Residual Metal Research Articles

Robust Catalytic SEAr H/D Exchange of Arenes with D2O: Metal-Free Deuteration of Natural Complexes and Drugs.

A catalytic metal-free approach for the H/D exchange in aromatic compounds using D2O as the terminal deuterating reagent has been developed. This metal-free protocol employs a triaryl carbenium as the mediator and showcases a wide applicability in the late-stage deuteration of various natural products and small-molecule drugs. Gram-scale deuteration was successfully demonstrated with β-Estradiol, highlighting the method's practicability. Detailed mechanistic insights, supported by DFT calculations, unveiled the essential role of in situ generated acidic species in this electrophilic aromatic substitution process. This newly developed method offers a sustainable and versatile alternative to traditional metal-catalyzed H/D exchange techniques, addressing challenges such as the use of expensive metals, impurity formation, and the necessity for residual metal removal from the final products.

A Sustainable Recycling Approach to Regenerate Graphite from Industrially Sourced Failed Anodes

Recycling graphite from Li-ion battery (LIB) waste plays an important role in increasing the accessibility of graphite resources and sustainable recovery. This presentation describes our work to purify graphite from failed (i.e., out-of-specification) anodes in LIB manufacturing by focusing on the most common contaminant: copper, used as the current collector in LIB anodes.A new, three-step scalable and environmentally friendly approach was used to provide a cost-effective and sustainable method in industrial settings to recycle failed anodes during the early stages of battery manufacturing.The study aimed to understand the differences between new, battery-grade graphite and recycled graphite from anode production waste. In particular, focus was placed on the effect of metallic Cu residues on electrochemical performance. The efficiency of Cu removal from graphite was quantified by Microwave Plasma – Atomic Emission Spectroscopy (MP-AES) analysis of leachates. The following experimental parameters were studied to maximize Cu leaching efficiency: solid-to-liquid ratio, temperature, acid concentration, time and stirring speed.The surface morphology and elemental composition of leached and thermally treated purified graphite were analysed by Scanning Electron Microscopy – Energy Dispersive Spectroscopy (SEM-EDS) and Laser Induced Breakdown Spectroscopy (LIBS). The specific surface area and crystallographic parameters were measured by Braunauer–Emmett–Teller Analysis (BET) and X-Ray Diffraction (XRD), respectively. The electrochemical performance was evaluated by galvanostatic cycling with potential limitation versus Li+/Li. These five techniques were carried out on the solid residues after each stage of the regeneration procedure. The results were compared with battery-grade graphite to assess the effectiveness of our sustainable recycling approach to reuse graphite from failed anodes in LIBs.

Reduction of the photogenerated electron transport path by modulating the conduction band region to achieve the highest lignin β–O–4 bond photocleavage efficiency under xenon excitation

Photocracking of lignin β–O–4 bonds is a green approach for the high-value modification of lignin. Graphitic carbon nitride (g-C3N4) that can photocleave the β–O–4 bond is presently the only stable, metal-free photocatalyst owing to the residual metal ions generated due to photocorrosion of metal sulfides. Herein, g-C3N4 with a N–C3 vacancy structure is prepared by etching site–engineering strategy based on the protection of C–N=C structure by chlorine atom. The N–C3 vacancy structure can reduce the transport path of the photogenerated electrons by tuning the conduction band (CB) region to the edge of the photocatalyst, which impedes the critical complexation of the photogenerated electron–hole pairs and enhances the photoelectric conversion efficiency five-fold. Combined with the unique chemisorption capacity (137.82 kJ/mol) of N–C3 vacancies for oxygen, the g-C3N4 photocatalysts with N–C3 vacancy structure can generate 9.6-fold higher superoxide radicals and 13-fold higher lignin β–O–4 bond photocleavage efficiency lignin compared with untreated g-C3N4. Based on the reaction enthalpy changes and free energies investigated through simulations, a route of lignin Cα–Cβ bonds being oxidized and dehydrogenated twice by photogenerated cavities is proposed for the first time. This work reveals the relation between the properties of g-C3N4 and the photocleavage efficiency of lignin β–O–4 bonds.

Closed-Loop recovery of spent lithium-ion batteries based on preferentially selective extraction of lithium strategy

From the perspective of sustainable energy utilization and green economic development, efficient and closed-loop recovery of spent lithium-ion batteries (LIBs) is imperative. This work has developed a closed-loop recovery process for spent LIBs based on preferentially selective extraction of lithium. After molten salt assisted roasting, the efficiency for preferential extraction of Li+ could be high up to 99.3 % after optimization of selectivity. Dilute sulfuric acid alone facilitated the leaching efficiency of valuable metals over 98 %, eliminating the need for reductants. Regeneration of residue into graphite and recovery of NaCl mixed powder could avoid the wastage of residual metals. Compared with the conventional process, this work shows a high recovery efficiency and closed-loop extent, with a profit of $6,820 per ton of recovered spent LIBs. This work provides a more environmentally friendly recovery strategy with higher economic profits and environmental impacts, thereby enhancing the potential for industrial applications.

Potential and characteristics of heavy metals electrokinetic removal from the copper-zinc mine tailings: Study on the simulated and actual tailings

Tailing ponds, as the storage of solid waste from metal mining processes, contain large amounts of residual heavy metals, potentially posing risks to the ecological environment. Despite extensive research on electrokinetic remediation of metals from tailings, comprehensive studies analyzing the migration dynamics of tailing metals under electric fields from multiple perspectives are limited. In this study, we comprehensively evaluated the removal of heavy metals from both simulated and actual tailings during the electrokinetic remediation processes. Zn, Cu, and Mn in simulated tailings showed accelerated migration rates under a 30 V two-dimensional electric field compared to the actual, achieving maximum removal efficiencies of 42.8 %, 20.1 %, and 52.1 %, respectively. This outcome was attributed to the lower effective concentration of heavy metals observed in actual tailings. Two monocotyledonous Poaceae plants, vetiver grass and sorghum, exhibited a robust growth in the remediated tailings with germination rates of 85 %. Moreover, microbial richness in these remediated tailings was clearly increased, indicating alleviation of heavy metal inhibition. The experimental results demonstrated the effective removal of residual heavy metals from tailings through electrokinetic remediation, alleviating the adverse impacts of heavy metals on both plant growth and microbial diversity, which holds significant implications for future reclamation and ecological restoration of tailing ponds. In conclusion, a comparative analysis between simulated and actual tailings, employing plant growth assessment and assessing the applicability of electrokinetic remediation for addressing metal pollution in tailing ponds from a microscopic perspective, presents a promising research direction.

Analysis of Pesticide Residue and Heavy Metals in Soil of Some Farm Area of Akko, Billiri and Kaltingo Local Government Area of Gombe State, Nigeria

Analysis of Pesticide Residue and Heavy Metals in Soil of Some Farm Area of Akko, Billiri and Kaltingo Local Government Area of Gombe State, Nigeria

Bio-availability of potential trace elements in urban dust, soil, and plants in arid northwest China

Potential trace elements pollution in cities poses a threat to the environment and human health. Bio-availability affects toxicity levels of potential trace elementss on organisms. This study focused on exploring the relationship between soil, plant, and atmospheric dust pollution in Urumqi, a typical city in western China. It aims to help reduce pollution and protect residents’ health. The following conclusions were drawn: 1) potential trace elementss like Cr, Pb, As, and Ni are more prevalent in atmospheric dust and soil than in plants. Chromium was in the first group, Cadmium and Mercury were in the second, and Plumb, Arsenic, and Nickel were in the third. Atmospheric dust and soil exhibit a significantly higher heavy metal content than plants. For example, The atmospheric dust summary Chromium content was up to 88 mg/kg. 2) Soil, atmospheric dust, and plants have the highest amount of residual form. Residual form had the highest percentage average of 53.3%, whereas Organic matter bound form had the lowest percentage of just 7.7%. The plants contained less residual heavy metal than the soil and atmospheric dust. 3) The correlation coefficient between the carbonated form content of Cd of soil and atmospheric dust is 0.95, which is closely related. Other potential trace elements show similar correlations in their bio-available contents in soil, plants, and atmospheric dust. This study suggests that in urban area, the focus should be on converting potential trace elements into residual form instead of increasing plants’ absorption of potential trace elements.

Simultaneous removal of diclofenac sodium, cadmium and bacterial inactivation from aqueous solutions by activated MgO nanoparticles

This study investigated whether MgO nanoparticles (NPs) produced via the sol–gel process can simultaneously remove the pharmaceutical diclofenac sodium (DCF) and cadmium ions (Cd2+) from water. The UV spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX) were used to confirm the composition, morphology and particle size of the MgO NPs. The adsorption performance of MgO NPs was compared to that of bentonite-nano zero valent iron (B-nZVI) and activated carbon (AC). The impact of contact time, adsorbate concentration, pH, and temperature on the removal efficacy of DCF and Cd2+ via MgO NPs in aqueous solutions were investigated, and the removal data was best described by the kinetic model of pseudo-second-order and the Langmuir isotherm model (R 2 > 0.996). The maximum removal capacity of MgO for DCF and Cd2+ at pH 7 was 66.2 mg.g−1 (%R = 90) and 50.8 mg.g−1 (%R = 80), respectively. The average adsorption enthalpy for DCF and Cd2+ (ΔH° 50 kJ. mol−1) demonstrates the occurrence of physical adsorption process, while the negative value of ΔG° reveals the spontaneous nature of DCF and Cd2+ adsorption on the surface of MgO NPs. The DCF and Cd2+ adsorbed MgO surfaces were reused against various gram-positive bacteria. Finally, it was shown that MgO and sand column were more effective for removal of persistent substances and heavy metal residues than a column packed by a mixture of B-nZVI and sand.

Exploring the central region of amylin and its analogs aggregation: the influence of metal ions and residue substitutions.

Human amylin (hIAPP) is found in the form of amyloid deposits within the pancreatic cells of nearly all patients diagnosed with type 2 diabetes mellitus (T2DM). However, rat amylin (rIAPP) and pramlintide - hIAPP analogs - are both non-toxic and non-amyloidogenic. Their primary sequences exhibit only slight variations in a few amino acid residues, primarily concentrated in the central region, spanning residues 20 to 29. This inspired us to study this fragment and investigate the impact on the aggregation properties of substituting residues within the central region of amylin and its analogs. Six fragments derived from amylin have undergone comprehensive testing against various metal ions by implementing a range of analytical techniques, including Nuclear Magnetic Resonance (NMR) spectroscopy, Thioflavin T (ThT) assays, Atomic Force Microscopy (AFM), and cytotoxicity assays. These methodologies serve to provide a thorough understanding of how the substitutions and interactions with metal ions impact the aggregation behavior of amylin and its analogs.

ВЛИЯНИЕ АНТИПРИГАРНЫХ ПОКРЫТИЙ НА КАЧЕСТВО АЛЮМИНИЕВЫХ СЛИТКОВ, ПОЛУЧЕННЫХ ПОЛУНЕПРЕРЫВНОЙ РАЗЛИВКОЙ

The results of the study of the effect of the separation coating applied to the lining of the filtration chamber at the foundry complex in the production of cylindrical ingots with a diameter of 0.127 m and a length of 5 m from alloy 6060 obtained by semi-continuous casting on the quality of ingots and the condition of the lining surface are presented. The composition of the coating under study, the methods of its preparation and application to the lining of the filtration chamber are shown. It was found that after casting a batch of cylindrical ingots and inspecting the filtration chamber, there was no evidence of metal residues sticking to the lining, the color of the chamber coating below the metal level did not change. The selection of three templets from the upper, bottom and middle parts of experimental aluminum ingots for the manufacture of micro-grinders did not reveal the presence of structural defects and non-metallic inclusions.

Determine the levels of heavy metal residues in different parts of chicken in the Tikrit and Beji cities of Iraq

The aim of this study was to determine the level of heavy metal residues in different parts of local chicken meat (thigh, bone, liver, and breast) obtaining from different houses in the Iraqi cities of Tikrit and Beji. Heavy metal contamination in poultry products is a major concern due to its potential health effects on consumers. Samples were collected from local markets and analyzed for the presence of cadmium (Cd), copper (Cu), cobalt (Co), and lead (Pb) using atomic absorption spectroscopy (AAS). The results indicated that chicken parts all sampled contained detectable level of heavy metals, with concentrations varying between parts. The high level of heavy metals cadmium (Cd) in the liver part in Tikrit was (0.422), also addition the high level of heavy metals copper (Cu) in L the liver part in Beji was (1.923), also the high level of heavy metals cobalt (Co) in the bone part in Tikrit was (1.403) and the high level of heavy metals lead (Pb) in the bone part in Tikrit was (1.045), indicating regional differences in contamination. These results emphasize the importance of monitoring heavy metal levels in different parts of chicken to ensure food safety and public health

Heavy Metal Residues and Bacterial Pathogens of Food Safety Significance in Edible Crustacean from Crude-Oil-Impacted Niger Delta, Nigeria

ABSTRACT The study investigated heavy metal residues and bacterial pathogens in blue crab (Callinectes amnicola), crayfish (Nematopaelemon hastatus), giant tiger prawn (Penaeus monodon), and Indian prawn (Fenneropenaeus indicus) from crude oil impacted Niger Delta waters. Standard methods of analysis were applied in all determinations. Results indicate that chromium, lead, and mercury were within regulatory acceptable levels. Total viable count (TVC) was below threshold, while Vibrio cholerae, Vibrio parahaemolyticus, and Salmonella typhimurium were isolated from all crustacean species. The distribution pattern of pathogens showed blue crab accumulated the highest population of pathogens. Consumption of crustaceans from the location exemplifies conflict of nutrient benefits and risks.

Determination of Heavy Metal Concentrations on some Selected Herbal Medicinal Preparations Marketed in Kano State, Nigeria

Study’s Novelty/Excerpt This study assesses heavy metal concentrations in traditional medicinal herbs consumed in Kano State, Nigeria, providing critical insights into their relative safety and potential health risks. By analyzing ten powdered herbal samples using Atomic Absorption Spectrometry, the research identifies concerning levels of lead, chromium, cadmium, and mercury, with lead concentrations in one sample exceeding the WHO's safety limits. The findings highlight significant variability in heavy metal content among different herbs, underscoring the need for stringent quality control and regulatory measures to ensure consumer safety. Full Abstract Herbs are extensively consumed in Nigeria, for their medicinal properties and availability. This study aimed at determining the concentration of heavy metals residues in some selected traditional medicinal herbs consumed in Kano State, Nigeria. This is to assess their relative safety and potential health risks to local inhabitants based on the World Health Organization standard limit. A total of ten (10) powdered samples of medicinal preparations were purchased from local markets in Kano metropolis and analyzed for the presence of lead, chromium, cadmium, and mercury contents. The samples underwent digestion, and heavy metal concentrations were determined using Atomic Absorption Spectrometry (AAS). The metals found to be present varied in different concentrations in the herbal samples. The presence of heavy metal ranges as follows: 0.6-6.5mg/kg for chromium, 3.10-22.10mg/kg for lead, 0.08-0.60mg/kg for cadmium, and 0.09-0.30mg/kg for mercury. However, mercury content was not detected in some samples. The study's findings conclude that the lead (Pb) values were found to be the highest in concentration, exceeding the W.H.O limits in sample J, which is used as a remedy for cough. This indicates that the sample is highly contaminated compared to others. Mercury was not detected in four of the samples, and when present, it was below the limits set by the World Health Organization, making all the samples free from mercury contamination.

Fate of Ca2+ and metal impurities of a typical coal fly ash in amino acid mediated CO2 mineralization and simultaneous CaCO3 recovery

CO2 mineralization is a promising technology to achieve a waste-to-resource chain by integrating CO2 sequestration and alkaline solid waste utilization. Amino acids as a multifunctional reagent was proposed to avoid the extensive consumption of acid and alkaline reagents in traditional processes. However, the detailed interaction between Ca-bearing minerals and amino acids are still not fully understood, as well as migration pathways of metal impurities. To fill these gaps, this paper investigated the leaching and carbonation behaviors of Ca2+ and metal impurities of a typical coal fly ash (CFA) at various reagent types, reagent concentrations and leaching temperatures, thereby exploring the fate of these metal impurities. Results showed that the leaching and carbonation of Ca2+ was influenced by various aspects such as initial pH, reagent pKa, complexation, and pH buffering. The CaCO3 products obtained from glycine (Gly) and alanine (Ala) were vaterite due to the stabilizing effect of these amino acids on vaterite preventing it from converting to calcite. The optimal reaction conditions were 1.0 M Gly and leaching temperature of 35 °C with 26.63 % leaching efficiency, 56.08 % carbonation efficiency, and 42.6 g/kg vaterite yield. In addition, Ala induced an unexpected high leaching efficiency of Cd (75.79 %), Pb (76.08 %), and Zn (41.62 %), respectively, indicating promising mitigation of the environment risk of leached residue and valuable metal recovery from CFA. Although Gly displayed limited metal leaching efficiency at 1.0 M and 25 °C, increasing leaching temperature induced a remarkable enhancement of Cd and Pb leaching, which were 88.54 % and near 100 % at 35 °C, indicating promising mitigation of the environment risk of leached CFA. However, the high binding affinity of amino acids to impurity metals led to the low purity of CaCO3 product. This study derives the migration pathways of various metal ions during the mineralization and utilization of CFA, making it of great significance for the resource management and utilization of solid wastes.

Leaching characteristics and environmental impact of heavy metals in tailings under rainfall conditions: A case study of an ion-adsorption rare earth mining area

Following ion-adsorption rare earth mining, the residual tailings experience considerable heavy metal contamination and gradually evolve into a pollution source. Therefore, the leaching characteristics and environmental impact of heavy metals in ion-adsorption rare earth tailings require immediate and thorough investigation. This study adopted batch and column experiments to investigate the leaching behaviour of heavy metals in tailings and assess the impact of tailings on paddy soil, thereby providing a scientific basis for environmental protection in mining areas. The results showed that Mn, Zn, and Pb contents were 431.67, 155.05, and 264.33 mg·kg−1, respectively, which were several times higher than their respective background values, thereby indicating significant heavy metal contamination in the tailings. The batch leaching experiment indicated that Mn and Pb were priority control heavy metals. Heavy metals were divided into fast and slow leaching stages. The Mn and Pb leaching concentrations far exceeded environmental limits. The DoseResp model perfectly fitted the leaching of all heavy metals from the tailings (R2 > 0.99). In conjunction with the findings of the column experiment and correlation analysis, the chemical form, rainfall pH, ammonia nitrogen, and mineral properties were identified as the primary factors controlling heavy metal release from tailings. Rainfall primarily caused heavy metal migration in the acid-extraction form from the tailings. The tailing leachate not only introduced heavy metals into the paddy soil but also caused the transformation of the chemical form of heavy metals in the paddy soil, further exacerbating the environmental risk posed by heavy metals. The study findings are significant for environmental conservation in mining areas and implementing environmentally friendly practices in rare earth mining.

Effective sludge management: Reuse of biowaste and sewer sediments for fired bricks

ABSTRACT This study partially replaced the clay with sewer sludge (SS) and rice husk (RH-SS) to make fired bricks. The brick samples were examed in terms of shrinkage, water absorption, and compressive strength. Besides, they were analyzed via XRD and metal extraction to determine the heavy metal residuals in the products. The results showed that it was possible to fabricate fired bricks using sewer sludge or rice husk-blended sludge with up to 30% by weight. These brick samples complied with the technical standard for clay brick production, in which the compressive strength was more than 7.5 MPa, water absorption was from 11–16%, and the linear shrinkage was all less than 5%. The rice husk addition helped mitigate the heavy metal residuals in the bricks and leaching liquid, in which all the values were lower than the US-EPA maximum concentration of contaminants for toxicity characteristics. Implications: Previous studies have proved the possibility of mixing sewage sludge from different origins (sewage sludge, river sediment, canal sediment, sewer sediment, etc.) with clay and some wastes to make bricks. In which, mostof the studies used sewage sludge from wastewater treatment plants, very fewdealt with lake/river or sewer sediment. This study shall be the first to study the possibility of employing sewer sediments with the addition of rice husk powder to achieve two targets, including (1) the reuse of biowaste and sludge for brick fabrication and (2) the reduction of heavy metals in final calcined bricks. Different ratios of the rice-husk blended sewer sludge (RH-SS) – clay mixture shall be tested to find the optimized compositions. The results showed that it was possible to fabricate fired bricks using sewer sludge or rice husk-blended sludge with up to 30% by weight, which meant reduce 30% of clay in the brick production. The final products were proved to meet the quality standard in terms of compressive strength (more than 10 MPa), water absorption(from 11–16%), and the linear shrinkage (less than 5%). Larger scale of this study can be an evident to recommend for policy change in the waste reuse in construction field.

Effect of white mud on carbonation resistance of alkali activated slag

White mud (WM) is a solid waste produced in the process of papermaking and it remains to be effectively utilized. It contains a large amount of CaCO3 and residual alkali metal ions. This paper aims to explore the effect of WM on carbonation resistance of alkali activated slag. The changes in mechanical properties and microstructure of alkali activated white mud/slag (AAWS) after natural carbonation and accelerated carbonation were analyzed. The results indicate that the mechanisms of natural carbonation and accelerated carbonation are different. The carbonation depth achieved in 90 days of natural carbonation can be reached in just 14 days of accelerated carbonation. Samples with 15 wt% WM blended possesses the smallest carbonation depth and the highest compressive strength. WM can effectively mitigate the natural carbonation of AAWS by dissolving Mg2+ and Ca2+. Mg2+ can migrate to increase the solubility of calcite, promote the generation of hydrotalcite to absorb carbon dioxide, and reduce the carbonation degree. Ca2+ will migrate after the carbonation and decalcification of the gel product and reduce the decalcification sensitivity. This study offers a sustainable approach for improving the carbonation resistance of AAWS.

Recent advances and trends in innovative biosensor-based devices for heavy metal ion detection in food.

Low-cost, reliable, and efficient biosensors are crucial in detecting residual heavy metal ions (HMIs) in food products. At present, based on distance-induced localized surface plasmon resonance of noble metal nanoparticles, enzyme-mimetic reaction of nanozymes, and chelation reaction of metal chelators, the constructed optical sensors have attracted wide attention in HMIs detection. Besides, based on the enrichment and signal amplification strategy of nanomaterials on HMIs and the construction of electrochemical aptamer sensing platforms, the developed electrochemical biosensors have overcome the plague of low sensitivity, poor selectivity, and the inability of multiplexed detection in the optical strategy. Moreover, along with an in-depth discussion of these different types of biosensors, a detailed overview of the design and application of innovative devices based on these sensing principles was provided, including microfluidic systems, hydrogel-based platforms, and test strip technologies. Finally, the challenges that hinder commercial application have also been mentioned. Overall, this review aims to establish a theoretical foundation for developing accurate and reliable sensing technologies and devices for HMIs, thereby promoting the widespread application of biosensors in the detection of HMIs in food.

Gender-specific responses in gene expression of Nile tilapia (Oreochromis niloticus) to heavy metal pollution in different aquatic habitats

Monitoring heavy metal accumulation is essential for assessing the viability of aquatic ecosystems. Our methodology involved integrating analysis of immunological, stress, inflammatory, and growth-related gene expression in male and female Nile tilapia with on-site recordings of physicochemical parameters. Additionally, we assessed the effect of different physicochemical parameters on heavy metal bioavailability and residual concentration in fish and water. Samples of fish and water were gathered from three different localities: Lake Brullus, a brackish lake sited in northern Egypt; Lake Nasser, an artificial freshwater reservoir located in southern Egypt; and El-Qanater El-Khayria, a middle-freshwater location belonging to the Rashid branch of the river Nile. The assessment of heavy metal residues (Fe, Cu, Zn, Mn, and Ni) revealed that their concentrations were higher in fish specimens compared to their counterparts in water (except for Ni). In addition, Lake Brullus emerges as the most polluted area, exhibiting elevated levels of heavy metals concentrations in water and fish specimens. In contrast, Lake Nasser showed the least degree of heavy metals pollution. Gene expression analysis revealed gender-specific responses to heavy metal exposure at the three investigated water bodies. The expression of hepatic antioxidant genes (GST and MT) and inflammatory-related genes (CC-chemokine and TNFα) increased in males compared to females. In females, the immune and pro-inflammatory-related genes (IgM and CXC2-chemokine) transcripts were upregulated. Additionally, growth-related genes were downregulated in both Lake Brullus and El-Qanater; on the contrary, fish samples from Lake Nasser exhibited a normal expression pattern of growth-related genes. Stress-related genes (HSP70 and HSP27) showed significant downregulation in gills of both genders from Lake Brullus. The minimal presence of heavy metal contaminants in Lake Nasser seems to endorse the normal patterns of gene expression across all gene categories. A potential gender-specific gene expression response towards pollution was noticed in genes associated with inflammation and antioxidant activities. This highlights the importance of considering gender-related responses in future environmental assessments.

Electrocatalytic degradation of ofloxacin by self-doped copper/carbon cathode materials derived from waste printed circuit boards

Using residual copper metal from waste circuit boards, ordered carbon materials containing copper (PCBs-Cu-800) were synthesized by self-doping for the electrocatalytic degradation of ofloxacin (OFL). Although PCBs-Cu-800 has a smaller specific surface area, its efficiency in degrading OFL was higher than that of carbon materials without copper (PCBs-800), reaching 95.9 % within 2 h. The PCBs-Cu-800 electrode can generate a large amount of H2O2 in the initial stage of degradation, thereby increasing the amount of hydroxyl radicals (·OH) generated and removing OFL. Density functional theory simulations were used to calculate the adsorption energies of O2 on both materials, demonstrating that the self-doped copper model was more prone to O2 adsorption, and elucidating the excellent electrocatalytic performance of PCBs-Cu. The residual copper metal in the raw material is important in the electrocatalytic processes. This study presents an environmentally friendly catalytic material capable of effectively degrading OFL in solution using waste circuit boards and further expands the application scope of advanced electrochemical oxidation technology in wastewater treatment.