scholarly journals Heavy metal-free visible-to-UV photon upconversion with over 20% efficiency sensitized by a ketocoumarin derivative

2021 ◽  
Author(s):  
Masanori Uji ◽  
Naoyuki Harada ◽  
Nobuo Kimizuka ◽  
Nobuhiro Yanai
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Uv Light ◽  
Uv Absorption ◽  
Intersystem Crossing ◽  
Visible Absorption ◽  
Metal Free ◽  
Triplet Triplet Annihilation

Efficient triplet-triplet annihilation-based photon upconversion (TTA-UC) from visible to UV light without using heavy metals is still a challenging task. Here we achieve a record-high TTA-UC efficiency of 20.3% among 100% maximum by employing a ketocoumarin derivative as a triplet sensitizer, which shows strong visible absorption, weak UV absorption, and efficient intersystem crossing.

Heavy metal-free visible-to-UV photon upconversion with over 20% efficiency sensitized by a ketocoumarin derivative

2022 ◽  
Author(s):  
Masanori Uji ◽  
Naoyuki Harada ◽  
Nobuo Kimizuka ◽  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Uv Light ◽  
Metal Free ◽  
Triplet Triplet Annihilation

Efficient triplet-triplet annihilation-based photon upconversion (TTA-UC) from visible to UV light without using heavy metals is still a challenging task. Here we achieve a record-high TTA-UC efficiency of 20.3% among...

scholarly journals Palladium-catalyzed direct β-arylation of ketones with diaryliodonium salts: a stoichiometric heavy metal-free and user-friendly approach

2015 ◽  
Vol 6 (10) ◽  
pp. 5491-5498 ◽  
Author(s):  
Zhongxing Huang ◽  
Quynh P. Sam ◽  
Guangbin Dong
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Free ◽  
Diaryliodonium Salts ◽  
Palladium Catalyzed ◽  
User Friendly

A user-friendly protocol for the Pd-catalyzed direct β-arylation of ketones is described, which avoids the use of stoichiometric heavy metals.

INFLUENCE OF THE ECOLOGICAL STATE OF THE SEREPOK RIVER (VIETNAM) ON ACCUMULATION OF HEAVY METALS IN ORGANS OF FISH

2017 ◽  
pp. 98-105
Author(s):  
Ngo The Cuong ◽  
Tran Hoan Quoc ◽  
Svetlana Vasilievna Zolotokopova
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
River Water ◽  
Bottom Sediments ◽  
Heavy Metal Concentration ◽  
Industrial Areas ◽  
Industrial Regions ◽  
Cadmium Lead ◽  
Sarotherodon Galilaeus ◽  
Water Bottom

The article focuses on the study of change of containing heavy metals (zinc, copper, iron, cadmium, lead, arsenic) in the abiotic and biotic components of the Serepok river (Vietman) influenced by wastewater discharge from industrial areas. Heavy metal content was determined in the river water and bottom sediments in the four zones: above and within the boundaries of industrial regions Xoa Phu and Tam Thang and in two water reservoirs situated below the boundaries of those industrial areas. Tilapia Galilean ( Sarotherodon galilaeus ), Hemibagrus ( Hemibagrus ), and sazan ( Cyprinus carpio ) caught in these areas were the hydrobionts under study in which liver, gills, skeleton and muscles accumulation of heavy metals was detected. In the organs of fish caught in the river within industrial region, heavy metals concentration was 3-7 times higher. The greatest concentration of heavy metals was found in the liver and gills of fish caught in the boundaries of industrial regions, the least concentration was in the muscles. In most cases, significant correlation between heavy metal concentration in organs of fishes and in river water, bottom sediments has been revealed.

Using A Segmented Voltage Sweep Mode and A Gaussian Curve Fitting Method to Improve Heavy Metal Measurement System Performance

2012 ◽  
Vol 19 (2) ◽  
pp. 381-394
Author(s):  
José Pereira ◽  
Octavian Postolache ◽  
Pedro Girão
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Measurement System ◽  
Curve Fitting ◽  
System Performance ◽  
Redox Potentials ◽  
Voltage Sweep ◽  
Gaussian Curve ◽  
Fitting Method ◽  
Curve Fitting Method

Using A Segmented Voltage Sweep Mode and A Gaussian Curve Fitting Method to Improve Heavy Metal Measurement System PerformanceThis paper presents a voltammetric segmented voltage sweep mode that can be used to identify and measure heavy metals' concentrations. The proposed sweep mode covers a set of voltage ranges that are centered around the redox potentials of the metals that are under analysis. The heavy metal measurement system can take advantage of the historical database of measurements to identify the metals with higher concentrations in a given geographical area, and perform a segmented sweep around predefined voltage ranges or, alternatively, the system can perform a fast linear voltage sweep to identify the voltammetric current peaks and then perform a segmented voltage sweep around the set of voltages that are associated with the voltammetric current peaks. The paper also includes the presentation of two auto-calibration modes that can be used to improve system's reliability and proposes the usage of a Gaussian curve fitting of voltammetric data to identify heavy metals and to evaluate their concentrations. Several simulation and experimental results, that validate the theoretical expectations, are also presented in the paper.

ASSESSMENT OF HEAVY METAL CONCENTRATION IN COCONUT WATER

1970 ◽  
pp. 07-10
Author(s):  
MdDidarul Islam, Ashiqur Rahaman, Aboni Afrose
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Heavy Metal Concentration ◽  
Coconut Water ◽  
Toxic Heavy Metals ◽  
High Concentration ◽  
Toxic Heavy Metal ◽  
Low Concentration ◽  
Wet Ashing ◽  
Aas Method

This study was based on determining concentration of essential and toxic heavy metal in coconut water available at a local Hazaribagh area in Dhaka, Bangladesh. All essential minerals, if present in the drinking water at high concentration or very low concentration, it has negative actions. In this study, fifteen samples and eight heavy metals were analyzed by Atomic Absorption Spectroscopy (AAS) method which was followed by wet ashing digestion method. The concentration obtained in mg/l were in the range of 0.3 to 1.5, 7.77 to 21.2, 0 to 0.71, 0 to 0.9, 0 to 0.2, 0.9 to 17.3, 0.1 to 0.9, 0 to 0.9 and 0 to 0.7 for Fe, Ni, Cu, Cd, Cr, Zn, Pb and Se respectively. From this data it was concluded that any toxic heavy metals like Cd, Cr, Pb and Ni exceed their toxicity level and some essential nutrients were in low concentration in those samples. 

HEAVY METALS IN WATER, SEDIMENTS AND MARINE FISHES FROM BULGARIAN BLACK SEA

2017 ◽  
Author(s):  
Katya Peycheva ◽  
Katya Peycheva ◽  
Mona Stancheva ◽  
Mona Stancheva ◽  
Stanislava Georgieva ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Black Sea ◽  
Fish Species ◽  
Distribution Patterns ◽  
Marine Fishes ◽  
Marine Water ◽  
Mean Values ◽  
Sprattus Sprattus ◽  
Cu And Zn

In this study, the ecosystem marine water-sediment-biota was investigated and the pollution was assessed. The concentrations of eight elements were determined in marine water, sediments and four fish species collected from Black Sea (Varna), Bulgaria during 2013. Marine water recorded the highest concentrations of Zn (15-22 μg/L), As (1.1–1.2 μg/L) and Pb (0.7-0.8 μg/L) while Zn (31-52 μg/g), Pb (21-29 μg/g) and Cu (20-34 μg/g) and show the highest concentrations in sediments. Water and sediments showed similar spatial distribution patterns for the highest mean values of the different metals. In the analysed fish species, the highest concentration of the metals Cu and Zn were found in Trachurus Mediterrneus (0.42 mg/kg w.w) and in Sprattus Sprattus (12.7 mg/kg w.w), respectively while the heavy metals As and Hg were found with maximum values in Pseta Maxima (3.99 mg/kg w.w and 0.08 mg/kg w.w respectively). The results from this study were compared with our data for a previous period (2004-2006) and they show decrease in the levels of heavy metal.

Analysis of Heavy Metal in Water used for Irrigation, Soil and Some Vegetables grown around Tin Mine Areas of Heipang District, Barkin-Ladi Local Government of Plateau State

2019 ◽  
pp. 111-119
Author(s):  
Agustina Onyebuchi Ijeomah ◽  
Rebecca Ngoholve Vesuwe ◽  
Bitrus Pam
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Food Safety ◽  
Safety Concern ◽  
Human Beings ◽  
Green Beans ◽  
Green Pepper ◽  
Transfer Factors ◽  
Mining Areas ◽  
Plateau State

Vegetables growing in mining areas have become a serious food safety concern because of the high levels of heavy metals always associated with mining. In this study, water used for irrigation, soil, cabbage, green pepper and green beans grown in tin mine areas of Heipang District, Barkin-Ladi LGA of Plateau State were analyzed for lead, cadmium and zinc, using Atomic Absorption Spectrophotometer (AAS). The concentrations of the heavy metals in water, soil, vegetables were all in the order Pb, >> Cd > Zn. In the vegetables, the order was: Pb → cabbage > green beans > green pepper; Cd → green beans > cabbage > green pepper; Zn → cabbage > green pepper = green beans. The transfer factors for all the metals (heavy metal in plant / heavy metal in soil) ranged from 0.95 to 1.48. There were high levels of Pb and Cd in all the vegetables, which may be attributed to the metals in the water used for irrigation. Whilst the concentration of Zn in all the samples were lower than recommended limits, the levels of Pb and Cd in the water, soil and vegetables were higher than the WHO/FEPA standard recommended limits reported for vegetables. The Cd concentrations of the vegetables also exceeded the tolerance thresholds for animals and human beings and therefore consumption of vegetable from the area would endanger the health of the population.

Distribution and Contamination Status of Heavy Metals in the Surface Sediments along Western Coast of Bali Strait, Banyuwangi

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Defri Yona ◽  
Syarifah Hikmah Julinda Sari ◽  
Anedathama Kretarta ◽  
Citra Ravena Putri Effendy ◽  
Misba Nur Aini ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Pollution ◽  
Contamination Factor ◽  
Pollution Index ◽  
Western Coast ◽  
Sampling Locations ◽  
Accumulation Index ◽  
Geo Accumulation Index ◽  
Geo Accumulation

This study attempted to analyze the distribution and contamination status of heavy metals (Cu, Fe and Zn) along western coast of Bali Strait in Banyuwangi, East Java. Bali Strait is one of the many straits in Indonesia with high fisheries activities that could potentially contributed to high heavy metal pollution. There were five sampling areas from the north to south: Pantai Watu Dodol, Pantai Kalipuro, Ketapang Port, Pantai Boom and Muncar as the fish landing area. Heavy metal pollution in these locations comes from many different activities such as tourism, fish capture and fish industry and also domestic activities. Contamination factor (CF), geo-accumulation index (Igeo) and enrichment factor (EF) of each heavy metal were calculated to obtain contamination status of the research area. The concentrations of Fe were observed the highest (1.5-129.9 mg/kg) followed by Zn (13.2-23.5 mg/kg) and Cu (2.2-7.8 mg/kg). The distribution of Cu, Fe and Zn showed variability among the sampling locations in which high concentrations of Cu and Zn were higher in Ketapang Port, whereas high concentration of Fe was high in almost all sampling locations. According to the pollution index, contamination factors of Cu, Fe and Zn were low (CF < 1 and Igeo < 1). However, high index of EF (> 50) showed high influence of the anthropogenic activities to the contribution of the metals to the environment. This could also because of the high background value used in the calculation of the index due to the difficulties in finding background value from the sampling areas.Keywords: heavy metals, pollution index, contamination factor, geo-accumulation index, Bali Strait

Applications of Bentonite to Soil Decontamination

2018 ◽  
Vol 69 (7) ◽  
pp. 1695-1698
Author(s):  
Marin Rusanescu ◽  
Carmen Otilia Rusanescu ◽  
Gheorghe Voicu ◽  
Mihaela Begea
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Laboratory Experiments ◽  
Experimental Studies ◽  
Heavy Metal Concentration ◽  
Polluted Soil ◽  
Raw Material ◽  
Soil Decontamination ◽  
Metal Retention ◽  
Removal Of Heavy Metals

A calcium bentonite from Orasu Nou deposit (Satu Mare Romania) was used as raw material. We have conducted laboratory experiments to determine the influence of bentonite on the degree of heavy metal retention. It has been observed that the rate of retention increases as the heavy metal concentration decreases. Experimental studies have been carried out on metal retention ( Zn) in bentonite. In this paper, we realized laboratory experiments for determining the influence of metal (Zn) on the growth and development of two types of plants (Pelargonium domesticum and Kalanchoe) and the effect of bentonite on the absorption of pollutants. These flowers were planted in unpolluted soil, in heavy metal polluted soil and in heavy metal polluted soil to which bentonite was added to observe the positive effect of bentonite. It has been noticed that the flowers planted in unpolluted soil and polluted with heavy metals to which bentonite has been added, the flowers have flourished, the leaves are still green and the plants whose soils have been polluted with heavy metals began to dry after 6 days, three weeks have yellowish leaves and flowers have dried. Experiments have demonstrated the essential role of bentonite for the removal of heavy metals polluted soil.

Benzylamine-Free, Heavy-Metal-Free Synthesis of CL-20

2006 ◽  
Author(s):  
Robert D. Chapman ◽  
Richard A. Hollins ◽  
Thomas J. Groshens ◽  
David A. Nissan
Keyword(s):  
Heavy Metal ◽  
Metal Free
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