Wyniki wyszukiwania - Biblioteka Nauki

1

Removal of Lead from Groundwater of Veppanthattai block, Perambalur district, Tamil Nadu, India using Sugarcane Bagasse as Adsorbent

100%

Ibraheem A. M. , Nazeeb Khan S. M. M.

World News of Natural Sciences

|

2018

|

tom 18

|

nr 2

213-222

EN

The present work measures the adsorption capacity of sugarcane bagasse to remove excess lead from groundwater. Batch adsorption experiments were carried out to evaluate the adsorption equilibrium, and the effects of four parameters (pH, adsorbent dosage, equilibrium time and particle size) on the adsorption of lead were investigated. Characterization of the adsorbent was carried out through SEM and FTIR instruments. Results confirm that the adsorption of lead takes place successfully on the surface of the adsorbent. The maximum efficiency of adsorption is up to 50% achieved in 5g adsorbent dosage, at an optimum pH 5, with a contact time of 120 minutes and 53 μm adsorbent size at 38.

2

Effects of lead on thyroid functions in lead-exposed workers

100%

Pekcici R. , Kavlakoğlu B. , Yilmaz S. , Şahin M. , Delibaşi T.

Open Medicine

|

2010

|

tom 5

|

nr 2

215-218

EN

Lead exposure is a common public health problem. Exposure to the metal can cause hematological, gastrointestinal, rheumatological, endocrine, neurological and renal problems in humans. However, effects on the thyroid gland are controversial. We retrospectively investigated thyroid function parameters in 65 adult males who had been occupationally exposed to lead. We then compared the findings with those of 60 male patients who had no history of lead exposure or thyroid abnormalities, who served as the control group. The mean ages of the lead-exposed workers and the controls were 34.3 ± 7.9 and 32.9 ± 6.6 years respectively. Blood lead levels in the lead-exposed workers were significantly higher than in the control group. The lead-exposed workers were assigned to one of three groups according to their blood lead levels, as follows: 40–59 μg/dl, 60–79 μg/dl, or 80 μg/dl and above. Thyroid Stimulating Hormone (TSH) levels in the 80 μg/dl and above group were significantly higher than in either the 40–59 μg/dl group or the 60–79 μg/dl group. However, TSH levels in the 40–59 μg/dl group did not differ significantly from those in the 60–79 μg/dl group. These results suggest that high levels of lead in the blood may affect thyroid physiology. Clinicians should be aware of the potential hazardous effects of lead on the thyroid, especially in patients who have been occupationally exposed to lead.

3

Adsorption behavior of Pb(II) onto xanthated rubber (Hevea brasiliensis) leaf powder

88%

Khalir W. , Hanafiah M. , So'ad S. , Ngah W.

Polish Journal of Chemical Technology

|

2011

|

tom 13

|

nr 4

84-88

EN

A plant waste, rubber (Hevea brasiliensis) leaf powder was modified with carbon disulfide (xanthation) for the purpose of introducing sulfur groups, and the adsorbent performance in removing Pb(II) ion was evaluated. Pb(II) adsorption was confirmed by spectroscopic analysis, which involved Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The amount of Pb(II) adsorbed increased with increasing pH, contact time and concentration but slightly decreased with increasing ionic strength. Adsorption equilibrium was achieved in less than 60 min and followed the pseudo-second order model. The isotherm data indicated that Pb(II) adsorption on xanthated rubber leaf (XRL) fitted well with Langmuir isotherm model. The maximum adsorption capacity computed from the Langmuir isotherm model was 166.7 mg/g. Pb(II) adsorption occurred via ion-exchange and complexation mechanisms.

4

Utilization of activated carbon of various charcoal types as absorbent in green shellfish (Perna viridis, Linnaeus, 1758) contaminated by lead heavy metal

88%

Yustindriarini V. , Hasan Z. , Hamdani H. , Sahidin A.

World Scientific News

|

2019

|

tom 116

157-168

EN

Aims of the research are to determine the type of activated carbon with high absorption rate in absorbing heavy metals of lead in green shells. This research used experimental method with complete randomized design then analyzed used analysis of variance and duncan test to see the decrease of lead in green shells by using different charcoal filters. The results showed that the highest decrease in green shell was by using coconut shell activated filter are 0,28 with a decrease percentage of 36,51%. The best lead decrease in water maintenance coconut shell activated filter treatment are 0,33 ppm. The coconut shell activated charcoal has a low ash content compared to other types and large pore charcoal size. Factors that supporting the metal absorption by charcoal include ash content on charcoal, charcoal pores, carbon concentration and pH concentration. Water quality measurements were measured in the morning and evening as supporting parameters in the study. Water quality measurements are in a range that can still be tolerated by green shells. Based on these results it can be concluded that the use of coconut shell activated charcoal is the best type of charcoal in lowering lead in green shells.

5

Preparation and characterization of activated carbon from Amygdalus Scoparia shell by chemical activation and its application for removal of lead from aqueous solutions

88%

Mohammadi S. , Karimi M. , Afzali D. , Mansouri F.

Open Chemistry

|

2010

|

tom 8

|

nr 6

1273-1280

EN

Two series of activated carbon have been prepared by chemical activation of Amygdalus Scoparia shell with phosphoric acid or zinc chloride for the removal of Pb(II) ions from aqueous solutions. Several methods were employed to characterize the active carbon produced. The surface area was calculated using the standard Brunauer-Emmet-Teller method. The microstructures of the resultant activated carbon were observed by scanning electron microscopy. The chemical composition of the surface resultant activated carbon was determined by Fourier transform infrared spectroscopy. In the batch tests, the effect of pH, initial concentration, and contact time on the adsorption were studied. The data were fitted with Langmuir and Freundlich equations to describe the equilibrium isotherms. The maximum adsorption capacity of Pb(II) on the resultant activated carbon was 36.63 mg g−1 with H3PO4 and 28.74 mg g−1 with ZnCl2. To regenerate the spent adsorbents, desorption experiments were performed using 0.25 mol L−1 HCl. Here we propose that the activated carbon produced from Amygdalus Scoparia shell is an alternative low-cost adsorbent for Pb(II) adsorption.

6

Saliva as a matrix for biomonitoring of occupational and environmental exposure to lead

88%

Morton J. , Leese E. , Harding A.-H. , Jones K. , Sepai O.

Biomonitoring

|

2014

|

tom 1

|

nr 1

EN

Background: To evaluate whether salivary lead can be used as a surrogate for blood lead, and if so, over what concentration range. Methodology: Three saliva devices were evaluated and one chosen to undertake this project. Paired saliva and blood samples were collected from 89 UK lead workers. Lead concentrations were determined using ICP-MS. In addition, haemoglobin and ZPP levels were determined in the blood samples and albumin was determined in the saliva samples to investigate standardisation using protein adjustments. Results: The chosen saliva device gave low but consistent recoveries for lead in saliva and the blank levels were low. The mean +/- SD blood lead level was 19.9 +/- 14 μg/dl; the mean +/- SD saliva lead level was 19.1 +/- 32.5 μg/l for 89 workers. Log10-transformed data showed correlation of r=0.69. The protein adjustments did not improve the blood-saliva correlation. Conclusions: This study has demonstrated that salivary lead measurement is feasible and correlated with blood lead levels, at least at occupational exposure levels, and may have value as a screening technique. Correlation may improve at environmental levels where exposures are generally more consistent and chronic, although this needs to be demonstrated in a genuine environmental population.

7

Biosorption of toxic metals using freely suspended Microcystis aeruginosa biomass

88%

Rzymski P. , Niedzielski P. , Karczewski J. , Poniedziałek B.

Open Chemistry

|

2014

|

tom 12

|

nr 12

1232-1238

EN

This paper describes the potential application of a freely suspended cyanobacterial biomass of Microcystis aeruginosa as a sorption material for toxic metals, cadmium (Cd) and lead (Pb) from aqueous solutions. In order to identify the most suitable conditions for removal of these elements (concentration range: 1–20 mg L−1), the laboratory experiments were carried out during different incubation times (1–48 h) and under various temperatures (10–40°C), pH (5–9) and with or without light irradiance. Competitive biosorption of Cd and Pb was also investigated. We found that M. aeruginosa demonstrates high efficiency in removing both of the studied metals from aqueous solutions. Sorption of Pb occurred, however, more rapidly and effectively, and was less disturbed by changes in physico-chemical conditions. Under pH=7, 25°C and light, the removal rates after 3 h and 6 h of incubation, were 90–100% for Pb and 79.5–100% for Cd, respectively. The co-occurrence of the metals decreased the rate of metal biosorption. Pb was sequestered preferentially over Cd. From the results we conclude that freely suspended M. aeruginosa can constitute a promising low-cost, easy-producible biosorbent material for toxic metals in contaminated wastewater.

8

Cadmium and lead recovery from yeast biomass

88%

Kordialik-Bogacka E.

Open Chemistry

|

2011

|

tom 9

|

nr 2

320-325

EN

The feasibility of the application of various eluents for recovery of lead and cadmium from Saccharomyces biomass has been investigated. Desorbing agents such as HCl, HNO3, H2SO4, Na2SO4, Na2CO3, EDTA and NaOH at concentrations of 0.05–0.5 M were used. The possibility of re-using of S. pastorianus for cadmium removal was assessed. Among the desorbing agents EDTA and mineral acids were the most effective, as approximately 85% of lead and cadmium could be recovered. However, when HNO3 and EDTA were used as desorbing agents, a dramatic loss in the cadmium adsorption by the biomass in the next cycles was observed.

9

Determination of lead in solution by solid phase extraction, elution, and spectrophotometric detection using 4-(2-pyridylazo)-resorcinol

88%

Rahman I. , Furusho Y. , Begum Z. , Sato R. , Okumura H. , Honda H. , Hasegawa H.

Open Chemistry

|

2013

|

tom 11

|

nr 5

672-678

EN

Lead (+2) was selectively adsorbed on a solid phase extraction (SPE) gel (molecular recognition technology, MRT), quantitatively extracted, and spectrophotometrically determined as the Pb(II)-PAR (4-(2-pyridylazo)-resorcinol) complex. The linear range was 0.01 to 0.75 mg L−1 and the detection limit was 6.4 µg L−1. The MRT-SPE allows selective Pb(II) extraction from complex ion-rich matrices, which is difficult with other techniques. Interference from common matrix ions such as Fe2+, Ni2+, Cu2+ or Co2+ is minimized. [...]

10

Determination of selected trace metals (Cr, Ni, Pb and Cd) in soils by slurry sampling GF AAS

75%

Cejner M. , Dobrowolski R. , Reszko-Zygmunt J.

Annales Universitatis Mariae Curie-Skłodowska, sectio AA – Chemia

|

2015

|

tom 70

|

nr 2

EN

Determination of cadmium, lead, chromium and nickel in soil samples by slurry sampling graphite furnace atomic absorption spectrometry (GFAAS) was presented. Optimization of determination conditions, stability test for slurries and metal partitioning between solid and liquid phase was investigated. The method was successfully tested by the analysis of certified reference materials.

11

Heavy metals concentration and distribution in soils around Oshiri and Ishiagu lead – zinc mining areas, southeastern Nigeria

75%

Igwe E. O. , Ede C. O. , Eyankware M. O.

World Scientific News

|

2021

|

tom 158

22-58

EN

The study area is characterized by ubiquitous ore deposits within the underlying Asu River Group of the southern Benue Trough of Nigeria. The extensive mineralization resulted in widespread artisan and unlawful mining activities, necessitating the need for the assessment of the effects on soils in the area. Careful evaluation of the soils was undertaken to give account of heavy metals concentrations and distribution, and pollution level in soils across the lead – zinc mines. The soil samples were digested and chemically analysed using Atomic Absorption Spectrophotometer (AAS). Results showed concentrations of heavy metals of the soil samples in the order trend Zn>Pb>Mn>Cd>Cu>Fe> Ni>Co>Cr and Pb>Zn>Mn>Fe>Cu>Cd>Ni>Cr>Co in both Oshiri and Ishiagu areas. Cd showed high contamination in the soils with higher amount of contamination occurring in Oshiri. Findings also revealed Co, Fe Cu, Mn, Zn, Pb and Ni whose Igeo’s values indicated uncontaminated to moderate contamination have an insignificant contribution to the pollution in the study area while Cd showed highest Igeo with moderate contamination. Co, Cr, Ni, Pb and Zn show deficiency to minimal enrichment while Cd recorded very high enrichment 23.95 – 37.48 and 25.66 – 34.21 mk/kg in the Oshiri and Ishiagu areas respectively. Cd showed high index of contamination ranging from 7.21 – 13.89, while other metals showed no index of contamination in the area. Pollution load index indicates that only few sites in Oshiri area require urgent rectification measures. The food chain in the area is not safe due to possible biomagnifications; hence arable soil around the mines is not suitable for production of food crops.

12

Adsorption of Pb(II) from aqueous media using mesoporous adsorbents obtained from Daniellia oliveri leaves

75%

Eletta O. A. A. , Tubi T. O. , Ighalo J. O.

World Scientific News

|

2020

|

tom 148

90-107

EN

Worldwide, there have been longstanding issues of heavy metal pollution of both ground and surface waters from industrial effluents. In this research, Daniella oliveri leaves were investigated as a precursor for the development of low-cost adsorbent for removing Pb(II) from aqueous media. The adsorbents (biosorbent and ash) were characterised using Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and Branueur-Emmet-Teller analysis (BET). The biosorbent (DO-B) and ash (DO-A) from Daniella oliveri leaves had a specific surface area of 574.5 m2/g and 723.0 m2/g respectively. Both adsorbents were mesoporous with pore diameter >2 nm. The ash was a better adsorbent for Pb(II) than the biosorbent powder, however, both adsorbents have over 99% removal of Pb(II) at optimal conditions. Best-fit isotherm for DO-B was Freundlich isotherm while no best fit for DO-A was observed. The adsorption for both adsorbents was best fit pseudo-second order kinetic model. Adsorbents from Daniella oliveri leaves could be used as an adsorbent for the removal of Pb(II) from aqueous media and can play an important role in mitigating the potential impact of the release of industrial effluent into the environment.

13

Metallurgical Slags as Traces of a 15th century Copper Smelter

63%

Kozana J. , Piękoś M. , Garbacz-Klempka A. , Kwak Z. , Wardas-Lasoń M.

|

tom 17

|

nr 2

14

Surface diffusion of Pb on clean Si surfaces

63%

Dolbak A. , Zhachuk R. , Olshanetsky B.

Open Physics

|

2004

|

tom 2

|

nr 2

254-265

EN

Pb diffusion on clean Si(111), (100), and (110) surfaces was studied by Auger electron spectroscopy and low energy electron diffraction in the temperature range from 100 to 300°C. It is shown that lead transport along sillicon surfaces takes place via the mechanism of solid-phase spreading with a sharp moving boundary. The temperature dependence of the Pb diffusion coefficients on Si(111), (100) and (110) surfaces have been obtained. A Si(110)-4×2-Pb surface structure has been observed for the first time.

15

Heavy metals in the waters of Dąbie Lake (North-West Poland) in the years 2008-2012

51%

Daniszewski P.

World Scientific News

|

2017

|

tom 69

75-85

EN

Heavy metal pollution is an ever increasing problem of our lakes. These toxic heavy metals entering in aquatic environment are adsorbed onto particulate matter, although they can form free metal ions and soluble complexes that are available for uptake by biological organisms. The increase in residue levels of heavy metal content in water, sediments and biota has resulted in decreased productivity and increase in exposure of humans to harmful substances. Many of these metals tend to remain in the ecosystem and eventually move from one compartment to the other within the food chain. Food chain contamination by heavy metals has become a burning issue in recent years because of their potential accumulation in biosystems through contaminated water, soil, sediment and air. The Dąbie Lake is an integral part of the River Odra estuary. It is a shallow (2.5 m mean depth) water body with two distinct basins: the large (Dąbie Wielkie) and the small (Dąbie Małe). The aim of the studies, carried out in the years 2008 - 2012, was to determine the content of Cadmium (Cd), Chromium (Cr), Copper (Cu), Mercury (Hg), Nickel (Ni), Lead (Pb) and Zinc (Zn) in the waters of Dąbie Lake, being the internal part of the tertiary Odra estuary. The range of observed concentrations (ppm) for the analysed metals was between: maximum concentration of Cd was 0.97 ppm and the minimum was 0.42 ppm; maximum concentration of Cr was 0.28 ppm and the minimum was 0.12 ppm; minimum concentration of Cu was 0.04 ppm and maximum of 0.08 ppm; maximum concentration of Hg was 0.07 ppm and the minimum was 0.03 ppm; minimum concentration of Ni was 2.29 ppm and maximum of 2.97 ppm; maximum concentration of Pb was 0.09 ppm and the minimum was 0.04 ppm; minimum concentration of Zn was 2.85 ppm and maximum 3.94 ppm.