Remediation Applications Research Articles

Solar-based technologies for removing potentially toxic metals from water sources: a review.

Technological advances have led to a proportional increase in the deposition of contaminants across various environmental compartments, including water sources. Heavy metals, also known as potentially toxic metals, are of particular concern due to their significant harmful impacts on environmental and human health. Among the available methods for mitigating the threat of these metals in water, solar radiation-based technologies stand out for their cleanliness, cost-effectiveness, and efficiency in removing or reducing the toxicity of heavy metals. The performance and productivity of these methods in removing heavy metals such as arsenic (As), chromium (Cr), mercury (Hg), and uranium (U) from water still need to be comprehensively synthesized. Thus, this work aims to address that gap. The performance, potential, and challenges of real-world applications of conventional solar stills (CSS), membrane-based solar stills, and solar heterogeneous photocatalysis are concisely summarized and critically reviewed. CSS and membrane-based stills are highly effective (efficacy > 98%) in removing and capturing heavy metals from water. However, structural and functional improvements are needed to enhance productivity (especially for CSS) and usability in real-world environmental remediation and drinking water supply scenarios. Solar heterogeneous photocatalysis is highly effective in removing and/or converting As, Cr, Hg, and U into their non-toxic or less toxic forms, which subsequent processes can easily remove. Further research is necessary to evaluate the safety of photocatalytic materials, their integration into scalable solar reactors, and their usability in real-world environmental remediation applications.

ZIF-8 metal-organic frameworks and their hybrid materials: emerging photocatalysts for energy and environmental applications.

In the face of escalating environmental challenges such as fossil fuel dependence and water pollution, innovative solutions are essential for sustainable development. In this regard, zeolitic imidazolate frameworks (ZIFs), specifically ZIF-8, act as promising photocatalysts for environmental remediation and renewable energy applications. ZIF-8, a subclass of metal-organic frameworks (MOFs), is renowned for its large specific surface area, high porosity, rapid electron transfer ability, abundant functionalities, ease of designing, controllable properties, and remarkable chemical and thermal stability. However, its application as a standalone photocatalyst is limited by issues such as particle aggregation, poor water stability, and insufficient visible light absorption. By integrating ZIF-8 with various photoactive materials to form composite catalysts, these drawbacks can be mitigated, leading to enhanced photocatalytic efficiency. The review discusses the synthesis, properties, and applications of ZIF-8-based photocatalysts in light-driven H2 evolution, H2O2 evolution, CO2 reduction, and dye and drug degradation. It also highlights the challenges and future research directions in developing cost-effective, scalable, and environmentally friendly ZIF-8 composites for industrial applications. The potential of ZIF-8 composites to contribute to sustainable global energy solutions and environmental cleanup is significant, yet further exploration is required to harness their capabilities thoroughly.

Chitosan/Polyvinyl Alcohol/g-C3N4 Nanocomposite Film: An Efficient Visible Light-Responsive Photocatalyst and Antimicrobial Agent

Biopolymer-based nanocomposite film is an efficient material for addressing the increasing levels of pollutants in the environment and also for the production of antimicrobial packing material due to its good film-forming properties, biodegradability, and minimal environmental impact. In particular, chitosan/polyvinyl alcohol/g-C3N4 (CS/PVA/g-C3N4) nanocomposite films with different weight percentages of PVA were prepared using simple methodologies and characterized using XRD, TGA, FT-IR, DSC, FE-SEM, EDX, and elemental mapping analysis. The XRD and FT-IR results validated the nanocomposite film formation. The FE-SEM images showed the smooth surface of the composite films without any wrinkles; the smoothness of the film increased with increases in the PVA loading, and the surface morphologies of the films were largely unchanged. The EDX and elemental mapping analysis validated the presence and uniform dispersion of g-C3N4 within the nanocomposite film. The photocatalytic activity of the CS/PVA/g-C3N4 composite films was assessed by the degradation of rhodamine B dye (RhB) and acetophenone under direct sunlight irradiation. The CS/PVA/g-C3N4 nanocomposite films exhibited superior degradation efficiency toward the RhB dye and acetophenone compared to the bare polymeric film and the g-C3N4 material. The order of degradation for the RhB dye and acetophenone was CS/PVA (1.0) g-C3N4 (95.34%, 33.33%) > CS/PVA (1.5) g-C3N4 (93.18%, 31.31%) > CS/PVA (0.5) g-C3N4 (93.02%, 29.29%) > CS/PVA (90.69%, 26.26%) > g-C3N4 (87.56%, 24%), respectively. Furthermore, the antimicrobial activity of the nanocomposite films was tested against E. coli, Pseudomonas sps., Klesiella sps., and Enterococcus sps., and the CS/PVA (1.5)/g-C3N4 nanocomposite film offered better antimicrobial properties than the other composite films and bare materials. In conclusion, these biopolymer-based nanocomposites are highly efficient and provide a promising path for the development of various biodegradable polymeric nanocomposites for environmental remediation and antibacterial packing applications.

Preparation, characterization of <i>Telfairia occidentalis</i> stem extract-silver nanocomposite and application in remediation of lead (ⅱ) ions from oilfield produced water

Every production day in Nigeria, and in other oil producing countries, millions of barrels of produced water is generated. Being very toxic, remediation of the produced water before discharge into environment or re-use is very essential. An eco-friendly and cost effective approach is hereby reported for remediative pre-treatment of produced water (PW) obtained from Nigerian oilfield. In this approach, Telfairia occidentalis stem extract-silver nanoparticles (TOSE-AgNPs) were synthesized, characterized and applied as bio-based adsorbent for treating the PW in situ. The nanoparticles were of average size 42.8 nm ± 5.3 nm, spherical to round shaped and mainly composed of nitrogen and oxygen as major atoms on the surface. Owing to the effect of addition of TOSE-AgNPs, the initially high levels (mg/L) of Total Dissolved Solids (TDS), Biological Oxygen Demand (BOD) and TSS of 607, 3.78 and 48.4 in the PW were reduced to 381, 1.22 and 19.6, respectively, whereas DO and COD improved from 161 and 48.4 to 276 and 19.6 respectively, most of which fell within WHO and US-EPA safe limits. Particularly, the added TOSE-AgNPs efficiently removed Pb (II) ions from the PW at temperatures between 25 ℃ to 50 ℃. Removal of TOSE-AgNPs occurred through the adsorption mechanism and was dependent contact time, temperature and dose of TOSE-AgNPs added. Optimal remediation was achieved with 0.5 g/L TOSE-AgNPs at 30 ℃ after 5 h contact time. Adsorption of Pb (Ⅱ) ions on TOSE-AgNPs was spontaneous and physical in nature with remediation efficiency of over 82% of the Pb (Ⅱ) ions in solution. Instead of discarding the stem of Telfairia occidentalis, it can be extracted and prepared into a new material and applied in the oilfield as reported here for the first time.

Environmental applications of metal-organic framework-based three-dimensional macrostructures: a review.

Metal-organic frameworks (MOFs) hold considerable promise for environmental remediation owing to their exceptional performance and distinctive structure. Nonetheless, the practical implementation of MOFs encounters persistent technical hurdles, notably susceptibility to loss, challenging recovery, and potential environmental toxicity arising from the fragility, insolubility, and poor processability of MOFs. MOF-based three-dimensional macrostructures (3DMs) inherit the advantageous attributes of the original MOFs, such as ultra-high specific surface area, tunable pore size, and customizable structure, while also incorporating the intriguing characteristics of bulk materials, including hierarchical structure, facile manipulation, and structural flexibility. Consequently, they exhibit rapid mass transfer and exceptional practicality, offering extensive potential applications in environmental remediation. This review presents a comprehensive overview of recent advancements in utilizing MOF-based 3DMs for environmental remediation, encompassing their fascinating characteristics, preparation strategies, and characterization methods, and highlighting their exceptional performance in pollutant adsorption, catalysis, and detection. Furthermore, existing challenges and prospects are presented to advance the utilization of MOF-based materials across various domains, particularly in environmental remediation.

Synthesis, structural characterization, and optical properties of two Co(II)-based coordination compounds

Two new Co(II)-based coordination compounds, [Co(Hmctrz)2(H2O)2] (1) and [Co(Hdctrz)(H2O)2]n (2), were synthesized via routine or hydrothermal reactions using cobalt salts, triazole derivatives, and auxiliary reagents. Characterizations, including single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, TGA, and PXRD, confirmed their formation. UV-Vis and fluorescence studies revealed distinct optical properties, with 1 and 2 exhibiting UV absorption peaks at 353 and 370 nm, respectively, and concentration-dependent fluorescence emission, indicating potential for optoelectronic and biological imaging applications. Additionally, adsorption studies showed excellent dye removal capabilities, with 1 achieving 98% removal of methylene blue (MB) and 93% of methyl orange (MO), outperforming 2, which removed 95% of MB and 87% of MO. These results highlight the compounds’ potential in both environmental remediation and advanced material applications.

Two Transition Metal Coordination Polymers: Potential Adsorbents for Contaminant Removal and Photoluminescent Properties.

Methylene blue (MB) contamination has become a significant environmental issue due to its widespread presence in industrial effluents, posing serious threats to ecosystems and human health. As a result, there is an urgent need for the development of novel adsorbent materials that can effectively remove these pollutants from water sources. In this context, the present study focuses on the design and synthesis of two coordination polymers (CPs) containing Zn(II) and Mn(II), namely, {[Mn3(L)2(tib)2]·4H2O}n (1) and [Zn(L)(3,5-bibp)]n (2), using a combined-ligand approach under solvothermal conditions. The ligands, H3L is 4-(3,5-dicarboxylatobenzyloxy)benzoic acid), 1,3,5-tris(1-imidazolyl)benzene and 3,5-bibp is 3,5-bis(imidazol-1-yl)biphenyl), were carefully selected to enhance the properties of the resulting polymers. These CPs were thoroughly characterized using a variety of techniques, including IR spectroscopy, elemental analysis (EA), single-crystal X-ray diffraction, thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD). Both CPs demonstrated ligand-dependent blue fluorescence emissions, suggesting their potential for use as photoluminescent materials in various applications. Furthermore, the adsorption capabilities of CP1 and CP2 for methylene blue (MB) were evaluated. The results revealed that both CPs exhibited excellent adsorption efficiencies, with CP1 achieving a 77.6% adsorption efficiency within 1h and completely removing 20mg/L of MB within 6h. These findings highlight the significant potential of CP1 as a highly effective adsorbent for organic dyes, particularly for environmental remediation applications. The ability of these coordination polymers to adsorb MB efficiently underscores the urgent need for the development of innovative and efficient materials to address the growing challenges of water pollution.

A tunable hybrid of Laponite and zein produces versatile adsorbent and mechanically robust porous polymeric membranes for water remediation

A multifunctional porous polymeric membrane was developed by incorporating tunable nanofillers, hybrids of anionic Laponite (L) and zwitterionic zein (Z), into thermoplastic polyurethane (TPU). By varying the weight fractions of L and Z, the hybrid fillers achieved a wide range of ζ-potentials, enabling the membrane properties to be tailored. The membranes were characterized by scanning electron microscopy (SEM), small-angle X-ray scattering (SAXS), X-ray diffraction (XRD), contact angle and pure water flux (PWF) measurements, mechanical properties and dynamic mechanical analysis (DMA). The membranes with higher L content exhibited increased pore size, porosity, hydrophilicity and PWF, with a 12 wt% L-filled membrane showing a remarkable 17-fold increase in PWF compared to pristine TPU. Conversely, membranes with higher Z content displayed enhanced mechanical properties, including up to 7-fold higher tensile strength and 18-fold higher modulus for 12 wt% Z-filled membranes. The membranes demonstrated versatile adsorption capabilities, efficiently capturing both cationic and anionic dyes, influenced by the L/Z ratio and solution pH. Additionally, the adsorption of heavy metal ions followed the trend: Hg2+ > Cd2+ > Cu2+, increasing with L content. Excellent antifouling performance and regeneration ability, maintained over ∼8 cycles, further highlighted the membranes’ potential for water remediation applications. These findings underscore the promise of L-Z/TPU membranes as highly efficient and customizable adsorbents for environmental purification.

Removal of tetracycline using an ultrastable Pt-decorated-BNCB photocatalyst under efficient solar-driven conditions

The pursuit of optimizing the photocatalytic performance of the novel perovskite-like Bi4NbO8X materials remains a vibrant area of research. In this paper, we report the successful synthesis of the Bi4Nb4O8Cl0.935Br0.065 (BNCB) composite photocatalyst, loaded with Pt nanoparticles, utilizing a combination of solid-state reaction and sodium borohydride reduction methods. Notably, the surface plasmon resonance (SPR) effect exhibited by Pt broadened the spectral response range, while the Schottky junction formed at the Pt/BNCB interface significantly accelerated the separation of photogenerated electron-hole pairs and facilitated the swift migration of photogenerated electrons towards Pt. Experimental outcomes underscore the superior photocatalytic degradation efficacy of the Pt/BNCB composite towards tetracycline (TC), achieving a degradation rate of up to 67%, significantly outperforming pure BNCB. Pt/BNCB exhibits excellent photocatalytic degradation and excellent stability in various pH and ionic environments. Collectively, this work presents a novel approach for designing highly efficient and stable perovskite-type photocatalytic materials, holding immense potential for applications in environmental remediation.

Recent updates on TiO2-based materials for various photocatalytic applications in environmental remediation and energy production

Recent updates on TiO2-based materials for various photocatalytic applications in environmental remediation and energy production

Trends on barrier characteristics improvement of emerging biopolymeric composite films using nanoparticles - A review

BackgroundBio-based films have wide applications in various areas, including medical, packaging, biosensor design, and environmental remediation. Unfortunately, their associated features restricted the application windows for these bio-based films. Barrier properties, such as H2O permeability, O2 permeability, and UV-barrier properties, are among the typical qualities important in designing packaging films because they safeguard food safety and extend shelf life. MethodsEnhancing the barrier qualities has been imperative in recent years owing to its significant impact on food preservation and the valorization of natural biopolymers. The most innovative method is adding metal and metal oxide nanoparticles to the biopolymer with carefully regulated loads and parameters. This review aims to examine the barrier performance as well as their enhancement methods using metal, metal-oxide, and the synergetic effects of nanoparticles. Significant findingsThe review concludes that incorporating metallic and metallic oxide NPs into films has improved their barrier quality. The current and future materials in the property improvement field include metallic and metallic oxide nanoparticles, such as Ag, ZnO, GO, and TiO2, as well as their binary effects. Improvements to the barrier characteristics of bio-based films address the environmental and socioeconomic problems brought on by using petro-based films.

Integrative multi-omic analyses reveal the molecular mechanisms of silicon nanoparticles in enhancing hyperaccumulator under Pb stress.

Lead (Pb), one of the most ubiquitous and harmful contaminants of farmland, seriously threatens soil health and food security. Silicon nanoparticles (SiNPs) have potential applications in soil remediation and phytoremediation. Yet, how SiNPs influence plant growth under Pb stress remains poorly understood. In this study, the candidate Pb-hyperaccumulator Lolium multiflorum was selected to investigate the toxicity of Pb and the mitigation of Pb stress by SiNPs. The application of SiNPs was able to enhance Pb enrichment and maintain proper photosynthesis and root growth of L. multiflorum. Transcriptomic and metabolomic analyses indicated that Pb exposure interfered with nitrogen metabolism and alanine, aspartate and glutamate metabolism pathways in roots, which changed the root exudate composition. Besides, SiNPs altered both the accumulation of metabolites and correlated gene expression in roots, further affecting root exudates and stimulating the defense system, consequently increasing Pb tolerance. Our findings both demonstrated that co-application of L. multiflorum with SiNPs has potential for phytoremediation of Pb-polluted soil and revealed the contributions of SiNP amendment to mitigating Pb toxicity, and provided a new strategy for phytoremediation of farmland ecosystems.

Enhancing NiS performance: Na-doping for advanced photocatalytic and electrocatalytic applications.

Alkali metal doping is a new and promising approach to enhance the photo/electrocatalytic activity of NiS-based catalyst systems. This work investigates the impact of sodium on the structural, electronic, and catalytic properties of NiS. Comprehensive characterization techniques demonstrate that Na-doping causes significant changes in the NiS lattice and surface chemistry translating into a larger bandgap than NiS. Photocatalytic experiments demonstrate 98.5% degradation of 2,4-DCP under visible light, attributing it to improved light absorption and charge separation by Na-NiS nanoparticles. The effect of pH and pKa on the degradation of 2,4-DCP has also been studied and reported. Additionally, electrochemical measurements of Na-NiS indicate overpotentials of 336 mV towards hydrogen evolution reaction (HER) and 350 mV towards oxygen evolution reaction (OER). The material's overall water splitting is found to be 2.61 V at a current density of 10 mA cm-2. The results highlight the potential of Na-NiS as a versatile catalyst for environmental remediation and clean energy applications, paving the way for further exploration and optimization of doped transition metal sulfides.

Template Free Direct Approach to Crystalline Mesoporous ZnO/Bi2O3 Mixed Oxide Nanosheets with Enhanced Photo reactivity

Template Free Direct Approach to Crystalline Mesoporous ZnO/Bi₂O₃ Mixed Oxide Nanosheets with Enhanced Photo reactivity

Emerging contaminants in polluted waters: Harnessing Biochar's potential for effective treatment.

Biochar is a carbon-rich, sponge-like material with intricate functionalities, making it suitable for various environmental remediation applications, including water treatment, soil amendment and, additives in construction materials, anaerobic digesters, and electrodes, among others. Its easy adaptability and low cost make it particularly attractive. This review highlights a range of biochar and surface-modified biochar exhibiting high uptake and degradation efficiencies for a broad spectrum of contaminants, including humic acid, disinfection by-products (DBPs), radioactive materials, dyes, heavy metals, antibiotics, microplastics, pathogens, Per- and polyfluoroalkyl substances (PFAS), and cytotoxins. The study provides a detailed discussion on different classes of pollutants and their removal mechanisms using biochar, covering processes like physical and chemical adsorption, electrostatic interactions, π-π interactions, hydrogen bonding, as well as surface complexation, chelation, among others. This review article stands out for its comprehensive exploration of biochar's effectiveness in removing a wide range of emerging contaminants, as well as recent advancements in the removal of conventional pollutants like heavy metals and antibiotics.

Environmental Microbiology: Microbes and Their Roles in Ecosystems

Environmental microbiology is a critical field that explores the intricate relationships between microorganisms and their environments. This study investigates the roles of microorganisms in various environmental contexts, focusing on their diversity, abundance, and ecological functions. Samples were collected from agricultural soils, freshwater bodies, industrial wastewater, and urban air, and analyzed using culture-based and molecular techniques. The results revealed significant variations in microbial abundance and diversity across the sampled environments. Agricultural soils exhibited the highest microbial abundance and diversity, with nitrogen-fixing bacteria playing a crucial role in nutrient cycling. In contrast, freshwater bodies showed moderate diversity, while industrial wastewater had the highest abundance but lower diversity, with a high prevalence of hydrocarbon-degrading microorganisms. Urban air samples had the lowest abundance but relatively high diversity. The biochemical capabilities of the isolates further emphasized the ecological roles of these microorganisms, particularly in bioremediation and soil fertility. The findings underscore the importance of preserving microbial diversity for maintaining ecosystem health and resilience. This research highlights the need for integrating microbiological insights into environmental management policies and suggests future research directions to explore microbial interactions and their potential applications in biotechnology and environmental remediation.

Enhanced degradation of Ciprofloxacin (CIP) antibiotic and methylene blue (MB) dye using ZnO/GO nanocomposites under solar irradiation

Modifying ZnO nanorods with graphene oxide (GO) is crucial for enhancing photocatalytic degradation by boosting the concentration of reactive oxygen species (ROS) in the reaction medium. In this study, we present a straightforward chemical synthesis of ZnO nanorods embedded on GO, forming a novel nanocomposite, GOZ. This composite serves as an efficient photocatalyst for the sunlight-driven degradation of methylene blue (MB) and ciprofloxacin (CIP). Rietveld refined X-ray diffraction (RXRD), Fourier-transform infrared (FTIR), and transmission electron microscopy (TEM) confirmed the formation of ZnO nanorods and GOZ nanocomposite. The possible defect states and oxygen vacancies were confirmed using the emission spectra that played a significant role in the photocatalytic activity. The values of the optical bandgap for GOZ-7 (7% GO) and GOZ-10 (10% GO) were found to be 2.8 eV and 2.7 eV using Tauc plot, respectively, showing a red shift as a result of increasing the concentration of GO. The photocatalytic efficiency of GOZ-7, GOZ-10 were evaluated under direct sunlight for degradation of MB dye and CIP antibiotic in an aqueous solution. The highest photocatalytic activity was observed by GOZ-10. The scavenging study confirmed that the photocatalysis occurred due to the generation of reactive oxygen species (ROS), especially by hydroxyl radical (OH.). The cost-effective GOZ-10 nanocomposite emerges as a promising candidate for the rapid photocatalytic degradation of both cationic dyes and antibiotics, demonstrating its potential in environmental remediation applications.

Effective Remedies for Breach of Commercial Contracts - An Empirical Study of the Vietnamese Courts’ Decisions

Remedies for breach of commercial contracts play an important role. However, the current literature has not focused comprehensively on the application of all remedies provided in the Vietnamese Commercial Law 2005 in the adjudication process of the Vietnamese courts. This study attempts to fill the gap. The authors collect and analyse all the first instance decisions of the provincial-level People's Courts in the country from the beginning of 2019 to the end of 2023. The results show that only half of the remedies stipulated in the law are usually awarded by the courts; and the simultaneous imposition of remedies is common. In addition, some of the shortcomings in the reasoning and application of remedies are also analyzed in detail, as a premise for future studies.

Green-mediated sol-gel fabrication of CuO/ZnO nanoparticles from orange peel extract for environmental remediation: insights from x-ray diffraction analysis using various models

Abstract This study introduces an eco-friendly and simple approach for synthesizing zinc oxide (ZnO), copper oxide (CuO), and ZnO-CuO composite nanoparticles using orange peel extract, minimizing the use of harmful chemicals while enhancing their antibacterial and photocatalytic properties. The nanoparticles were annealed at 400 °C for 2 h in the air. Characterization was conducted using x-ray Diffraction (XRD), Dynamic Light Scattering, Fourier Transform Infrared Spectroscopy (FTIR), and UV-visible Spectroscopy. XRD revealed that ZnO and CuO nanoparticles crystallized in hexagonal wurtzite and monoclinic structures, respectively, with crystallite size and lattice strain analyzed through Williamson–Hall, Size-Strain Plot, Halder-Wagner, and Wagner-Aqua methods. FTIR spectra confirmed the presence of Zn-O and CuO bonds, verifying successful synthesis. The optical bandgaps measured were 3.07 eV for ZnO, 2.702 eV for CuO, and 1.842 eV for the ZnO-CuO nanocomposite. Antimicrobial efficacy, assessed via the disc diffusion method, showed the ZnO-CuO composite exhibited enhanced antibacterial activity against both gram-positive and gram-negative strains compared to individual ZnO and CuO. Photocatalytic experiments demonstrated that under sunlight, the ZnO-CuO nanocomposite achieved 78% degradation of 10 ppm methylene blue within 90 min, outperforming individual ZnO (55%) and CuO (38%). These results highlight the ZnO-CuO composite’s potential for effective dye degradation and environmental remediation applications.

Seed regeneration aided by nanomaterials in a climate change scenario: A comprehensive review

Abstract Nanotechnology has demonstrated its potential for advancing sustainable agriculture. This article explores new advancements in nanotechnology in agriculture, including plant extraction and validation, by emphasizing nano-fertilizers, nano-pesticides, nano-biosensors, and nanoenergy recycling processes. Nanomaterials are important for the formation, transport, and degradation of soil toxins and are a fundamental starting point for various biotic and abiotic rehabilitation processes. Research on nanoparticles’ remediation applications and soil stay insufficient and are generally restricted. When integrated into agricultural systems, nanomaterials may influence the soil quality and plant development examined by setting their impacts on supplement discharge in target soils, soil biota, soil natural matter, and plant morphological and physiological reactions. The current research works show that the seed coat acts as a barrier to nanomaterial penetration, in which both the seed coat and cell wall allowed easy water passage. Additionally, the uptake, movement, and associated defense mechanisms of nanomaterials within plants have been investigated. Future research directions have been identified to further the study toward the sustainable development of nano-enabled agriculture.