Articles

The plant leaves used as adsorbent in this study were Guava plant leaves (GPL) and Cashew plant leaves (CPL). The samples were collected within Gombe State. Batch adsorption method was used in determining the adsorption process. Fourier Transform Spectroscopy (FT-IR), Scan-ning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) were used for the characterization. The results show promising signs as they were in agreement with most literatures; various per-centage removals were obtained from Pb²⁺ and Cd²⁺ (GPL and CPL) at optimum conditions. The equilibrium data fitted well with both Langmuir and Freundlich isotherm models. Langmuir mod-el fitted well for Pb²⁺ (CPL) with R² value (0.9855) and Cd²⁺ for (GPL and CPL) with R²values (0.9945 and 0.9948) while Pb²⁺ (GPL) with correlation coefficient at 0.9116 best fits well with Freundlich isotherm model. Pseudo first order and second order were used in testing the kinetics study from which pseudo second order best fitted better than that of the first order kinetics. The thermodynamic study shows that ΔG is negative in most cases except for Cd²⁺ (GPL) where ΔG is positive. Whereas ΔH and ΔS are positive in some cases showing an endothermic and spontane-ous adsorption processes respectively, as well as negative in some. Based on this study, GPL and CPL could be used as a natural adsorbent to remove Pb²⁺ and Cd²⁺ heavy metals from wastewater and environment due to their high removal efficiencies.

This study aimed to assess the floristic composition, vegetation structure and species associations of Cashew agro-ecosystems in the North region of Cameroon. The data were collected in 100 m x 20 m transect methods. An analysis of the data collected in the field was conducted around the diversity and richness of the flora, but also the structure of Cashew agro-ecosystems. For the analyzes of vegetation structure, tree density, basal area and biovolume were calculated. The inventory included trees with a dbh greater than or equal to 5 cm on an area of ​​1 ha per plot. The experimental device installed is a complete random Fisher block with five repetitions. A total of 7849 individuals in 17 families, 20 genera and 38 species were recorded<i>. </i>Species Important value of vegetation cover indicated that <i>Diospyros </i><i>mespiliformis</i><i>, </i><i>Anogeissus</i><i> </i><i>leiocarpus</i><i>, Annona senegalensis and Terminalia </i><i>laxiflora</i> are the most represented. Combretaceae are the most ecologically important families. Additionally, the grouping of species into four subdivisions showed that the Shannon diversity index varies from 2.18 ± 0.09 - 3.47 ± 0.17 bits, Pielou index vary from 0.98 ± 0.01 - 0.99 ± 0.01, Simpson's index ranges from 0.70 ± 0.18 - 0.93 ± 0.11, density ranges from 102 ± 1.92 - 128 ± 6.36 indiv/ha, basal area ranges from 2.02 ± 0.31 - 12.68 ± 2.01 m²/ha, biovolume ranges from 11.58 ± 1.29 - 68.03 ± 13.21 m<SUP>3</SUP>/ha. The Sörensen similarity index is very high with floristic affinities greater than or equal to 90%. The diameters and heights structure show a predominance of young individuals for the diameter and height classes on all plots. The most represented species associations are legumes (<i>Arachis </i><i>hypogeae</i>: 40.54%) and native fruit trees (<i>Vitellaria </i><i>paradoxa</i>: 15%). These results show the contribution of Cashew agro-ecosystems in biodiversity conservation.