Search Results (11)

Herein, we rationally designed a molecular catalytic filter for effective micropollutants decontamination via peroxymonosulfate (PMS) activation. Specifically, iron phthalocanine (FePc) molecules with defined Fe–N₄ coordination were immobilized onto carbon nanotubes (CNTs), forming a hybrid catalyst that integrated molecular precision with heterogeneous catalytic properties. The resulting CNT-FePc filter achieved a 98.4% removal efficiency for bisphenol A (10 ppm) in a single-pass operation system, significantly outperforming the CNT/PMS system without FePc (41.6%). Additionally, the CNT-FePc/PMS system demonstrated remarkable resistance to performance inhibition by common water matrix components. Unlike typical radical-dominated PMS activation processes, mechanistic investigations confirmed that the CNT-FePc/PMS system selectively promoted singlet oxygen (¹O₂) generation as the primary oxidative pathway. Density functional theory (DFT) calculations revealed that PMS exhibited stronger adsorption on FePc (−3.05 eV) compared to CNT (−2.86 eV), and that FePc effectively facilitated O–O bond elongation in PMS, thereby facilitating ¹O₂ generation. Additionally, seed germination assays indicated a significant reduction in the biotoxicity of the treated effluents. Overall, this work presents a catalyst design strategy that merges molecular-level coordination chemistry with practical flow-through configuration, enabling rapid, selective, and environmentally benign micropollutant removal. Full article

UV-C LEDs, which offer short-wavelength characteristics and serve as an alternative to traditional UV mercury lamps, represent a new light source for applications in space decontamination and surface disinfection. This paper presents the design and development of a UV-C LED lamp driver circuit configured to operate with a DC-input voltage source for sterilization and germicidal purposes. The primary circuit integrates a modified buck converter with a flyback converter, resulting in an innovative single-stage, single-switch DC-DC power converter. Additionally, the proposed electronic driver recovers energy stored in the transformer’s leakage inductors, enhancing overall circuit efficiency. A prototype driver circuit with a 3.3 W power rating (10 V/330 mA) is developed for a UV-C LED lamp intended for sterilization and germicidal applications with a DC-input voltage source. The experimental results from the prototype circuit, tested at an 18 V DC input, confirm the functionality of the proposed electronic driver for UV-C LED sterilization and germicidal lighting. Additionally, the circuit achieves efficiency exceeding 91%. Full article

The growing volume of plastics derived from electronic waste (e-waste) underscores the imperative for environmentally sustainable strategies for the management of this waste. In light of the paramount importance of this issue, a pilot demonstrator for the decontamination of polymers containing Brominated Flame Retardants (BFRs) has been developed. The objective is to investigate the potential for decontaminating BFR-containing polymers from e-waste via UV-visible irradiation using a rotatory laboratory pilot operating under primary vacuum conditions. This report focuses on binary model blends composed of 90 weight% (wt%) poly(Acrylo-Butadiene-Styrene) (ABS) pellets and 10 wt% Deca-Bromo-Diphenyl Ether (DBDE), which is one of the most toxic BFRs. The efficiency of the irradiation process was evaluated as a function of pellet diameter and irradiation time using Fourier Transform InfraRed spectroscopy (FTIR) and High-Resolution Laser Desorption/Ionization Mass Spectroscopy (HR-LDI-MS). As a consequence, ABS + DBDE achieved a decontamination efficiency of 97% when irradiated with pellets of less than 1 mm in diameter for a period of 4 h. Additionally, the thermal behavior of the irradiated samples was investigated through thermogravimetric analysis and differential scanning calorimetry. It was thus established that the application of UV-visible irradiation had no significant impact on the overall thermal properties of ABS. Full article

The substrate that adheres between the teeth of the traveling track plate during the operation of a deep-sea polymetallic nodule mining vehicle affects the driving performance, so this study aimed to investigate the effect of the water jet on the cleaning and decontamination performance of the track under different conditions. An optimization design method based on response surface methodology (RSM) is proposed. Based on the Box–Behnken design, the optimization variables of jet pressure, jet target distance, and impact angle, and the target response of jet strike pressure on tracks, were selected, and the numerical simulation method was combined with the response surface method to establish the regression model of the response of each optimization variable to the jet strike pressure on tracks and to determine the optimal parameter combinations. The study findings indicate that the primary factor influencing the pressure of the jet striking the crawler is the jet pressure. The hierarchical order of influence on the pressure of the jet striking the crawler, under the interaction of the three factors, is as follows: jet pressure and impact angle, jet pressure and target distance of the jet, and target distance of the jet and impact angle. The maximum pressure of the jet striking the crawler occurs when the jet pressure is 0.983 MPa, the target distance is 0.14 m, and the impact angle is 89.5°. Overall, the proposed design serves as a systematic framework for parameter optimization in the cleaning and decontamination process, and the research method and results provide theoretical references for the optimal design of mining truck desorption efficiency, which is critical for increasing mining efficiency and lowering energy consumption. Full article

This study describes the development of hydrogel formulations with ionic crosslinking capacity and photocatalytic characteristics. The objective of this research is to provide an effective, accessible, “green”, and facile route for the decontamination of chemical warfare agents (CWAs, namely the blistering agent—mustard gas/sulfur mustard (HD)) from contaminated surfaces, by decomposition and entrapment of CWAs and their degradation products inside the hydrogel films generated “on-site”. The decontamination of the notorious warfare agent HD was successfully achieved through a dual hydrolytic–photocatalytic degradation process. Subsequently, the post-decontamination residues were encapsulated within a hydrogel membrane film produced via an ionic crosslinking mechanism. Polyvinyl alcohol (PVA) and sodium alginate (ALG) are the primary constituents of the decontaminating formulations. These polymeric components were chosen for this application due to their cost-effectiveness, versatility, and their ability to form hydrogen bonds, facilitating hydrogel formation. In the presence of divalent metallic ions, ALG undergoes ionic crosslinking, resulting in rapid gelation. This facilitated prompt PVA-ALG film curing and allowed for immediate decontamination of targeted surfaces. Additionally, bentonite nanoclay, titanium nanoparticles, and a tetrasulfonated nickel phthalocyanine (NiPc) derivative were incorporated into the formulations to enhance absorption capacity, improve mechanical properties, and confer photocatalytic activity to the hydrogels obtained via Zn²⁺—mediated ionic crosslinking. The resulting hydrogels underwent characterization using a variety of analytical techniques, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), viscometry, and mechanical analysis (shear, tensile, and compression tests), as well as swelling investigations, to establish the optimal formulations for CWA decontamination applications. The introduction of the fillers led to an increase in the maximum strain up to 0.14 MPa (maximum tensile resistance) and 0.39 MPa (maximum compressive stress). The UV-Vis characterization of the hydrogels allowed the determination of the band-gap value and absorption domain. A gas chromatography–mass spectrometry assay was employed to evaluate the decontamination efficacy for a chemical warfare agent (sulfur mustard—HD) and confirmed that the ionic crosslinked hydrogel films achieved decontamination efficiencies of up to 92.3%. Furthermore, the presence of the photocatalytic species can facilitate the degradation of up to 90% of the HD removed from the surface and entrapped inside the hydrogel matrix, which renders the post-decontamination residue significantly less dangerous. Full article

Nuclear power components contain radioactivity on their surfaces after long-term service, which can be harmful to personnel and the environment during maintenance, dismantling, and decommissioning. In this experiment, laser decontamination technology is utilized to remove radioactivity from their surfaces. In order to meet the actual needs, a laser decontamination process without spot overlapping has been studied. Under the same equipment conditions, the decontamination efficiency of the non-spot overlapping process is 10 times higher than that of the spot overlapping process. Alloy 690 is used as the test substrate, and non-radioactive specimens are prepared by simulating primary-circuit hydrochemical conditions. The surface morphology, elemental composition, and phase composition of the specimens before and after laser decontamination are investigated with SEM and XRD using the single-pulse experiment and power single-factor experiment methods, and the laser decontamination effect was evaluated. The results show that the decontamination efficiency reached 10.8 m²/h under the conditions of a pulse width of 500 ns, a laser repetition frequency of 40 kHz, a scanning speed of 15,000 mm/s, and a line spacing of 0.2 mm, according to which the removal effect was achieved when the laser power was 160 W and the oxygen content on the surface was 6.29%; additionally, there were no oxide phases in the XRD spectra after decontamination. Therefore, the laser cleaning process without spot overlap can provide reference for future practical operations to achieve efficient removal of radioactivity from nuclear power components. Full article

Current industrial developments, advanced farming techniques, and further anthropogenic activities are adding substantial amounts of heavy metals into the ecosystem and having dangerous effects on lifeforms, including plants and animals, and changing their biological activities. Decontamination following the heavy metal contamination is an important point deserving attention in the current scenario. Among all the other approaches used for this purpose, bioremediation is ecofriendly and green approach that can be used to remediate heavy metal toxicity. In plant cells, the regulation of ionic homeostasis is a primary physiological prerequisite for upholding plant development, growth, and production. To avoid the dreadful effects of toxic heavy metal exposure, plants manifest physiological, biochemical, and structural responses. In the present research, we reported on the isolation and molecular identification of an effective heavy-metal-tolerant bacterial strain, Staphylococcus lentus (E3), having a minimum inhibitory concentration of 300 µg/mL for chromium, Cr, taken from soil polluted with industrial effluents at Kasur, Pakistan. Bacterial inoculations enhanced all the growth parameters of Triticum aestivum and Helianthus annus. To observe the physiological strain, the proline content and peroxidase (POD) activities were estimated under Cr stress in the bacterial-inoculated plants. The chlorophyll content and Cr uptake in the aerial parts the of plants were also studied, along with the overexpression of proteins. The bacterial inoculations produced encouraging results. Bioremediation using PGPR is an efficient, convincing, and reliable approach to attenuating heavy metal toxicity. Full article

The need for fresh and conveniently treated water has become a major concern in recent years. Molybdenum disulfide (MoS₂) nanomaterials are attracting attention in various fields, such as energy, hydrogen production, and water decontamination. This review provides an overview of the recent developments in MoS₂-based nanomaterials for water treatment via adsorption and photodegradation. Primary attention is given to the structure, properties, and major methods for the synthesis and modification of MoS₂, aiming for efficient water-contaminant removal. The combination of MoS₂ with other components results in nanocomposites that can be separated easily or that present enhanced adsorptive and photocatalytic properties. The performance of these materials in the adsorption of heavy metal ions and organic contaminants, such as dyes and drugs, is reviewed. The review also summarizes current progress in the photocatalytic degradation of various water pollutants, using MoS₂-based nanomaterials under UV-VIS light irradiation. MoS₂-based materials showed good activity after several reuse cycles and in real water scenarios. Regarding the ecotoxicity of the MoS₂, the number of studies is still limited, and more work is needed to effectively evaluate the risks of using this nanomaterial in water treatment. Full article

Dichloromethane (DCM, methylene chloride) is a toxic halogenated volatile organic compound massively used for industrial applications, and consequently often detected in the environment as a major pollutant. DCM biotransformation suggests a sustainable decontamination strategy of polluted sites. Among methylotrophic bacteria able to use DCM as a sole source of carbon and energy for growth, Methylorubrum extorquens DM4 is a longstanding reference strain. Here, the primary 5′-ends of transcripts were obtained using a differential RNA-seq (dRNA-seq) approach to provide the first transcription start site (TSS) genome-wide landscape of a methylotroph using DCM or methanol. In total, 7231 putative TSSs were annotated and classified with respect to their localization to coding sequences (CDSs). TSSs on the opposite strand of CDS (antisense TSS) account for 31% of all identified TSSs. One-third of the detected TSSs were located at a distance to the start codon inferior to 250 nt (average of 84 nt) with 7% of leaderless mRNA. Taken together, the global TSS map for bacterial growth using DCM or methanol will facilitate future studies in which transcriptional regulation is crucial, and efficient DCM removal at polluted sites is limited by regulatory processes. Full article

The decontamination of radioactive materials on the surfaces of nuclear facilities has generated large quantities of waste from the rapid development of the nuclear industry, posing a potential threat globally. Strippable coating has been employed for some time to remove radioactive contamination due to its high performance and removability, flexibility, and compatibility with various substrates. Herein, an aqueous strippable coating based on an adsorbent/polyvinyl alcohol (PVA) polymer was developed to remove radioactive uranium from stainless-steel surfaces that showed greater decontamination than that of DeconGel, with an efficiency of 87.2% for 5 g/L uranium and 95.5% for 22.5 g/L uranium, along with a high repeatability and better mechanical properties. Furthermore, the prepared coating was versatile and could be applied to a range of substrate surfaces (lacquered, aluminum, glass, plastic, and ceramic), with outstanding performance ranging from 79.2 to 95.4% for 1 g/L uranium. The prepared coating could also be applied through brushing or spraying to horizontal or vertical substrates. The exceptional performance could be due to the synergistic effect of the introduction of ethylene diamine tetra-acetic acid disodium salt (EDTA-2Na) as a chelating agent and the nano-adsorbent CaCO₃/TiO₂. Full article

Anthropogenic lead pollution is an environmental problem that threatens the quality of soils and waters and endangers living organisms in numerous surface and subsurface habitats. Lead coprecipitation on mineral surfaces through dissolution-recrystallization processes has long-term effects on lead bioavailability. Gypsum and calcite are among the most abundant and reactive rock forming minerals present in numerous geological settings. In this work, we studied the interaction of slightly acidic (pH_i = 5.5) Pb-bearing aqueous solutions ([Pb]_i = 1 and 10 mM) with crystals of gypsum and/or calcite under atmospheric conditions. This interaction resulted in a reduction of the concentration of lead in the liquid phase due to the precipitation of newly formed Pb-bearing solid phases. The extent of this Pb removal mainly depended on the nature of the primary mineral phase involved in the interaction. Thus, when gypsum was the only solid phase initially present in the system, the Pb-bearing liquid-gypsum interaction resulted in Pb removals in the 98–99.8% range, regardless of [Pb]_i. In contrast, when the interaction took place with calcite, Pb removal strongly depended on [Pb]_i. It reached 99% when [Pb]_i = 1 mM, while it was much more modest (~13%) when [Pb]_i = 10 mM. Interestingly, Pb-removal was maximized for both [Pb]_i (99.9% for solutions with [Pb]_i = 10 mM and 99.7% for solutions with [Pb]_i = 1 mM) when Pb-polluted solutions simultaneously interacted with gypsum and calcite crystals. Despite the large Pb removals found in most of the cases studied, the final Pb concentration ([Pb]_f) in the liquid phase was always well above the maximum permitted in drinking water (0.01 ppm), with the minimum ([Pb]_f = 0.7 ppm) being obtained for solutions with [Pb]_i = 1 mM after their interaction with mixtures of gypsum and calcite crystals. This result suggests that integrating the use of mixtures of gypsum-calcite crystals might help to develop more efficient strategies for in-situ decontaminating Pb-polluted waters through mineral coprecipitation processes. Full article