Nanocellulose-Block Copolymer Films for the Removal of Emerging Organic Contaminants from Aqueous Solutions

Abstract

The prevalence of emerging organic contaminants (EOCs) in ground and surface water has sparked the search for more effective methods to remove EOCs from the environment. In pursuit of a solution for this environmental concern, herein we present the development of reusable films based on cellulose nanofibers (CNFs) and the block copolymer, poly(4-vinylpyridine-b-ethylene oxide) (P4VP-PEO) to adsorb sulfamethoxazole (SMX) as an EOC model compound. We hypothesize that the adsorption of SMX was achieved mainly by π-π interactions between the pyridine functionalities of the block copolymer and the electron deficient phenyl group of the SMX. Preceding preparation of the films, CNFs were modified with the alkoxysilane trimethoxy(2-phenylethyl)silane (TMPES) to increase their stability in aqueous solution. After the addition of P4VP-PEO, the process was completed by filtration followed by oven-drying. XPS and FTIR were employed to confirm the addition of TMPES and P4VP-PEO, respectively. Adsorption batch experiments were performed in aqueous solutions of SMX at a neutral pH, obtaining adsorptions of up to 0.014 mmol/g in a moderate time of 60 min. For the reusability tests, films were immersed in ethanol 95 wt.% to elude the adsorbed SMX, rinsed with deionized (DI) water, and dried at room temperature to be reused in a new adsorption cycle. We found that this new composite material could be reused several times with negligible loss of adsorption capacity. The films presented have been shown to be of substantial importance for water remediation as they find direct application in the adsorption of electron deficient aromatic compounds and are reusable.

Porous Cellulose Acetate/Block Copolymer Membranes for the Recovery of Polyphenolic Compounds from Aquatic Environments

“…It has been established that the PEO-b-P4VP is able to adsorb pharmaceutical compounds through electron donor−acceptor or π-π interactions. 21,22 Additionally, PEO-b-P4VP can interact with water molecules through hydrogen bonding, thus maintaining a hydrophilic character. Furthermore, the interaction between PEO and polyphenols has been widely studied and hydrogen bonds have been identified as the main mechanism of interaction.…”

Nanocellulose for Sustainable Water Purification

“…Because of the hydrophilic character of NC, which becomes soft and unstable when surrounded by water, Herrera-Morales et al functionalized the CNF surface with a hydrophobic functionality called alkoxysilane trimethoxy­(2-phenylethyl)­silane (TMPES) . Subsequently, a BCP compound termed poly­(4-vinylpyridine-b-ethylene oxide) (P4VP–PEO) was used to modify the TMPES–CNF film, which has been used to remove sulfamethoxazole (SMX), an emerging organic contaminant (Figure S6).…”

“…Similar interaction bonding has been observed for sulfamethoxazole (hb1 and BE = 7.21 kcal/mol) and DEET (BE = 5.70 kcal/ mol). 453 (e) Hydrophobic interaction: As shown in Figure 31e, the adsorption of diuron onto CNC/CTM, followed the pathway of hydrophobic interactions (i.e., between diuron and the alkyl chains of CNC/CTM), hydrogen bonding (i.e., 476 Subsequently, a BCP compound termed poly(4-vinylpyridine-b-ethylene oxide) (P4VP−PEO) was used to modify the TMPES−CNF film, which has been used to remove sulfamethoxazole (SMX), an emerging organic contaminant (Figure S6). It was seen in Figure S6b, despite the hydrophobic modification, the film could still hold water after immersion.…”

Enabling future nanomanufacturing through block copolymer self-assembly: A review

“…In 2019 a novel technique using P4VP-b-PEO was applied for coating cellulose nanofibers where the BCP is dispersed to act as an adsorption film. [210] The method allows removal of any pollutant with electron deficient aromatic structures such as antibiotics, e.g.…”