Fractionation, spatial distribution, ecological and health risk assessment of cobalt and nickel in surface sediment of a bay along the southeast coast of China.

The fractionation and distribution of two potentially toxic elements (Co and Ni) were investigated in surface sediments to explore the pollution in Xiamen Bay, a special zone experiencing rapid economic growth and enormous environmental pressure. Relatively high concentrations were observed in nearshore areas with frequent human activities. The dominant fractions for Co and Ni were found to be residual, followed by exchangeable phase. Spatial differences in mobility and bioavailability inferred from chemical fractionations were more pronounced for Ni. Multiple evaluation methods including geo-accumulation index, risk assessment code, modified potential ecological risk index, etc., consistently indicated that pollution levels and ecological risks in the entire bay were generally classified as medium-low. However, non-carcinogenic risks of Co for children and carcinogenic risks of Ni for adults exceeded safety thresholds. Terrestrial weathering processes and industrial activities primarily contributed to the presence of these elements, while their distributions were mainly influenced by organic matter.

Predicting nickel concentration in soil using fractional-order derivative and visible-near-infrared spectroscopy indices.

Accurate monitoring and estimation of heavy metal concentrations is an important process in the prevention and treatment of soil pollution. However, the weak correlation between spectra and heavy metals in soil makes it difficult to use spectroscopy in predicting areas with a risk of heavy metal pollution. In this paper, a method for detection of Ni in soil in eastern China using the fractional-order derivative (FOD) and spectral indices was proposed. The visible-near-infrared (Vis-NIR) spectra were preprocessed using the FOD (range: 0 to 2, interval: 0.1) to solve the problems of baseline drift and overlapping peaks in the original spectra. The product index (PI), ratio index (RI), sum index (SI), difference index (DI), normalized difference index (NDI), and brightness index (BI) were applied and compared. The results showed that the spectral detail increased as the FOD increased, and the interference of the baseline drift and overlapping peaks was eliminated as the spectral reflectance decreased. Furthermore, the FOD extracted the spectral sensitivity information more effectively and improved the correlation between the Vis-NIR spectra and the Ni concentration, and the NDI had a maximum correlation coefficient (r) of 0.803 for order 1.9. The estimation model based on the NDI dataset constructed after FOD processing had the best performance, with a validation accuracy [Formula: see text] of 0.735, RMSE of 3.848, and RPD of 2.423. In addition, this method is easy to carry out and suitable for estimating other heavy metal elements in soil.

Toward a more realistic estimate of exposure to chromium and nickel in soils of geogenic and/or anthropogenic origin: importance of oral bioaccessibility.

To enhance risk assessment for contaminated sites, incorporating bioavailability through bioaccessibility as a corrective factor to total concentration is essential to provide a more realistic estimate of exposure. While the main in vitro tests have been validated for As, Cd, and/or Pb, their potential for assessing the bioaccessibility of additional elements remains underexplored. In this study, the physicochemical parameters, pseudototal Cr and Ni concentrations, soil phase distribution, and oral bioaccessibility of twenty-seven soil samples were analysed using both the ISO 17924 standard and a simplified test based on hydrochloric acid. The results showed wide variability in terms of the concentrations (from 31 to 21,079 mg kg-1 for Cr, and from 26 to 11,663 mg kg-1 for Ni) and generally low bioaccessibility for Cr and Ni, with levels below 20% and 30%, respectively. Bioaccessibility variability was greater for anthropogenic soils, while geogenic enriched soils exhibited low bioaccessibility. The soil parameters had an influence on bioaccessibility, but the effects depended on the soils of interest. Sequential extractions provided the most comprehensive explanation for bioaccessibility. Cr and Ni were mostly associated with the residual fraction, indicating limited bioaccessibility. Ni was distributed in all phases, whereas Cr was absent from the most mobile phase, which may explain the lower bioaccessibility of Cr compared to that of Ni. The study showed promising results for the use of the simplified test to predict Cr and Ni bioaccessibility, and its importance for more accurate human exposure evaluation and effective soil management practices.

Electrochemical and statistical study of Nickel ion assessment in daily children intake samples relying on magnesium aluminate spinel nanoparticles.

Lately, children's daily consumption of some products, such as cereals and candies, has been rising, which provides a compelling rationale for determining any metallic substances that may be present. Monitoring the concentration of certain metals, like nickel, in these products is necessary due to medical issues in humans when consumed regularly. So, in this work, a novel and highly selective carbon paste as a Ni(II) ion-selective sensor was prepared and investigated using ceramic magnesium aluminum spinel nanoparticles as the ionophore and tritolyl phosphate (TOCP) as a plasticizer. A modified co-precipitation method was used to synthesize the spinel nanoparticles. X-ray diffraction, scanning electron microscope with EDAX, transmission electron microscope, and BET surface area were used to determine the phase composition, microstructure, pores size, particle size, and surface area of the synthesized nanoparticles. The spinel nanoparticle was found to have a nano crystallite size with a cubic crystal system, a particle size ranging from 17.2 to 51.52 nm, mesoporous nature (average pore size = 8.72 nm), and a large surface area (61.75 m2/g). The composition ratio of graphite carbon as a base: TOCP as binder: spinal as ionophore was 67.3:30.0:2.7 (wt%) based on potentiometric detections over concentrations from 5.0 × 10-8 to 1.0 × 10-2 mol L-1 with LOD of 5.0 × 10-8 mol L-1. A measurement of 29.22 ± 0.12 mV decade-1 over pH 2.0-7.0 was made for the Nernstian slope. This sensor demonstrated good repeatability over nine weeks and a rapid response of 8 s. A good selectivity was shown for Ni(II) ions across many interferents, tri-, di-, and monovalent cations. The Ni(II) content in spiked real samples, including cocaine, sweets, coca, chocolate, carbonated drinks, cereals, and packages, were measured. The results obtained indicated no significant difference between the proposed potentiometric method and the officially reported ICP method according to the F- and t-test data. In addition to utilizing ANOVA statistical analysis, validation procedures have been implemented, and the results exceed the ICP-MS methodology.

The effects of organic waste materials on Miscanthus × giganteus yield and Zn and Ni content.

The aim of the experiment was to determine the yield of Miscanthus × giganteus M 19 in the first three years of cultivation and its bioaccumulation of Zn and Ni in aboveground and underground parts in response to different doses of sewage sludge and substrate left after the production of white mushrooms. Miscanthus × giganteus is a grass species that adapts to different environmental conditions and can be grown in various climatic zones of Europe and North America. In April 2018 the experiment was established in a randomized block design and with four replications in central-eastern Poland. Waste organic materials (municipal sewage sludge and mushroom substrate) were applied to the soil in 2018 in the spring before the rhizomes of giant miscanthus were planted. Each year (from 2018 to 2020) biomass was harvested in December. The yield of fresh and dry matter and the total content of Zn and Ni, after wet mineralization of plant samples, were determined by optical emission spectrometry (ICP-OES). After the third year of cultivation, the content of Zn and Ni in rhizomes and in the soil was determined again. In relation to control, an increase in the yield of miscanthus biomass in response to organic waste materials was noted. Plants responded to mushroom substrate (SMS) with the highest average yield (16.89 Mgha-1DM), while on the control plot it was 13.86 Mg  ha-1DM. After the third year of cultivation, rhizomes of Miscanthus x giganteus contained higher amounts of Zn (63.3 mg kg-1) and Ni (7.54 mg kg-1) than aboveground parts (40.52 and 2.07 mg kg-1), which indicated that heavy metals were retained in underground parts.

Strength and functionalized borage biochar for effective elimination of nickel contamination: Insight into batch and dynamic flow mode treatment applications.

A silica gel-modified borage biochar (BB@Si) was first produced and used as a binding agent for potentially hazardous Ni2+ ions in aqueous systems. The recommended biochar was more effective in eliminating Ni2+ than pristine biochar (BB). Its maximum qm could reach up to 1.39 × 10-3 mol/g at 30 °C, and sorption isotherms showed that the Langmuir model could more accurately define its sorption behavior. The Dubinin-Radushkevich isotherm also revealed that the average sorption energy ranged from 11.00 to 11.14 kJ/mol. Zeta potential tests, SEM images, and FT-IR scans confirmed the interactions between BB@Si and Ni2+ ions. Dynamic flow treatment studies showed high uptake effectiveness when the flow rate and amount of BB@Si were suitable. Nickel desorption yield of around 80% from BB@Si was noted with 0.01 M HCl. The BB@Si column's breakthrough and exhausted points were identified to be 45 and 352 min, respectively. Its maximum exhaustion capacity value was determined to be 52.73 mg/g. Ni2+ removal from the actual wastewater sample exceeded 75%. The resulting outcomes imply the immense potential of employing BB@Si in the treatment of Ni2+- contaminated aqueous systems.

Catalytic pyrolysis of fish waste oil using ZSM-5 catalyst for the production of renewable biofuel.

This present study enlightens the eco-friendly green synthesis of ZSM-5 from natural clay montmorillonite, and its proper incorporation with 'Ni'. Nickle (Ni) was wet impregnated onto HZSM-5 and the resulting catalyst was characterized by various techniques including XRD, BET, N2 Sorption Studies, TPD, SEM and TEM techniques. The SEM images revealed the uniform distribution of Ni over HZSM-5 zeolite catalyst and the XRD results indicated the undistorted crystalline structure of HZSM-5 even after impregnation of Ni. The latter part of the work concentrates on the strength of the catalyst in cracking oil derived from discarded fish parts. Discarded fish waste was pyrolyzed to obtain the fish oil, which was then used for cracking studies. The fish oil was efficiently converted (99% conversion) by Ni/ZSM5 (50 wt %) and yielded 70% liquid fractions, which formed gasoline (78.6%), kerosene (12.3%) and diesel (9.1%). The research is a complete parcel to examine the working potential of the produced biofuel in pre-existing engines. The quality of gasoline fraction was tested according to ASTM standards, which showed that the heating value was slightly lower compared to fossil gasoline. The torque and brake fuel consumption were also examined and it indicated that the fish oil derived gasoline fuel may need to be mixed with the commercial gasoline to optimize its performance.

Development of a Whole-Cell System Based on the Use of Genetically Modified Protoplasts to Detect Nickel Ions in Food Matrices.

Heavy metals are dangerous contaminants that constitute a threat to human health because they persist in soils and are easily transferred into the food chain, causing damage to human health. Among heavy metals, nickel appears to be one of the most dangerous, being responsible for different disorders. Public health protection requires nickel detection in the environment and food chains. Biosensors represent simple, rapid, and sensitive methods for detecting nickel contamination. In this paper, we report on the setting up a whole-cell-based system, in which protoplasts, obtained from Nicotiana tabacum leaves, were used as transducers to detect the presence of heavy metal ions and, in particular, nickel ions. Protoplasts were genetically modified with a plasmid containing the Green Fluorescent Protein reporter gene (GFP) under control of the promoter region of a sunflower gene coding for a small Heat Shock Protein (HSP). Using this device, the presence of heavy metal ions was detected. Thus, the possibility of using this whole-cell system as a novel tool to detect the presence of nickel ions in food matrices was assessed.

Exploring the diverse performance of nickel and cobalt spinel ferrite nanoparticles in hazardous pollutant removal and gas sensing performance.

A simple sol-gel combustion process was employed for the creation of MFe2O4 (M=Ni, Co) nanoparticles. The synthesized nanoparticles, acting as both photocatalysts and gas sensors, were analyzed using various analytical techniques. MFe2O4 (M=Ni, Co) material improved the degradation of methylene blue (MB) under UV-light irradiation, serving as an enhanced electron transport medium. UV-vis studies demonstrated that NiFe2O4 achieved a 60% degradation, while CoFe2O4 nanostructure exhibited a 76% degradation efficacy in the MB dye removal process. Furthermore, MFe2O4 (M=Ni, Co) demonstrated chemosensitive-type sensor capabilities at ambient temperature. The sensor response and recovery times for CoFe2O4 at a concentration of 100 ppm were 15 and 20, respectively. Overall, the synthesis of MFe2O4 (M=Ni, Co) holds the potential to significantly improve the photocatalytic and gas sensing properties, particularly enhancing the performance of CoFe2O4. The observed enhancements make honey MFe2O4 (M=Ni, Co) a preferable choice for environmental remediation applications.

Chemical fractionation and mobility of Cd, Mn, Ni, and Pb in farmland soils near a ceramics company.

Soil contamination due to industrial activity in ceramics production is of concern because of the risk of heavy metal pollution. Successive extraction was used to measure and identify the concentrations of Cd, Mn, Ni, and Pb in farming soils near a ceramics company in Nigeria. Furthermore, soil pH and particle size analyses were determined. The concentration of Pb was the highest, followed by that of Ni, Mn, and Cd (lowest), and the mean level of Cd exceeded the regulatory allowed limit of 1.4 mg kg-1. The order of the metals' mobility factors was as follows: Cd > Mn > Ni, Pb. While the Fe-Mn oxide phase had 37% (Mn) and 20 to 83% (Ni), the residual fraction had approximately 30% (Cd) and 19 to 50% (Pb). Soil pollution evaluation was performed using enrichment factor (EF), contamination factor (CF), pollution load index (PLI), and geoaccumulation index (Igeo). Values of EF indicated significant enrichment for all metals, as the EF mean values for Cd, Ni, and Pb in soil were > 1.5. Total EF is of the order Cd > Pb > Ni > Mn. CF results revealed moderate to very high contamination (CF < 1: 3 ≤ CF ≥ 6). Similarly, the PLI indicated moderately to severely polluted soil. The order is 100 m > 200 m > 300 m > 400 m. The Igeo ranged from 1.46 to 2.76 (Cd), 0.07 to 1.62 (Ni), and 0.05 to 2.81 (Pb). The PCA, CA, and EF analyses suggest that the metals are a consequence of anthropogenic activities.

Spatial health risk assessments of nickel in the groundwater sources of a mining-impacted area.

Mining activities have increased the potential risks of metal pollution to the groundwater resources in arid areas across the globe. Therefore, this study aimed to examine the health risk associated with nickel (Ni) in the groundwater sources of a mining-impacted area, South Khorasan, Eastern Iran. A total of 110 stations were included in the study, comprising 62 wells, 40 qanats, and 8 springs in summer, 2020. Initially, the collected samples were tested for temperature, pH, and electrical conductivity (EC). Subsequently, the samples were filtered and treated with nitric acid (HNO3) to measure the concentration of Ni using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Hazard quotient (HQ) and non-carcinogenic risk assessments were employed to evaluate the potential risks of Ni to the inhabitants. The findings revealed that the concentration of Ni ranged from 0.02 to 132.39 µg l-1, and only two stations exhibited Ni concentrations above the WHO standards (20 µg l-1). The results demonstrated that 98.21% of the sampled locations had HQ values below one, indicating negligible risk, while 1.78% of the stations exhibited HQ values of one or higher, representing a high non-carcinogenic risk for water consumers. Overall, the concentration of nickel in the groundwater of South Khorasan exceeded the World Health Organization (WHO) limit solely in the Halvan station, posing a non-carcinogenic risk for the residents in that area, and therefore, additional efforts should be made to provide healthier groundwater to consumers in this region.

The use of a portable X-ray fluorescence spectrometer for measuring nickel in plants: sample preparation and validation.

X-ray fluorescence is a fast, cost-effective, and eco-friendly method for elemental analyses. Portable X-ray fluorescence spectrometers (pXRF) have proven instrumental in detecting metals across diverse matrices, including plants. However, sample preparation and measurement procedures need to be standardized for each instrument. This study examined sample preparation methods and predictive capabilities for nickel (Ni) concentrations in various plants using pXRF, employing empirical calibration based on inductively coupled plasma optical emission spectroscopy (ICP-OES) Ni data. The evaluation involved 300 plant samples of 14 species with variable of Ni accumulation. Various dwell times (30, 60, 90, 120, 300 s) and sample masses (0.5, 1.0, 1.5, 2.0 g) were tested. Calibration models were developed through empirical and correction factor approaches. The results showed that the use of 1.0 g of sample (0.14 g cm-2) and a dwell time of 60 s for the study conditions were appropriate for detection by pXRF. Ni concentrations determined by ICP-OES were highly correlated (R2 = 0.94) with those measured by the pXRF instrument. Therefore, pXRF can provide reliable detection of Ni in plant samples, avoiding the digestion of samples and reducing the decision-making time in environmental management.

Bimetal Cu/Ni-BTC@SiO2 metal-organic framework as high performance photocatalyst for degradation of azo dyes under visible light irradiation.

There has been significant attention on the efficient degradation of pollutants in wastewater using metal-organic frameworks (MOFs) photocatalytic methods over the past decade. Herein, we examined the elimination of two different types of water-contaminating dyes, specifically cationic dye methylene blue (MB) and anionic dye methyl orange (MO), through the application of bimetal Cu/Ni-BTC@SiO2 MOF as high performance photocatalyst. The bimetal Cu/Ni-BTC@SiO2 photocatalyst was synthesized and characterized by XRD, FTIR, SEM, TEM, TGA, BET, DRS, and VSM techniques. The examination of the impact of different operational factors on the elimination of pollutants involved a comprehensive analysis of variables including the photocatalyst type, initial pollutant concentration, quantity of photocatalyst, and pH levels. The highest removal efficiency for MO and MB dyes by the photocatalyst was found to be 98 and 71%, respectively, within 60 min. In the fifth reaction stage, degradation efficiency for MO and MB was 76 and 56% respectively. Kinetic investigations demonstrated that, in the context of the uptake of MB and MO dyes, the interparticle diffusion, and pseudo-second-order models emerged as possessing the most robust correlation coefficients with the experimental data, registering values of 0.988 and 0.961, respectively. The examination of isotherms reveals that the isotherm models proposed by BET, and Anderson (V) demonstrate the highest level of conformity with the empirical data for the decomposition of MB and MO dyes, correspondingly. The TOC levels decreased significantly from 51 to 14 and 47 to 3 mg/L for MB and MO dyes, indicating the effective mineralization process using Cu/Ni-BTC@SiO2.

Development of a NiFe2O4 covalent organic framework based magnetic solid-phase extraction approach for specific capture of quinolones in animal innards prior to UHPLC-Q-Orbitrap HRMS detection.

This study aimed to present a selective and effective method for analyzing quinolones (QNs) in food matrix. Herein, a NiFe2O4-based magnetic sodium disulfonate covalent organic framework (NiFe2O4/COF) was prepared using a simple solvent-free grinding method, and was adopted as a selective adsorbent for magnetic solid phase extraction of QNs. Coupled with UHPLC-Q-Orbitrap HRMS, an efficient method for simultaneous detection of 18 kinds of QNs was established. The method exhibited good linearity (0.01-100 ng g-1), high sensitivity (LODs ranging from 0.0011 to 0.0652 ng g-1) and precision (RSDs below 9.5%). Successful extraction of QNs from liver and kidney samples was achieved with satisfactory recoveries ranging from 82.2% to 108.4%. The abundant sulfonate functional groups on NiFe2O4/COF facilitated strong affinity to QNs through electrostatic and hydrogen bonding interactions. The proposed method provides a new idea for the extraction of contaminants with target selectivity.

Flower-like 3D SnS decorated on nickel metal-organic framework for electrochemical detection of dimetridazole in food samples.

Dimetridazole (DMZ) is a broad-spectrum antibiotic effective against bacterial and protozoan infections in humans and poultry farms. However, excessive DMZ intake leads to harmful effects. Thus, minimizing its environmental presence is crucial for sustaining daily life. This study presents an innovative approach to construct flower-like SnS particle decorations on a nickel metal-organic framework (Ni-MOF@SnS) as an electrocatalyst for DMZ detection. The Ni-MOF@SnS/GCE sensor exhibits exceptional electrocatalytic behavior, including a significantly reduced detection limit of 1.6 nM, extensive linear ranges from 0.01 µM to 60 µM and from 60 µM to 231 µM at lower and higher DMZ concentrations, respectively. It also shows enhanced sensitivity (0.139 µA µM-1 cm-2) and remarkable selectivity for DMZ detection using differential-pulse voltammetry (DPV). Furthermore, the proposed sensor demonstrates good recovery results with actual food samples.

Human health risks of heavy metal(loid)s mediated through crop ingestion in a coal mining area in Eastern China.

The heavy metal(loid)s (HMs) in soils can be accumulated by crops grown, which is accompanied by crop ingestion into the human body and then causes harm to human health. Hence, the health risks posed by HMs in three crops for different populations were assessed using Health risk assessment (HRA) model coupled with Monte Carlo simulation. Results revealed that Zn had the highest concentration among three crops; while Ni was the main polluting element in maize and soybean, and As in rice. Non-carcinogenic risk for all populations through rice ingestion was at an "unacceptable" level, and teenagers suffered higher risk than adults and children. All populations through ingestion of three crops might suffer Carcinogenic risk, with the similar order of Total carcinogenic risk (TCR): TCRAdults > TCRTeenagers > TCRChildren. As and Ni were identified as priority control HMs in this study area due to their high contribution rates to health risks. According to the HRA results, the human health risk was associated with crop varieties, HM species, and age groups. Our findings suggest that only limiting the Maximum allowable intake rate is not sufficient to prevent health risks caused by crop HMs, thus more risk precautions are needed.

Ecological impacts and potential hazards of nickel on soil microbes, plants, and human health.

Nickel (Ni) contamination poses a serious environmental concern, particularly in developing countries: where, anthropogenic activities significantly contributes to Ni accumulations in soils and waters. The contamination of agricultural soils with Ni, increases risks of its entry to terrestrial ecosystems and food production systems posing a threat to both food security and safety. We examined the existing published articles regarding the origin, source, accumulation, and transport of Ni in soil environments. Particularly, we reviewed the bioavailability and toxic effects of Ni to soil invertebrates and microbes, as well as its impact on soil-plant interactions including seed germination, nutrient uptake, photosynthesis, oxidative stress, antioxidant enzyme activity, and biomass production. Moreover, it underscores the potential health hazards associated with consuming crops cultivated in Ni-contaminated soils and elucidates the pathways through which Ni enters the food chain. The published literature suggests that chronic Ni exposure may have long-term implications for the food supply chain and the health of the public. Therefore, an aggressive effort is required for interdisciplinary collaboration for assessing and mitigating the ecological and health risks associated with Ni contamination. It also argues that these measures are necessary in light of the increasing level of Ni pollution in soil ecosystems and the potential impacts on public health and the environment.

High-efficiency combination washing agents with eco-friendliness simultaneously removing Cd, Cu and Ni from soil of e-waste recycling site: A lab-scale experiment.

Soil washing technology plays an important role in the removal of heavy metals, and the efficacy of this process depends on the washing agent used. Due to the difficulty in treating soils contaminated by multiple heavy metals, there is still a need for further exploration of efficient washing agents with low environmental impact. Although single washing agents, such as chelators, can also effectively remove heavy metals from soil, combining efficient washing agents and determining their optimal washing conditions can effectively improve their removal efficiency for multiple heavy metals in soil simultaneously. Based on the previous research, the present study was carried out to combine different types of washing agents to remediate contaminated soils at a commonly e-waste recycling site. The objectives were to investigate their efficient washing conditions and assess the impact of the washing process on the speciation distribution and pollution level associated with heavy metals in soil. The results showed that the combination of HEDP (1-hydroxyethylidene-1,1-diphosphonic acid) and FeCl3 at a ratio of 6:4 exhibited the most effective removal of Cd, Cu and Ni from the contaminated soil at an e-waste recycling site. Under optimal washing conditions, with a soil-to-liquid ratio of 1:20 and a washing time of 48 h, the removal rates of Cd, Cu and Ni were 96.72%, 69.91% and 76.08%, respectively. It needed to be emphasized that the combination washing agents were able to remove most of the acid-soluble, reducible and oxidizable fractions of heavy metals, and even the removal rates of the stable residual fraction (e.g., of Cd) was at a relatively high level. In addition, the washing process significantly reduced the pollution level associated with heavy metals in soil. This study aid in the development of combined efficient washing agents and explores optimal washing strategies for the remediation of Cd, Cu, and Ni-contaminated soil at e-waste recycling sites. The findings may play a role in enhancing the remediation capabilities for soils contaminated with multiple heavy metals, due to its characteristics of and high-efficiency and environmental friendliness.

Adding carbon sources to the substrates enhances Cr and Ni removal and mitigates greenhouse gas emissions in constructed wetlands.

Constructed wetlands for wastewater treatment pose challenges related to long-term operational efficiency and greenhouse gas emissions on a global scale. This study investigated the impact of adding peat, humic acid, and biochar into the substrates of constructed wetlands and focused on Cr, and Ni removal, greenhouse gas emissions, and microbial communities in constructed wetlands. Biochar addition treatment achieved the highest removal efficiencies for total Cr (99.96%), Cr (VI) (100%), and total Ni (91.04%). Humic acid and biochar addition both significantly increased the heavy metal content in wetland plant Leersia hexandra and substrates of constructed wetlands. Further analysis of microbial community proportions by high-throughput sequencing revealed that biochar and humic acid treatments enhanced Cr and Ni removal efficiency by increasing the abundance of Bacteroidetes, Geobacter and Ascomycota. Humic acid addition treatment reduced CO2 emissions by decreasing the abundance of Bacteroidetes and increasing that of Basidiomycota. Peat treatment decreased CH4 emissions by reducing the abundance of the Bacteroidetes. Biochar treatment increased the abundance of the Firmicutes, Bacteroidetes, Proteobacteria as well as Basidiomycota, resulting in reduced N2O emissions. Biochar and humic acid treatments efficiently removed heavy metals from wastewater and mitigated greenhouse gas emissions in constructed wetlands by modifying the microbial communities.

A highly-sensitive electrochemical sensor based on Ni nanoparticles modified carbon nanotubes/sulfonated reduced graphene oxide for the detection of capsaicinoids in leisure sauced meat products.

Unclear labeling of spiciness degrees on leisure sauced meat products is prone to resulting in customer complaints and commercial disputes. The content of capsaicinoids is the basis for evaluating the spiciness of food. In this work, an electrochemical sensor based on nickel nanoparticles modified carbon nanotubes (Ni-CNTs) and sulfonated reduced graphene oxide (S-rGO) was developed for the rapid detection of capsaicinoids content in leisure sauced meat products. The linear ranges of capsaicins are 0.01-100 µmol/L with ultra-low detection limits of 1 nmol/L. The outstanding performances are primarily due to the synergistic effect between Ni-CNTs and S-rGO. This effect not only created a three-dimensional stacked structure that improved the electrochemically active surface area, but also generated an internal electric field that improved the charge transfer rate. This work provides a basis for standardized evaluation of spiciness.