جستجوی مقالات مرتبط با کلیدواژه « نیکل » در نشریات گروه « محیط زیست »

In the present study, cypress cone raw biochar was modified using walnut peel extract under the chemical modification process and its performance optimization on nickel (Ni) removal in aqueous solutions was affected by various factors was evaluated using the RSM. Contrary to expectation, chemical modification caused a decrease in the specific surface area and a decrease in effective functional groups in Ni removal (functional groups containing oxygen and C-C) compared to the non-modified biochar sample. The investigations of Ni removal by modified biochar also showed a significant reduction of Ni removal by this adsorbent in the same conditions compared to the non-amended sample, so that the average amount of Ni removal in the same conditions in the non-modified adsorbent was 1.8 times more than modified biochar. The investigation of the factors affecting the removal of Ni in two modified and non-modified adsorbents showed that with the increase of the initial concentration of Ni, the removal of Ni had a decreasing trend; while with the increase of other factors, Ni removal showed a relatively increasing trend. The results of the present study show that the modification and engineering of biochars by the mentioned chemical method, with the effect of reducing the physical absorption (reduction the specific surface area) and chemical adsorption (reduction of the intensity of the active groups affecting the adsorption), caused the reduction of Ni removal efficiency compared to the raw sample, which challenges the hypothesis of constant increase of heavy metal removal efficiency by chemical modification of biochar.

Nano material has attracted much attention due to its functional groups and special properties. In this study, silica nanoparticles immobilized on zeolite 13X granules (SZX13), by sol gel method was synthesized. The aim of this study was determination of the performance of prepared nano sorbent in nickel ions removal from aqueous solution.

The present historical research, with an analytical-comparative approach, has used inferential and deductive reasoning. First, the principles of organic style architecture, derived from a comparative study of written evidence and existing documents, were explained as a criterion of measurement. Then, a list of works of organic architecture in Iran was prepared to select samples for analysis by purposive sampling. Finally, the analyzed samples were compared with the principles of organic architecture.

Scanning Electron Microscope analysis showed that the immobilization process was successfully carried out and the immobilized particles has a nano size distribution. Optimized values for each factor to achieve the highest uptake were found to be as follows: The Ni initial concentration of 60 mg/L, the pH 6, the adsorbent (SZX13) dose of 1 g, at 40 ° C.

Results showed that the immobilization of nano particles on the zeolite not only led to that the particles were distributed in an expanded volume, but also prepare the accessible usage of that in an industrial scale. In addition, with immobilization of silica nanoparticles onto zeolite granules, the sorption of nickel ions were increased in comparison to that by using zeolite 13X, and the removal percentage was increased from %26 to %43.98.

As a result of the development of industries and the entry of waste water from industrial factories into the environment, the ecosystem around the factories and surface and underground waters are in danger of pollution.  In this research, the effect of released wastewater plating industry in Safadasht Industrial Park of Karaj on the concentration of heavy metals in the area was studied in spring and summer.

Sampling was carried out at a distance of 70, 120, 220, 320 and 430 meters from the industrial complex around the discharge path. The method of digestion and atomic absorption of flame was used to measure chromium and nickel content in samples.

The average results of soil samples were 1.15 to 2.12 for chromium and 1.07 to 1.73 for nickel in spring and 1.39 to 3.46 for chromium and 1.83 to 3.13 for μg / g for nickel in summer.

The results of the comparison of the levels of chromium and nickel in the soil in spring and summer, according to global standards, show that at all stations in both seasons the amount of chromium and nickel is lower than global standards. The zoning results show that the concentration of the elements in the samples increased with increasing distance from the wastewater to the environment at a distance of 430 meters. The reason for this can be the release of wastewater and its washed off by runoff during seasons from the industrial complex around the distances.

The discharge of heavy metals from various industries has negative effects on the environment and living organisms. Conventional technologies for removing heavy metals from aqueous solutions are not economically viable and, in addition to not being effective at low concentrations of metal ions, produce large amounts of chemical sludge. Nickel's biological uptake by living, inactive, microbial or plant-derived biomass is an alternative and innovative technology to remove this contamination from aqueous solutions. It has high absorbency and reabsorption capacity.
Investigation

In this research, in a review study with the aim of introducing different types of microbial and plant-derived biological adsorbents in order to remove nickel from aqueous solution and reveal the adsorption capacity of each adsorbent, articles found between 2001 and 2020 have been used.

Research has shown that the use of these biomass as a biological adsorbent for the removal of nickel in aqueous solution is a promising and environmentally friendly prospect.

Based on thermodynamic studies in most nickel biosorption processes with different adsorbents, the value of ∆G° is negative and the value of ∆S° is positive due to the increase of random collisions between solid and solution during the process.

Biological uptake nickel by living, inactive, microbial or plant-derived biomass is an alternative and innovative technology to remove this contaminat from aqueous solutions. It has high adsorbency and readsorption capacity. In this study, with the aim of introducing different types of microbial and plant-derived biological adsorbents in order to remove nickel from aqueous solution and revealing the adsorption capacity of each adsorbent, articles published between 2001 and 2020 were used. The results of research works performed were used to compare the adsorption capacity of microbial and plant-derived biosorbents to remove nickel from aqueous solution. Studies showed that the skin uptake capacity of grapefruit with 95% is more favorable than other plant derivatives. Curtobacterium sp also has the best performance with 100% adsorption capacity among microbial biosorbents. Research showed that the use of these biomasses, as a biological adsorbent, for the removal of nickel in aqueous solution is a promising and environmentally friendly prospect.

Declining water resources caused usage of recycled water that sometimes not purified well.  The growing population and consequently increasing water demand, along with a shortage of available freshwater resources have inevitably led to the use of unconventional water resources. Irrigation lands with urban wastewater requires quality and quantity control for achieving food security. Therefore, the present study was conducted to investigate the effects of irrigation with urban wastewater on the concentration of Nickel and Cadmium in soils and their effects on plant, root, shoot, and functional characteristics of wheat.

  Field sampling was carried out at random from a depth of 0 to 20 cm. Wheat samples were taken at harvest from a 1-meter by 1-meter area. A total of 20 samples for Cadmium metal and 20 samples of Nickel metal were taken.

The results showed that the average concentration of Cadmium and Nickel was 10.6 and 49.43 kg, respectively, which resulted in an accumulation in various parts of the wheat plant. Increasing the concentration of Cadmium and Nickel in the soil increases the accumulation in the root, upper parts, and wheat seeds. Also, increasing the concentration of Cadmium and Nickel in the soil decreases the dry weight of the root, the shoot, and the weight of the thousand seed. However, there was no significant effect on two traits, number of grains per spike and number of spikes per square meter. The effect of Cadmium concentration was higher than that of Nickel.

Increasing 1 mg of soil Cadmium caused increasing, 0.81, 0.56, 0.6 mg Cadmium in root, upper parts and seed. For Nickel increasing the soil concentrations caused 0.29, 0.29, 0.11 mg in root, upper parts and seed.

Today, hazard of surface and underground water contamination with heavy metals has led to a global concern. Therefore, the current study was carried out to assess the effects of different types and rates of biochar on irrigation water heavy metals content.

For this purpose, 12 different biochars were produced using 6 different biomasses including wheat stubble, pea stubble, maize residual, reed stem and leaves, olive meal and beet pulp at 500 and 700 C under low oxygen condition. According to specific area results, cation exchange capacity and infrared spectrophotometry, wheat stubble, reed stem and leaves and residual maize biochars, which produced at 700 °C were selected for further studies. Then effect of nine levels of these biochars on irrigation water heavy metals (cadmium, nickel and lead) content were investigated using a completely randomized design(CRD) with three replicates. 

The results indicated that increase in temperature significantly reduce biochars yield, volatile compound percentage but increase acidity, cation exchange capacity, specific area and ash percentage. In addition, the results revealed that biochars and their applied doses could significantly reduce heavy metals content in irrigation water.

Increase in specific area, cation exchange capacity and acidity led to heavy metals elimination from irrigation water. Application of MB700 (compared with WB700 and RB700) and WB700 (compared with MB700 and RB700) could significantly reduce cadmium and nickel, respectively, whereas the effect of MB700 and WB700 in eliminating of lead was more pronounced than RB700. The maximum cadmium, lead and Nickel reduction was related to apply 32 g per liter biochar.

Soil microbial properties such as biomass, microbial respiration and nitrogen mineralization can be used as indicators to show the stress caused by heavy metal pollution on soil quality. The aim of this study was the measurement soil microbial activity to evaluate the effect of soil Ni contamination on soil quality and determination of ecological dose 50 (ED50).

This study was conducted as a factorial experiment in year 2016 based on a randomized completely design with three replications. The experiment factors including Ni concentration in six levels (0, 50, 100, 150, 300 and 600 mg Ni kg-1) and two incubation times (15 and 60 days). Soils sample was spiked uniformly with different concentrations of NiCl2. Microbial respiration, microbial biomass carbon, heterotrophic population and metabolic quotient were measured after incubation times of 15 and 60 days, then according to the results, ED50 was determined by using the dose-response curve.

Soil Nickel contamination on the indicator was significantly effective at P<0.01 level. Heterotrophic population, respiration and microbial carbon biomass decreased significantly (P<0.01) compared to control by increasing the Ni concentration and incubation times, whereas the increase of Ni concentration and incubation times were not significantly affected on metabolic quotient. The minimum amount of microbial respiration, microbial biomass carbon, and the heterotrophic population was observed at the end of incubation times and 600 mg Ni kg-1 with 77.07, 75.72 and 99.99% decrement compared to the control, respectively. ED50 value (mg/kg soil) of microbial respiration, microbial biomass carbon, and heterotroph population increased from 77.55, 78.63, 81.34 to 97.84, 111.04 and 84.67 respectively, with increased incubation time.

The soil contaminated with Nickel acutely decreased the biological activity of soil and the ecological dose increased with increasing the incubation time, suggesting that toxicity of Ni to soil microbial activity was decreased with increased incubation time. Ni concentration of 100 mgNikg-1 soil can be considered as the critical range of Ni for soil quality at which negative effect was observed.

Most industrial synthesis and processes require catalysis. Large quantities of catalysts are used in petroleum and petrochemical industry. These catalysts deactivate over time, and when the activity of a catalyst declines below an acceptable level, the catalyst has to be regenerated and reused. However, when regeneration is not possible, the catalyst activity might decrease to very low levels, so that further regeneration might not be economically feasible. In such cases, spent catalysts tend to be discarded as solid wastes.

Recycling of spent catalysts has become an unavoidable task to reduce the catalyst waste and prevent the environmental pollution. The kinetics of spent nickel oxide catalyst (NiO/Al2O3) from Razi petrochemical company leaching in nitric acid solutions was investigated. The effects of time reaction (60-360 min), nitric acid concentration (10%, 20%, 30%) and temperature (35oC, 85oC) on the rate of nickel leaching were studied. In addition, the reaction residues at various levels of nickel extraction were examined by XRD.

The results of XRD analysis of catalysts showed that the most important elements in the catalyst were aluminum (43%) in the form of aluminum oxide and nickel (12.15%) in the form of nickel oxide. A maximum extraction of 92% was achieved at 85oC, 30% HNO3 and 360min.

Time reaction, temperature and acid concentration showed positive effect. The leaching kinetics indicates that chemical reaction at the surface of the particles is the rate-controlling process during the reaction.

Thyme is a medicinal plant in the Lamiaceae family. According to no certain reports about tolerance or accumulation of nickel in native thymes Iran and also its various forms is used in various industries, accordingly, the effect of different levels of nickel sulfate (0, 10, 25, 50 and 100 μM) on growth and germination indices of two thyme species including daenensis (Thymus daenensis) and garden thyme (Thymus vulgaris) in a completely randomized design with three replications laboratory conditions (petri dish, hydroponics and in vitro) were evaluated. Two weeks after the above treatments, germination and growth indices were investigated. In hydroponic culture, obtained results showed that root length, root dry weight and chlorophyll content was decreased by increasing of nickel sulfate concentrations. According to the results of this experiment, it seems to daenensis thyme was more tolerant to this stress than garden thyme. In in vitro experiment, with increasing levels of nickel sulfate, reduction of root length was observed so the reduction in daenensis thyme was more severe than garden thyme. In this experiment, root length in the levels of 25, 50 and 75 μM nickel sulfate showed non-significant difference in garden thyme, but this difference was significant in daenensis thyme.

Abstract Presence of toxic heavy metals like nickel in water resources is a major environmental problem in many communities.   In this study, to stimulate the removal of Ni (II) from aqueous solution by silica aerogel-activated carbon nanocomposite, the parameters affecting the adsorption process such as pH, amount of adsorbent, contact time, temperature and concentration were investigated and optimized. The results showed the maximum adsorption at pH= 5. The lower pH, the more H+ ion competing with the metal ion for adsorption sites. Kinetic studies indicated that the adsorption process followed the pseudo-second order kinetics. Moreover, the equilibrium data related to adsorption isotherms showed a superiority of the Langmuir isotherm compared to other models. Discussion and Calculation of thermodynamic factors, such as ΔG◦, ΔH◦ and ΔS◦, indicated that the adsorption process is spontaneous, endothermic and irreversible. The results showed that silica aerogel-activated carbon nanocomposite has been successfully employed for the removal of Ni (II) from aqueous solutions.

The environmental pollution caused by oil waste is one of the main concerns in drilling industry. Contamination has increased with the expansion of exploration and production activities, which has imposed enormous environmental challenges to the drilling industry. This study has been carried out to determine the concentration of nickel and cadmium in a drilling cutting dump site in Azadegan plain in Khuzestan province. Soil samples were obtained from 13 sampling points in drill cutting dump site in Azadegan Plain, Khuzestan province to investigate soil pollution with nickel and cadmium. A-1 was selected as a background station. The rest of 12 stations were named as sample points (B2-M13) and 2 samples were obtained for each station in order to determine the concentrations of heavy metals in different depths. In this study, the Simple Random Cluster Sampling and Stratification Sampling methods were used in an area of 100*100 m2. After preparation, samples were analyzed by atomic absorption spectroscopy. Findings: The results showed that the concentration of cadmium in the soil varied from trace amount to 3.1 mg/kg, which was below the standard limit. Moreover, the concentration of nickel varied from 0.08 to 200 mg/kg. According to the results, the concentrations of heavy metals were lower than the toxicity limits for heavy metals in natural soil. Also there was no significant deviation from EPA, WHO standards and Europe action level for soil. Nickel concentration is negligible in all surface samples. Cadmium concentrations in all samples were below the standard limits. Nickel concentration was found to be over the threshold only in two sample points in depth of 40 cm. Nickel concentrations in K-11 and H-8 were 172 mg/kg and 200 mg/kg respectively. Although there is no sever environmental concerns related to these heavy metals in dumping site, land spreading was suggested as the best alternative for managing the area. Discussion and Conclusions: After performing the experiments, no significant environmental concerns associated with heavy metals was seen. However, land spreading method was chosen as the best method for environmental management in the area.

In recent years, zero-valent iron has drawn a great deal of attention in wastewater treatment and ground water remediation. It can effectively remove priority water contaminants, but there are some disadvantages in the use of nZVI particles, such as a high tendency to agglomerate, lack of stability, secondary iron pollution, separation and recovery of the fine nZVI particles after utilization. Using supporting material for nZVI is a promising way to solve these problems. Clay minerals as abundant natural resources are appropriate candidates to act as supporting materials. In this study, the use of fibrous clays-supported nZVI composite for the remediation of contaminated aqueous solutions will be discussed. Sepiolite and Palygorskite nano zero-valent iron composites were made using green tea extract. In order to determine the sorption capacity of nZVI, sepiolite and palygorskite composites for phosphorous, cadmium and nickel based on isotherm models, different concentrations of these ions were equilibrated with the composites in 1% suspensions for 24 hours. After adsorption, the supernatant liquids were filtered and the residual pollutant concentrations were determined. Results showed that Langmuir and Freundlich were the best models for describing p sorption on both composites. The estimated maximum adsorption capacity of the Sep-nZVI and Pal-nZVI using the Langmuir model (qmax) was 11. 38 mg P/g and 8. 57 mg P/g. The cadmium adsorption data for both sorbents was best fitted to the Langmuir, Fruendlich and Dubinin–Radushkevich models. Results clearly demonstrated the much higher Cd sorption potential of sepiolite compared with palygorskite. The sorption capacities (qmax) of Sepiolite-nZVI and palygorskite nZVI composites for Ni were 11. 14 and 32. 3 mgr/gr, respectively. The Ni sorption affinity (KL) of palygorskite nZVI was also greater than that of Sepiolite-nZVI. The favourability of a sorption system can be predicted by the constant separation factor RL. In the current study, RL values for palygorskite nZVI and Sepiolite-nZVI were greater than zero and less than unity, indicating favourable sorption of P, Cd and Ni onto the two composites. Fibrous clays and nano zero-valent iron can be used as efficient sorbents for phosphorus removal from urban wastewater and the removal of cadmium and nickel from industrial wastewater due to their environmentally friendly nature and high performance in pollutant removal.

The main objective of this research was to study three heavy metals (nickel, cadmium and lead) in the shrimp’s muscle tissue and shell. This research was conducted in shrimp farms of Bushehr Province in 2009.
Muscle tissues and the shells of the collected samples were separated, dried in oven and after grinding were digested in acid until they reached the volume, and then flame atomic absorption spectroscopy was used to assess the level of metals in the tissues and shells.
Findings: The findings of this study show an average of 0.2 and 0.5 milligram per kilo (wet weight) of cadmium in tissue and shell; 1.92 and 4.82 milligram per kilogram (wet weight) of lead; and 1.4 and 5.5 milligram per kilogram (wet weight) of nickel in tissue and shell respectively. A comparison of the results with the international standards of the World Health Organization, British Ministry of Agriculture, Fishing and Food and Australian National Medical, Health and Research Association and that of the European Union shows that the concentration of these metals is below the permitted level. Meanwhile, the results show a reverse linear relationship between the accumulation of the three metals in shell texture and the passage of time. Also there is a reverse linear relationship between accumulation of cadmium in the muscle tissue and the passage of time. But a direct linear relationship was observed between accumulation of lead and nickel in the muscle tissue and the passage of time. Moreover, a significant relationship was found between accumulation of cadmium and lead in the muscle tissue and the passage of time. Also a significant relationship was found between accumulation of cadmium in the shell and the passage of time.

Increasing pollution in water and soil has caused large environmental problems. The contamination of soil and water resources with various organic and inorganic compounds is important because of the close relationship between living organisms and nutrition, in terms both of environmental and human health, due to their direct involvement in supplying food for living organisms. This study was done with the purpose of introducing and investigating rangeland plants, namely Stipagrostis plumosa, Calotropis procera and Medicago sativa, under two types of treatments - urban waste compost and biochar - at three levels (0, 1 and 2 percentage) under greenhouse conditions for the remediation of contaminated soils with heavy metal Ni. The soils used in this study were collected from the traditional petroleum-contaminated Pazanan in Gachsaran. This experiment was conducted in a completely randomized design with 5 replications. After a six-month planting period, the aerial and underground parts of plants have collected and some soil important characteristics and plant morphological properties and metals were measured. ICP-OES was used for Ni measurement. For statistical analysis of the measured data, an analysis of variance was applied using SPSS software with comparison of data from the Duncan test. The translocation factor, remediation factor and biological aggregation factor were all addressed for assessment of the plants’ potential. Results showed that the amount of TF Ni in S. plumose was greater and the translocation factor higher than one and significantly greater than for C. procera and M.sativa. According to this result, the amount of TF in S. plumosa is greater than one, as S. plumosa with phyto-extraction can be attracted during the procedure and the extraction of nickel from the soil. C. procera had the highest RF for nickel under the biochar 1 and 2 percentage treatment with a rate of 0.08, when the least amount of RF was found for S. plumosa and the control sample with rate 0.02. Results showed that Biochar and urban waste compost treatments increase both soil pH and EC compared to the control treatment. The results indicated that biochar 2 % has the highest amounts of nitrogen, potassium and phosphorus among all treatments. Mean comparison showed that the 2% urban waste compost treatment had the highest percentage of organic carbon and the control treatment showed the lowest percentage of soil organic carbon. Mean comparison indicated that CEC in the biochar 2 % treatment was the highest and in the control treatment was the lowest. The results indicated that the effects of treatments on morphological characteristics are significant, the treatments used in this study having increased the stem length, root length, root volume, root dry weight, shoot dry weight and total dry weight compared to the control treatment. Generally speaking, the biochar 2 % treatment led to the highest root length, stem length, root volume, root dry weight, shoot dry weight and total dry weight. Generally, S. plumosa is an appropriate plant for absorbing and extracting Ni through phyto-extraction, while the biochar 2% treatment demonstrated the highest effect on promoting the phyto-remediation of Ni. Therefore, according to these results, S. plumosa is an appropriate plant for Ni remediation in soils contaminated by petroleum products.

A study was done to identify and measure concentration of heavy metals including Cr, Ni, and Hg in Iran on the ground water sources on Lavasanat area of Shemiranat district in the northern Tehran. In this study atomic absorption spectrometry (AAS), graphite stove and laboratory methods were used. Seven sampling stations were determined based on geographical, climatic, physical, biological and chemical characteristics of this region. Results showed that the highest concentration of Hg was related to stations Barg-e-Jahan (1) and Zard-e-Band (4) while the lowest was observed at station Niknam Deh (5). Concentration diagram indicated that the trend of Hg concentration was inconsistent and irregular the stations Kond-e-Sofla (6) and Rahatabad (7) showed the highest and lowest concentration of Cr respectively. There was a descending trend for Cr concentration. The highest and lowest amount of Ni was related to stations Zard-e-Band (4) and Rahatabad (7) respectively. The variation of Ni concentration showed the same trend as Hg.

In this work, the batch removal of Ni ions from aqueous solution and wastewater using marine brown alga Sargassum was investigated. Activated carbon, prepared from Sargassum by acid decomposition, was also used for the removal of Ni from aqueous solution and wastewater. The effects of pH, biosorption time, adsorbent dose, metal ions concentration were considered. The most effective pH was found to be 5.0. The maximum uptake rates for nickel with initial concentrations of 30, 50 and 70 mg/L were obtained to be 97.8% , 84.53% and 60.34% respectively at pH=5. The equilibrium adsorption data were fitted to isotherm models. The adsorption followed second order kinetic. This study shows the application of activated carbon as valuable material for the removal of Ni from aqueous solution and wastewater

Agricultural and specifically industrial activities have led to the substantial release of toxic heavy metals into the environment posing a major hazard to ecosystem and human health. Today, contamination of soil, groundwater, sediments, surface water and air with hazardous and toxic metal is considered as a serious problem worldwide. In assessment of the risk associated with metal contaminated soils, metal absorption by food chain is one of the major problems. Thus, it is highly important to assess and control metal concentration in industrial wastewater before it isreleased to the natural environments. The presence of heavy metals, such as Ni, Cr, Cu, Cd and Pb, that are phenomenally seen in industrial sawage can be toxic to human and other organisms, even at low concentration. Nowadays, soils in many places have been contaminated with heavy metals and these soils have turned into one of the most important problems specially in disposal areas.
Material and

In this study, in order to investigate the effect of an industrial wastewater on the heavy metals contaminated soil, it was sampled in 4 points and 4 depths including 0-25, 25-50, 50-75 and 75-100 cm, along the soil draine. Soil samples went through a physical and chemical analysis and were assessed for the heavy metal concentration. The electrical coductivity of soil saturation extract was determined by ohm-meter; soil texture was investigated by the Hydrometer method; the lime percentage was detrmined by Titrimetric method; total heavy metals concentration was specified by the acid nitric digestion method; and cation exchangable capacity in soil samples was identified by the Acetate method. Finally, the data analysis was done by SASS.

According to the obtained results and based on the standard limits in agricultural and industrial lands, soil samples were found to be toxic only for Ni, refering to low heavy metal concentration in wastewater samples. Statistical analysis results showed that there is a negative correlation between the soil depth and heavy metal concentration, which refers to low mobility rate of heavy metals specially in soils with a high content of lime and pH.