Quantum dots as ecofriendly and aqueous phase substitutes of carbon family for traditional corrosion inhibitors: A perspective

Pyrimidine-5-carbonitrile derivatives as sprout for CQDs proveniences: Antitumor and anti-inflammatory potentiality

A comparative study is proposed to show the effect of variation in the heteroatoms in the main skeleton of CQDs proveniences, on their affinity for nucleation of CQDs, as anti-inflammatory and anticancer drugs. Heterocyclic-based CQDs sprout was successfully exploited for preparation of three CQDs proveniences, named as; 2-(2,5-dimethoxyphenyl)-4,6-dioxo-6,11-dihydro-4H-pyrimido[2,1-b] quinazoline-3-carbonitrile (compound A), 2-(2,5-dimethoxyphenyl)-4,6-dioxo-4H,6H-benzo[e]pyrimido[2,1-b][1,3]oxazine-3-carbonitrile (compound S) and 2-(2,5-dimethoxyphenyl)-4,6-dioxo-4H,6H-benzo[e]pyrimido[2,1-b][1,3] thiazine-3-carbonitrile (compound T). Chemical formulas of CQDs proveniences & CQDs were verified via FTIR, 1HNMR, 13CNMR & XRD. Particle size of TM-CQDs, A-CQDs, S-CQDs & T-CQDs were estimated to be 3.7 ± 1.4, 4.6 ± 1.6, 5.9 ± 1.6 nm and 3.0 ± 1.3 nm, respectively. All of CQDs proveniences & CQDs were examined for their affinity as anti-inflammatory drugs via Griess assay. CQDs ingrained from TM (TM-CQDs) were detected with the highest NO inhibition% by increasing its concentration from 10 up to 100 μM to be 40 % to 89 %, respectively. Moreover, their anti-tumor performance against MCF-7: breast Adenocarcinoma cell line was approved via sulforhodamine B assay, whereas, IC50 was evaluated for TM-CQDs, A-CQDs, S-CQDs and T-CQDs to be 38.16, 36.09, 100 and 100 μg/ml, respectively.

Nanomaterials and Their Recent Applications in Impedimetric Biosensing

Impedimetric biosensors measure changes in the electrical impedance due to a biochemical process, typically the binding of a biomolecule to a bioreceptor on the sensor surface. Nanomaterials can be employed to modify the biosensor's surface to increase the surface area available for biorecognition events, thereby improving the sensitivity and detection limits of the biosensor. Various nanomaterials, such as carbon nanotubes, carbon nanofibers, quantum dots, metal nanoparticles, and graphene oxide nanoparticles, have been investigated for impedimetric biosensors. These nanomaterials have yielded promising results in improving sensitivity, selectivity, and overall biosensor performance. Hence, they offer a wide range of possibilities for developing advanced biosensing platforms that can be employed in various fields, including healthcare, environmental monitoring, and food safety. This review focuses on the recent developments in nanoparticle-functionalized electrochemical-impedimetric biosensors.

Comprehensive evaluation of corrosion inhibition performance and ecotoxicological effect of cinchona IIa as a green corrosion inhibitor for pickling of Q235 steel

Here, to prevent the corrosion of Q235 steel in the pickling and discover novel green corrosion inhibitors, the corrosion inhibition performance and eco-toxicity of cinchonain IIa were evaluated. Electrochemical experiments confirms that 200 mg/L cinchonain IIa reveals good corrosion inhibition performance with 94.08% on Q235 steel in HCl for 48 h. Scanning electron microscope (SEM) and atomic force microscope (AFM) observations suggest that cinchonain IIa can be firmly attached to the metal surface by forming a barrier film. The X-ray photoelectron spectroscopy (XPS) results further verify the bonding interaction between the functional groups and the steel matrix, and indicate the existence of protective film on the steel. Meanwhile, the inhibition mechanism at the molecular/atomic level is revealed through molecular dynamics simulation. Additionally, acute toxicity test shows that cinchonain IIa is a low toxic corrosion inhibitor. Moreover, the antioxidant enzyme activity experiments confirm that cinchonain IIa discloses no obvious damage to the antioxidant system of zebrafish. Overall, cinchonain IIa exhibits low potential risks to the healthy development of aquatic organisms and ecosystems. As a proven green and low toxic corrosion inhibitor, cinchonain IIa has a sustainable application in the anti-corrosion industry.

Green β-cyclodextrin-based corrosion inhibitors: Recent developments, innovations and future opportunities

β-Cyclodextrin-based compounds are used to develop and innovate materials that protect against corrosion due to their sustainability, low cost, environmental friendliness, excellent water solubility and high inhibition efficiency. However, corrosion potentials of β-CD-based compounds were not reviewed with the modern trends. The essence of the problem is that a deep understanding of the development and innovation of β-CD-based compounds as corrosion inhibitors is very important in creating next-generation materials for corrosion protection. In this review, the fundamental behaviour, importance, developments and innovations of β-CD modified with natural and synthetic polymers, β-CD grafted with the organic compounds, β-CD-based supramolecular (host-guest) systems with organic molecules, polymer β-CD-based supramolecular (host-guest) systems, β-CD-based graphene oxide materials, β-CD-based nanoparticle materials and β-CD-based nanocarriers as corrosion inhibitors for various metals were reviewed and discussed with recent research works as examples. In addition, the corrosion inhibition of β-CD-based compounds for biocorrosion, microbial corrosion and biofouling was reviewed. It was found that (i) these compounds are sustainable, inexpensive, environmentally friendly, and highly water-soluble and have high inhibition efficiency; (ii) the molecular structure of β-CD makes it an excellent molecular container for corrosion inhibitors compounds; (iii) the β-CD is excellent core to develop the next generation of corrosion inhibitors. It is recommended that (i) β-CD compounds would be synthesized by green methods, such as using biological sustainable catalysts and green solvents, green methods include irradiation or heating, energy-efficient microwave irradiation, mechanochemical mixing, solid-state reactions, hydrothermal reactions and multicomponent reactions; (ii) this review will be helpful in creating, enhancing and innovating the next green and efficient materials for future corrosion protection in high-impact industries.

Comparative study on corrosion inhibition of N doped and N,S codoped carbon dots for carbon steel in strong acidic solution

Carbon steel is the most widely used engineering material, and its corrosion is one of the main areas of concern in many industries. The most practical approach to control this problem is to use corrosion inhibitors. Currently, because of their good water solubility, excellent chemical stability, low cost and nontoxic features, carbon dots (CDs), especially heteroatom-doped CDs, have been developed as green corrosion inhibitors, but the corrosion inhibition efficiency and underlying mechanisms of single- or dual-element doping have not yet been accurately compared and analyzed. Inspired by this, eco-friendly nitrogen-doped and nitrogen, sulfur codoped CDs (N-CDs and N,S-CDs) are prepared via a one-step hydrothermal process, and a comparative study on their inhibition performance for carbon steel corrosion in strong acidic solution is performed. The results show that both N-CDs and N,S-CDs can restrain the corrosion of carbon steel, and their inhibition efficiency increases with increasing concentration and immersion time, reaching approximately 87.9% (N-CDs) and 96.4% (N,S-CDs) at 200 ppm after 1 h of immersion. Molecular dynamics simulation indicates that the strong interaction ability between N,S-CDs and the Fe substrate leads to higher corrosion inhibition performance than the single N doping case, benefiting from the multi-anchor adsorption of N,S-CDs on carbon steel in a strong acidic solution. Therefore, the facile preparation, eco-friendliness and high corrosion inhibition performance of N,S-CDs will provide a new approach for designing highly efficient carbon dots and broadening the application of carbon dots in the corrosion field.