Bioinspired Assembly of Carbon Nanotube into Graphene Aerogel with “Cabbagelike” Hierarchical Porous Structure for Highly Efficient Organic Pollutants Cleanup

Abstract

Nowadays, physical absorption has become a feasible method offering an efficient and green route to remove organic pollutants from the industrial wastewater. Inspired by polydopamine (PDA) chemistry, one-dimensional PDA-functionalized multiwalled carbon nanotubes (MWCNT-PDA) were creatively introduced into graphene aerogel framework to synthesize a robust graphene/MWCNT-PDA composite aerogel (GCPCA). The whole forming process needed no additional reducing agents, significantly reducing the contamination emissions to the environment. The GCPCA exhibited outstanding repeatable compressibility, ultralight weight, as well as hydrophobic nature, which were crucial for highly efficient organic pollution absorption. The MWCNTs in moderate amounts can provide the composite aerogels with desirable structure stability and extra specific surface area. Meanwhile, the eventual absorption performance of GCPCAs can be improved by optimizing the microporous structure. In particular, a novel "cabbagelike" hierarchical porous structure was obtained as the prefreezing temperature was decreased to -80 °C. The miniaturization of pore size around the periphery of GCPCA enhanced the capillary flow in aerogel channels, and the super-absorption capacity for organic solvents was up to 501 times (chloroform) its own mass. Besides, the GCPCAs exhibited excellent reusable performance in absorption-squeezing, absorption-combustion, and absorption-distillation cycles according to the characteristic of different organic solvents. Because of the viable synthesis method, the resulting GCPCAs with unique performance possess broad and important application prospects, such as oil pollution cleanup and treatment of chemical industrial wastewater.

Carbon Aerogels for Environmental Clean‐Up

“…Carbon aerogels are frequently used as the selective adsorbent for oil/water separation due to the intrinsic characteristics , , . Oxygen and hydrogen containing groups in aerogels are decomposed in the hydrothermal or carbonization process, leaving the graphitization structure, which is mainly composed by low‐surface‐energy sp 2 carbon.…”

“…Moreover, CNTs were added to the graphene aerogel to improve the mechanical strength and specific surface area. The composite aerogels are more suitable for environmental clean‐up, especially for oil/water separation , , , . Zhan et al creatively introduced PDA‐functionalized carbon nanotubes into graphene aerogel to form a robust PDA/MWCNT/graphene composite aerogel with a novel “cabbagelike” hierarchical porous structure ( Figure ) .…”

“…The composite aerogels are more suitable for environmental clean‐up, especially for oil/water separation , , , . Zhan et al creatively introduced PDA‐functionalized carbon nanotubes into graphene aerogel to form a robust PDA/MWCNT/graphene composite aerogel with a novel “cabbagelike” hierarchical porous structure ( Figure ) . The miniaturization of pore size around the composite aerogel periphery enhanced the capillary flow in aerogel channels, and the super‐absorption capacity for organic solvents was up to 501 times to its own mass.…”

“…At present, lots of carbon aerogels are commercially available which have been applied in real scenarios. According to the various sources of precursor, they are commonly divided into the following types: polymer carbon aerogels (PCAs),, graphene carbon aerogels (GCAs),, carbon nanotube carbon aerogels (CNCAs), and composite carbon aerogels (CCAs) , . Different types of carbon aerogels have their own unique characteristics and are suitable for different applications.…”

Analysis of Pesticide Residue in Tomatoes by Carbon Nanotubes/β‐Cyclodextrin Nanocomposite Reinforced Hollow Fiber Coupled with HPLC

“…Sol-gel technique has been commonly used to achieve it, in which gel would be formed in situ after injecting a sol solution (Amiri, 2016). CNTs have been proved to be an effective absorbent material, particularly to organic molecules, owing to their highly hydrophobic surface, unique internal tube cavity, and interstitial spaces between tubes (Hou, Du, Meng, Zhao, & Du, 2018;Zhan, et al, 2018). In addition, CNTs could provide a high flux for solute transport due to the atomic-scale smoothness of their walls and the molecular ordering phenomena inside the nanopores (Konduri, Tong, Chempath, & Nair, 2008).…”