Use of Corrosion Inhibitors for Steel Protection in Cementitious Composites-A Review

Steel reinforced cementitious composite is one of the most commonly used materials in construction industries. This is mainly because of its excellent mechanical properties that can withstand various types of loading conditions and low cost. But, the corrosion of embedded steel reinforcement is a main problem associated with steel reinforced cementitious composite because it shortens the life of structure. The most important causes of corrosion initiation of steel reinforcement are the ingress of carbon dioxide and chloride ions to the surface of steel. Though, the corrosion initiation of embedded steel can be delayed using corrosion inhibitors. However, after starting of corrosion, the effectiveness of corrosion inhibitor was reported to be reduced significantly and propagation of corrosion becomes more rapidly. Generally, the negative effects of the corrosion inhibitors on properties of cementitious composite were reported to be negligible. Also, the information regarding the long-term performance of the corrosion inhibitors in actual practice are very limited. Various investigations reported several types of corrosion inhibitors in order to control the corrosion of steel that were also used in construction industries commercially. However, some of the corrosion inhibitors were found to be poisonous and harmful to the environment. Therefore, there is need for more research on the corrosion inhibitors in order to find out the suitable inhibitor with low cost and without side effects to the environment

Optical properties of chitosan/hydroxyl-functionalized graphene quantum dots thin film for potential optical detection of ferric (III) ion

In this research, the preparation of chitosan and hydroxyl-functionalized graphene quantum dots (HGQDs) composite has been described. The spin coating technique was used to prepare the chitosan/hydroxyl-functionalized graphene quantum dots (Cs/HGQDs) thin film. The Cs/HGQDs thin film was then characterized using the Fourier transform infrared spectroscopy which confirmed the existence of amino groups, carboxylic acid groups, carboxyl groups and hydroxyl groups in Cs/HGQDs. UV–Vis absorption spectroscopy and photoluminescence (PL) were used to study the optical properties of the thin film. The absorption of Cs/HGQDs thin film was high with optical band gap of 3.797 eV. The intensity of PL spectra of the thin film was observed around wavelength of 420 nm. The incorporation of Cs/HGQDs thin film with surface plasmon resonance spectroscopy produced positive responses towards the Fe³⁺ ion solutions of different concentration and it was found that Cs/HGQDs thin film able to detect Fe³⁺ as low as 0.5 ppm with a sensitivity of 0.11396° ppm⁻¹. Subsequently, Cs/HGQDs layer have high potential as sensing layer to detect Fe³⁺ due to high affinity of Fe³⁺ ion towards the thin film with a value of binding affinity constant, K equals to 5.79 ppm⁻¹. Atomic force microscopy was used to observe the surface morphology of the thin film and the result indicates that the thin film is relatively smooth and homogenous which also confirmed the interaction of Fe³⁺ with the thin film. Thus, Cs/HGQDs thin film shows potential for the detection of Fe³⁺ in solution

Highly sensitive surface plasmon resonance optical detection of ferric ion using CTAB/hydroxylated graphene quantum dots thin film

The development of optical sensors for heavy metal ion detection has been rapidly growing; unfortunately, the current methods suffer limitations that led to the emergence of an outstanding technique called surface plasmon resonance (SPR) spectroscopy. In this paper, the performance of the SPR optical sensor in detecting ferric ions (Fe3+) was successfully enhanced by depositing novel cetyltrimethylammonium bromide modified hydroxylated graphene quantum dots (CTAB/HGQDs) onto a gold (Au) thin film using the spin coating technique. Upon exposure to Fe3+, the SPR responses of both CTAB/HGQDs thin film and bare Au thin film were compared and studied, emphasizing the sensitivity, binding affinity, full width at half maxima, signal-to-noise ratio, and data accuracy. The CTAB/HGQDs thin film achieved a high sensitivity value of 29.886° ppm−1 for Fe3+ up to 0.1 ppm. The strong binding affinity was confirmed using the Langmuir isotherm model calculation. To the end, the CTAB/HGQDs thin film was characterized using atomic force microscopy for morphological study, confirming its interaction with Fe3+

Exploration on structural and optical properties of nanocrystalline cellulose/Poly(3,4-Ethylenedioxythiophene) thin film for potential plasmonic sensing application

There are extensive studies on the development of composite solutions involving various types of materials. Therefore, this works aims to incorporate two polymers of nanocrystalline cellulose (NCC) and poly(3,4-ethylenethiophene) (PEDOT) to develop a composite thin film via the spin-coating method. Then, Fourier transform infrared (FTIR) spectroscopy is employed to confirm the functional groups of the NCC/PEDOT thin film. The atomic force microscopy (AFM) results revealed a relatively homogeneous surface with the roughness of the NCC/PEDOT thin film being slightly higher compared with individual thin films. Meanwhile, the ultraviolet/visible (UV/vis) spectrometer evaluated the optical properties of synthesized thin films, where the absorbance peaks can be observed around a wavelength of 220 to 700 nm. An optical band gap of 4.082 eV was obtained for the composite thin film, which is slightly lower as compared with a single material thin film. The NCC/PEDOT thin film was also incorporated into a plasmonic sensor based on the surface plasmon resonance principle to evaluate the potential for sensing mercury ions in an aqueous medium. Resultantly, the NCC/PEDOT thin film shows a positive response in detecting the various concentrations of mercury ions. In conclusion, this work has successfully developed a new sensing layer in fabricating an effective and potential heavy metal ions sensor

GIS-based assessment of groundwater vulnerability to heavy metal contamination via water quality pollution indices in urban Aligarh, India

The study presents an assessment of groundwater vulnerability due to heavy-metal contamination using Heavy Metal Pollution and Contamination Index of Urban Aligarh. Globally, hazardous compounds in industrially contaminated sites are pressing and high-priority issue. A detailed risk assessment was carried out to determine the potential health hazards linked to locations that were recently polluted. A total of 17 groundwater samples were taken from hand-pump and 20 industrial drainage samples were collected from selected areas of Aligarh. The concentration of heavy-metals in the collected samples analyzed were shown on maps using ArcGIS software and interpreted for Heavy Metal Pollution Index (HPIx) and Contamination Index (CDx). These analyzed values were subsequently compared with the permissible limits established by the agencies like EPA, WHO, and BIS. The mean concentration of heavy-metals in groundwater of different locations was observed as follows particular sequence: Ni (1.40), Cu (0.58), Zn (0.06), Fe (0.08), Mn (0.04), Cr (0.001), Pb (0.00025) mg/l. Additionally in industrial effluent, Cr (18.3), Ni (13.34), Mn (1.16), Cu (1.99), Pb (1.2), Fe (6.3), Zn (0.51) mg/l. According to HPIx, the analysis reveals 64.7%, of visited areas belonged to have safe groundwater. Conversely, a smaller proportion, 35.3%, was found falling into heavy metal-polluted group. HIGHLIGHTS The study provides a comprehensive assessment of heavy metal contamination.; GIS-driven vulnerability mapping is conducted in the study.; The study includes an evaluation of real-world impact.; The study systematically validates scientific indices for accuracy and reliability.; The study investigates health effects resulting from heavy metal contamination.; A comprehensive analysis of drinking water quality.

Analysis of friction and wear of aluminium AA 5083/ WC composites for building applications using advanced machine learning models

The aluminium composites have gained greater attention, especially in wear resistant applications. However, reinforcing the ceramic particulates in the aluminium matrix is a major factor influencing the tribological characteristics. In this regard, the influence of Fly Ash inoculants on the uniform distribution of reinforcements and the subsequent tribological characteristics are studied. The composite specimens are produced by reinforcing different wt.% (in the range of 3 to 9 wt%) of Tungsten Carbide (WC) and the Fly Ash (FA) in Aluminium AA 5083 matrix by ultrasonic assisted stir casting in a controlled environment. The wt.% of the reinforcements are chosen based on initial trials and related literature reviews. The stir cast aluminium composites are machined in accordance with the specimen standards to accomplish the pin on disc - adhesive wear following the ASTM G99 standards. The results of the wear test clearly depicts that the increase in the wt.% of fly ash upto a threshold limit (6 wt%) improves the wear behaviour of the composites. This is majorly due to the homogeneity brought about by the fly ash inoculants in dispersing the ceramic reinforcements of WC uniformly in the matrix phase. The experimental findings are also ascertained by the statistical validations and correlated. The results of the experiments and the statistical validations and the outcomes of the optimization will be a base for the use of the composites for wear resistant applications, since the wear of the aluminium composite castings are of prime concern for advanced industrial uses. Further, Artificial Neural Network (ANN) and Machine Learning (ML) models are evolved to predict the tribological characteristics of the composite specimens. The predictions of these models are found to be in clore correlation to the experimental outcomes

Development of graphene quantum dots-based optical sensor for toxic metal ion detection

About 71% of the Earth’s surface is covered with water. Human beings, animals, and plants need water in order to survive. Therefore, it is one of the most important substances that exist on Earth. However, most of the water resources nowadays are insufficiently clean, since they are contaminated with toxic metal ions due to the improper disposal of pollutants into water through industrial and agricultural activities. These toxic metal ions need to be detected as fast as possible so that the situation will not become more critical and cause more harm in the future. Since then, numerous sensing methods have been proposed, including chemical and optical sensors that aim to detect these toxic metal ions. All of the researchers compete with each other to build sensors with the lowest limit of detection and high sensitivity and selectivity. Graphene quantum dots (GQDs) have emerged as a highly potential sensing material to incorporate with the developed sensors due to the advantages of GQDs. Several recent studies showed that GQDs, functionalized GQDs, and their composites were able to enhance the optical detection of metal ions. The aim of this paper is to review the existing, latest, and updated studies on optical sensing applications of GQDs-based materials toward toxic metal ions and future developments of an excellent GQDs-based SPR sensor as an alternative toxic metal ion sensor

Waste slags as sustainable construction materials: a compressive review on physico mechanical properties

Rapid industrialization and urbanization in emerging nations have resulted in the accumulation of various industrial wastes. As a result, reusing and recycling these wastes into an economical, durable, and environmentally friendly building material may be the most effective means of mitigating their environmental impact. Such wastes are being dumped in greater quantities, which pollute the ecosystem and the land. As a result, its efficient use and management are required, which presents a global issue for its viable recycling and safe disposal. The current review examines the use of various slags, including cupola slag, electric arc furnace slag (EAFS), steel furnace slag (SFS), and ground granulated blast furnace slag (GGBFS) in the development of sustainable construction materials considering the potential of such waste in greener concrete composites towards eco-friendly infrastructure. In order to produce environmentally acceptable construction materials, these waste slags have been used as a partial and full replacement of cement, fine and coarse aggregate with or without supplementary materials ranging from 10 to 60% for cupola slag, 20 to 50% for EAFS, 10 to 50% for GGBFS, and 10 to 30% for SFS are suggested. This review will be an inclusion that helps readers to identify gaps in experimental viability, material characterization, and physico-mechanical behaviour of waste slags, pointing to the potential for application in the production of sustainable building materials

Cationically modified nanocrystalline cellulose/carboxyl-functionalized graphene quantum dots nanocomposite thin film: characterization and potential sensing application

In this study, highly functional cationically modified nanocrystalline cellulose (NCC)/carboxyl-functionalized graphene quantum dots (CGQD) has been described. The surface of NCC was first modified with hexadecyltrimethylammonium bromide (CTA) before combining with CGQD. The CGQD, CTA-NCC and CTA-NCC/CGQD nanocomposites thin films were prepared using spin coating technique. The obtained nanocomposite thin films were then characterized by using the Fourier transform infrared spectroscopy (FTIR) which confirmed the existence of hydroxyl groups, carboxyl groups and alkyl groups in CTA-NCC/CGQD. The optical properties of the thin films were characterized using UV–Vis spectroscopy. The absorption of CTA-NCC/CGQD was high with an optical band gap of 4.127 eV. On the other hand, the CTA-NCC/CGQD nanocomposite thin film showed positive responses towards glucose solution of different concentration using an optical method based on surface pla.smon resonance phenomenon. This work suggests that the novel nanocomposite thin film has potential for a sensing application in glucose detectio