Adsorption characteristics of Cu and Ni on Irish peat moss

Peat has been widely used as a low cost adsorbent to remove a variety of materials including organic compounds and heavy metals from water. Various functional groups in lignin allow such compounds to bind on active sites of peat. The adsorption of Cu²⁺ and Ni²⁺ from aqueous solutions on Irish peat moss was studied both as a pure ion and from their binary mixtures under both equilibrium and dynamic conditions in the concentration range of 5–100 mg/L. The pH of the solutions containing either Cu²⁺ or Ni²⁺ was varied over a range of 2–8. The adsorption of Cu²⁺ and Ni⁺² on peat was found to be pH dependent. The adsorption data could be fitted to a two-site Langmuir adsorption isotherm and the maximum adsorption capacity of peat was determined to be 17.6 mg/g for Cu²⁺ and 14.5 mg/g for Ni²⁺ at 298 K when the initial concentration for both Cu²⁺ and Ni²⁺ was 100 mg/L, and the pH of the solution was 4.0 and 4.5, respectively. Column studies were conducted to generate breakthrough data for both pure component and binary mixtures of copper and nickel. Desorption experiments showed that 2 mM EDTA solution could be used to remove all of the adsorbed copper and nickel from the bed.

Peat multi-proxy data from Mannikjarve bog as indicators of late Holocene climate changes in Estonia

As part of a wider project on European climate change over the past 4500 years, a 4.5-m peat core was taken from a lawn microform on Mannikjarve bog, Estonia. Several methods were used to yield proxy-climate data: (i) a quadrat and leaf-count method for plant macrofossil data, (ii) testate amoebae analysis, and (iii) colorimetric determination of peat humification. These data are provided with an exceptionally high resolution and precise chronology. Changes in bog surface wetness were inferred using Detrended Correspondence Analysis (DCA) and zonation of macrofossil data, particularly concerning the occurrence of Sphagnum balticum, and a transfer function for water-table depth for testate amoebae data. Based on the results, periods of high bog surface wetness appear to have occurred at c. 3100, 3010-2990, 2300, 1750-1610, 1510, 14 10, 1110, 540 and 3 10 cal. yr BP, during four longer periods between c. 3170 and 2850 cal. yr BP, 2450 and 2000 cal. yr BP, 1770 and 1530 cal. yr BP and in the period from 880 cal. yr BP until the present. In the period between 1770 and 1530 cal. yr BP. the extension or initiation of a hollow microtope occurred, which corresponds with other research results from Mannikjarve bog. This and other changes towards increasing bog surface wetness may be the responses to colder temperatures and the predominance of a more continental climate in the region, which favoured the development of bog microdepressions and a complex bog microtopography. Located in the border zone of oceanic and continental climatic sectors, in an area almost without land uplift, this study site may provide valuable information about changes in palaeohydrological and palaeoclimatological conditions in the northern parts of the eastern Baltic Sea region.

Age and palaeoenvironmental significance of an inter-tidal peat bed at Ballywoolen, Bann estuary, Co. Londonderry.

A recently exposed inter-tidal peat bed at Ballywoolen, Bann estuary, Co. Londonderry, has yielded new information about mid-Holocene coastal environmental change in the northeast of Ireland. Pollen analytical data and wood detritus demonstrate that peat accumulation occurred in a terrestrial environment that was free from marine influence. Radiocarbon dates suggest that the peat accumulated rapidly during a period of low relative sea level subsequent to the maximum of Holocene relative sea-level rise along the north coast of Northern Ireland. The absence of marine/brackish indicator taxa at the site suggests that the tidal range was somewhat less than that at present and/or that the channel of the river was located some distance east of its present alignment. The dates indicate that the low stand lasted for at least ~0.2 ka and possibly for ~1.1 ka. Stable, woodland-dominated landscapes are indicated at both this site and neighbouring ones around ~6.4-5.3 cal ka BP. There is no evidence for large-scale aeolian sand movement or human impact on the landscape during the period of peat accumulation.

Late Holocene climatic changes in Tierra del Fuego based on multiproxy analyses of peat deposits

A ca. 1400-yr record from a raised bog in Isla Grande, Tierra del Fuego, Argentina, registers climate fluctuations, including a Medieval Warm Period, although evidence for the 'Little Ice Age' is less clear. Changes in temperature and/or precipitation were inferred from plant macrofossils, pollen, fungal spores, testate amebae, and peat humification. The chronology was established using a C-14 wiggle-matching technique that provides improved age control for at least part of the record compared to other sites. These new data are presented and compared with other lines of evidence from the Southern and Northern Hemispheres. A period of low local water tables occurred in the bog between A.D. 960-1020, which may correspond to the Medieval Warm Period date range of A.D. 950-1045 generated from Northern Hemisphere tree-ring data. A period of cooler and/or wetter conditions was detected between ca. A.D. 1030 and I 100 and a later period of cooler/wetter conditions estimated at ca. cal A.D. 1800-1930, which may correspond to a cooling episode inferred from Law Dome, Antarctica. (C) 2004 University of Washington. All rights reserved.

Evaluation of a new peat-based sorbent for metals capture

A new peat-based sorbent was evaluated for the capture of heavy metals from waste streams. The media is a pelletted blend of organic humic material targeted for the capture of soluble metals from industrial waste streams and stormwater. The metals chosen for the media evaluation were Cd, Cu, Ni, and Zn due to their occurrence and abundance in waste streams and runoff. Sorption tests included an evaluation of the rate and extent of metals capture by the media, single versus multicomponent metals uptake, pH, anion influence, leaching effects and the effect of media moisture content on uptake rate and capacity. Isotherms of the sorption results showed that the presence of multiple metals increased the total sorption capacity of the media compared to the single component metal capacity; a result of site selectivity within the media. However the capacity for an individual metal in a multicomponent metal matrix was reduced compared to its single component capacity, due to competition for sites. Evidence of ion exchange behavior was observed but did not account for all metals capture. The media also provided a buffering action to counter the pH drop typically associated with metals capture.