Decontamination Efficiency Research Articles

Green synthesis of N-doped-carbon dots/ZnO for enhanced photocatalytic degradation of methylene blue dye: optimization of reaction parameters.

In this research work, nitrogen-doped carbon dots (N-CDs) adorned zinc oxide nanoparticles (N-CDs/ZnO) were successfully synthesized by a simple and cost-effective solution dispersion method and later on used as photocatalyst for decontamination of aqueous methylene blue (MB) dye on irradiation of UV light (300 W, 320-400nm) at room temperature. Both the N-CDs and ZnO were prepared through green technique utilizing non-toxic, inexpensive and eco-friendly precursors, namely Foeniculum vulgare and Psidium guajava leaf extract, respectively. All the synthesized samples exhibited crystalline nature with average diameter of particle 4.42nm, 12.38nm and 14.11nm corresponding to N-CDs, ZnO and N-CDs/ZnO, respectively. Further, band gap energy value (Eg) of 3.43, 2.76 and 2.49eV for N-CDs, ZnO and N-CDs/ZnO, respectively, were obtained by using Tauc's plot. The photocatalytic capability of the sample N-CDs/ZnO was compared with bare ZnO nanoparticles, utilizing identical experimental conditions. The results demonstrated that the composite exhibited notably higher photocatalytic degradation efficiency than bare ZnO nanoparticles up to 15.54%. Lower band gap value of N-CDs/ZnO was the major factor for exhibiting this behaviour, decreasing the recombination rate and thus enhancing the efficiency. Furthermore, N-CDs/ZnO exhibited 98.17% MB degradation under optimized conditions (0.03g, 5ppm, pH 10). The resultant N-CDs/ZnO exhibited good stability and decontamination efficiency up to five cycles with efficiency loss of only 7.89%. Along with, trapping experiments was conducted to analyze the role of active species involved for deep understanding of mechanism. The order of efficiency of active constituents was observed to be: •O2- > h+ > •OH. The study analyzed the non-toxic nature of treated water, revealing normal plant growth, suggesting its potential use in irrigation of parks and roadside areas. Overall, present research work obeys the green chemistry principles with the fabrication of highly efficient, eco-friendly, cost-effective photocatalyst N-CDs/ZnO by utilizing the green precursors for the whole research work.

Degradation of Decabromodiphenyl Ether Dispersed in Poly (Acrylo-Butadiene-Styrene) Using a Rotatory Laboratory Pilot Under UV-Visible Irradiation

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.

How to alleviate seasonal limitations on water quality in farmland ditches? The importance of plant selection and configuration

In subtropical monsoon climate regions, traditional plants in constructed wetlands such as farmland ditches underperform in cold months, detracting from both purification capacity and esthetic appeal. To alleviate this weakness, this study introduced Phalaris arundinacea, a species with strong adaptability and cold tolerance, into a plant community dominated by Phragmites australis, constructing an ingenious composite plant community for year‐round water quality restoration and enhancement of attractiveness. First, laboratory simulations revealed significant seasonal differences in the removal rates of ammonia nitrogen (NH3‐N), total nitrogen (TN), and total phosphorus (TP) by the P. arundinacea community and P. australis community under different pollutant loads. Phragmites australis showed superior NH3‐N and TN removal capabilities from May to October, whereas P. arundinacea excelled in the rest of the months throughout the year. For TP removal, P. australis outperformed P. arundinacea from July to October, while P. arundinacea was more effective from January to May. We then verified this in rear farmland ditches, where P. australis were strategically partial substituted with P. arundinacea (Partial Replacement Treatment [PRT]), and compared it with unchanged farmland ditches (Control Treatment). We found that PRT enhanced decontamination efficiency over the year, especially significantly improving the water quality during colder months. Hence, this study advocates a novel strategy for effective annual decontamination and maintenance of wetlands such as farmland ditches, highlighting the importance of seasonally adaptive plant communities for water restoration. This transformative approach dramatically advances the field of wetland management, insisting on the important role of cold‐resistant species for year‐round ecosystem service optimization.

Synthesis and evaluation of radioactive decontamination efficiency of carboxylic 4-tert-butylcalix[6]arene derivative with decontamination solution

ABSTRACT Scientists have recently conducted thorough investigations on tert-butylcalix[6]arene and its derivatives owing to their ability to form complexes with radioactive elements for applications in radioactive decontamination. Current research presents the result of synthesising compounds 1,3,5-trimethoxy-2,4,6-tri (carboxylic acid)-4-tert-butylcalix[6]arene and evaluates the influence of this compound on the decontamination efficiency of a new skin decontamination (SD) kit developed by Lequidon laboratory. Decontamination effectiveness for short-lived radionuclides: metal (134Cs) and non-metallic (131I) determined by in vivo method. Adding 1% of 4-tert-butyl calix[6]arene derivative significantly enhanced the efficiency of the radioactive decontamination solution (SD).

The operating performance of Modified Basalt Fibers (MBF) bio-nest reactor exposed to nano-plastics

Biological nests made of Modified Basalt Fiber (MBF bio-nests) serve as effective carriers for enhancing wastewater treatment. However, little is known about their performance when exposed to nano-plastics. This study investigates the decontamination efficiency and microbial functionality of four types of MBF and traditional Basalt Fibers (BF) as carriers in contact oxidation reactors. Compared to BF, MBF demonstrated superior growth effects and biocompatibility within the bio-nest. Ca-MBF and Mn-MBF bio-nests exhibited the highest and most uniform absorption capacities, respectively, alongside increased secretion of total Extracellular Polymeric Substances (EPS) and higher Protein to Sugar (PN/PS) ratios. In sewage environments, all MBF groups displayed stable performance in removing NH4+-N and COD. Significant removal of TN and TP was notably observed in Mn-MBF treatments. Mn and Ca treatments predominantly influenced the Proteobacteria and Bacteroidetes phyla, crucial for nitrogen and phosphorus removal. Following exposure to nano-plastics, Mn-MBF and Ca-MBF treatments maintained high decontamination efficiency, particularly for TP and COD (48.64 % to 57.78 % and 90.91 % to 92.89 %, respectively). The significant removal of NH4+-N and TP only occurred in Mn-MBF and Ca-MBF treatments, which stimulated the growth of bacteria resistant to nano-plastics. Key genera such as Zoogloea and Meganema were identified as dominant, contributing to organic matter decomposition, EPS secretion, biofilm condensation, and enhanced microbial attachment. The findings underscore the structural stability enhancement of Mn-MBF and Ca-MBF bio-nests in contact oxidation reactors, demonstrating their resilience against nano-plastic pollution.

Removal of Surface Radioactive Uranium(Ⅵ) by Graphene Oxide Modified κ-carrageenan/Konjac Glucomannan Composite Hydrogel

Hydrogel is an effective surface decontamination technology. However, traditional colloid decontaminants face a long curing time and low decontamination rate. A peelable hydrogel coating composed of carrageenan, konjac glucan, and graphene oxide with excellent film-forming performance and decontamination efficiency was explored in this study. The results showed that the graphene oxide was effectively dispersed inside the hydrogel, improving the crosslink density and thermal stability of the hydrogel by forming hydrogen bonds with polysaccharide molecules. The graphene oxide can effectively enhance the decontamination performance of the hydrogel. For stainless steel, ceramic, glass, and rubber surfaces, the decontamination rates of the hydrogel for 30min were 96.95%, 87.6%, 96.27%, and 74.5%, respectively. The decontamination effect was stable to temperature. For cement surfaces, the hydrogel could reach a maximum decontamination rate of 70.68% after 24h. The decontamination efficiency of hydrogel was affected by porosity, surface roughness, and graphene oxide addition. The characterization results of XPS, FT-IR, and SEM/EDS showed that the decontamination process of the composite hydrogel may involve surface wetting, ion diffusion, electrostatic attraction, and physical entanglement.

Tough strippable hydrogel films based on acrylic acid/acrylamide/zirconyl chloride for surface radioactive decontamination at low temperatures

Strippable films are extensively utilised for the decontamination of radioactive surfaces because of their cost-effectiveness, ease of operation, and minimal liquid waste. However, traditional strippable detergents are formulated for use at normal ambient temperatures and typically lose their efficacy at low temperatures because of poor performance or excessively long film-forming time. In this study, we have developed an anti-freezing and sprayable AMZW detergent based on acrylic acid (AA), acrylamide (AM), zirconyl chloride octahydrate (ZrOCl2·8H2O), and water (H2O), which possesses a freezing point of approximately −34 ℃ due to the solvation interaction between Zr4+ and H2O. Even at temperatures as low as −25 ℃, the AMZW detergent can be easily sprayed using a conventional apparatus and rapidly cured into a strippable hydrogel film under irradiation by 365 nm UV LED light (LED@365 nm), household LED panel light, or sunlight. The coordination bond formed between Zr4+ and the carboxyl group of the polymer chain imparts excellent mechanical properties to the hydrogel while the carboxyl group can complex with uranyl nitrate hexahydrate (UO2(NO3)2·6H2O)—a radioactive simulant. As a result, the strippable hydrogel film demonstrates high tensile strength (6.1 ∼ 19.3 MPa), excellent flexibility (elongation of 90 ∼ 855 %), moderate peel strength (0.05 ∼ 3 N/cm, room temperature (RT)), and high decontamination efficiency (>91.6 % on stainless steel and glass; >81.3 % on concrete) over a wide range of temperatures (−25 ∼ 25 ℃). This work presents a novel approach for producing anti-freezing, fast-forming, flexible, and high-strength strippable hydrogel films for surface radioactive decontamination at low temperatures.

Boosting the photocatalytic decontamination efficiency using a supramolecular photoenzyme ensemble.

Continuous industrialization has raised daunting environmental concerns, and there is an urgent need to develop a sustainable strategy to tackle the contamination issues. Here, we report a supramolecular photoenzyme ensemble enabling the harvest of solar energy to remove contaminations in water. The well-sourced oxidoreductase, laccase, is confined into a photoactive hydrogen-bonded organic framework (PHOF) through an in situ encapsulation method. The direct electron migration between the oxidation center in a PHOF and the reduction center in laccase facilitates synergistic photoenzyme-coupled catalysis, showing two orders of magnitude higher activity than free laccase for pollutant degradation under visible light, without the need for sacrificial agents or costly co-mediators. Such high decontamination efficiency also surpasses the reported catalysts. The structure and decontamination function of this supramolecular photoenzyme ensemble remain highly stable in complex environment matrices, presenting desirable reusability and almost 100% conversion efficiency of pollutants for real sewage samples. Our conceptual photoenzyme hybrid catalyst offers important insights into green and sustainable water decontamination.

Valorization of polyurethane foam waste through the decoration with nano-polyaniline for dye decontamination from polluted water.

Two polyurethane polyaniline nanocomposites have been synthesized using two in situ polymerization routes of dried and wet bases to valorize the polyurethane waste. The physical and chemical properties of polyurethane-based nanocomposites were compared using SEM, XRD, FTIR, and Zeta potential. SEM images showed that the average particle size of the dried-based composite was 56 nm, while the wet-based composite had an average size of 75 nm. The separation efficiency for methylene blue (MB) and Congo red (CR) dyes was evaluated against free polyurethane foam waste. It was evident that pure polyurethane (PPU) achieved only 4.79% and 16.71% removal for MB and CR, respectively. These dye decontamination efficiencies were enhanced after nano polyaniline decoration of polyurethane foam either through dried base polymerization (DPUP) or wet base polymerization (WPUP). WPUP composite records 11.23% and 85.99% for MB and CR removal, respectively, improved to 26.69% and 90.07% removal using DPUP composite for the respective dyes. The adsorption kinetics, isotherms, and thermodynamics were investigated. The experimental results revealed the pseudo-second-order kinetic model as the most accurately described kinetics model for both CR and MB adsorption. The Langmuir model provided the best fit for the data, with maximum adsorption capacities of 110.98 mg/g for CR and 26.86 mg/g for MB, with corresponding R-squared values of 0.9974 and 0.9608, respectively. Regeneration and reusability studies of PPU, WPUP, and DPUP showed effective reusability, with DPUP displaying the highest adsorption capacity. These results aid in creating eco-friendly and cost-efficient adsorbents for dye removal in environmental sanitation.

Constructing Cu-Mn bimetallic synergistic sites in 2D metal-organic framework nanosheets to induce polarized charge distribution: Electronic structure transformation and evaluation of Fenton-like performance

Heterogeneous Fenton-like process based on H2O2 was an efficient method for the abatement of micropollutants in water. However, the mass transport resistance caused by the limited access between catalytic sites and target chemicals still restrict the decontamination efficiencies. Metal-organic frameworks (MOFs) with uniformed pores and anbundant metal sites shows great potentail in environmental remediation, Here, a novel two-dimensional nanosheet consisting of Cu and Mn bimetallic-oxygen clusters (CuMn-BDC, BDC refers to terephthalic acid organic ligand) was rationally designed and characterized. The introduction of second metal Mn changed the surface electronic distribution and accelerated the electron transfer of pristine Cu-based nanosheet, leading to improved catalytical acticities and removal effeciencies (kSA) for Sulfamethoxazole (SMX). The catalytic activity of CuMn-BDC obtained (5.76 × 10–4) was 3.95 times higher than that of Cu-BDC (1.46 × 10–4), demonstrating that the CuMn-BDC showed higher reaction rates than that of Cu-BDC when same amount of H2O2 was added. The interfacial micro-electric fields in bimetallic MOFs increased the interaction of organic pollutants and transfer the electron to activate H2O2. Several quenching experiments, electron paramagnetic resonance spectra and theoretical calculations were performed to study the reaction mechanism systematically. Further the powder was fabricated into membrane with higher water stablities. This study shed light on develop efficient 2D-MOFs catalyst for the abatement of micropollutants in water.

Experimental study for the decontamination of various surfaces from 99Mo using PVA/Borax/Al(OH)3 strippable hydrogel

Polyvinyl alcohol (PVA) is a beneficial polymer capable of forming hydrogels helpful in a wide range of applications. Hydrogels based on cross-linking of PVA with borax, and able to incorporate with a decontaminating agent have been used in the decontamination of 99Mo from contaminated surfaces. Aluminum hydroxide has been introduced in the formulations of PVA-borax, to increase the gel efficiency for 99Mo decontamination from surfaces. The formulations were investigated with glass, stainless steel, and wood as examples of different surfaces. When the hydrogel is sprayed on different surfaces, it forms rapidly and adheres well. Moreover, the hydrogel was shown to efficiently decontaminate surfaces contaminated with 99Mo by a maximum value of decontamination factor (D.F) for glass, stainless steel, and wood to be 43.5, 31.3, and 19.6 respectively.

Overlooked pyrite-mediated heterogeneous Fenton processes: Mechanisms of surface hydroxyl radical generation and associated decontamination performance

Pyrite-based Fenton-like processes have been extensively studied for wastewater decontamination; however, most relevant studies placed excessive emphasis on the homogeneous Fenton reaction mediated by aqueous Fe2+, resulting in the proposed technologies facing issues such as additional acid requirements for pH adjustment and excessive iron sludge production. Herein, through in situ shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS), custom dual-chamber reactor experiments, and a series of control experiments, significant hydroxyl radical generation was identified during the pyrite/H2O2 process, while the dominant reactive iron species was verified to the structural Fe sites on the pyrite surface, rather than structural Fe(II) in secondary iron minerals and surface adsorbed Fe2+. Consequently, even with significant suppression of the homogeneous Fenton pathway, the pyrite/H2O2 process exhibited significant degradation efficiency for sulfamethoxazole (SMX) at pH 4. Moreover, the pyrite/H2O2 process was found to selectively remove 50 μM of pollutants with high affinity for pyrite (bisphenol A, carbamazepine, nitrobenzene, and SMX), even in the presence of 50–100 mM methanol. Compared to the typical iron-based reductive catalyst (zero-valent iron, ZVI), pyrite mediated a Fenton process with greater potential for practical applications at pH 4, achieving a 43.75-fold reduction in iron sludge production and almost doubling the H2O2 utilization efficiency. Additionally, in contrast to ZVI, minimal iron oxide formed on the pyrite surface during the oxidation process. Thus, after seven cycles of degradation experiments, the decontamination efficiency of the pyrite/H2O2 process remained stable. These findings are crucial for understanding the complex environmental behavior of pyrite in both natural and engineering processes and provide a new perspective for the efficient utilization of pyrite resources as well.

Deep eutectic solvent microemulsions with abundant hydrogen ions in supercritical CO2 for decontamination of radioactive solid waste: Overcoming roadblocks to hydrogen ions deficiency

Deep eutectic solvents (DESs) dispersed in supercritical CO2 (SC-CO2) as microemulsions have shown promise for the removal of radioactive contaminants from solid surfaces. However, the current technology needs urgent improvement in terms of decontamination performance. This study reported a novel strategy to enhance the decontamination ability of DESs-in-CO2 systems by adding hydrogen ion (H+) supplemental reagents. The type and acidity of the added H+ reagents were found to be critical factors in dictating the decontamination performance. For instance, fluorinated carboxylic acids with higher acidity and higher CO2 affinity were more competitive for decontamination compared to other non-fluorinated carboxylic acids. Additionally, when nitric acid was used as the H+ supplemental reagent for microemulsions in SC-CO2, outstanding decontamination results were achieved. It could remove 99 % of UO3 contaminants on the specimen surfaces. The formation of microemulsions was demonstrated by molecular dynamics (MD) simulations. Meanwhile, low-cost nitric acid was more promising for scale-up applications. Remarkably, the versatility of the decontamination technology with the addition of nitric acid was demonstrated by its ability to completely decontaminate multiple radioactive wastes made of various materials, as well as different simulated radionuclides. Decontamination efficiency reached more than 99.0 %. More importantly, the DESs-in-CO2 systems with nitric acid also reduced the radioactivity of real radioactive metal waste to the clearance level with the decontamination efficiency reaching 99.0 %. Overall, this study provided valuable insights into the design of advanced decontamination technologies based on microemulsions of DESs in SC-CO2 and opened new avenues for the sustainable management of radioactive waste.

Safety assessment of the process Lietpak, based on the EREMA MPR technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Lietpak (EU register number RECYC327), which uses the EREMA MPR technology. The input material is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post-consumer PET containers, including no more than 5% PET from non-food consumer applications. The flakes are heated in a ■■■■■ reactor under vacuum. Having examined the challenge test provided, the Panel concluded that the ■■■■■ decontamination (step 2), for which a challenge test was provided, is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migration of 0.1 μg/kg food, derived from the exposure scenario for infants, when such recycled PET is used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long-term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave or conventional ovens and such uses are not covered by this evaluation.

Bacterial microcompartment-mimicking Pickering emulsion droplets for detoxification of chemical threats under sweet conditions

Chemical warfare agents represent a severe threat to mankind and their efficient decontamination is a global necessity. However, traditional disposal strategies have limitations, including high energy consumption, use of aggressive reagents and generation of toxic byproducts. Here, inspired by the compartmentalized architecture and detoxification mechanism of bacterial micro-compartments, we constructed oil-in-water Pickering emulsion droplets stabilized by hydrogen-bonded organic framework immobilized cascade enzymes for decontaminating mustard gas simulant (2-chloroethyl ethyl sulfide, CEES) under sweet conditions. Two exemplified droplet systems were developed with two-enzyme (glucose oxidase/chloroperoxidase) and three-enzyme (invertase/glucose oxidase/chloroperoxidase) cascades, both achieving over 6-fold enhancement in decontamination efficiency compared with free enzymes and >99% selectivity towards non-toxic sulfoxide. We found that the favored mass transfer of sugars and CEES from their respective phases to approach the cascade enzymes located at the droplet surface and the facilitated substrate channeling between proximally immobilized enzymes were key factors in augmenting the decontamination efficacy. More importantly, the robustness of immobilized enzymes enabled easy reproduction of both the droplet formation and detoxification performance over 10 cycles, following long-term storage and in far-field locations.

Autocatalytic oxidation of thiophene derivatives and co-degradation of refractory contaminants in Fenton reaction

The sluggish reduction of Fe(III) to Fe(II) restricts the decontamination efficiency of Fenton reactions. New strategy development toward enhancing Fe(II) regeneration and decontamination efficiency relies primarily on the well-established inorganic Fenton chemistry, yet the involvement of organic contaminants and its potential role in the Fenton reactions have been insufficiently concerned. Here, using 2,5-thiophene carboxylic acid (TDA) as a representative sulfur-containing heterocyclic contaminant and atrazine as a coexisting contaminant, we uncovered the promoting effect of thiophene derivatives on Fenton oxidation. The degradation of TDA and coexisting refractory contaminants was highly efficient in the sluggish Fe(III)/H2O2 oxidation process with autocatalytic features. Spin trapping and chemical scavenging results underpinned the crucial contribution of hydroxyl radicals (HO•) to organic oxidation. Analysis of iron cycling combined with theoretical calculations revealed that the enhancement of TDA on Fenton oxidation originated from the rapid reduction of Fe(III) by the primary radicals generated from addition of HO• to the thiophene ring.

Evaluation of emergency skin decontamination protocols in response to an acid attack (vitreolage)

The incidence of “acid attacks” (vitreolage) is a global concern, with those affected often receiving lifelong medical care due to physical and psychological damage. The purpose of this study was to evaluate the effectiveness of several emergency skin decontamination approaches against concentrated (>99 %) sulphuric acid and to identify the effective window of opportunity for decontamination. The effects of four decontamination methods (dry, wet, combined dry & wet and cotton cloth) were assessed using an in vitro diffusion cell system containing dermatomed porcine skin. Sulphuric acid (H2SO4) was applied to the skin with decontamination protocols performed at 10 s, 30 s, 8 min, and 30 min post exposure. Skin damage was quantified by tritiated water (3H2O) penetration, receptor fluid pH and photometric stereo imaging (PSI), with quantification of residual sulphur (by SEM-EDS) to determine overall decontamination efficiency. Skin translucency (quantified by PSI) demonstrated a time-dependent loss of dermal tissue integrity from 10 s. Quantification of dermal sulphur content confirmed the rapid (exponential) decrease in decontamination efficiency with time. The pH of the water effluent indicated complete neutralisation of acid from the skin surface after 90 s of irrigation. Wet decontamination (either alone or immediately following dry decontamination) was the most effective intervention evaluated, although no decontamination technique was statistically effective after 30 s exposure to the acid. These data demonstrate the time-critical consequences of dermal exposure to concentrated sulphuric acid: we find no practical window of opportunity for acid decontamination, as physical damage is virtually instantaneous.

Performance and microbial community in a constructed rapid infiltration system with hydrochar and coke as filler for advanced treatment of N, N-dimethylformamide

In this study, the treatment of wastewater with N, N-dimethylformamide (DMF) was carried out by a constructed rapid infiltration system (CRIS). The decontamination efficiency of the system with different fillers was investigated and the microbial communities and metabolic pathway were also analyzed. It was indicated that the removal of COD and DMF in the hydrochar-coke group (RA) and coke group (RB) were 58.91–59.93 % and 71.89–51.46 %, respectively. Compared with the influent, the average NH3-N concentration in the effluent increased by 77.04 % and 55.09 %, and the average removal rate of NO3--N by the two group was 72.95 % and 62.04 %, respectively. The abundance of DMF-degrading Paracoccus (5.10 %, 21.01 %) in the hydrochar and coke layers in RA was higher than the coke layer of RB (0.44 %), indicating that hydrochar promoted the growth and propagation of DMF-degrading bacteria. Hydrochar promoted the expression of gene PFK (0.2113 %), GADPH (0.3038 %), IDH (0.1832 %) and MDH (0.1758 %). In nitrogen metabolism, the relative abundance of glutamine synthetase was the highest. This research provided a theoretical foundation and technical support for the treatment DMF wastewater by CRIS.

Scientific Guidance on the criteria for the evaluation and on the preparation of applications for the safety assessment of post-consumer mechanical PET recycling processes intended to be used for manufacture of materials and articles in contact with food.

In the context of entry into force of Regulation (EU) 2022/1616, EFSA updated the scientific guidance to assist applicants in the preparation of applications for the authorisation or for the modification of an existing authorisation of a 'post-consumer mechanical PET' recycling process (as defined in Annex I of Regulation (EU) 2022/1616) intended to be used for manufacturing materials and articles intended to come into contact with food. This Guidance describes the evaluation criteria and the scientific evaluation approach that EFSA will apply to assess the decontamination capability of recycling processes, as well as the information required to be included in an application dossier. The principle of the scientific evaluation approach is to apply the decontamination efficiency of a recycling process, obtained from a challenge test with surrogate contaminants, to a reference contamination level for post-consumer PET, set at 3 mg/kg PET for a contaminant resulting from possible misuse. The resulting residual concentration of each surrogate in recycled PET is then compared to a modelled concentration in PET that is calculated using generally recognised conservative migration models, such that the related migration does not give rise to a dietary exposure exceeding 0.0025 μg/kg body weight (bw) per day. This is the lowest threshold for toxicological concern (TTC) value, i.e. for potential genotoxicity, below which the risk to human health would be negligible. The information to be provided in the applications relates to: the recycling process (i.e. collection and pre-processing of the input, decontamination process, post-processing and intended use); the determination of the decontamination efficiency by the challenge test; the self-evaluation of the recycling process. On the basis of the submitted data, EFSA will assess the safety of the mechanical PET recycling process.

Safety assessment of the process Ecopacking, based on the EREMA Basic technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Ecopacking (EU register number RECYC324), which uses the EREMA Basic technology. The input material is ■■■■■ washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post-consumer PET containers, including no more than 5% PET from non-food consumer applications. The flakes are heated in a ■■■■■ reactor ■■■■■ before being extruded. Having examined the challenge test provided, the Panel concluded that the ■■■■■ decontamination (step 2), for which a challenge test was provided, is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migrations of 0.1 and 0.15 μg/kg food, derived from the exposure scenarios for infants and toddlers, when such recycled PET is used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long-term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave or conventional ovens and such uses are not covered by this evaluation.