Recent Developments and Advancements in Graphene-Based Technologies for Oil Spill Cleanup and Oil-Water Separation Processes

Application of PLA/GO/ZnO and PLA/GO/Cu2O as sensor

Polylactic acid modified with graphene oxide (PLA/GO) is proposed to interact with ZnO through 6 different schemes. Density functional theory at B3LYP/LANL2DZ level was utilized to calculate total dipole moment (TDM), HOMO/LUMO energy gap (ΔE) and to map the molecular electrostatic potential (MESP). Results indicated that PLA/GO interacted with ZnO through O-atom forming PLA/GO/OZn composite. This composite interacts with methane, hydrogen sulfide, humidity (H2O), carbon dioxide and ethanol. The same gases were supposed to interact further with PLA/GO/Cu2O. Adsorption energy for the interaction between each composite and the proposed gases were calculated. Both PLA/GO/OZn and PLA/GO/Cu2O composites interacted favorably with H2O. Adsorption energy for interaction of other gases with studied structures are generally low compared to H2O. PLA/GO/OZn have adsorption energy slightly higher than that of PLA/GO/Cu2O. PLA/GO/OZn has higher TDM values than those of PLA/GO/Cu2O, indicating a more polar material. Conversely, PLA/GO/Cu2O exhibited larger ΔE values than those of PLA/GO/OZn. TDM and energy gap results for both studied structures indicated good sensing capabilities. Further insights come from analyzing the calculated density of states (DOS) and partial density of states (PDOS). PLA/GO/Cu2O exhibited high peak for copper in its DOS and PDOS spectra compared to zinc and oxygen in case of PLA/GO/OZn. This means a higher density of available electronic states associated with Cu.

Exploring the superior adsorption capacity of multi-layer graphene/alginate granules for the removal of methylene blue dye from water

Graphene-based materials are gaining increasing attention towards their use in manufacturing and environmental applications. In this context, multi-layer graphene (MG) has been recently applied for the adsorption of contaminants from water resulting in promising results. However, the extreme lightness of this material often makes it difficult to handle due to its potential dispersion in the surrounding environment as well as to its transport and loss with the effluent. In this study, a novel granular material was synthesized by embedding MG into an alginate matrix, resulting in the so-called granular MG (GMG). This material was tested for the adsorption of methylene blue (MB) from water, which is a typical dye used in textile industries and must be removed from the effluent. GMG materials with different MG contents (5 and 20 %) were compared with MG and a commercial adsorbent to assess their adsorption capacity and the most performing material was selected for in-depth physical and chemical characterization. The structural, surface, kinetic, isotherm, and thermodynamic properties, the pH and temperature dependence, as well as the regeneration and reuse of GMG 5% were investigated through batch adsorption tests under different operating conditions. The study reveals that GMG 5% has a superior adsorption capacity compared to the tested materials and can be considered as a promising alternative to commercial carbon-based materials according to techno-economic considerations.

Applications of graphene oxide (GO) in oily wastewater treatment: Recent developments, challenges, and opportunities

The treatment of oily wastewater has become a serious environmental challenge, for which graphene oxide has emerged as a promising material in solving the problem. The ever-growing utilization of graphene oxide (GO) in the treatment of oily wastewater necessitates a constant review. This review article employs a comprehensive literature survey methodology, systematically examining peer-reviewed articles, focusing on, but not entirely limited to, the last five years. Major databases such as EBSCOhost, Scopus, ScienceDirect, Web of Science and Google Scholar were searched using specific keywords related to GO and oily wastewater treatment. The inclusion criteria focused on studies that specifically address the application, efficiency, and mechanisms of GO in treating oily wastewater. The data extracted from these sources were then synthesized to highlight the most important developments, challenges, and prospects in this field. As far as oily wastewater treatment is concerned, the majority of the studies revolve around the use of GO in mitigating fouling in membrane processes, improving the stability, capacity and reusability of sorbents, and enhancing photodegradation by minimizing charge recombination.

A comprehensive study on applications of nanomaterials in petroleum upstream and downstream industry

Nanotechnology has emerged as a revolutionary technology that has been applied in the oil and gas industry for over a decade, spanning the upstream, midstream, and downstream sectors. Nanotechnology has made significant contributions to the exploration of crude oil and natural gas, both in underground and deep-water environments. It has also played a crucial role in improving the drilling process, enabling the extraction of oil and gas resources from beneath the Earth's surface. Nanoparticles, with their unique physical and chemical properties, such as high specific surface area, high pore volume, and small size, have demonstrated considerable potential in the oil industry. Extensive research has been conducted to explore various types of nanoparticles for advanced applications, including oil exploration, drilling, production, and enhanced oil recovery (EOR). Moreover, nanomaterials have found applications in downstream and intermediate sectors, such as crude oil refining, natural gas processing, and transportation and storage of petroleum products. Ongoing advancements in nanomaterial synthesis methods, the exploration of new nanomaterial uses, and understanding the remarkable properties of nanomaterials will continue to make them increasingly valuable in the oil and gas sector. The oil and gas industry recognises the potential of nanotechnology and nanoparticles and is investing significantly in research and development in this area. This comprehensive review aims to summarise successful applications of nanotechnology while addressing associated challenges. It serves as a valuable resource for future research and application endeavours in the field, highlighting the potential of nanotechnology in the oil and gas industry.

Recent advances in the applications of graphene materials for the oil and gas industry

Graphene is a material formed with carbon atoms connected by sp2 hybridization. It is extremely strong and very ductile, and is superhydrophobic and superlipophilic. It has important application prospects in materials science, micro and nano processing, energy, aerospace and biomedicine. Graphene also has some applications in the petroleum industry. As nanoscale materials, graphene-based materials can plug nano-pores and prevent water intrusion into clay minerals during the drilling process, they are suitable for sliding between layers and can be used as lubricants due to the two-dimensional structure. The adsorption properties of graphene-based materials allow them to improve the treatment rate when treating oily wastewater. This paper compiles recent advances in the application of graphene and its derivatives in oilfield extraction, including improving drilling fluid performance, enhanced oil recovery and oily wastewater treatment. We compare the performance advantages of graphene-based materials over other additives, and summarize the mechanism of action of graphene-based materials. The shortcomings of current research are identified and future research and improvement directions are envisaged.

Fabrication of Carbon Aerogels Derived from Metal-Organic Frameworks/Carbon Nanotubes/Cotton Composites as an Efficient Sorbent for Sustainable Oil–Water Separation

Due to the continuous occurrence of water pollution problems, practical separation methods for oil–water mixtures have attracted more and more attention. To date, different kinds of materials have been developed with good hydrophobic properties and strong separation ability. Carbon aerogels, as a promising ideal adsorbent for dealing with oil-spill accidents, have received extensive attention. In this work, zeolitic imidazolate frameworks (ZIFs), nanoparticles, and carbon nanotubes (CNTs) in the three-dimensional (3D) interconnected network structure of cotton balls (CBs) were successfully prepared by a simple and scalable process. The as-prepared carbonized CBs with carbonized ZIF-8 and CNTs (CZIF-8/CNTs/CCBs) were characterized. The oil–water separation performance of the composite was also measured. The results show that the ZIF-8 clusters intercalated with abundant CNTs are fully loaded into the porous structure of the CBs after the in situ synthesis process. Additionally, ZIF-8/CNTs/CBs was carbonized in nitrogen, leading to the formation of CZIF-8/CNTs/CCBs. The prepared material possesses excellent hydrophobicity with a water contact angle of 152.7°, showing good absorption capacities Q1 in the range of 48 to 84 times its original weight for oil and organic liquids. In addition, CZIF-8/CNTs/CCBs exhibits good recyclability in the absorption–distillation test. In summary, this study proposes a novel and simple method for the preparation of a superhydrophobic material that could have wide application in the separation of oil–water mixtures.

Facile Construction and Fabrication of a Superhydrophobic and Super Oleophilic Stainless Steel Mesh for Separation of Water and Oil

The fluoride-free fabrication of superhydrophobic materials for the separation of oil/water mixtures has received widespread attention because of frequent offshore oil exploration and chemical leakage. In recent years, oil/water separation materials, based on metal meshes, have drawn much attention, with significant advantages in terms of their high mechanical strength, easy availability, and long durability. However, it is still challenging to prepare superhydrophobic metal meshes with high-separation capacity, low costs, and high recyclability for dealing with oil–water separation. In this work, a superhydrophobic and super oleophilic stainless steel mesh (SSM) was successfully prepared by anchoring Fe₂O₃ nanoclusters (Fe₂O₃-NCs) on SSM via the in-situ flame synthesis method and followed by further modification with octadecyltrimethoxysilane (OTS). The as-prepared SSM with Fe₂O₃-NCs and OTS (OTS@Fe₂O₃-NCs@SSM) was confirmed by a field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectrometer (XPS), and X-ray diffractometer (XRD). The oil–water separation capacity of the sample was also measured. The results show that the interlaced and dense Fe₂O₃-NCs, composed of Fe₂O₃ nanoparticles, were uniformly coated on the surface of the SSM after the immerging-burning process. Additionally, a compact self-assembled OTS layer with low surface energy is coated on the surface of Fe₂O₃-NCs@SSM, leading to the formation of OTS@Fe₂O₃-NCs@SSM. The prepared OTS@Fe₂O₃-NCs@SSM shows excellent superhydrophobicity, with a water static contact angle of 151.3°. The separation efficiencies of OTS@Fe₂O₃-NCs@SSM for the mixtures of oil/water are all above 98.5%, except for corn oil/water (97.5%) because of its high viscosity. Moreover, the modified SSM exhibits excellent stability and recyclability. This work provides a facile approach for the preparation of superhydrophobic and super oleophilic metal meshes, which will lead to advancements in their large-scale applications on separating oil/water mixtures.

Facile Fabrication of Highly Hydrophobic Onion-like Candle Soot-Coated Mesh for Durable Oil/Water Separation

Although sundry superhydrophobic filtrating materials have been extensively exploited for remediating water pollution arising from frequent oil spills and oily wastewater emission, the expensive reagents, rigorous reaction conditions, and poor durability severely restrict their water purification performance in practical applications. Herein, we present a facile and cost-effective method to fabricate highly hydrophobic onion-like candle soot (CS)-coated mesh for versatile oil/water separation with excellent reusability and durability. Benefiting from a superglue acting as a binder, the sub-micron CS coating composed of interconnected and intrinsic hydrophobic carbon nanoparticles stably anchors on the surface of porous substrates, which enables the mesh to be highly hydrophobic (146.8 ± 0.5°)/superoleophilic and resist the harsh environmental conditions, including acid, alkali, and salt solutions, and even ultrasonic wear. The as-prepared mesh can efficiently separate light or heavy oil/water mixtures with high separation efficiency (>99.95%), among which all the water content in filtrates is below 75 ppm. Besides, such mesh retains excellent separation performance and high hydrophobicity even after 20 cyclic tests, demonstrating its superior reusability and durability. Overall, this work not only makes the CS-coated mesh promising for durable oil/water separation, but also develops an eco-friendly approach to construct robust superhydrophobic surfaces.