Total Nickel Content Research Articles

Visbreaking of heavy oil with high metal and asphaltene content

The visbreaking of Canadian oil sands bitumen (OSB) and Tahe atmospheric residue (AR) with high metal and asphaltene content was studied to deepen the understanding of the utilization of ultra-inferior heavy oil. The total content of nickel and vanadium in the asphaltenes contained in Canadian OSB reaches 1300 ppm, promoting large-scale aggregation of asphaltenes. Driven by high asphaltene content of 19.3 wt% and large-scale aggregation of asphaltenes, Canadian OSB with an initial boiling point (IBP) of 500 °C exhibits rapid condensation during visbreaking. Furthermore, those asphaltenes with the highest metal content participate in condensation first, producing metallic nickel in the formed coke. By changing cutting strategy, the group composition and metal distribution of Canadian OSB can be adjusted. A viscosity reduction rate above 99 % is obtained during the visbreaking of Canadian OSB with an IBP of 350 °C, similar to the visbreaking of Tahe AR with an asphaltene content of 15.4 wt% and a total metal content of 300 ppm.

Assessing phytoremediation potentials of selected plant species in restoration of environments contaminated by heavy metals in gold mining areas of Tanzania

This study assessed and classified the phytoremediation potentials of selected plant species around gold mining areas in restoring the environments contaminated by heavy metals. The geographic focuses of the study were the Golden Pride Gold Mine (GPGM) and Geita Gold Mine (GGM) in Tanzania. The shoots and roots of plant species surrounding the mining areas and the samples of associated soils were collected and analysed for total concentrations of lead (Pb), chromium (Cr), cadmium (Cd), copper (Cu), arsenic (As), manganese (Mn) and nickel (Ni) using Atomic Absorption Spectrophotometer (AAS) and UV-VIS spectrophotometry. Results indicated that the soils from study areas were loamy textured and slightly acid (pH 6.1–6.5), soil organic carbon and organic matter were low (0.6–2.0%), total nitrogen was very low (<0.10%), phosphorous ranged from low (6–12 mg kg−1 soil) to high (13–25 mg kg−1 soil), and cation exchange capacity ranged from low (6.0–12.0 cmol(+) kg−1 soil) to medium (12.1–25.0 cmol(+) kg−1 soil). In assessing heavy metals using plant parts, the roots of giant rats-tail grass (Sporobolus pyramidalis) accumulated highest Pb (757.78 μg g−1), Creeping Blepharis (Blepharis maderaspatensis) the Cd (158.11 μg g−1), lantana (Lantana camara) the As (68.61 μg g−1), and leuceana (Leucaena leucocephala) accumulated higher Mn (2734.61 μg g−1) and Ni (4464.33 μg g−1). In shoots, L. leucocephala accumulated higher Cr (1276.67 μg g−1) and higher Cu (2744.44 μg g−1) in L. camara. Although S. pyramidalis, M. repens, L. camara, B. maderaspatensis and L. leucocephala are likely to pose hazards to herbivores (grazing animals) while entering the food chain, they are still potential hyperaccumulators thus can be used to decontaminate metalliferous affected soils. Blepharis maderaspatensis has never been reported anywhere as Pb, Cd, Cu, Mn and Ni uptake plant hence this can be regarded as a new finding.

Trace Element Accumulation in Two Turtle Species, Malaclemys terrapin and Chelydra serpentina, in New Jersey, USA.

Trace elements in aquatic environments pose a risk to biological communities; this study investigates the total concentrations of arsenic (As), silver (Ag), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), selenium (Se), lead (Pb), and zinc (Zn) within muscle, carapace, liver, and adipose tissues of diamondback terrapins and common snapping turtles in New Jersey. The effects of tissue type, sex, size, and location upon trace element accumulation were studied. The data obtained indicates that within diamondback terrapins and common snapping turtles, trace element accumulations displayed a significant difference among tissue types and sex (p < 0.005). The data indicates that Ag, Cd, Cu, and Hg can accumulate within the liver of diamondback terrapin. Se was found to accumulate in the livers of both diamondback terrapin and common snapping turtles. The highest mean concentrations of Co, Cr, Ni, and Pb were found in the carapace of both turtle species. Sex was found to have an impact on As, Hg, and Zn accumulation within different tissue types of diamondback terrapins. Diamondback terrapin males were found to have higher concentrations of As within the carapace. Diamondback terrapin females possessed higher concentrations of Hg in muscle tissues and Hg and Zn in the carapace. Turtle size and collection location land type and land cover did not display any correlation with trace element bioaccumulation for either species.

Natural enrichment of chromium and nickel in the soil surrounds the karst watershed

BACKGROUND AND OBJECTIVES: As a public concern, monitoring and controlling toxic metals pollution is needed worldwide. Due to the ability of poisonous metals in biomagnification and bioaccumulation, they can cause several adverse impacts on ecological and human health. The study aims to assess chromium and nickel enrichment levels and estimate the soil''s ecological risk surrounds the Pangkajene watershed.METHODS: The total concentrations of chromium and nickel were determined using the Flame Atomic Absorption Spectrophotometer. This study used contamination factor, geo-accumulation index, and pollution load index to evaluate soil enrichment status. The ecological hazard index is used to estimate the potential hazard that may occur due to contamination. FINDINGS: The mean concentrations of chromium and nickel were 92.9 and 43.18 mg/kg, respectively. Chromium concentration exceeded the soil quality guideline for the protection of environment and human health, while Ni still below the standards. The geo-accumulation index value indicated no human-made-derived contamination in the soil. Weathering of carbonate rocks is the chromium and nickel major enrichment factor in the Pangkep regency. Contamination factor and pollution load index values showed low pollution in the studied soil. However, all study sites exceeded the ecological hazard index value (Ecological hazard index>1), which indicates a considerable ecological risk in the Pangkajene watershed area. CONCLUSION: These findings may provide baseline information related to chromium and nickel enrichment in the soil for Pangkep regency municipality. The Pangkep regency municipality must highlight the importance of strengthening environmental standards and monitoring mechanism as the priority to maintain a healthy environment.

Ionic liquid functionlized on multiwall carbon nanotubes for nickel and lead determination in human serum and urine samples by micro solid-phase extraction

In this study, a novel synthesis adsorbent, 1-(3-aminopropyl)-3-methylimidazolium hexafluorophosphate functionlized on multiwall carbon nanotubes ([Apmim][PF6]-MWCNTs, IL@MWCNTS) was used for nickel/lead (Ni/Pb) extraction and determination by dispersive ionic liquid micro solid-phase extraction (DIL-μ-SPE) coupled to electrothermal atomic absorption spectrometry (ET-AAS). After dilution of 20 mg of IL@MWCNTS in 200 μL of acetone, the mixture was injected to 10 mL of human serum/urine samples at pH of 8.0. After sonication for 5 min, the Ni(II) / Pb(II) were extracted by ionic liquid phase and then centrifuged for 2.5 min. The upper liquid phase set aside and Ni(II) / Pb(II) loaded in adsorbent were back-extracted by acidic solution at pH=2-3. Finally, the concentration of total nickel and lead was determined by ET-AAS. By optimizing, the limit of detection, linear range, and enrichment factor for nickel and lead were obtained (0.05 μg L−1; 0.1 μg L−1), (0.2-5.8 μg L−1; 0.4-30 μg L−1) and 24.7; 5.1, respectively (RSD less than 5%). Also, the capacity absorption of IL@MWCNTS for nickel and lead ions were achieved 149.3 mg g-1 and 162.5 mg g-1, respectively. The DIL-μ-SPE procedure was validated for nickel and lead extraction by spiking of real samples and ICP-MS analyzer.

A risk-based approach for the safety analysis of eight trace elements in Chinese flowering cabbage (Brassica parachinensis L.) in China.

Most countries set regulatory values for the total trace element (TE) concentrations in soil, although there is growing interest in using a risk-based approach to evaluate the bioavailable TE using dilute salt extractants or other soil parameters, including pH and organic carbon. The present study compares the current regulatory system (based on total TEs and pH) and a risk-based approach using 0.01 mol L-1 CaCl2 to estimate the bioavailable fraction. In total, 150 paired samples of Chinese flowering cabbages (Brassica parachinensis) and their growth soils were collected, and the total and extractable concentrations of chromium (Cr), cadmium (Cd), lead (Pb), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As) and mercury (Hg), as well as soil pH and organic matter content, were measured. No more than 3.33% of the edible parts exceeded Chinese food safety standards, even when growing in soils exceeding the current regulatory thresholds by over 50%. The total soil Cd (1.5mg kg-1 ), as well as the extractable concentrations of Cd (0.1mg kg-1 ), Ni (0.03 mg kg-1 ) and Zn (0.1mg kg-1 ), are the key factors affecting the TE concentrations in B. parachinensis. Our findings suggest that the current soil regulatory guidelines for safe production of B. parachinensis are overly strict and conservative. A risk-based approach based on the extractable TE concentrations would provide a better indication for plant uptake of soil TEs and avoid the waste of farmlands that can still produce safe vegetables. Future research should focus on providing crop-specific available TE concentration guidelines to promote effective utilization of farmlands. © 2021 Society of Chemical Industry.

Atmospheric sources of anthropogenic and geogenic trace metals in Australian lichen and fungi

Trace metals in archived lichen and fungi samples, dating back over 158 years, were measured to ascertain their potential to record temporal shifts in atmospheric source inputs, starting from the onset of industrial activity in Australia to the present. Lichen (Cladonia n = 85; Usnea n = 47) and fungi (Trametes n = 40) samples from the greater Sydney and Melbourne areas were analysed for their total aluminium (Al), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), titanium (Ti) and zinc (Zn) concentrations using inductively coupled mass-spectrometry. We determined enrichment factors (EFs) of each metal, normalised using Al concentration. All metal concentrations were input to the United States Environmental Protection Agency’s Positive Matrix Factorisation (PMF) model to determine the probable contributing sources, with Sydney (n = 81) and Melbourne (n = 91) samples considered separately. Elevated EFs for Cd, Cu, Pb and Zn (14–1211) suggest that anthropogenic inputs have influenced lichen and fungi concentrations, whilst low EFs for Fe and Ti (1–4) imply geogenic source inputs. Elevated EFs for Pb in samples from 1932 to 2002 correspond with the 70-year period of leaded petrol emissions. PMF modelling determined four distinct source factors: Factor 1 – Cr, Co, Fe, Ni, Zn (19.8 % of the total recovered mass) corresponding to metalliferous industries; Factor 2 – Cd, Cu, Zn (5.3 %) typical of smelting, mining and coal combustion emissions; Factor 3 – Pb (6.6 %) dominated by leaded petrol emissions; Factor 4 – Al, Fe and Ti (68.2 %) relating to geogenic sources. The data show that archived Australian lichen and fungi samples provide effective biomarker proxies for atmospheric trace metal contamination. These new data, extending back to the mid-1800s, provide a more nuanced understanding of anthropogenic atmospheric pollution sources since the onset of post European industrialisation on the Australian continent.

Assessing Phytoremediation Potentials of Selected Plant Species in Restoration of Environments Contaminated by Heavy Metals in Gold Mining Areas of Tanzania

Phytoremediation uses green plants for in-situ removal, degradation, and containment of contaminants in soils, surface waters and groundwaters. However, little research has been conducted on the phytoremediation potential of plant species in removing heavy metals in the contaminated soils within the gold mining concession areas. Therefore, this study assessed and classified the phytoremediation potentials of selected plant species around gold mining areas in restoring the environments contaminated by heavy metals. The geographic focuses of the study were the Golden Pride Gold Mine (GPGM) and Geita Gold Mine (GGM) in Tanzania. The shoots and roots of plant species surrounding the mining areas and the samples of associated soils were collected and analysed for total concentrations of lead (Pb), chromium (Cr), cadmium (Cd), copper (Cu), arsenic (As), manganese (Mn) and nickel (Ni) using Atomic Absorption Spectrophotometer (AAS) and UV-VIS spectrophotometry. Routine soil analysis was performed to provide an impression of the fertility status of soils in these gold mining areas. Further, the plants were classified based on their ability to accumulate or exclude heavy metals from the soils. Results indicated that the soils from study areas were loamy textured and slightly acid (pH 6.1–6.5), soil organic carbon and organic matter were low (0.6–2.0%), total nitrogen was very low (<0.10%), phosphorous ranged from low (6–12 mg kg-1 soil) to high (13–25 mg kg-1 soil), and cation exchange capacity ranged from low (6.0–12.0 cmol(+) kg-1 soil) to medium (12.1–25.0 cmol(+) kg-1 soil). In assessing heavy metals using plant parts, the roots of giant rats-tail grass (Sporobolus pyramidalis) accumulated highest Pb (757.78 µg g-1), Creeping Blepharis (Blepharis maderaspatensis) Cd (158.11 µg g-1), lantana (Lantana camara) As (68.61 µg g-1), and leuceana (Leucaena leucocephala) accumulated higher Mn (2734.61 µg g-1) and Ni (4464.33 µg g-1). In shoots, L. leucocephala accumulated higher Cr (1276.67 µg g-1) and higher Cu (2744.44 µg g-1) in L. camara. Results indicated that S.pyramidalis and L.camara are hyper-accumulators of Pb and Cu, respectively. No hyper-accumulator of Cr, Cd, As, Mn and Ni in the areas. Results further revealed that S. pyramidalis, Natal grass (Melinis repens), L. camara, L. leucocephala and B. maderaspatensis are potential phytoremediators, as were either accumulators or excluders of Pb, Cr, Cd, Cu, As, Mn and Ni. Although S. pyramidalis, M. repens, L. camara, B. maderaspatensis and L. leucocephala are likely to pose hazards to herbivores (grazing animals) while entering the food chain, they are still the potential phytoremediators in decontaminating of metalliferous affected ecosystems.

Quantification of cobalt and nickel in urine using inductively coupled plasma atomic emission spectroscopy

Cobalt and nickel are micronutrients indispensable for the body, therefore, their use with food or as part of vitamin complexes is necessary to maintain health. As a result, trace cobalt and nickel contents are present in human biological fluids – blood and urine. According to the World Anti-Doping Agency prohibited list, they belong to the group of blood doping preparations – erythropoiesis stimulants. Nowadays, methods for their control in biological fluids are being actively developed to establish reasonable allowable contents of these trace elements in human biological fluids. However, in addition to developing highly sensitive methods for the determination of the total content of cobalt and nickel using ICP-MS and ETAAS, the development and comparison of various sample preparation methods that can provide the greatest accuracy, reproducibility and express analysis are also relevant. In the present paper, a comparison of different sample preparation methods – direct analysis, dilution and microwave mineralization of urine samples was shown, the detection and quantification limits were compared, some metrological characteristics that can be achieved using these sample preparation methods were evaluated. The procedure was tested on artificial and real urine samples. Taking the course of vitamin complexes in therapeutic concentrations was shown not to lead to a significant increase in the concentrations of analytes in urine, while taking elevated concentrations (for example, 2-fold) makes it possible to determine them even using ICP-AES. However, even in this case, cobalt and nickel concentrations remain at a relatively low level, not able to lead to a significant increase in erythropoiesis.

Potential of invasive alien top predator as a biomonitor of nickel deposition – the case of American mink in Iceland

American mink Neovison vison is one of the most harmful non-indigenous species in Iceland and has been proven to be a useful indirect bioindicator and biomonitor for numerous environmental pollutants. Therefore, the main objective of the study was to determine the total nickel concentration in the spleen of 35 females and 30 males obtained from Brokey archipelago and the south coast of Hvammsfjörður (Dalabyggð, Iceland) using graphite furnace atomic absorption spectroscopy. We also assessed the correlation between nickel concentration and selected anatomical and morphological parameters, hypothesising that invasive alien N. vison is a promising candidate species for biomonitoring the deposition of this trace element. The results indicated a substantial variation in nickel concentration in the spleen tissue of examined animals. For males, the maximum concentration exceeded the average level by more than 16 times, and for females by more than 7 times. The correlation coefficient between morphometric features and the level of nickel concentration in the spleen did not show a significant relationship in any of the tested combinations, for all tested animals or for each sex separately. In conclusion, American mink in Iceland can be considered a promising species for qualitative and quantitative assessment of ecosystems in terms of nickel pollution.

Spatial distribution and ecological assessment of nickel in sediments of a typical small plateau lake from Yunnan Province, China.

Nickel (Ni) in small plateau lake sediments plays an important role in influencing the quality of lake ecosystems with a high degree of endemism and toxicity. This paper focuses on the spatial distribution and ecological risks of nickel in the sediments of Jianhu Lake, a small plateau lake in China, and the influence of pH and total organic carbon (TOC) on nickel concentrations. The results showed that average total nickel concentrations were 138.99 ± 57.57 mg/kg (n = 38) and 184.31 ± 92.12 mg/kg (n = 60) in surface sediments (0-10 cm top layer) and sediment cores (0-75 cm depth), respectively, and that the residual fraction was the main form of nickel. Simultaneously, through a semivariogram model, strong spatial dependence among pH, TOC, and the oxidizable fraction was revealed, whereas total nickel, exchangeable and the weak acid soluble fraction, reducible fraction, and residual fraction showed moderate spatial dependence. The vertical distribution revealed that nickel accumulated mainly in the bottom 5 cm (70-75 cm) of the sediment layer and that the pH was higher there, whereas TOC was concentrated mainly in the top 5 cm of sediment. Using geoaccumulation and a potential ecological risk index, moderate nickel pollution and moderate risk levels were found in most surface sediments, but moderate nickel pollution and high risk levels were observed in most sediment cores. In addition, pH and TOC were found to have a strong effect on the distribution and concentration of nickel and its fractions in the small plateau lake. In summary, nickel posed a certain degree of pollution and ecological risk, which deserves attention in the sediments of small plateau lakes.

Choosing a Microspherical Catalyst for Partial Oxidation of Methane to a Hydrogen-Containing Gas

The influence of the chemical composition of microspherical nickel–cobalt catalysts on aluminosilicate and aluminum oxide supports on the catalytic characteristics of methane oxidative conversion to a hydrogen-containing gas was studied on a pulse laboratory installation with separate supply of the feed and oxidant. The physicochemical and catalytic studies show that the total content of nickel and cobalt oxides on the level of 10 wt % is sufficient for preparing a catalyst capable of repeated redox transitions.

Oxidized Nickel Ore and Galvanic Sludge Combined Treatment Investigation

Galvanic sludges have been accumulated in large quantities in Ural region. These materials contain low concentration of non-ferrous metals (nickel, zinc, chromium) and iron, and are not being processed. Another difficult for treatment nickel containing materials are oxidized nickel ores, deposits of which are located in Ural. However, the nickel ores aren’t processed due to low economic efficiency. In this article simultaneous treatment of oxidized nickel ore and galvanic sludge was investigated. The proposed technology includes nickel ore sulfatization at high temperature in presence of sulfuric acid and further water leaching. Therefore, maximum nickel extraction in solution at leaching of oxidized nickel ore after sulfatization was 82 %. Solutions after leaching are neutralized by nickel containing galvanic sludge. Due to partial nickel chromite dissolution in sulfuric acid a total nickel concentration has been substantially increased. Selective nickel extraction from such solutions is possible by sorption methods, and further metal nickel obtaining – by electrowinning.

Nickel uptake kinetics and its structural and physiological impacts in the seagrass Halophila stipulacea

The present work aims to provide insight into interactions between trace metals and higher plants, focusing on nickel uptake and its effects in seagrasses at environmentally relevant concentrations. Total and intracellular nickel accumulation kinetics, nickel effects on structural cell components, oxidative stress marker and cellular viability, and the accumulation kinetics-toxic effects relationship were investigated in leaves of Halophila stipulacea plants incubated in seawater under laboratory conditions containing nickel ions at 0.01–10 mg L−1 for 14 days. Nickel accumulation kinetics in H. stipulacea young and older apical leaves followed a Michaelis-Menten-type equation, allowing the calculation of uptake parameters; uptake rate (Vc) and equilibrium concentration (Ceq) tended to increase with the increase of nickel concentration in the medium. A dose- and uptake parameter-dependent actin filament (AF) and endoplasmic reticulum (ER) impairment was observed, whereas no effects occurred on microtubules and cell ultrastructure. AF disturbance and ER aggregation were firstly observed in differentiated cells at the lowest concentration on the 12th and 14th day, respectively, while AF disruption in meristematic cells firstly occurred at 0.05 mg L−1; the effects appeared earlier and were more acute at higher concentrations. Increased H2O2 levels were detected, while, at the highest exposures, a significant reduction in epidermal cell viability in older leaves occurred. The lowest total nickel concentrations in young leaves associated with AF disturbance onset at nickel exposure concentrations of 0.01–1 mg L−1 varied between 18.98 and 63.93 μg g−1 dry wt; importantly, they were comparable to nickel concentrations detected in seagrass leaves from various locations. The relationships between exposure concentration, uptake kinetic parameters and toxic effect onset were satisfactorily described by regression models. Our findings suggest that (a) nickel may pose a threat to seagrass meadows, (b) H. stipulacea can be regarded as an efficient biomonitor of nickel, (c) AF and ER impairment in seagrass leaves can be considered as early biomarkers of nickel-induced stress, and (d) the regression models obtained can be used as a tool to evaluate ambient nickel levels and to detect ecotoxicologically significant nickel contamination. The data presented can be utilized in the management and conservation of the coastal environment.

Catalytic adsorptive of nickel metal from Iraqi crude oil using non-conventional catalysts

The existence of heavy metals together with the essential hydrocarbon components of crude oil causes a significant issue that leads to harmful effects on many petroleum processes industries in addition to reducing the value of oil product produced from refineries. The current research aims to study the possibility of removing the nickel element from Iraqi crude oil by a simple pre-treatment method based on adsorption technology. Treating of crude oil was performed using two types of adsorbents, the first one that had a high surface area, namely commercial granular activated carbon (GAC) and the other was non-valuable material, i.e., white egg shells (WES). The adsorption process was conducted in a batch mode unit and at different operating parameters of the adsorbent media amount, (water/crude oil) ratio, the contact time and the agitation speed in order to optimize the conditions for the best removal of the nickel substance from crude oil. The results indicated that the GAC had a high adsorption capacity reached to 87%, while the WES had a modest efficiency of about 45% removed of total nickel content. The results also showed that the efficiency of the treatment was increased with increase in the amount of adsorbent material, the (water/crude oil) ratio, the contact time and the agitation speed to a certain limit and then fixing or decreasing according to the type of variable. The present paper provides a simple pre-treatment method for removing one of the harmful heavy metals from crude oil in an easy and eco-friendly layout accessing to zero residue level concept.

Assessment of bioaccessible and dialyzable fractions of nickel in food products and their impact on the chronic exposure of Belgian population to nickel

This study aimed to investigate bioaccessible/dialyzable fractions of nickel in selected foods and to clarify the impact of the food digestion/absorption on the final exposure of consumers to nickel. In vitro gastrointestinal incubation experiments were conducted to estimate the bioaccessibility of nickel in different foods. For estimation of a dialyzable fraction, dialysis filtration was conducted. Highest bioaccessibility (99.6%) was observed for wheat-based breakfast cereals. Lowest bioaccessibilities was observed for dried-fruits (on average 20.4%). Highest (61.5%) and lowest (24.5%) dialyzable fractions were observed for wheat-based breakfast cereal and chocolate respectively. Bioaccessible/dialyzable fractions based exposure assessments were highlighted the overestimation of exposures calculated based on total nickel concentrations in foods. This is particularly important when exposure values were compared with toxicological thresholds in a risk characterization study. When threshold values have been obtained through animal studies in which nickel was dosed at 100% accessibility/availability, e.g. nickel salts this is even more important.

Bioavailability of heavy metal load in soil, groundwater, and food crops manihot esculenta and carica papaya in dumpsite environment

The need for consciousness of the impact of heavy metal on crop production and human health risk through policy formulation necessitated the study. Screening of the total heavy metal iron (Fe), nickel (Ni), cadmium (Cd), lead (Pb), chromium (Cr), and copper (Cu) concentration in soils collected at random at a depth of 0–30 cm within and around dumpsite environment in Ikhueniro, Iguomo, and Okhuahe suburban communities, Benin City, Nigeria was carried out. Cassava tubers, Pawpaw pods (manihot esculenta and carica papaya) cultivated and groundwater within and around the dumpsite environment were also tested for the selected heavy metal. The study employed integrated scientific methods in actualizing its aim. The results show that mean values of 520.97 ± 1.66 mg/kg Fe, 39.07 ± 0.33 mg/kg Ni, 1.41 ± 0.10 mg/kg Cd, 1.92 ± 0.00 mg/kg Pb, 1.24 ± 0.02 mg/kg Cr, and 24.97 ± 5.16 mg/kg Cu were recorded for soil. On the other hand, 127.00 ± 2.01: 22.36 ± 1.20 mg/kg Fe and 5.70 ± 2.11: 0.98 ± 1.11 mg/kg, respectively, amongst other metals measured in cassava and pawpaw. The results were compared to Standard Organization of Nigeria (SON), National Food and Drug Administration Control (NAFDAC), and Food and Agricultural Organisation/World Health Organisation (FAO/WHO) standards; it was observed that Fe, Ni, and Pb exceeded the threshold values for metal concentration in soil and drinking water. Policy formulation restricting farming and drilling of boreholes within the locus of dumpsite environment is advocated to fostering the attainment of green environment for sustainable development and public consciousness of the detrimental effects of heavy metals on human health.

Accumulation of potentially toxic elements in agricultural soil and scenario analysis of cadmium inputs by fertilization: A case study in Quzhou county

Fertilizer application has greatly increased crop yield, however impurities in mineral or organic fertilizers, such as heavy metals, are being added to agricultural soils, which would pose a high risk for soil and crop production. 115 soil samples were collected from Quzhou, a typical agricultural county in the North China Plain, to investigate the total content of cadmium (Cd), arsenic (As), lead (Pb), nickel (Ni), copper (Cu), zinc (Zn) and chromium (Cr) in soils. The contamination levels and source apportionment of studied elements were explored by the pollution indices, multivariate statistical approaches and geostatistical analysis. The ranges of Cd, As, Pb, Ni, Cu, Zn and Cr were between 0.08 and 0.35, 5.34–15.9, 7.34–38.9, 12.9–61.3, 7.80–27.0, 31.4–154, and 17.0–50.5 mg/kg and with the mean values 0.16, 9.20, 16.0, 24.7, 17.6, 61.1, and 29.5 mg/kg, respectively. The studied area was slightly polluted mainly by Cd, and higher pollution was found in soils under vegetable crops. The application of mineral phosphate fertilizer and livestock manure were the main source of Cd and Zn, and other elements (As, Pb, Ni and Cu) might originate from soil parent materials. Scenario analyses were performed using the R programming language, based on the cadmium contents in mineral phosphate fertilizers and livestock manures. The results showed that the long-term application of phosphate fertilizers would lead to some Cd enrichment in soil without risk of substantial pollution. Compared to pure mineral fertilizers, the long-term application of blended fertilizers (30% livestock manures and 70% phosphate fertilizers) or livestock manures would incur a higher Cd pollution risk within a short period, with a maximum probability of Cd risk of 55.21%. Mitigation measurements and scientific agronomic practices should be developed to minimize the risk of potential toxic elements in agricultural soil.

Effect of the Phase Composition of a Titanium Nickelide-Based Alloy on the Formation of Liquid in Sintering

The formation of a liquid phase in titanium nickelide–based alloys, which are enriched in nickel (55.8–55.9 wt %) and abundant in Ti2Ni/Ti4Ni2Ox phase intermetallic particles, is studied. The phase transformations in the alloys are investigated during heating in argon and helium atmospheres in a temperature range of 900–1200°C by differential thermal analysis. The cause for the formation of liquid in the alloys in a gas medium is found to be their oxidation. Oxidation results in the redistribution of the main chemical elements of the alloy on its surface and the formation of titanium- and nickel-rich phases. This leads to the eutectic transformation TiNi + TiNi3 → L. On heating in a vacuum, the formation of liquid is possible only in the alloy characterized by a high volume fraction of Ti2Ni/Ti4Ni2Ox phase particles. The precipitation of the particles during melting of the alloy depletes its matrix of titanium; this leads to a substantial increase in the nickel content in the matrix as compared to the total nickel content in the alloy. This effect, likely in combination with oxidation, also initiates the eutectic reaction in heating. Liquid-phase (supersolidus) sintering is shown to be possible for titanium nickelide–based alloys due to the eutectic reaction.

Calcined electroplating sludge as a novel bifunctional material for removing Ni(II)-citrate in electroplating wastewater

Electroplating sludge as the hazardous waste produced from the electroplating wastewater treatment plants, is also precious resources of various transition metals. In this study, the novel calcined electroplating sludge (CES) was prepared via facile calcination and subsequently used as an effective bifunctional material for removing Ni(II)-citrate in electroplating wastewater. The CES displayed a high removal efficiency of Ni(II)-citrate in the CES/H2O2 system via oxidative degradation of complex compounds and adsorptive removal of Ni2+. The high removal efficiency could be ascribed to the excellent catalysis and adsorption ability of the CES. The Fe and Cu oxides in the CES were considered as reactive components for the activation of H2O2 to degrade the complex compound, while the oxygen-containing functional groups on the CES surfaces were responsible for the adsorption of Ni2+. Various parameters affecting Ni(II)-citrate in the electroplating wastewater removal efficiency were tested. With the addition of 50 mmol/L H2O2 and 1.5 g/L CES, 87% of the total nickel could be removed within 50 min when the total nickel concentration in the Ni(II)-citrate containing electroplating wastewater was 283 mg/L. This study provides a new method for the treatment of electroplating wastewater containing nickel-organic complexes by the electroplating sludge wastes. This technology can reduce the treatment cost of electroplating wastewater and achieve the concept of disposal waste with waste.