Embedding of L–Arginine Into Graphene Oxide (Go) for Endotoxin Removal From Water: Modeling and Optimization Approach Publisher



Amini Tapouk F¹ ; Nabizadeh R^{2, 5} ; Nasseri S^{2, 4} ; Mesdaghinia A^{2, 4} ; Khorsandi H⁶ ; Yousefi M⁹ ; Alimohammadi M^{2, 3, 4} ; Khoobi M^{7, 8}
Source: Colloids and Surfaces A: Physicochemical and Engineering Aspects Published:2020

Abstract

Endotoxin, also called lipopolysaccharides (LPS), has strong biological effects, even at a very low concentration in humans. In this study, surface functionalization of graphene oxide (GO) with L–Arginine amino acid was successfully prepared using epichlorohydrin as a coupling agent (GO–EPI–L–Arg) for endotoxin removal from water. Characterization of Novel GO–EPI–L–Arg was confirmed by an analytical technique. The model was optimized using response surface methodology (RSM) via various input parameters. The effect of concomitant anions was also investigated to establish and simulate competitive endotoxin adsorption in real hemodialysis water supply. The pH and endotoxin concentration had an antagonistic effect on the quadratic model. The endotoxin adsorption process was better fitted by pseudo-second-order model with Qmax value of 139.47 EU/mg, while the equilibrium followed the Langmuir isotherm with the maximum monolayer adsorption capacity of 154.85 EU/mg. The coefficient of determination (R2=0.9761), non–significant lack of fit (p > 0.05), and p–value with low probability (<5.596 × 10–11) revealed a regression model with a good fit with input variables. The GO–EPI–L–Arg nanocomposite could be regenerated more than four times based on their adsorption-desorption cycles, with a slight loss in adsorption capacity. The results suggested that the GO–EPI–L–Arg can be applied as an effective adsorbent for endotoxin removal from water. © 2020 Elsevier B.V.