Cucurbituril-Functionalized Nanocomposite as a Promising Industrial Adsorbent for Rapid Cationic Dye Removal

Abstract

A supramolecular cucurbit[6]­uril (CB[6])-enriched magnetic montmorillonite (CBCM) nanocomposite was prepared and characterized. CB[6] played a prominent role as a capping agent, helping in better distribution of the nanoparticles, and as a binder between nanoparticles. Montmorillonite provided structural stability and fortified ultrafast adsorption toward dyes. Its application in the removal of cationic dyes from wastewater was systematically assessed. Process parameters such as pH, initial dye concentration, dosage, temperature, and time were optimized. Kinetics and isotherms of the process were described using pseudo-second-order kinetics and the Langmuir isotherm, respectively. CBCM exhibited rapid dye removal capacity in short reaction times with q max of 199.20, 78.31, and 55.62 mg g–1 and K2 of 0.0281, 0.0.0823, and 0.0953 L mg–1 min–1 for crystal violet, methylene blue, and rhodamine B, respectively. Benefiting from the synergetic effects of montmorillonite surface hydrophobicity, abundant carbonyl groups of CB[6], and magnetic properties of copper ferrite, CBCM demonstrated outstanding dye removal capacity, negligible leaching at saturation, and high tolerance toward harsh conditions. This intrinsic nature is expedient in prolonged industrial operations. To demonstrate industrial viability, syringe filtration and continuous flow fixed-bed column operations were validated. The CBCM fixed-bed column demonstrated stable dye removal efficiency with 10–100 mg mL–1 dye at 10–50 mL min–1 flow rates. Utilizing the magnetic and catalytic activities of the copper ferrite nanoparticles, CBCM was recycled using a magnet, regenerated, and reused for several cycles. CB[6] remarkably improved the performance of the nanocomposite and made it suitable for different effluent treatment techniques. This may pave a sustainable way toward the efficient onsite treatment of effluent at the industrial scale.

Rational Fabrication of Multiple Dimensional Assemblies from Tryptophan‐Based Racemate

“…The maximum adsorption capacity of the assembly for RhB was about 500 mg/g (Figure S16), which partly exceeds that of nanocomposite adsorbents and are particularly well suited for dye removal. [53][54][55] The same qualitative experiments were conducted with other commercial dyes, methylene blue and Thioflavin T. Similar with RhB, each tested dye was mostly encapsulated in the RPWM assemblies and visibly removed from water (Figure S17). The removal efficiency was separately calculated as 99.2 % and 98.7 % for methylene blue and Thioflavin T, suggesting the remarkable capability of RPWM assemblies for dye removal from aqueous solution.…”

“…The removal efficiency could reach as high as 99.5 %, comparable to the previously reported materials. [51][52][53] Afterwards, the precipitates were mixed with water again and placed under 4 °C for the further release. As shown in Figure S15, only few dye molecules (< 3%) were detected to be released from the assemblies after 24 h. Since the system was kept at 4 °C, the initially formed nanosphere structures were not destroyed, thus the adsorbed or embedded RhB molecules were still persisted in the assembly system.…”

Cobalt Ferrite Incorporated Ocimum sanctum Nanocomposite Matrix as an Interface for Adsorption of Organic Dyes: A Sustainable Alternative

“…This method employs various adsorbents, such as activated carbon, clays, ion exchange materials, biosorbents, zeolite, biodegradable composites, and hybrid materials, depending on the targeted pollutants. Moreover, the process of adsorption possesses numerous advantages like elevated effectiveness, stumpy cost, high commercial availability, and eco‐friendliness [5] …”

“…Moreover, the process of adsorption possesses numerous advantages like elevated effectiveness, stumpy cost, high commercial availability, and ecofriendliness. [5] With the advent of nanotechnology in this 21 st century, the science and engineering of nano-sized materials has developed significantly and has revolutionised almost every discipline of science such as medicine, material science, agriculture, food industry, biology etc. [6,7] One of the appealing aspects of nanomaterials is their huge surface area owing to their minute particle dimension.…”

Separation of mercuric ions using 2-thienylbenzimidazole/cucurbit[7]uril/iron-oxide nanoparticles by pH control

“…From another perspective, the dyes encapsulated by CB7 have been adsorbed on the surface of metal nanoparticles 17 – 21 for drug delivery 18 magnetic resonance imaging 20 , and the fabrication of solar cell materials 19 . The iron-oxide magnetic nanoparticles (γ-Fe 3 O 4 ) have been specifically utilized for chemical detection and sensing 22 .…”