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A method for obtaining carbonaceous adsorbents from pine cones by chemical activation with NaOH is described. Activated carbons were obtained by two methods of activation (physical mixing and impregnation) and two variants of thermal treatment. It has been shown that pine cones can be successfully used as cheap precursor of carbonaceous adsorbents of well-developed surface area, large pore volume and good sorption properties. All activated carbon samples obtained show strongly microporous structure and surface of acidic character. The best physicochemical properties and greatest sorption capacity towards iodine were found for the carbon samples obtained by physical mixing of the precursor with the activating agent and then subjected to thermal activation at 600°C.
Three profiles were sited on the major landscape elements of crest, middle slope and lower slope on three land uses; Forest (FS), Rubber (RS) and arable cropping (AS) at Agoi-Ibami in Central Cross River State, Nigeria. For study purposes, soil samples were collected from the morphogenetic horizons for the analysis of physical and chemical properties. Results showed that the surface horizon textures were mostly sandy loams with little sandy clay loam, while subsurface textures were mostly sandy clay loams with few silt clay loams and clays. The bulk densities were below the ranges of 1.46 to 1.63 g cm-3 for silts and clays and 1.75 g cm-3 for sands. This imposes stresses such as mechanical resistance to root penetration, decrease in cultivation and organic matter. The surface and subsurface pH values vary from 4.9–4.5 in FS, 4.9-4.6 in RS and 4.9 in AS, indicating that the soils are very strongly acidic. The Organic carbon contents was low with mean values of 4.33 and 0.6 % in surface and subsurface for FS, 2.10 and 0.50 % for surface and subsurface for RS, while surface and subsurface values proved to be 0.57 and 0.31 % for AS. The nitrogen contents was also low, mean values of 0.16 and 0.06 % for surface and subsurface for FS, 0.23 and 0.08 % for surface and subsurface for RS, and 0.19 and 0.10 % for surface and subsurface for AS. The content and available phosphorus are equally low, except for AS, with surface mean values ranging from 11.52 mg kg-1 to 13.87 mg kg-1. The exchangeable cations, Ca, Mg, K, and Na were very low, while exchangeable H+ and Al3+ were high. Base saturation was also low in FS and AS (< 50%) in surface soils, but higher in AS in the surface and in RS in the subsurface soils. The mean values of organic matter were 4.33 and 0.16 %. The land use should, therefore, be adjusted by application of recommended inorganic fertilizers and organic matter so as to support growth of crops such as maize, yams, cassava etc.
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