Nanofibrous Membranes for Low-Concentration Cr^VI Adsorption: Kinetic, Thermodynamic and the Influence on ZFL Cells Viability

Abstract

There is a great demand to develop different techniques for the continuous removal, immobilization, and remediation of metallic ions from contaminated water. Human contamination by metallic ions could even occur by ingestion of seafood causing carcinogenic and mutagenic activities. In this study, a nanofibrous membrane of poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) produced by electrospinning technique and coated with polyaniline (PAni) was tested for the removal of chromium in low-concentration solutions. The viability of ZFL cells (zebrafish liver cells) was performed to evaluate the water quality enhancement after chromium adsorption. The results indicated that the nanofibrous membrane successfully adsorbed the chromium species in low-concentration ($Q_e$= 2.44 mg/g, at pH 4.5, room temperature (RT) and 24h) by Freundlich model and followed a pseudo-second-order kinetics model indicating a possible chemisorption in multilayers, at pH 4.5, RT and [Cr^VI] = 5.0 mg/L. At pH 2.0 (24h, RT and [Cr^VI] = 5.0 mg/L), the membrane adsorbed around 91.64% of Cr^VI contaminants. The thermodynamic studies revealed that the process was spontaneous and exothermic. The cells viability demonstrated the efficiency of the membrane tested in the aquatic ecosystem protection; the viability increased 19.2% in 5.0 mg/L Cr^VI solution. Thus, the results of this study shows that the nanofibrous membrane can be an alternative to remove low concentration of Cr^VI from aqueous solutions.

Keywords:
Membrane Technology; Nanofibers; Adsorption; Chromium; Water Decontamination