Embryotoxicity assessment and efficient removal of naphthalene from water by irradiated graphene aerogels
Introduction
Naphthalene [CAS no.91-20-3], the simplest and volatile member of polycyclic aromatic hydrocarbons (PAHs), have been commonly used in industrial materials and moth-proofing (Dutta et al., 2018). Owing to the excellent electrochemical stability, the extremely high melting point and boiling point of naphthalene, it has been continuously discharged into the environment and accumulated in soil and water for a long time (Chang et al., 2004). Naphthalene has been considered as a class-C carcinogen by US-EPA (Peng et al., 2011) the fact that it is based largely on animal data (Bailey et al., 2016; Ohnishi et al., 2018). What is more, naphthalene and its metabolites were detected in human urinary and blood (Khoury et al., 2018). Currently, scarce data shows how to effectively remove naphthalene so as to mitigate the embryonic toxicity.
So far, the multiple technologies of naphthalene removal from aqueous solutions have been paid close attention, such as electrolysis, photocatalysis, bioremediation and adsorption (Pei et al., 2013; San Miguel et al., 2009; Wu et al., 2018). Among these approaches, adsorption by various materials has been extensively studied as a very simple, efficient, and widespread method to eliminate naphthalene from water solution (Gu et al., 2011; Lamichhane et al., 2016; Wang et al., 2017). In recent years, graphene nanomaterials including graphene (G) and reduce graphene oxide (rGO) have been reported to a high sorption capacity for naphthalene, because of unique π-electronic structure and a large specific surface area (Bayazit et al., 2017; Ji et al., 2013; Wang et al., 2014). However, nanostructure of G and rGO can readily transfer into natural aquatic environments, leading to different degrees of toxicity in animal, including an intense inflammatory response, even the cell death (Hu et al., 2017; Jeong et al., 2015; Ou et al., 2016). Graphene aerogel composed of the three-dimensional porous architecture of rGO, maintains the remarkable properties of graphene nanomaterials, and simultaneously can avoid the mobility of individual rGO sheets for its robust mechanical stability (Chen and Yan, 2011; Xu et al., 2010). Therefore, graphene aerogel are gaining a lot of attention in environmental bio-applications (Meng et al., 2015).
A high developmental similarity to mammals is in the early embryonic stages of zebrafish, such as the development of somite, cardiovascular, skeletal, muscular and neuronal systems (Chakraborty et al., 2016; McCollum et al., 2011). Moreover, the outcomes from Manjunatha et al. (2018) and Ou et al. (2016) reported that the graphene nanomaterials led to the toxicity effects of cardiovascular and reproductive systems in zebrafish. Herein, irradiated graphene aerogel (IGA) was obtained to modify its surface and structure, and used for eliminating naphthalene. On the other hand, the embryonic/larval zebrafish exposed to naphthalene were systemically studied with or without IGA supplement for evaluating the biotoxicity and removal of naphthalene in water.
Section snippets
Chemicals
The powdered natural graphite was purchased from Shenzhen Nanotech Co. Ltd. The reagents, such as potassium permanganate (KMnO4), concentrated sulfuric acid (98%), hydrogen peroxide (H2O2), used for graphene oxide (GO) preparation were products of Sinopharm Chemical Reagent Co. Ltd, China. These reagents were of analytical reagent grade. L-ascorbic acid and naphthalene were acquired from Alfa Aesar China (Tianjin) and Sinopharm Chemical Reagent Co., Ltd, respectively.
Preparation of irradiated graphene aerogel (IGA)
GOs with and without
Characterization of GA and IGA
Fig. 1 showed that both GA and IGA were a 3D porous structure with numerous micro-pores and meso-pores randomly distributed in their architecture (Fig. 1a and b). However, reduced graphene oxide (rGO) in the GA structure seems thicker than rGO in the IGA structure, and more wrinkles and folds were appeared in the structure of IGA. The reason for this difference was GO with less layer and more oxygen-containing functional groups can be prepared after electron beam irradiation (Bai et al., 2016),
Conclusion
Toxicological characteristics of naphthalene were prominently manifested in the whole-embryo development of the zebrafish, as marked by increased mortality and malformation as well as decreased hatchability, in the organ-level development, as reflected by cardio-, ocular-, intestinal-, hepatic- and neurotoxicity. After irradiated with high-energy electron beam, IGA was obtained to generate the optimal microstructure with more wrinkles, folds and defects, and a strong absorption capability for
Author Contributions Section
Yang Liu: Conceived the idea, executed the research and prepared the manuscript. Jing Bai and Huijun Yao: analyzed the data and prepared the graphs. Guo Li, Taofeng Zhang, Sirui Li and Rong Zhou: executed the research. Luwei Zhang, Jing Si, Hong Zhang: reviewed and revised the manuscript.
Declaration of competing interest
There are no conflicts to declare.
Acknowledgments
This study was supported by grants from the National Natural Science Foundation of China (No. 11575262, 11575260 and 11605255), and Scientific Technology Research Projects of Gansu Province (18JR3RA377).
References (48)
Toxicity of effluents from gasoline stations oil-water separators to early life stages of zebrafish Danio rerio
Chemosphere
(2017)Rapid adsorptive removal of naphthalene from water using graphene nanoplatelet/MIL-101 (Cr) nanocomposite
J. Alloy. Comp.
(2017)The heat-inducible zebrafish hsp70 gene is expressed during normal lens development under non-stress conditions
Mech. Dev.
(2002)Adsorption of naphthalene on zeolite from aqueous solution
J. Colloid Interface Sci.
(2004)Investigating the potential impact of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) on gene biomarker expression and global DNA methylation in loggerhead sea turtles (Caretta caretta) from the Adriatic Sea
Sci. Total Environ.
(2018)Effects of secondary carbon supplement on biofilm-mediated biodegradation of naphthalene by mutated naphthalene 1, 2-dioxygenase encoded by Pseudomonas putida strain KD9
J. Hazard Mater.
(2018)- et al.
Cardiac development in zebrafish: coordination of form and function
Semin. Cell Dev. Biol.
(2002) Combined humic acid adsorption and enhanced Fenton processes for the treatment of naphthalene dye intermediate wastewater
J. Hazard Mater.
(2011)Zebrafish models for assessing developmental and reproductive toxicity
Neurotoxicol. Teratol.
(2014)Graphene oxide nanosheets at trace concentrations elicit neurotoxicity in the offspring of zebrafish
Carbon
(2017)