Eco-Friendly Polymer Nanocomposite Coatings for Next-Generation Fire Retardants for Building Materials.

The increasing global commitment to carbon neutrality has propelled a heightened focus on sustainable construction materials, with wood emerging as pivotal due to its environmental benefits. This review explores the development and application of eco-friendly polymer nanocomposite coatings to enhance wood's fire resistance, addressing a critical limitation in its widespread adoption. These nanocomposites demonstrate improved thermal stability and char formation properties by integrating nanoparticles, such as nano-clays, graphene oxide, and metal oxides, into biopolymer matrices. This significantly mitigates the flammability of wood substrates, creating a robust barrier against heat and oxygen. The review provides a comprehensive examination of these advanced coatings' synthesis, characterization, and performance. By emphasizing recent innovations and outlining future research directions, this review underscores the potential of eco-friendly polymer nanocomposite coatings as next-generation fire retardants. This advancement supports the expanded utilization of wood in sustainable construction practices and aligns with global initiatives toward achieving carbon neutrality.

Unveiling enhanced sound absorption in coconut wood through hemicellulose and lignin modification.

Coconut wood (Cocos nucifera L.) is lightweight and has variable quality, making it a potential candidate for manufacturing sound absorption boards. However, its sound absorption coefficient needs enhancement to optimize its effectiveness in this application. This study aims to enhance its sound absorption properties using eco-friendly hydrogen peroxide and acetic acid treatments. This treatment modified the carbohydrate polymers (hemicellulose and cellulose) and lignin structures in the wood cell wall. The novelty of this approach lies in using these chemicals to improve acoustic performance significantly. Coconut wood samples were treated with a 1:1 acetic acid and hydrogen peroxide mixture for 20, 40, 60, and 80 min. Characterization techniques such as FTIR, XPS, and XRD, and 3D optical profilometry analyzed changes in chemical functionalities, crystallinity, and surface roughness. Sound absorption coefficients were measured using the impedance tube method. Results showed a significant improvement in sound absorption for all treated samples, especially at 60 min. The treatment also enhanced surface roughness, air permeability, porosity, and pore sizes, contributing to better sound absorption. This proposed treatment method addresses environmental consciousness and enhances the sustainable use and utilization of coconut wood.

Toxicity of Metal Oxides, Dyes, and Dissolved Organic Matter in Water: Implications for the Environment and Human Health.

This study delves into the critical issue of water pollution caused by the presence of metal oxides, synthetic dyes, and dissolved organic matter, shedding light on their potential ramifications for both the environment and human health. Metal oxides, ubiquitous in industrial processes and consumer products, are known to leach into water bodies, posing a significant threat to aquatic ecosystems. Additionally, synthetic dyes, extensively used in various industries, can persist in water systems and exhibit complex chemical behavior. This review provides a comprehensive examination of the toxicity associated with metal oxides, synthetic dyes, and dissolved organic matter in water systems. We delve into the sources and environmental fate of these contaminants, highlighting their prevalence in natural water bodies and wastewater effluents. The study highlights the multifaceted impacts of them on human health and aquatic ecosystems, encompassing effects on microbial communities, aquatic flora and fauna, and the overall ecological balance. The novelty of this review lies in its unique presentation, focusing on the toxicity of metal oxides, dyes, and dissolved organic matter. This approach aims to facilitate the accessibility of results for readers, providing a streamlined and clear understanding of the reported findings.

Next-Generation Water Treatment: Exploring the Potential of Biopolymer-Based Nanocomposites in Adsorption and Membrane Filtration.

This review article focuses on the potential of biopolymer-based nanocomposites incorporating nanoparticles, graphene oxide (GO), carbon nanotubes (CNTs), and nanoclays in adsorption and membrane filtration processes for water treatment. The aim is to explore the effectiveness of these innovative materials in addressing water scarcity and contamination issues. The review highlights the exceptional adsorption capacities and improved membrane performance offered by chitosan, GO, and CNTs, which make them effective in removing heavy metals, organic pollutants, and emerging contaminants from water. It also emphasizes the high surface area and ion exchange capacity of nanoclays, enabling the removal of heavy metals, organic contaminants, and dyes. Integrating magnetic (Fe2O4) adsorbents and membrane filtration technologies is highlighted to enhance adsorption and separation efficiency. The limitations and challenges associated are also discussed. The review concludes by emphasizing the importance of collaboration with industry stakeholders in advancing biopolymer-based nanocomposites for sustainable and comprehensive water treatment solutions.

Synthesis of starch-based smart hydrogel derived from rice-cooked wastewater for agricultural use.

The synthesis of biodegradable hydrogel based on naturally available macromolecules is an important area of research. We synthesized new hydrogel using rice-cooked wastewater (starch), acrylamide, and 2-acrylamido-2-methylpropansulfonic acid in an aqueous medium. The synthesis approach is facile, low-cost, eco-friendly, and novel. The synthesized materials were characterized by scanning electron microscope, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and Thermogravimetric analysis. The hydrogel exhibited maximum tap water absorbency (158.3 g/g) at pH 7, saline water absorbency (50 g/g), urea solution absorbency (141.2 g/g) at 24 h, and excellent water retention capability (47 wt% at 70 °C, 12 h, and 89 wt% at 30 °C, 24 h). Chili plants, mung beans, and pea seeds germinated and grew well in the hydrogel and hydrogel-mixed soil, respectively. The biodegradability study shows 34.6 % at 120 days in soil and 6.5 % at 30 days in the open air. These findings could entice agricultural development in dry soil.

Ammonium persulfate treatment on carbohydrate polymers and lignin of wood improved sound absorption capacity.

The rational design of sound absorption boards made of wood materials is an exciting area of research. This article describes a simple and inexpensive method to increase the sound absorptions capacity of Malas hardwood (Homalium foetidum Roxb.) using ammonium persulfate treatment. The reaction parameters such as the concentration of ammonium persulfate and reaction time were optimized. The results of X-ray photoelectron spectroscopy, X-ray diffraction, attenuated total reflectance-Fourier transforms infrared spectroscopy, and scanning electron microscopy demonstrated that ammonium persulfate could significantly affect carbohydrate polymers and lignin of wood by improving oxygen functionalities. The quantitative analysis of carbohydrate polymers (hemicellulose and cellulose) and lignin were evaluated. These changes in carbohydrate polymers and lignin enhanced the air permeability (83.6%) and average sound absorption coefficient at each frequency range 500-1000 Hz (2.6%), 1000-2000 Hz (4.9%), 2000-4000 Hz (17.4%), and overall 500-6400 Hz (20.8%) compared to the control samples. These results could be beneficial for new research and wood-based sound absorption materials to regulate the acoustic environment in houses.

Molecular Crowded ″Water-in-Salt″ Polymer Gel Electrolyte for an Ultra-stable Zn-Ion Battery.

Recently, the use of a gel polymer electrolyte for the development of robust, flexible, quasi-solid, ultra-stable, high-performance zinc-ion batteries (ZiBs) as an alternative to lithium-ion batteries has attracted widespread attention. However, the performance of ZiBs is limited due to the lack of suitable gel electrolytes. Herein, a ″water-in-salt″ (WiS)-based hydrophilic molecular crowded polymer gel electrolyte and binder free V2O5@MnO2 cathode are introduced to augment the durability, flexibility, safety, and electrochemical performance of ZiBs. The ″free water trapping″ capability of the WiS-based cross-linked molecular crowded polymer electrolyte provides an extended electrochemical stability window (ESW) of the device. The quasi-solid-state ZiB delivers ∼422 mAh g-1 discharge capacity and shows excellent cycling stability as high as ∼79.83% retention of the initial capacity after 5000 cycles. The durable, flexible, and ultra-stable ZiB with the polymer gel electrolyte performs well under various severe conditions where both the battery safety and energy density are of high priority. This work demonstrates a new approach and application for the development of durable, flexible, ultra-stable, quasi-solid-state ZiBs.

Oxidation treatment on wood cell walls affects gas permeability and sound absorption capacity.

This research aimed to study the efficacy of oxidation in wood cell walls by ammonium persulfate solution and the performances in sound absorption coefficients and gas permeability for cross sectional Oak wood (Quercus mongolica) species. Reaction parameters were optimized and extensive instrumental characterization techniques were used to study cell wall modifications, such as X-ray photoelectron spectroscopy, X-ray diffraction, attenuated total reflectance Fourier transforms infrared spectroscopy, and scanning electron microscope. The oxidation treatment changed the chemical compositions of wood (hemicellulose, cellulose, and lignin), boosting wood porosity (12%) and gas permeability (39%). The effectiveness accelerates improvement of average sound absorption coefficient at each frequency range: 250-500 Hz (4.6%), 500-1000 Hz (26.8%), 1000-2000 Hz (31.8%), 2000-6400 Hz (57.8%) and overall 250-6400 Hz (47.1%) compared to the control samples. Simple wood oxidation treatment could be helpful for novel research and wood based sound absorption materials to manage the acoustic housing environment.

Recent Advances in Colorimetric Detection of Arsenic Using Metal-Based Nanoparticles.

Nowadays, arsenic (III) contamination of drinking water is a global issue. Laboratory and instrument-based techniques are typically used to detect arsenic in water, with an accuracy of 1 ppb. However, such detection methods require a laboratory-based environment, skilled labor, and additional costs for setup. As a result, several metal-based nanoparticles have been studied to prepare a cost-effective and straightforward detector for arsenic (III) ions. Among the developed strategies, colorimetric detection is one of the simplest methods to detect arsenic (III) in water. Several portable digital detection technologies make nanoparticle-based colorimetric detectors useful for on-site arsenic detection. The present review showcases several metal-based nanoparticles that can detect arsenic (III) colorimetrically at a concentration of ~0.12 ppb or lower in water. A literature survey suggests that biomolecule-based metal nanoparticles could serve as low-cost, facile, susceptible, and eco-friendly alternatives for detecting arsenic (III). This review also describes future directions, perspectives and challenges in developing this alternative technology, which will help us reach a new milestone in designing an effective arsenic detector for commercial use.

Selective adsorption of Pb (II) ions by amylopectin-g-poly (acrylamide-co-acrylic acid): A bio-degradable graft copolymer.

Amylopectin-g-poly (acrylamide-co-acrylic acid) [AP-g-poly (AM-co-AA)] was synthesised in water medium by using potassium perdisulphate as an initiator. The graft copolymer was characterized by molecular weight determination by size exclusion chromatography (SEC), fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscope (SEM) studies, thermal analysis, measurement of neutralisation equivalent and biodegradation studies. The graft copolymer was used for Pb (II) ion removal from aqueous solution. The Pb (II) ion removal capacity of the graft copolymer was also compared with another laboratory developed graft copolymer Amylopectin-g-poly (acrylamide) (AP-g-PAM). Both the graft copolymers were also used for the competitive metal ions removal with Pb (II)/Cd (II), Pb (II)/Zn (II), Pb (II)/Ni (II), Pb (II)/Cu (II) pairs separately under similar conditions. AP-g-poly (AM-co-AA) showed better Pb (II) ion adsorbing power over AP-g-PAM and also much selective towards Pb (II) ions. The adsorption follows a second order rate equation and Langmuir isotherm model.

Amylopectin-g-poly(methylacrylate-co-sodium acrylate): An efficient Cd(II) binder.

Synthesis, characterization and Cd(II) adsorption studies of a novel biodegradable graft copolymer based on partially hydrolysed polymethylacrylate (PMA) grafted amylopectin was reported, which was prepared by first grafting of PMA chains onto the amylopectin backbone followed by partial alkaline hydrolysis. The hydrolysed graft copolymer (PHAP) was characterized by measuring saponification equivalent (SE), FTIR, (1)H NMR and (13)C NMR spectroscopy and thermal analysis (TG/DTG). The graft copolymer was biodegradable. Various operating variables affecting the metal sorption such as, amount of adsorbent, solution pH, contact time, temperature and Cd(II) solution concentration were studied which showed that the maximum adsorption of Cd(II) was found at pH 5.5, temperature 90°C, time 120min, polymer dose, 0.02g/L and initial Cd(II) concentration, 50mg/L. The adsorption data were well described by the pseudo-second-order and Langmuir isotherm model. Metal complexation studies were carried out experimentally using UV-visible, FTIR spectroscopy and theoretically using Density Functional Theory by Gaussian 09 and Gauss view 5.0 programmes which confirms a square planer geometry involving Cd(II) and COO(-) groups. Calculation of the various thermodynamic parameters was also done. The negative value of free energy change indicates the spontaneous nature of the adsorption.

Starch based biodegradable graft copolymer for the preparation of silver nanoparticles.

The synthesis and characterization of a novel biodegradable graft copolymer based on partially hydrolyzed polymethylacrylate (PMA) grafted amylopectin (AP) was reported which was developed for the synthesis of silver nanoparticles from silver nitrate solution by facile green technique. The prepared graft copolymer was biodegradable which was shown by fungal growth. Characterization of silver nanoparticles was carried out by UV-VIS spectroscopy (417nm), HR-TEM, SAED and FESEM analysis. The TEM findings revealed that the silver nanoparticles are crystalline and globular shaped with average particle size ranging from 11 to 15nm. The synthesized silver nanoparticles exhibit excellent antibacterial sensitivity towards both Gram negative and Gram positive bacteria namely Vibrio parahaemolyticus (ATCC-17802) and Bacillus cereus (ATCC-14579) respectively and were also shown a good catalytic activity towards 4-nitrophenol reduction.

Starch-g-Poly-(N, N-dimethyl acrylamide-co-acrylic acid): an efficient Cr (VI) ion binder.

Synthesis of Starch-g-(Poly N, N-dimethylacrylamide-co-acrylic acid) was carried out by solution polymerization technique using potassium perdisulfate (K(2)S(2)O(8)) as the initiator. The graft copolymer was characterized by measuring molecular weight, using size exclusion chromatography (SEC), FTIR spectroscopy and X-ray diffraction (XRD) studies. The synthetic graft copolymer was used for removal of hexavalent chromium ion [Cr (VI)] from its aqueous solution. Various operating variables affecting the metal sorption such as, the amount of adsorbent, solution pH, contact time, temperature and the Cr (VI) solution concentration were extensively investigated. FTIR and UV-VIS spectroscopy, cyclic voltammetry (CV) were employed to study the metal complexation. The adsorption data could be well described by the pseudo-second-order and Langmuir isotherm model which indicate a chemisorption process. Calculation of the various thermodynamic parameters for the adsorption was also done. The negative value of free energy change (ΔG°) indicates the spontaneous nature of the adsorption.

Biodegradable flocculants based on polyacrylamide and poly(N,N-dimethylacrylamide) grafted amylopectin.

Synthesis of amylopectin grafted polyacrylamide (AP-g-PAM) and poly(N,N-dimethylacrylamide) (AP-g-PDMA) was carried out by Ce4+ in water medium. The reaction conditions for maximum grafting was optimized by varying the reaction variables, including the concentration of monomers, ceric ammonium nitrate (CAN), amylopectin, reaction time and temperature. The graft copolymers were characterized by FTIR spectroscopy, NMR (both 1H and 13C) spectroscopy, molecular weight determination and molecular weight distribution by using size exclusion chromatography (SEC), thermal analysis (TGA), SEM studies. Biodegradation of the graft copolymers was carried out by enzyme hydrolysis. Flocculation performances of the graft copolymers were evaluated in 1.0 wt% coal and 1.0 wt% silica suspensions. A comparative study of the flocculation performances of AP-g-PDMA and AP-g-PAM was also made. It shows that the flocculation performance of AP-g-PDMA was better than that of AP-g-PAM. AP-g-PDMA performed best when compared with other commercial flocculants in the same suspensions.

Preparation, investigation of metal ion removal and flocculation performances of grafted hydroxyethyl starch.

Ceric ion induced graft copolymerization of N,N-dimethyl acrylamide (DMA) and acryl amide (AM) were carried out onto the hydroxyethyl starch (HES). These grafted copolymers were used for the removal of metal ions from their aqueous solutions. Flocculation performances of the synthesized graft copolymers were evaluated in 1.0 wt% silica suspensions. A comparative study of the flocculation performances of the synthetic graft copolymers was also made. The different factors affecting metal ion absorption, namely pH, treatment time, temperature and polymer dose were studied. A comparative study of the metal ion removal capacity of the two synthetic graft copolymers was also made in five metal ions namely Ni(II), Zn(II), Cu(II), Pb(II) and Hg(II). The metal ion removal capacity follows the order Hg(II)>Cu(II)>Zn(II)>Ni(II)>Pb(II) in both the two synthetic polymers. Between the two graft copolymers, graft copolymer based on AM shows better performance than that based on DMA in all the metal solutions. But the flocculation performance of DMA based graft copolymer showed better performances than that AM based graft copolymer. The former also performed best when compared to the commercial flocculants in the same suspension.