Fabrication of a biological metal-organic framework based superhydrophobic textile fabric for efficient oil/water separation

Eco-friendly approach for the fabrication of biо copper based superhydrophobic coating on steel metal and its corrosion resistance evaluation

This study presents an eco-friendly approach for constructing superhydrophobic (S.H.) coatings on steel surfaces. The biо Сu nanoparticles are synthesized using a biоgenic process. Two types of coatings, Ni-Ѕ.Α and Ni-biо Сu-Ѕ.Α, were developed and characterized. The EDX results confirm the successful fabrication of two distinct coatings on the steel substrate: one involving the modification of nickel with stearic acid, Ni-Ѕ.Α, and the other involving the modification of nickel with both bio-Cu and stearic acid, Ni-biо Сu-Ѕ.Α. The SEM results revealed that the S.H. coats exhibit circular microstructures which contribute to the surface roughness. The contact angles of water droplets on the Ni-Ѕ.Α and Ni-biо Сu-Ѕ.Α coatings were measured at 158° ± 0.9° and 162° ± 1.1°, respectively. Chemical stability tests demonstrated that the Ni-Ѕ.Α coating maintains its S.H. behaviour in a pH range of 3-11, whereas the Ni-biо Сu-Ѕ.Α coating exhibits excellent chemical stability in a broader range of pH (1-13). The coating's mechanical stability was evaluated through abrasion tests. The Ni-Ѕ.Α coating retained its S.H. properties even after an abrasion length equal 1100 mm, while the Ni-biо Сu-Ѕ.Α coating maintained its S.H. behaviour till an abrasion length equal 1900 mm. The corrosion behavior and protective properties of the S.H. coatings were studied via electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) techniques. The PDP and EIS findings demonstrated that both Ni-Ѕ.Α and Ni-biо Сu-Ѕ.Α coatings significantly reduced the corrosion rate compared to uncoated steel.

Fiber Integrated Metal-Organic Frameworks as Functional Components in Smart Textiles

Owing to high modularity and synthetic tunability, metal-organic frameworks (MOFs) on textiles are poised to contribute to the development of state-of-the-art wearable systems with multifunctional performance. While these composite materials have demonstrated promising functions in sensing, filtration, detoxification, and biomedicine, their applicability in multifunctional systems is only beginning to materialize. This review highlights the multifunctionality and versatility of MOF-integrated textile systems. It summarizes the operational goals of MOF@textile composites, encompassing sensing, filtration, detoxification, drug delivery, UV protection, and photocatalysis. Building upon these recent advances, this review concludes with an outlook on emerging opportunities for the diverse applications of MOF@textile systems in the realm of smart wearables.

Green Synthesis of a Carbon Quantum Dots-Based Superhydrophobic Membrane for Efficient Oil/Water Separation

The efficient separation of oil and water is a significant challenge worldwide due to the increasing frequency of industrial oily wastewater. Previous work by our group utilizes biological metal-organic framework-based superhydrophobic (S.P) textile fabric for oil/water separation. However, this system is limited due to the low mechanical stability, so there is a need for producing a more robust S.P membrane for oil/water separation. In this study, we report on the synthesis of carbon quantum dots (CQD) from banana leaves via a hydrothermal process and their application in producing a robust S.P coating on textile fabric for oil/water separation. The CQDs were characterized using various techniques including TEM, XRD, absorbance spectroscopy, and the BET method. The TEM images showed that the CQDs were circular in shape with a size of 4.4 nm, while the XRD micrograph indicated that the CQDs were crystalline in nature. The UV-vis graph showed a peak at a wavelength of 278 nm, suggesting strong absorption in the ultraviolet region. The BET-specific surface area of the prepared CQDs is 845 m2/g, with a pore volume of 0.33 cm3/g, and a mean pore diameter of 1.62 nm. We examined the surface wettability, morphology, composition, oil absorption capacity, oil/water separation performance, flux rate, chemical stability, and mechanical stability of the S.P membrane. Our findings indicate that the developed CQD-based S.P membrane possesses excellent S.P properties, displaying high water contact angles of 163° and low water sliding angles of 1°. The membrane demonstrated superior oil absorption capacity, separation efficiency, and flux rate towards three different oils-petroleum ether, n-hexane, and silicone oil. Petroleum ether has the highest separation efficiency (99.5%), and flux rate (13,500 L m-2 h-1), while silicone oil has the lowest. However, silicone oil has the highest absorption capacity (218.9 g/g) and petroleum ether has the lowest (194.8 g/g). For the absorption capacity and separation efficiency, a one-way ANOVA test was conducted. The statistical analyses revealed significant differences in absorption capacity and separation efficiency for the three oils, highlighting the efficacy of the superhydrophobic membrane for tailored oil/water separation. Additionally, the S.P membrane exhibited good mechanical (the membrane maintains its superhydrophobicity until an abrasion length of 850 cm) and chemical stability (the membrane maintains its superhydrophobicity in pH range 1-13), withstanding abrasion and immersion in solutions of varying pH values. The CQD-based S.P membrane shows great potential as a promising material for oil/water separation applications, with excellent performance and stability under various environmental conditions.

Recent Developments in Two-Dimensional Materials-Based Membranes for Oil-Water Separation

The industrialization witnessed in the last century has resulted in an unprecedented increase in water pollution. In particular, the water pollution induced by oil contaminants from oil spill accidents, as well as discharges from pharmaceutical, oil/gas, and metal processing industries, have raised concerns due to their potential to pose irreversible threats to the ecosystems. Therefore, the effective treating of these large volumes of oily wastewater is an inevitable challenge to address. Separating oil-water mixtures by membranes has been an attractive technology due to the high oil removal efficiency and low energy consumption. However, conventional oil-water separation membranes may not meet the complex requirements for the sustainable treatment of wastewater due to their relatively shorter life cycle, lower chemical and thermal stability, and permeability/selectivity trade-off. Recent advancements in two-dimensional (2D) materials have provided opportunities to address these challenges. In this article, we provide a brief review of the most recent advancements in oil-water separation membranes modified with 2D materials, with a focus on MXenes, graphenes, metal-organic frameworks, and covalent organic frameworks. The review briefly covers the backgrounds, concepts, fabrication methods, and the most recent representative studies. Finally, the review concludes by describing the challenges and future research directions.

Eco-Friendly Approach for the Construction of Superhydrophobic Coating on Stainless Steel Metal Based on Biological Metal-Organic Framework and Its Corrosion Resistance Performance

In this paper, we present a sustainable approach for the creation of superhydrophobic (SP) coating on a stainless-steel substrate based on a biological metal-organic framework (MOF). The MOF was synthesized using aspartic acid as a linker and copper ions as a core metal. Two SP coatings were well constructed on stainless steel utilizing electrodeposition of nickel (Ni) and nickel altered by MOF (Ni@Bio-MOF) coatings followed by soaking in a solution of stearic acid in ethanol. The results of Fourier transform infrared spectroscopy demonstrate that the stearic acid-grafted nickel coating (Ni@SA) and the stearic acid-grafted Ni@Bio-MOF composite (Ni@Bio-MOF@SA), were effectively deposited on the stainless steel. The wettability findings displayed that the water contact angle of Ni@SA and Ni@Cu-As MOF@SA are 160° ± 1.1°, and 168° ± 1.2°, respectively. The prepared SP coating was also found to be chemically and mechanically stable. The results show that the Ni@SA coating maintains SP characteristics in a pH range of 3-11 while the Ni@Cu-As MOF@SA coating retained SP characteristics in a pH range of 1-13. Additionally, the superhydrophobic Ni@SA coating demonstrated SP characteristics up to a length of abrasion equal to 1300 mm, while the Ni@Cu-As MOF@SA coating exhibited SP characteristics up to a length of abrasion equal to 2700 mm. Furthermore, the Ni@SA and Ni@Cu-As MOF@SA coatings exhibited significantly improved corrosion protection in a 0.5 M NaCl solution compared with bare stainless steel, with protection efficiencies of approximately 94% and 99%, respectively. The results of this study demonstrate that the proposed approach is a promising method for the fabrication of eco-friendly and corrosion-resistant SP coatings on stainless steel substrate.

Construction of superhydrophobic graphene-based coating on steel substrate and its ultraviolet durability and corrosion resistance properties

For the first time, a facile and environmentally friendly approach for producing high-quality graphene from the biomass of banana leaves is described in this paper. Two rough coats of Ni-graphene, Ni@G, and Ni-graphene doped with chromium, Ni@Cr-G, were created on steel substrates by electrostatic deposition. These coatings were then submerged in an ethanolic solution of myristic acid, MA, to produce a superhydrophobic, SHP, surface. The Raman spectra demonstrated that the generated graphene was of high quality. Fourier transform infrared spectroscopy findings confirm the modification of the Ni@G coating by MA, Ni@G@MA, and the modification of the Ni@Cr-G composite with MA, Ni@Cr-G@MA. The results of the scanning electron microscope revealed that the created SHP coatings have nanoscale features. The wettability results showed that the water contact angle values for Ni@G@MA and Ni@Cr-G@MA coatings are 158° and 168°, while the water sliding angle values for both coatings are 4.0 ^o and 1.0°, respectively. The atomic force microscopy results show that both Ni@G and Ni@Cr-G coatings increase the roughness of the steel. The chemical and mechanical stability of the Ni@Cr-G@MA coating was higher than those of the Ni@G@MA coating. The coated steel by Ni@Cr-G@MA exhibits UV stability up to 110 h, while the SHP-coated steel by Ni@G@MA exhibits UV stability for 60 h. The potentiodynamic polarization results show that the value of the corrosion current density for bare steel is 13 times that of steel coated with Ni@G@MA, and 21 times that of coated steel with Ni@Cr-G@MA. The electrochemical impedance spectroscopy, EIS, results show that the charge transfer resistance for steel coated with Ni@G@MA is 38 times that of bare steel, while steel coated with Ni@Cr-G@MA is 57 times that of bare steel. Potentiodynamic polarization and EIS results show that the SHP Ni@Cr-G@MA film exhibits higher corrosion resistance than Ni@G@MA film.

Fenugreek seed and cape gooseberry leaf extracts as green corrosion inhibitors for steel in the phosphoric acid industry

Phosphoric acid is the core material for the fertilizer industry; however, it is incredibly corrosive to manufacturing plants' structures, mainly steel. Corrosion is one of the most severe problems encountered during phosphate fertilizer manufacturing. Recently, plant extracts have been commonly used as corrosion inhibitors because they are cheap and environmentally friendly. Steel corrosion in a 20% aqueous phosphoric acid solution in the absence and presence of fenugreek seed (Fen) or cape gooseberry leaf (CgL) extracts was investigated using the electrochemical impedance spectroscopy technique, potentiodynamic polarization measurement, scanning electron microscope, and quantum chemical calculations. Fourier Transform Infrared, FTIR, was used to identify the functional groups in Fen and CgL extracts. The inhibition efficiency for steel in 20% aqueous phosphoric acid was roughly equal to 80% for 0.4 g/L CgL and 1.2 g/L Fen extracts. A scanning electron microscope showed that the chemical constituents of extracts block the surface roughness of steel, decreasing the corrosion rate. The activation parameters indicated the effectiveness of the extracts at a higher temperature. Measurements of the potential of zero charges showed that the steel surface is positively charged in the phosphoric acid solution. Quantum chemical computations were also employed to examine the corrosion inhibition mechanisms of the natural extracts.

Eco-friendly method for construction of superhydrophobic graphene-based coating on copper substrate and its corrosion resistance performance

In this work, Ni and Ni-graphene, Ni-G, films were electrodeposited on copper substrate by potentiostatic deposition. To achieve superhydrophobicity, myristic acid, MA, was used to modify the surface of the electrodeposited coatings. The manufactured Ni film modified with myristic acid, Ni-MA, and the Ni-G film modified with myristic acid, Ni-G-MA, show excellent superhydrophobic, SHP, properties with a water contact angle of 159° and 162°, respectively. The surface morphology of the prepared SHP films was investigated using a Scanning Electron Microscope, and the results revealed micro-nano structures in both Ni-MA and Ni-G-MA films. The Fourier Transform Infrared Spectrophotometer data showed that the Ni-MA and Ni-G-MA films were successfully grafted on the copper metal. The Ni-G-MA film possessed higher chemical stability and mechanical abrasion resistance than Ni-MA. The Ni-MA and Ni-G-MA films exhibit long-term durability in the outdoor environment for more than four months. The potentiodynamic polarization and electrochemical impedance spectroscopy results demonstrated that the SHP films on the copper substrate exhibit remarkable corrosion resistance in 0.5 M NaCl.