Powdered adsorbent prepared from Albizia lebbeck pods as agricultural waste has been used for the adsorption of Pb(II), Cd(II), Zn(II) and Cu(II) ions from aqueous solutions. The powdered adsorbent was characterized by X-ray diffraction, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller. Effects of various parameters like contact time, solution pH, initial concentration dosage and temperature were investigated on a batch adsorption system. Equilibrium and kinetic experiments were carried out at the optimum pH of 6, 8 and 10 at 29 °C using particle size of 250 μm for Cd(II), Pb(II), Zn(II) and Cu(II) ions. Changes in free energy, enthalpy and entropy were also evaluated. The adsorption data fitted well with the Langmuir isotherm model with correlation coefficient (R 2 > 0.94), whereas the adsorption kinetics followed the pseudo-second-order kinetics. The thermodynamic parameters proved that adsorption of metal ions is endothermic and non-spontaneous at low temperatures, while spontaneity occurred at higher temperatures. This study shows that powdered Albizia lebbeck pods prove to be a promising inexpensive adsorbent for metal ion removal from aqueous solutions.

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Farmers are eager to know the various types of weeds in paddy fields. This will help in choosing the best weed management practice for effective weed control as well as reducing rice yield losses. The objectives of the study are to identify the weeds species affecting the rice field, to assess the composition of weeds species, to classify the weed species into different families, genera, species, common names, Hausa names, lifecycles, life forms, native/exotic species, propagation and uses, and to determine the dominant weed species. Random vegetation surveys were conducted. Weeds observed were photographed, and prepared as herbarium specimens. Standard key manuals and checklists were utilized for weed identification and later organized using the Angiosperm Phylogeny Group (APG) classification system. A total number of 72 plants species distributed within 16 families and 50 genera were inventoried. The annuals (66.67%) were the dominant weed followed by perennials (33.33%) while biennials were the least. The broad leaves were the dominant weed (44.61%) identified followed by Poaceae (27.7%) and Sedges (11.11%). Results obtained from this study could be useful in choosing the best management practice and in making a decision on the choice of herbicides and directing research towards improved weed control measures.