Nonpolar Surface Modification Using Fatty Acids and Its Effect on Calcite from Mineral Carbonation of Desulfurized Gypsum

Revolutionizing applications: the impact of controlled surface chemistry on marble powder

A large amount of marble powder is abundantly available as a byproduct and waste in the marble industry, and its reinforcement has been attempted in several applications through surface modification. This article examines the use of MP in the production of rubber, paper, foam stabilizers, asphalt, paint, textiles, and adhesives. This article aims to provide a foundation for the surface modification of MP to enhance its properties and broaden its range of applications. Data on modifiers such as organic acids, coupling agents, polymers, and surfactants have been gathered, along with comprehensive reaction details for various techniques, including wet modification, dry modification, in situ modification, ultrasonication, and sol-gel methods. A general overview of MP modification and its impact on composite properties is provided in this review paper, mainly focusing on the distinctive features of composites, contemporary field challenges, and the correlation between the properties and applications of MP.

Corrosion-Resistant Hydrophobic Thermal Barrier Composite Coating on Metal Strip: A New Dimension to Steel Strips for Roofing Segment

This study demonstrates a cost-effective, thin, multifunctional composite coating system with outstanding thermal insulation for thermal management and heat shield applications, such as roofs, as well as outstanding resistance to corrosion. The hydrophobic multifunctional epoxy composite coating systems were designed with surface-modified fillers to impart both reduced heat conduction and high infrared reflectance in a thin coating with a 65-100 μm dry film thickness (DFT). With a judicial combination of hollow microspheres (HMS) activated and modified with silica (sHMS) and stearic acid-modified TiO2 (sMO), the developed composite coating attained the highest thermal insulation property with a temperature drop of 21-31 °C at different distances below the coated panel, which is superior to the values of temperature drop reported earlier. The high solar reflectance of the composite coating in the near-infrared (NIR) region exceeds 72% with a low thermal conductivity of 0.178 W m-1 K-1. After 720 h of exposure in a 3.5 wt % NaCl solution, the composite coating revealed a corrosion protection efficiency of 99%. The work demonstrates that high solar reflectivity and low thermal conductivity must be active simultaneously to achieve superior thermal shielding in a thin coating on a metal. A careful selection of fillers and appropriate surface modifications ensures hydrophobicity and proper distribution of the fillers in the coating for a high barrier effect to prevent environmental deterioration. With these superior performance parameters, the developed composite coatings make an essential contribution to energy sustainability and the protection against environmental degradation.

Calcium carbonate: controlled synthesis, surface functionalization, and nanostructured materials

Calcium carbonate (CaCO₃) is an important inorganic mineral in biological and geological systems. Traditionally, it is widely used in plastics, papermaking, ink, building materials, textiles, cosmetics, and food. Over the last decade, there has been rapid development in the controlled synthesis and surface modification of CaCO₃, the stabilization of amorphous CaCO₃ (ACC), and CaCO₃-based nanostructured materials. In this review, the controlled synthesis of CaCO₃ is first examined, including Ca²⁺-CO₃^2- systems, solid-liquid-gas carbonation, water-in-oil reverse emulsions, and biomineralization. Advancing insights into the nucleation and crystallization of CaCO₃ have led to the development of efficient routes towards the controlled synthesis of CaCO₃ with specific sizes, morphologies, and polymorphs. Recently-developed surface modification methods of CaCO₃ include organic and inorganic modifications, as well as intensified surface reactions. The resultant CaCO₃ can then be further engineered via template-induced biomineralization and layer-by-layer assembly into porous, hollow, or core-shell organic-inorganic nanocomposites. The introduction of CaCO₃ into nanostructured materials has led to a significant improvement in the mechanical, optical, magnetic, and catalytic properties of such materials, with the resultant CaCO₃-based nanostructured materials showing great potential for use in biomaterials and biomedicine, environmental remediation, and energy production and storage. The influences that the preparation conditions and additives have on ACC preparation and stabilization are also discussed. Studies indicate that ACC can be used to construct environmentally-friendly hybrid films, supramolecular hydrogels, and drug vehicles. Finally, the existing challenges and future directions of the controlled synthesis and functionalization of CaCO₃ and its expanding applications are highlighted.

Recycling of Industrial Waste Gypsum Using Mineral Carbonation

Direct mineral carbonation (MC) is used to mitigate carbon dioxide (CO2) emissions. This method has the great advantages of reducing the amount of industrial residues and creating valuable materials by incorporating CO2. Waste gypsum, industrial waste including flue gas desulfurization (FGD) gypsum (25.27–53.40 wt% of CaO), and phosphogypsum (30.50–39.06 wt% of CaO) can be used for direct MC (conversion rate up to 96%). Mineral carbonation converts waste gypsum into calcium carbonate (CaCO3), which can be recycled during desulfurization. Furthermore, ammonium sulfate ((NH4)2SO4), which is used as a fertilizer, can be prepared as a by-product when the carbonation reaction is performed using ammonia (NH3) as a base. In this study, recent progress in the carbonation kinetics and preparation of CaCO3 using FGD gypsum and phosphogypsum with NH3 was investigated. Temperature, CO2 partial pressure, CO2 flow rate, and NH3 concentration were reviewed as factors affecting carbonation kinetics and efficiency. The factors influencing the polymorphs of the prepared CaCO3 were also reviewed and summarized. A state-of-the-art bench-scale plant study was also proposed. In addition, economic feasibility was investigated based on a bench-scale study to analyze the future applicability of this technology.

Preparation and characterization of ancient recipe of organic Lime Putty-Evaluation for its suitability in restoration of Padmanabhapuram Palace, India

The study aims at preparation and characterization of six organic lime putty (hydraulic Lime + fermented plant extract) using regionally available plants namely Terminalia Chebula (kadukkai), Rosa Sinensis (hibiscus), Palm jaggery (refined sugar), Xanthorrhoeaceae (aloe vera), and Indigofera Tinctoria (neelamari) as per the methods given in the ancient palm leaf of Padmanabhapuram Palace, India. Advanced analytical techniques like Gas chromatography-mass spectroscopy (GC–MS), UV-Spectrophotometer and carbon dioxide quantification were used to study the fermented plant extracts and Fourier transform-infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), Field emission-scanning electron microscopy (FESEM) to study hydrated phases and microstructure of organic lime putty. GC–MS recorded the phytochemical compounds like fatty acids, traces of proteins, polysaccharides and carbohydrates. Fermented kadukkai and neelamari extracts reported as fatty acid, palm jaggery as carbohydrate, hibiscus as polysaccharide and aloevera rich in all the biomolecules. The detection limit of Quantification:0.013 and limit of detection:0.067 for polysaccharides, 0.026 and 0.088 for unsaturated fatty acids was reported through a U.V spectrophotometer for all the herbs. Aloevera and neelamari fermented extracts recorded the CO₂ release around 96,000 and 90,000 ppm on 4th day of fermentation, whereas for other herbs it ranged below the recorded readings. Supply of CO₂ has initiated the internal carbonation of the lime putty and precipitation of calcite in three different forms aragonite, calcite and vaterite minerals. The addition of organics resulted in high-intensity portlandite peaks and calcium carbonate polymorphs as reported in XRD graphs in agreement with FT-IR analysis. FESEM morphology validated the early formation of carbonate polymorphs, and EDX. has shown that kadukkai lime putty, jaggery lime putty and reference lime putty. mixes have calcium around 35–45%. From the overall results, 3% addition of eco-friendly biopolymers has altered the properties like setting time, water repellency and higher carbonation rate, which is the main reason behind longevity of the structure.

Green Nanofabrication Opportunities in the Semiconductor Industry: A Life Cycle Perspective

The turn of the 21st century heralded in the semiconductor age alongside the Anthropocene epoch, characterised by the ever-increasing human impact on the environment. The ecological consequences of semiconductor chip manufacturing are the most predominant within the electronics industry. This is due to current reliance upon large amounts of solvents, acids and gases that have numerous toxicological impacts. Management and assessment of hazardous chemicals is complicated by trade secrets and continual rapid change in the electronic manufacturing process. Of the many subprocesses involved in chip manufacturing, lithographic processes are of particular concern. Current developments in bottom-up lithography, such as directed self-assembly (DSA) of block copolymers (BCPs), are being considered as a next-generation technology for semiconductor chip production. These nanofabrication techniques present a novel opportunity for improving the sustainability of lithography by reducing the number of processing steps, energy and chemical waste products involved. At present, to the extent of our knowledge, there is no published life cycle assessment (LCA) evaluating the environmental impact of new bottom-up lithography versus conventional lithographic techniques. Quantification of this impact is central to verifying whether these new nanofabrication routes can replace conventional deposition techniques in industry as a more environmentally friendly option.

Patterned dextran ester films as a tailorable cell culture platform

The elucidation of cell-surface interactions and the development of model platforms to help uncover their underlying mechanisms remains vital to the design of effective biomaterials. To this end, dextran palmitates with varying degrees of substitution were synthesised with a multipurpose functionality: an ability to modulate surface energy through surface chemistry, and an ideal thermal behaviour for patterning. Herein, dextran palmitate films are produced by spin coating, and patterned by thermal nanoimprint lithography with nano-to-microscale topographies. These films of moderately hydrophobic polysaccharide esters with low nanoscale roughness performed as well as fibronectin coatings in the culture of bovine aortic endothelial cells. Upon patterning, they display distinct regions of roughness, restricting cell adhesion to the smoothest surfaces, while guiding multicellular arrangements in the patterned topographies. The development of biomaterial interfaces through topochemical fabrication such as this could prove useful in understanding protein and cell-surface interactions.

Comparative cytotoxicity of respirable surface-treated/untreated calcium carbonate rock dust particles in vitro

Calcium carbonate rock dust (RD) is used in mining to reduce the explosivity of aerosolized coal. During the dusting procedures, potential for human exposure occurs, raising health concerns. To improve RD aerosolization, several types of anti-caking surface treatments exist. The aim of the study was to evaluate cytotoxicity of four respirable RD samples: untreated/treated limestone (UL/TL), untreated/treated marble (UM/TM), and crystalline silica (SiO₂) as a positive control in A549 and THP-1 transformed human cell lines. Respirable fractions were generated and collected using FSP10 high flow-rate cyclone samplers. THP-1 cells were differentiated with phorbol-12-myristate-13-acetate (20 ng/ml, 48 h). Cells were exposed to seven different concentrations of RD and SiO₂ (0-0.2 mg/ml). RD caused a slight decrease in viability at 24 or 72 h post-exposure and were able to induce inflammatory cytokine production in A549 cells, however, with considerably less potency than SiO₂. In THP-1 cells at 24 h, there was significant dose-dependent lactate dehydrogenase, inflammatory cytokine and chemokine release. Caspase-1 activity was increased in SiO₂- and, on a lesser scale, in TM- exposed cells. To test if the increased toxicity of TM was uptake-related, THP-1 cells were pretreated with Cytochalasin D (CytD) or Bafilomycin A (BafA), followed by exposure to RD or SiO₂ for 6 h. CytD blocked the uptake and significantly decreased cytotoxicity of all particles, while BafA prevented caspase-1 activation but not cytotoxic effects of TM. Only TM was able to induce an inflammatory response in THP-1 cells, however it was much less pronounced compared to silica.