Synthesis of nanocellulose aerogels and Cu-BTC/nanocellulose aerogel composites for adsorption of organic dyes and heavy metal ions

Abstract

MOFs compounds with open metal sites, particularly Cu-BTC, have great potential for adsorption and catalysis applications. However, the powdery morphology limits their applications. One of the almost new ways to overcome this problem is to trap them in a standing and flexible aerogel matrix to form a hierarchical porous composite. In this work, Cu-BTC/CNC (crystalline nanocellulose) and Cu-BTC/NFC (nanofibrillated cellulose) aerogel composites were synthesized using a direct mixing method by the addition of Cu-BTC powder to the liquid precursor solution followed by gelation and freeze-drying. Also, pure nanocellulose aerogels (CNC and NFC aerogels) have been synthesized from cellulose isolated from peanut shells. Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectra, and X-ray diffraction (XRD) were utilized to evaluate the structure and morphology of the prepared materials. The adsorption ability of pure CNC aerogel and Cu-BTC/NFC aerogel composite for organic dye (Congo Red) and heavy metal ion (Mn7+) was studied and determined by the UV–Vis spectrophotometry and inductively-coupled plasma optical emission spectrometry (ICP-OES), respectively. It was concluded that Cu-BTC/NFC aerogel composite shows excellent adsorption capacity for Congo Red. The adsorption process of this composite is better described by the pseudo-second-order kinetic model and Langmuir isotherm, with a maximum monolayer adsorption capacity of 39 mg/g for Congo Red. Nevertheless, CNC aerogel shows no adsorption for Congo Red. Both CNC aerogel and Cu-BTC/NFC aerogel composite act as a monolith standing solid reducer, which means they could remove permanganate ions from water by reducing it into manganese dioxide without releasing any secondary product in the solution.

Preparation of Bio-Based Aerogel and Its Adsorption Properties for Organic Dyes

“…In the first stage, a small weight loss of the aerogel is observed below 230 °C, corresponding to the evaporation of water. As previously reported, a severe mass reduction is observed in the phase around 270–420 °C, which may be related to the depolymerization and decomposition of glucose units in cellulose [ 28 ]. The mass loss of 9.28% in the final stage (400–600 °C) is attributed to the decomposition of the aerogel cross-linked structure and further conversion to CO 2 and H 2 O [ 29 ].…”

Adsorption and Removal of Industrial Dyes by Water-Stabilized Aluminum-Based Metal–Organic Frameworks

“…This indicates that CAU-23 adsorbed CR. Al–OH in the MOF can interact with the −SO 3 group of the dye component through rather strong interactions, like hydrogen bonds. − The X-ray photoelectron spectra (XPS) of each element before and after adsorption were compared. Two samples were prepared, i.e., activated CAU-23 and CAU-23 adsorbed with CR.…”

Multi‐Functional Cu‐BTC and ZIF‐67 Grown Chitosan Air Filters for Efficient NO and Particular Matter Removal

“…Moreover, numerous peaks between 600 and 1300 cm −1 contribute to the out‐of‐plane vibrations in BTC 3− anions. [ 38,39 ] The peak at 490 cm −1 is assigned to M (Cu)‐O bonds. [ 40 ] Regarding the adsorption peaks of C‐ZIF67 shown as red dotted lines in Figure 4c, the new peaks at 1583, 1148, and 756 cm −1 were related to the CN stretching vibration, and the stretching and bending vibrations of the imidazole ring, respectively.…”