Magnetic magnesium oxide composites for rapid removal of polycyclic aromatic hydrocarbons and cadmium ions from water

2020 ◽  
Vol 17 (7) ◽  
pp. 479
Author(s):  
Dongqin Tan ◽  
Jing Jin ◽  
Cuicui Guo ◽  
Dhanjai ◽  
Jiping Chen

Environmental contextRemediation of wastewater containing polycyclic aromatic hydrocarbons and metals is essential to limit adverse effects on the environment and human health. Using a simple precipitation method, we prepared porous magnetic MgO hybrids for use as a material for removing pollutants from wastewater. The material showed excellent removal performance for 12 polycyclic aromatic hydrocarbons and cadmium ions, and thus has potential applications in wastewater treatment. AbstractHierarchical porous magnetic MgO hybrids (Fe3O4/MgO) are controllably synthesised based on a facile precipitation process. The resulting material displays a three-dimensional architecture with nest-like morphology, large surface area (135.2m2 g−1) and uniform mesochannels (5–35nm). The adsorption equilibrium data of target polycyclic aromatic hydrocarbons (PAHs) on Fe3O4/MgO sorbents are described by the Langmuir isotherm model. The composites show a strong tendency for the removal of PAHs owing to their porous structure that possesses an excellent affinity for PAHs. Under the optimal conditions, a removal of more than 70% is achieved for 12 PAHs. The materials also exhibit a good removal ability of cadmium (Cd2+) from water with fast adsorption (<5min) and high removal percentage (>80%). Moreover, the composites possess sufficient magnetism for separation. To demonstrate the performance of the sorbents, Fe3O4/MgO is exposed to aqueous samples spiked with low concentrations of PAHs and Cd2+. In almost all cases, the composites are superior to the commercially available sorbents as well as un-functionalised Fe3O4 nanoparticles. Therefore, this work provides a promising approach for the simultaneous removal of PAHs and Cd2+ from water using multifunctional MgO microspheres.

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
Haiying Wang ◽  
Chuantao Li

The general (α,t)-path connectivity index of a molecular graph originates from many practical problems such as three-dimensional quantitative structure-activity (3D QSAR) and molecular chirality. It is defined as Rtα(G)=∑Pt=vi1vi2⋯vit+1⊆G[d(vi1)d(vi2)⋯d(vit+1)]α, where the summation is taken over all possible paths of length t of G and we do not distinguish between the paths vi1vi2⋯vit+1 and vit+1⋯vi2vi1. In this paper, we focus on the structures of Polycyclic Aromatic Hydrocarbons (PAHn), which play a role in organic materials and medical sciences. We try to compute the exact general (α,3)-path connectivity indices of this family of hydrocarbon structures. Furthermore, we exactly derive the monotonicity and the extremal values of R3α(PAHn) for any real number α. These valuable results could produce strong guiding significance to these applied sciences.


Molecules ◽  
2022 ◽  
Vol 27 (1) ◽  
pp. 327
Author(s):  
Hang Xiao ◽  
Tao Li ◽  
Xiao-Li Sun ◽  
Wen-Ming Wan ◽  
Hongli Bao ◽  
...  

Pyrene molecules containing NBN-doped polycyclic aromatic hydrocarbons (PAHs) have been synthesized by a simple and efficient intermolecular dehydration reaction between 1-pyrenylboronic acid and aromatic diamine. Pyrene-B (o-phenylenediamine) with a five-membered NBN ring and pyrene-B (1,8-diaminonaphthalene) with a six-membered NBN ring show differing luminescence. Pyrene-B (o-phenylenediamine) shows concentration-dependent luminescence and enhanced emission after grinding at solid state. Pyrene-B (1,8-diaminonaphthalene) exhibits a turn-on type luminescence upon fluoride ion addition at lower concentration, as well as concentration-dependent stability. Further potential applications of Pyrene-B (o-phenylenediamine) on artificial light-harvesting film were demonstrated by using commercial NiR dye as acceptor.


2020 ◽  
Vol 163 ◽  
pp. 03005
Author(s):  
Aleksandr Khaustov ◽  
Margarita Redina ◽  
Inna Nemirovskaya

The efficiency of the study of polycyclic aromatic hydrocarbons (PAHs) as markers of many environmental and hydrological processes is disclosed. On the example of the interaction between sea and river water the flows of substances and problems of their detection in media, as well as the laws of fractionation during phase transitions at geochemical barriers (GCB) are presented. The authors have collected an extensive database for almost all types of natural environments. Own research was conducted at specialized water testing sites (springs, a mud volcano, brine of a lake, the Northern Dvina River, water of Black and White Seas, water bodies of the Moscow Region and Albena region (Bulgaria), etc. This allowed substantiating the optimal markers and creating effective methods for identifying a complex of hydrological processes.


Author(s):  
Beijing Zhong ◽  
Shuai Dang ◽  
Jun Xi

In this study, numerical simulations for an n-heptane fueled Chaochai 6102bzl direct injection diesel engine are performed in order to predict the chemical details of the combustion process and resulting polycyclic aromatic hydrocarbons (such as benzene, naphthalene, phenanthrene and pyrene) formation. The diesel geometry and reduced kinetic mechanism of n-heptane oxidation, which includes only 86 reactions and 57 species, have been developed and incorporated into the computational fluid dynamics code, FLUENT. The diesel unsteady laminar flamelet model, turbulence model and spray model have been employed in the numerical simulations. The numerical simulation results showed that the polycyclic aromatic hydrocarbons were firstly increased with the increase of diesel crank angel and then decreased, which was mostly located at the bottom of diesel combustion chamber wall.


2016 ◽  
Vol 22 (3) ◽  
pp. 293-299 ◽  
Author(s):  
Jelena Milic ◽  
Jelena Avdalovic ◽  
Tatjana Solevic-Knudsen ◽  
Gordana Gojgic-Cvijovic ◽  
Tanja Jednak ◽  
...  

The group of polycyclic aromatic hydrocarbons (PAHs) are very hazardous environmental pollutants because of their mutagenic, carcinogenic and toxic effects on living systems. The aim of this study was to examine and compare the ability and efficiency of selected bacterial isolates obtained from oil-contaminated areas to biodegrade PAHs. The potential of the bacteria to biodegrade various aromatic hydrocarbons was assessed using the 2,6-dichlorophenol-indophenol assay. Further biodegradation of PAHs was monitored by gravimetric and gas-chromatographic analysis. Among the eight bacterial isolates, identified on the basis of 16S rDNA sequences, two isolates, Planomicrobium sp. RNP01 and Rhodococcus sp. RNP05, had the ability to grow on and utilize almost all examined hydrocarbons. Those isolates were further examined for biodegradation of phenanthrene and pyrene, as single substrates, and as a mixture, in vitro for ten days. After three days, both isolates degraded a significant amount phenanthrene, which has a simpler chemical structure than pyrene. Planomicrobium sp.RNP01 commenced biodegradation of pyrene in the PAH mixture only after it had almost completly degraded phenanthrene. The isolated and characterized bacteria, Planomicrobium sp. RNP01 and Rhodococcus sp. RNP05, have shown high bioremediation potential and are likely candidates to be used for degradation of highly toxic PAHs in contaminated areas.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wataru Matsuoka ◽  
Hideto Ito ◽  
David Sarlah ◽  
Kenichiro Itami

AbstractNanographenes and polycyclic aromatic hydrocarbons (PAHs) are among the most important classes of compounds, with potential applications in nearly all areas of science and technology. While the theoretically possible number of nanographene structures is extraordinary, most of these molecules remain synthetically out of reach due to a lack of programmable and diversity-oriented synthetic methods, and their potentially huge structure-property diversity has not been fully exploited. Herein we report a diversity-oriented, growth-from-template synthesis of nanographenes enabled by iterative annulative π-extension (APEX) reactions from small PAH starting materials. The developed dearomative annulative π-extension (DAPEX) reaction enables π-elongation at the less-reactive M-regions of PAHs, and is successfully combined with complementary APEX reactions that occur at K- and bay-regions to access a variety of previously untapped nanographenes.


Sign in / Sign up

Export Citation Format

Share Document