Polyvinyl chloride/calcium carbonate (PVC/CaCO 3 ) composites are widely used in the construction industry to fabricate flooring materials. However, PVC materials have raised concern due to the large quantity of plasticizers introduced during PVC product processing. Studies have reported that volatile organic chemicals (VOCs) are toxic with side effects on human health and the environment. Therefore, polypropylene (PP) is proposed as an alternative polymer for developing calcium carbonate-based polymer composite sheets for flooring applications with improved thermal, mechanical, and flammability properties. This work reviews the scientific and technological advances in the field of polypropylene/calcium carbonate–carbon nanomaterials or clay nanocomposites to develop a better understanding of how to develop superior nanocomposites for use in flooring applications. This work explores various studies about the synergistic effect of combining nanofillers (i.e., carbon nanomaterials or layered clays) with intumescent flame retardants and the synergist effect of nanofillers (i.e., multi-walled carbon nanotubes/montmorillonite) without intumescent flame retardants on thermal, mechanical, flammability properties, and morphologies of polypropylene. The generated information will facilitate the design of flooring materials based on PP with improved thermal, mechanical, and flammability properties. Therefore, it was confirmed that there is a relationship between the morphology (dispersion state of nanofillers in the PP), and mechanical properties, as well as the flammability of PP composites.
Organochlorine pesticides have been widely used in agriculture to control agricultural pests. Although effective in controlling pests, organochlorine pesticides present numerous hazards to ecosystems and human health due to their persistence in the environment, bioaccumulation, and toxicity. Scientific studies have shown that organochlorines may be associated with endocrine and neurological problems. Several strategies have been developed to apply treatment techniques to remove pesticides from various ecosystems, both aquatic and terrestrial. Physicochemical and biological methods have revealed other potentialities for remediation of aqueous environments contaminated with organochlorine pesticides. In addition, combined processes using different approaches have been highlighted as efficient alternatives to mitigate the impacts of agrochemicals on the environment, e.g., physical technique followed by a biological process. However, there are still numerous gaps that need to be explored and elucidated. Therefore, this review addressed the impacts of organochlorine pesticides on ecosystems and some treatment techniques used to remove agrochemicals from water. Furthermore, new findings, technological perspectives, and opportunities on this subject were presented and discussed.
AbstractThe textile industry comprises technologies that transform synthetic or natural fibers into yarn, cloth, and felt for manufacturing clothing, upholstery, and household linens. The major public health threat in tropical and subtropical countries is mosquito‐borne malaria. Nowadays, the demand for insect repellent‐based textiles is continuously rising, as they are used for protection against diseases transmitted by mosquitoes. The present work reviews studies on the fabrication of insect repellent containing electrospun polymeric nanofibers as principal tools for protecting people against mosquito bites. Electrospinning technology is a remarkably facile technique for fabricating polymeric nanofiber devices. The technique is outlined and elucidated. The performance of insect repellent‐based polymeric nanofibers against mosquitoes is carefully reported and comprehensively reviewed in‐depth. Furthermore, the progress made on the mathematical modeling of the release rate of repellents through polymeric nanofiber devices is reviewed. The reviewed studies demonstrate that repellents can be released slowly from electrospun nanofibers, increasing the product's protection period against insects. The reviewed works suggest that electrospinning technology has led to an effective and facile methodology for fabricating functional nanofiber textiles with insect repellent. The reviewed studies showed that product‐based repellents can be effective not only against malaria but also against other mosquito‐borne diseases.
Polyolefins, such as polyethylene (PE), are highly flammable and electrically insulative, limiting their applicability. The study explored the flame-retardancy and electrical conductivity of PE/polyaniline (PE/PANI) nanocomposites containing undoped PANI, PANI doped, and co-doped with various acids and PANI modified with a double layered hydroxide or ammonium polyphosphate (APP). The nanocomposites were synthesized through in situ chemical oxidative polymerization of aniline and compression molding. Flame retardancy was evaluated using UL 94 tests and cone calorimetry. All nanocomposites, except the de-doped PANI nanocomposite, attained a UL 94 V2 rating. Cone calorimeter results showed that PANI doped with H3PO4 reduced the peak heat release rate by 20% compared to neat PE, whereas co-doping PANI with H3PO4 and phytic acid reduced it by 31%. The nanocomposites exhibited volume resistivity for suitable for electrotactic dissipation applications but showed marginally reduced mechanical properties. This study demonstrates the potential to develop electrostatic dissipative and flame-retardant PE nanocomposites incorporating PANI.Highlights PE/PANI nanocomposites were synthesized. PANI doped with H3PO4 reduced the peak HRR by 20%. Co-doping PANI with H3PO4 and phytic acid further reduced peak HRR. Nanocomposites attained a UL 94 V2 rating. PE/PANI nanocomposites were electrostatic dissipative. Effecft of co-doping polyaniline with phosphoric acid and phytic acid on the heat release rate of polyethylene. image
Real-world energy efficiency in the building sector is currently inadequate due to significant discrepancies between predicted and actual building energy performance. As operational energy is optimized through improved building envelopes, embodied energy typically increases, further exacerbating the problem. This gap underscores the critical need to re-evaluate current practices and materials used in energy-efficient building construction. It is well established that adopting a life cycle view of energy efficiency is essential to mitigate the building sector’s contribution to rising global energy consumption and CO2 emissions. Therefore, this study aims to examine existing research on sustainable building materials for life cycle energy efficiency. Specifically, it reviews recent research to identify key trends, challenges, and suggestions from tested novel materials. A combination of theoretical analysis and narrative synthesis is employed in a four-stage framework discussing the challenges, context, concepts, and the reviewed literature. Key trends include the growing adoption of sustainable materials, such as bio-fabricated and 3D printed materials, which offer improved insulation, thermal regulation, and energy management capabilities. Multifunctional materials with self-healing properties are also emerging as promising solutions for reducing energy loss and enhancing building durability. The focus on reusing materials from the agricultural, food production, and paper manufacturing industries in building construction highlights the opportunity to facilitate a circular economy. However, the challenges are substantial, with more research required to ascertain long-term performance, show opportunities to scale the implementation of these novel materials, and drive market acceptance.
The need to develop more effective coagulants to remove Natural Organic Matter (NOM) from water has gained great attention. Recently, many scientists and researchers have studied the development and application of polymeric coagulants for the removal of (NOM) in wastewater in comparison to the conventional traditional inorganic coagulants. The use of traditional inorganic coagulants to remove NOM is known to cause environmental problems in water treatment processes such as membrane fouling and disinfection byproduct formation. A healthy and sustainable ecosystem in our water sector environment is created through the management of NOM to acceptable levels. The conventional interventions on NOM by using traditional inorganic coagulants have proved to be ineffective in removing NOMs from water, hence the use of polymeric coagulants. Polymeric coagulants offer superior characteristics than traditional inorganic coagulants due to their higher molecular weight and more complex structure which is associated with the effective removal of a wider range of contaminants, reduced sludge formation, and less environmental impacts due to the less heavy metals that can accumulate in the environment due to the use of traditional inorganic coagulants. The present book chapter initially reviews various interventions applied in the removal of NOM from wastewater by exploring the performance of traditional inorganic coagulations and their limitations, types of traditional inorganic coagulants, and how the use of polymeric coagulants has overcome performance limitations exhibited by traditional inorganic coagulants in the removal of NOM from water. The superiority of polymeric coagulants in terms of the enhanced removal of contaminants, reduced sludge production, improved removal efficiency, lower operating costs, and improved process efficiency is also discussed. The book chapter also features recent research on the characterization of various polymeric coagulants and their performance in NOM removal. Various studies highlighting comprehensive insights on the recent environmental remediation on the use and potential of polymeric coagulants in improving water quality and sustainability are also discussed and finally, the overall impacts polymeric coagulants have in the field of water and wastewater treatment and the management of water resources.
This study investigates the effects of inorganic flame retardants, zinc borate, and magnesium hydroxide, on the thermal, morphological, flame retardancy, and mechanical properties of polypropylene (PP)/calcium carbonate composites for potential construction industry applications. Polypropylene/calcium carbonate (50 wt.%) composites containing 5 and 10 wt.% flame retardants were prepared using a batch mixer, followed by compression moulding. The results demonstrated enhanced thermal stability, with the highest char residue reaching 47.2% for polypropylene/calcium carbonate/zinc borate (10 wt.%)/magnesium hydroxide (10 wt.%) composite, a notably strong outcome. Additionally, the composite exhibited an elevated limited oxygen index (LOI) of 29.4%, indicating a synergistic effect between zinc borate and magnesium hydroxide. The proposed flame retardancy mechanism suggests that the flammability performance is driven by the interaction between the flame retardants within the polypropylene/calcium carbonate matrix. Magnesium hydroxide contributes to smoke suppression by releasing water, while zinc borate forms a protective glassy foam that covers the burning surface, promoting char formation and acting as a physical barrier to heat transmission and fire spread. Scanning electron microscopy confirmed good dispersion of the additives alongside calcium carbonate within the polymer matrix. Despite the addition of up to 10 wt.% flame retardants, the composites maintained high-notched impact strength.
AbstractThis article reports recent advances in thermally induced phase separation technology in fabricating microporous scaffold polymeric membranes as devices suitable for the controlled release of insect repellent. The key aspects, such as the crystallization behavior and morphological study of the polymeric membrane‐based repellent, were reported and discussed. Studies demonstrated that trapping of such repellents into microporous polymeric materials can be achieved by spinodal decomposition of the polymer/liquid repellent system. Usually, solubility is enhanced at elevated temperatures. Rapid cooling of such solution below the UCST leads to the formation of cocontinuous phase structures by decomposition. The polymer then forms an open‐cell structure with the repellent trapped inside. Approaches to forming such an open‐cell polymer structure containing mosquito repellent were successfully performed and confirmed with the SEM and POM techniques. It showed the structure of a polymer and liquid repellent prepared by spinodal decomposition, providing proof that thermally induced spinodal decomposition is a route to trap liquid mosquito repellent into a microporous polymer matrix. Additionally, the effects of polymer type, repellent nature, cooling conditions, and fillers on the morphology and performance of TIPS membranes are also discussed. Finally, challenges in developing microporous polymeric membrane‐based repellent using TIPS technology are addressed.
For the past decade, the high entropy concept has become a major research interest for both industries and academia, attributed to the high entropy mixing effect, which allows any material composition to attain structures with unique and attractive properties as opposed to conventional materials. Bionanocomposites as high entropy alloys are biomaterials comprising at least five or more biopolymers as the matrix and inorganic solids as the reinforcement in the nanoscale. These materials are potential alternatives to replace nondegradable waste plastic, which are currently of environmental concern due to their toxic nature and unhealthy method of disposal. The bionanocomposites can be applied in cosmetics, food packaging, electronics, textile, bone and tissue engineering, automobile, and water purification industries. Therefore, this study discusses the recent advances in research on the high entropy concept as composites, nanocomposites and bionanocomposites and their relative applications as potential replacements to waste plastics alongside the prospects and general outlook of high entropy alloys.
In this study, the photocatalytic activity of nanomaterials Ag/AgX (X = Cl, Br, I) is reported. Highly efficient silver halide (Ag/AgX where X = Cl, Br, I) photocatalysts were synthesized through a hydrothermal method. The samples were characterized using a range of techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) to check their structural, morphology, textural and optical properties. In addition, the photocatalytic activity of photocatalysts was evaluated through the degradation of 2,4-dichlorophenol (2,4-DCP) under UV and visible light irradiation. XRD analysis confirmed the presence of a single-phase structure (pure phase) in the synthesized photocatalysts. SEM micrographs showed agglomeration with a non-uniform distribution of particles, which is a characteristic of surfactant-free precipitation reactions in aqueous media. The Ag/AgBr photocatalyst exhibited the best degradation efficiency, resulting in 83.37% and 89.39% photodegradation after 5 h of UV and visible light irradiation, respectively. The effect of catalyst loading, initial solution pH, and 2,4-DCP concentration was investigated for the best-performing Ag/AgBr photocatalyst. The degradation kinetics were best described by the pseudo-first-order Langmuir–Hinshelwood model. The photocatalytic capacity of Ag/AgBr decreased by 50% after five reuse cycles. SEM images revealed heightened levels of photodegradation on the catalyst surface. The study proved the feasibility of using simple synthesis methods to produce visible light active photocatalysts capable of degrading refractory phenolic pollutants in aqueous systems.
Society confronts the pressing environmental challenges posed by the pervasive presence of toxic pollutants in aquatic ecosystems. The repercussions of contaminant release extend far and wide, endangering marine life and human well-being. While various techniques such as bioremediation, filtration, and adsorption have been employed for wastewater treatment, they grapple with cost effectiveness and overall efficiency issues. Advanced oxidative processes, including photocatalysis and Fenton, have emerged as viable solutions in response to the emerging contaminants. However, the efficacy of photocatalysis largely hinges on the choice of catalyst. Their distinctive attributes, such as chemical defects and exceptional stability, make perovskite oxides a promising catalyst. These materials can be synthesized through diverse methods, rendering them versatile and adaptable for widespread applications. Ongoing research endeavors are diligently focused on enhancing the performance of perovskite oxides, optimizing their integration into catalytic processes, and exploring innovative approaches for material immobilization. This comprehensive review seeks to elucidate the most pivotal advances in perovskite oxides and their composites within the wastewater treatment domain. Additionally, it sheds light on burgeoning research trends and multifaceted challenges confronting this field, which present insights into techniques for treating the antibiotic-contaminated environment, delving into innovative strategies, green technologies, challenges, and emerging trends.
The increase in the world population and the intensification of agricultural practices have resulted in the release of several contaminants into the environment, especially pesticides and heavy metals. This article reviews recent advances in using adsorbent and catalytic materials for environmental decontamination. Different materials, including clays, carbonaceous, metallic, polymeric, and hybrid materials, are evaluated for their effectiveness in pollutant removal. Adsorption is an effective technique due to its low cost, operational simplicity, and possibility of adsorbent regeneration. Catalytic processes, especially those using metallic nanoparticles, offer high efficiency in degrading complex pesticides. Combining these technologies can enhance the efficiency of remediation processes, promoting a more sustainable and practical approach to mitigate the impacts of pesticides and other agricultural pollutants on the environment. Therefore, this review article aims to present several types of materials used as adsorbents and catalysts for decontaminating ecosystems affected by agricultural pollutants. It discusses recent works in literature and future perspectives on using these materials in environmental remediation. Additionally, it explores the possibilities of using green chemistry principles in producing sustainable materials and using agro-industrial waste as precursors of new materials to remove contaminants from the environment.
The extensive use of non-biodegradable plastic products has resulted in significant environmental problems caused by their accumulation in landfills and their proliferation into water bodies. Biodegradable polymers offer a potential solution to mitigate these issues through the utilization of renewable resources which are abundantly available and biodegradable, making them environmentally friendly. However, biodegradable polymers face challenges such as relatively low mechanical strength and thermal resistance, relatively inferior gas barrier properties, low processability, and economic viability. To overcome these limitations, researchers are investigating the incorporation of nanofillers, specifically bentonite clay, into biodegradable polymeric matrices. Bentonite clay is an aluminum phyllosilicate with interesting properties such as a high cation exchange capacity, a large surface area, and environmental compatibility. However, achieving complete dispersion of nanoclays in polymeric matrices remains a challenge due to these materials’ hydrophilic and hydrophobic nature. Several methods are employed to prepare polymer–clay nanocomposites, including solution casting, melt extrusion, spraying, inkjet printing, and electrospinning. Biodegradable polymeric nanocomposites are versatile and promising in various industrial applications such as electromagnetic shielding, energy storage, electronics, and flexible electronics. Additionally, combining bentonite clay with other fillers such as graphene can significantly reduce production costs compared to the exclusive use of carbon nanotubes or metallic fillers in the matrix. This work reviews the development of bentonite clay-based composites with biodegradable polymers for multifunctional applications. The composition, structure, preparation methods, and characterization techniques of these nanocomposites are discussed, along with the challenges and future directions in this field.
This manuscript reports the investigation of the polymorphic behaviour of fipronil using a systematic comparison of the thermochemical and structural properties of different crystal forms obtained in this study as well as those previously reported in literature. The analytical techniques employed include DSC, TGA, PXRD, SCXRD and hot stage microscopy. DSC proved particularly useful because it made it possible to differentiate between the two different crystal forms found in the as-received neat fipronil. The DSC scans revealed the presence of two polymorphs which had melting endotherms with peak maxima at ca . 196 °C and 205 °C, respectively. These polymorphs were successfully separated via sublimation and resulted in a metastable, lower melting polymorph in the sublimate and a thermodynamically stable, higher melting form in the sublimation residue. Clear evidence for the instability of the lower melting polymorph was found when the endotherms were examined under a range of heating rates. The proportion of the metastable form appeared to increase as the rate was increased, indicating that the metastable form underwent a solid–solid phase transition to the stable form at low heating rates. Recrystallization of fipronil from different solvents yielded five different forms. TGA curves revealed that all forms, except the acetone-derived one, were solvate pseudo-polymorphs that showed solvent loss between 60 and 100 °C. The acetone-derived sample was a hemihydrate that only started to show mass loss at 120 °C. SCXRD studies revealed that three of the five forms have similar structural characteristics, while the other two forms differ notably from each other and the rest of the structures. Despite these structural differences, all five forms exhibit near-identical intra- and intermolecular hydrogen bond networks.
Magnetic (CoFe2O4)x/Ag2S-ZnO composites (where x = 0.25, 0.5, 0.75 and 1 wt% CoFe2O4) were successfully synthesised and investigated in the removal of methylene blue (MB) from aqueous medium under visible-light irradiation. X-ray diffraction (XRD) analysis confirmed the crystallinity of the as-synthesised materials and established the average crystal size of these materials to be <8.5 nm. Vibrating sample magnetometer (VSM) analysis confirmed that all cobalt ferrite doped nanocomposites exhibited ferrimagnetic behavior with saturation magnetization values varying from 6.55 to 40.52 emu/g being recorded. Near complete degradation (99 %) was attained when 1 gL-1 of (CoFe2O4)0.5/Ag2S-ZnO composite was added to a 10 ppm solution of methylene blue (MB) at neutral pH for 4 h of visible light irradiation. The catalyst showed good stability, removing 93.1 % of MB dye after five reuse cycles. The composite catalyst reported in this study is therefore a promising material for large-scale water and wastewater treatment processes.
Textile chemistry and textile processing laboratories are essential environments for textile product research and development, but they also pose hazards that require rigorous precautions. Among the most common risks is handling chemicals used in the textile industry, such as dyes, solvents, and finishing chemicals, which can be contaminants, corrosive, and flammable, presenting risks of poisoning and fire. Textile processing laboratories also require proper ventilation, as a lack of appropriate ventilation in these environments can accumulate toxic vapors in the air. The most relevant risks and hazards of using textile chemistry laboratories include using equipment such as dyeing autoclaves under pressure and high temperature; drying ovens like furnaces/lab stenters; cylinders of squeezing, calenders, and others, capable of causing severe accidents. These laboratories also generate or handle solid waste and effluents containing, heavy metals to pathogens (e.g., from industrial sludge). It is essential to adopt rigorous safety measures in textile chemistry laboratories, including using personal protective equipment (PPE), proper training of workers, effective ventilation systems, and safe waste disposal protocols. Good laboratory work practices not only reduce risk but also promote better research; more accurate results; and better data. Therefore, this study aimed to map the risks and hazards of textile processing laboratories with a view to accident prevention and formalizing a protocol for good practices.
Carvone and spearmint essential oil vapours are suitable candidates for the control of citrus postharvest pathogens due to their strong antifungal activity. However, the high volatility of essential oils remains a hurdle that needs to be overcome before it can be applied as an alternative fungicide. This work investigates the antifungal activity of 20 and 30 wt-% spearmint essential oil or carvone, incorporated into ethylene–vinyl acetate (EVA) and linear low-density polyethylene (LLDPE) strands postharvest pathogens affecting kumquats. Following the melt-extrusion process, an average yield of 16–29 % and 15–28 % of the total carvone and spearmint essential oil, respectively, was determined in the polymer strands. Morphological studies using scanning electron microscopy (SEM) revealed the presence of microporous structures in the internal structure of the strands. The membrane-like skin that covers the polymer strand was also confirmed by SEM. Variations in the release rates were observed between carvone and spearmint essential oils, which was attributed to the difference in the vapour pressure of the neat essential oils. Furthermore, in this study, the results demonstrated that the diffusion exponent ‘n’ of the Korsmeyer–Peppas, Weibull and Log-logistic models exceeded 1.0. In most cases, the Super Case II mechanism was observed. In the case of the Mapossa model, as k2 was ˃> 1, it implies that the outer skin-like membrane covering the polymer strand fully controlled the carvone release. The application of the essential oil-loaded polymer strands resulted in a significant reduction in deterioration, caused by citrus postharvest pathogens, of kumquats kept at room temperature for 21 days. This study indicates that the incorporation of spearmint essential oil or carvone into LLDPE or EVA polymer strands promoted the preservation of kumquat over a 21-day period.
Nowadays, the development of magnetic heterogeneous catalysts for biodiesel production is gaining increased attention from many researchers compared to homogeneous catalysts. This is because the magnetic nanoparticles (MNPs) are nanometric scale, and have a larger surface area, good stability and higher active sites added to the magnetic property, that constitute an appropriate and pertinent contribution to the chemical reactions of transesterification for biodiesel production. These heterogeneous catalysts due to their magnetic behaviour can be easily separated, regenerated and reused for a further cycle during the transesterification reaction. Therefore, the method of synthesis of MNPs plays a principal role in the physicochemical properties of the nanomagnetic catalyst obtained. This chapter includes an overview of the methods of synthesis of magnetic nanoparticles including sol–gel, co-precipitation, precipitation, hydrothermal and combustion, which are most commonly used methods. Additionally, we present the most used characterization methods to investigate the properties of MNPs, for example, X-ray diffraction, energy-dispersive X-ray diffraction, transmission electron microscopy and scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, vibrating sample magnetometry, zeta potential measurements and TPD-NH3 analysis. Moreover, applications of magnetic nanoparticles for transesterification reactions, the reactional parameters such as the amount of nanocatalyst, molar ratio oil/alcohol, reaction temperature and time that affect the transesterification reaction for biodiesel yield, and reusability of magnetic nanoparticles during transesterification reactions are also discussed.
This study aimed to develop cellulose-based polymer matrices as controlled release devices for plant-based insect repellents and attractants, with the aim of finding sustainable and environmentally friendly pest control methods for agricultural applications. Citronellol, terpineol and methyl salicylate were the selected active compounds for this study. Their compatibility with cellulose diacetate was predicted using Hansen Solubility Parameters, which predicted terpineol as the most compatible with cellulose diacetate, followed by methyl salicylate and citronellol. This was consistent with the plasticization efficiency trend from DMA results of solvent cast cellulose diacetate films containing the active compounds. The chemical identity of the films and cellulose diacetate-active compound intermolecular interactions were verified by FTIR. TGA demonstrated the thermal stability of cellulose diacetate/active compound/clay formulations at temperatures not exceeding 170 °C. Cellulose diacetate/organoclay nanocomposite matrices containing the active compounds at 35 wt-% were prepared by twin screw extrusion compounding, with the active compounds also functioning as plasticizers. The amount of active compound in the strands was determined by solvent extraction and TGA. Both methods showed that small amounts of active compound were lost during the compounding process. SEM demonstrated the effect of organoclay on the internal morphology of the matrix, whereas TEM showed clay dispersion and intercalation within the matrix. The matrix served as a reservoir for the active compounds while simultaneously controlling their release into the environment. Release profiles, obtained through oven ageing at 40 °C for 70 days, were fitted to existing Log-logistic and Weibull models, and novel Diffusion and Modified Weibull release models. Citronellol was released the fastest, followed by methyl salicylate and terpineol. The findings suggest that cellulose diacetate/organoclay strands are promising controlled-release matrices for pest control purposes.