Self-generated synthesis of nanocomposites: Incorporating PVA-derived nanocarbon into electrospun nanofiber matrices to improve water remediation

Abstract

Remediation of emerging contaminants (ECs) using powdered activated carbon is limited by its difficult recovery and tendency to agglomerate. This study addresses these issues by employing a strategy of autogenous synthesis of nanocomposite membrane. This process involves the pyrolysis of a polyvinyl alcohol (PVA) network to produce nanocarbon (SBET = 1007 m2. g−1), which is then sonicated and introduced into the PVA/citric acid solution before being electrospun. A matrix of cross-linked nanofibres (68 ± 3 nm) with homogeneously dispersed nanocarbons was produced by the final heat treatment. This architecture prevented the aggregation of active sites, achieving maximum capacities of 243, 223, and 161 mg/g for tetracycline (TC), methylene blue (MB), and rhodamine B (RhB), respectively. The composite exhibited a dual-mode adsorption mechanism governed by the nature of the contaminant: TC and MB adsorption followed Langmuir isotherms, with Weber–Morris intraparticle diffusion, indicating uptake at internal sites, whereas RhB adsorption proceeded via rapid surface interactions in heterogeneous domains, as described by the Freundlich and pseudo-first order models. Binary-contaminant adsorption tests further demonstrated modulated selectivity with minimal competitive interference. A selectivity factor (S(TC/RhB)) of 4.08 was quantified. The membrane structure morphology allowed the adsorbent to be recovered without filtration, with 96% removal efficiency after five cycles. This method offers a scalable, sustainable material that surpasses traditional carbons by transforming a low-cost polymer into a carbonaceous filler with a high surface area and an efficient, well-structured support.