Construction and Adsorption Performance Study of GO-CNT/Activated Carbon Composites for High Efficient Adsorption of Pollutants in Wastewater

Abstract

Based on the increasing application requirements for the efficient adsorption of wastewater pollutants, graphene oxide-carbon nanotube/activated carbon (GO-CNT/AC) composites are constructed from the optimal microstructure matching of GO, CNTs, and AC materials by solution impregnation and freeze-drying methods. Three-dimensional structures with nano-micro hierarchical pores are established, with GO and CNTs uniformly dispersed on the AC surface, effectively restrain the agglomeration. The added CNTs played a “spring” role, supporting the gap between the GO sheets and AC matrix. Meanwhile, stable links are formed between GO, CNTs, and AC, realizing the synergistic matching of the microstructure, which provides abundant active absorption sites beneficial for improving the adsorption performance. The influences of the CNT contents, adsorbent amounts, methylene blue (MB) concentrations, and pH values on the adsorption property of GO-CNT/AC composites are systematically investigated. The results show that when the pH value of the MB solution is 13, the CNT concentration is 3 mg/mL and the MB concentration is 200 mg/L, the adsorption property of the composite is the best, with an adsorption capacity of 190.8 mg/g and a removal percentage of 95.4%. Compared with the raw AC, the adsorption capacity and removal percentage of the composites are increased by 73.9% and 72.8%, respectively. The GO-CNT/AC composites exhibit excellent cyclic adsorption performance, with a cyclic stability of 91.8% after six rounds of adsorption–desorption cycles. The kinetic analysis shows that the adsorption process conforms to the PSO kinetic model. By fitting of the IPD model, the adsorption mechanisms of the GO-CNT/AC composites are divided into two adsorption stages and described respectively. This study provides a new way to achieve highly efficient adsorption of pollutants in wastewater.

Template-Free Synthesis of Magnetic La-Mn-Fe Tri-Metal Oxide Nanofibers for Efficient Fluoride Remediation: Kinetics, Isotherms, Thermodynamics and Reusability

“…A shown in Figure 5, the fluoride uptake of LMF11 NFs elevates gradually with an in crease in C0 (10 mg F − /L to 45 mg F − /L). The reason is that with the increase in F − concen tration, the number of fluoride ions near the surface of the LMF11 NFs increases appar ently, and the binding sites on the surface of LMF11 NFs are more fully surrounded by fluoride ions, thus, more fluoride ions are adsorbed by the adsorbent, resulting in the in creasing of fluoride binding amount [53]. Then it approaches saturation at higher C0 due to the saturation of active sites.…”

“…Figure9depicts four linear adsorption kinetic curves namely PFO, PSO, Elovich and Weber and Morris models[53] of LMF11 NFs for fluoride at C 0 = 20 and 50 mg F − /L and pH = 3. Correlative parameters are listed in Table3.…”

Application of Infrared Pyrolysis and Chemical Post-Activation in the Conversion of Polyethylene Terephthalate Waste into Porous Carbons for Water Purification

“…Table 5 summarizes the synthesis conditions, specific surface area (SSA) and adsorption value of materials from other works investigating carbon adsorbents for MB water purification. GO-CNT/AC Complex preparation (see [60]) 1361.9 174.8 [60] As can be seen from Table 5, the obtained carbon adsorbent is superior to other PET-derived carbons both in adsorption capacity and in time and energy costs for their production. Typically, furnaces with heating rates rarely exceeding 10 • C min −1 are used in the preparation of carbon materials.…”

“…In such instances, the production process for each constituent tends to be notably complex and costly. For instance, in [60], an adsorbent featuring a surface area of 1361.9 m 2 g −1 and an adsorption capacity of 174.8 mg g −1 is proposed. Although it surpasses our suggested adsorbent in performance, this method lacks economic viability and fails to address the challenge of PET waste utilization.…”

Porous amorphous metal–organic frameworks based on heterotopic triangular ligands for iodine and high-capacity dye adsorption

“…[1][2][3][4][5][6][7][8][9][10] Among them, adsorption has attracted considerable attention because it has the advantages of high feasibility, easy oper-ation, low cost, absence of byproducts, and so on. [11][12][13][14][15] Traditional adsorbents (such as carbon, zeolites, and ceramics) have been used in this field; however, they may not have enough porosity and lack adsorption sites, thus making them possess deficiencies in adsorption capacity, adsorption kinetics and selectivity. Therefore, searching for new porous materials that are capable of pollutant adsorption is of great interest.…”