Adsorption of Methylene Blue from Aqueous Solution Using Gelatin-Based Carboxylic Acid-Functionalized Carbon Nanotubes@Metal–Organic Framework Composite Beads

Abstract

A novel gelatin-based functionalized carbon nanotubes@metal–organic framework (F-CNTs@MOF@Gel) adsorbent was prepared by the green and simple method for the adsorption of methylene blue (MB). Cu-BTC (also known as HKUST-1) was selected as the MOF type. F-CNTs@Cu-BTC particles were fixed by gelatin, thus avoiding the secondary pollution of carbon nanomaterial particles to the environment. CNTs were used as the connecting skeleton to make more effective adsorption sites exposed on the surface of the internal pore structure of the adsorbent. In this paper, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), thermogravimetry (TGA) and BET analysis methods were used to characterize the new adsorbent. The effects of time, temperature, pH, dosage and initial concentration on the adsorption process were investigated by batch adsorption experiments. The adsorption mechanism was further analyzed by several commonly used kinetic and isotherm models, and the reliability of several fitting models was evaluated by the Akaike information criterion (AIC), Bayesian information criterion (BIC) and Hannan information criterion (HIC). After five regeneration experiments, the adsorbent still had 61.23% adsorption capacity. In general, the new adsorbent studied in this paper has an optimistic application prospect.

Photocatalytic remediation of methylene blue using hydrothermally synthesized H-Titania and Na-Titania nanotubes

“…At a pH 6.0 (pH > PZC), the surface of the adsorbents was negatively charge and its absorption for cationic MB was enhanced because of electrostatic attraction. In addition, increase in pH led to a reduction in the adsorption of MB, which may be ascribed to the high stability of MB under alkaline medium [ 64 , 65 ]. Interestingly, a degradation performance more than 99% was attained within 10 min of light illumination under pH 12.0.…”

Advances in the Applications of Nanomaterials for Wastewater Treatment

“…The CNT provided a greater surface area for a greater adsorption, and the adsorption capacity of 106 mg/g of methylene blue was achieved under the conditions of a 289K and 100 mg/L initial dye concentration. The adsorption isotherm and kinetics suggested a chemisorption mechanism with an activated energy of 83.33 kJ/mol, and the adsorbent could be reused six times [49]. Another study on methylene blue removal using a polyethylene terephthalate nanofiber-MWCNT adsorbent revealed a physisorption mechanism with a very low maximum adsorption capacity of 7.047 mg/g [50].…”

Adsorption and Photocatalytic Degradation of Methylene Blue in Carbon Nanotubes: A Review with Bibliometric Analysis

“…Among these carbon nanomaterials are the three-dimensional carbon nanostructures of interest reported, such as graphene oxide and reduced graphene oxide platelets pillared with CNTs [72]. CNTs/catalyst nanocomposites have received a lot of interest due to the inherent properties thanks to the incorporation of CNTs into the composite, such as the enhancement of the photocatalytic activity of metal oxides [73,74]. Figure 6 shows the growth of research by the increase in the number of research documents about "Photocatalysis" and "Photocatalysis and visible light" during the last 20 years.…”