses.…”

Constructing Hierarchically Porous N-Doped Carbons Derived from Poly(ionic liquids) with the Multifunctional Fe-Based Template for CO2 Adsorption

“…The spectra showed that two intensive bands at about 1350 cm –1 (D band) and 1580 cm –1 (G band) corresponded to the defective carbon structure and the ordered structure of carbon with the sp 2 electronic configuration, respectively. 42 , 43 Usually, the degree of graphitization was estimated via the intensity ratio of the G/D band ( I G / I D ). Meanwhile, the value of I G / I D could also be influenced by the nitrogen content.…”