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Soils consist of various components that can influence significantly heavy metal control in the environment. Understanding the adsorption characteristic of soil is important in combating pollution problems around farming areas. This work explored the sorption characteristics and retention of Pb and Cd by soils from Isu Aniocha farming area in Anambra state, Nigeria. The influence of temperature, metal concentration, pH and time on the sequestration of Pb 2+ and Cd 2+ was evaluated by batch sorption technique. Physicochemical properties of the soil were determined by standard techniques. Isotherm evaluation was performed by the Langmuir, Tempkin and Freundlich models. Pb (II) ion showed higher adsorption characteristics on the soil than Cd (II) from the maximum uptake capacity obtained. The maximum adsorption values for Pb range from 38.46 to 47.62 mg/g, while that for Cd range from 30.30 to 41.46 mg/g. Kinetic evaluation was conducted by the application of the pseudo first order, pseudo second order and intraparticle diffusion rate equations. The best fit on metal removal on the soils was achieved with the pseudo-second order model. The results showed that soils from a farming area can be effective in decreasing heavy metals pollution, especially Pb and Cd ions from solution phase.

N-(Benzothiazol-2-yl)-4-chlorobenzenesulphonamide (NBTCS) was synthesized by condensation reaction of 4-chlorobenzenesulphonyl chloride and 2-aminobenzothiazole in acetone under reflux. Neodymium(III) and thallium(III) complexes of the ligand were also synthesized. Both ligand and metal complexes were characterized using UV-Vis, IR, 1H- and 13C-NMR spectroscopies, elemental analysis and molar conductance measurement. IR studies revealed that the ligand is tridentate and coordinates to the metal ions through nitrogen and oxygen atoms of the sulphonamide group and nitrogen atom attached to benzothiazole ring. The neodymium(III) complex displays a coordination number of eight while thallium(III) complex displays a coordination number of six. The ligand and its complexes were screened in vitro for their antibacterial activities against Escherichia coli strains (E. coli 6 and E. coli 13), Proteus species, Staphylococcus aureus and Pseudomonas aeruginosa using the agar well diffusion technique. The synthesized compounds were found to be more active against the microorganisms screened relative to ciprofloxacin, gentamicin and co-trimoxazole.

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Removal of arsenic(III) from aqueous solution has been studied using activated carbon produced from Dialium guineense seed shell by impregnation of carbonized sample with zinc chloride and thermal activation. The zinc chloride activated sample was selected because it produced the highest iodine number, mg/g (962.52) compared to the raw sample (601.57), phosphoric acid and nitric acid impregnated samples (802.10, 868.95). Proximate analysis of raw D. guineense seed shell revealed low ash content of 1.70% and moderate fixed carbon of 32.97%. The prepared adsorbent was characterized using Brunaeur-Emmett-Teller surface area, SEM and FTIR analyses. The surface area of the zinc chloride activated adsorbent was 533.94 m 2 /g and its micropore volume 0.475 cm 3 /g, with a porous structure that is well organized. Batch adsorption experiments were done by changing the following parameters: adsorbent dose, pH, contact time, initial metal ion concentration and temperature. Adsorption increased as each parameter was varied but decreased with increase in initial arsenic(III) concentration. The Freundlich model presented better fit with R 2 of 0.998 compared to the Freundlich isotherm (0.991) and Tempkin isotherm (0.984). The positive value of ∆H° 51.68 kJ/mol showed the endothermic nature of adsorption. The study demonstrated the potential of D. guineense seed shell as low cost adsorbent for removing arsenic(III) from polluted water.