A 3-Amino-Propyl Trimethoxy Silane (APTS) functionalized silica was prepared and investigated. The functionalized silica showed a powerful removal behavior towards Chromium (III) [Cr (III)] and Cadmium (II) [Cd (II)] ions in aqueous solution. Different factors affecting the heavy metal ions adsorption on these substrates such as pH, initial concentration, contact time, and temperature were investigated. FT-IR analyses were carried out to characterize the functionalization of salicylaldehyde unto 3-aminopropyl silica. Results showed that optimum adsorption of the metal ions occurred at a pH of 7 and 6 by the pure silica and functionalized silica, respectively. Removal efficiencies of the adsorbents showed the trend: Salicylaldehyde-APTS modified > pure silica. The adsorption was described by the Langmuir adsorption isotherm. The kinetic results showed that the adsorption was described well with the pseudo second-order kinetic model. The study reveals that both pure silica and functionalized silica can be used as good adsorbents for the removal of the heavy metal pollutants from aqueous solutions and may be applied in the treatment of industrial waste waters, and they may be useful in detoxifying our already polluted environments.

The study aimed to evaluate the potential of Hibiscus sabdariffa leaf extract (HSLE) to retard the corrosion of aluminum in 0.1 M and 1 M HCl. Aluminium is an important material used in fabrication of industrial vessels, and understanding its corrosion behaviour will provide the industrialist with vital information about the choice of protection methods used to prolong its lifespan. Weight loss measurements and potentiodynamic polarization techniques were employed for the study. These methods are common and complementary methods used for corrosion studies, as they validate the corrosion rate measurements. The mechanism of corrosion was also determined using Langmuir adsorption isotherm. Ethanolic extracts of Hibiscus sabdariffa leaves were used to prepare different concentrations ranging from 500 mg/l to 3000 mg/l and corrosion rate measurements were taken over time intervals of 24-120 hours for aluminium immersed in 0.1 M and 1 M HCl in the presence and absence of HSLE, at a temperature of 303 K. The results showed that HSLE is a good inhibitor of aluminum corrosion under the studied conditions. Excellent inhibition efficiencies of 95.1 % and 96.2 % were obtained for 0.1 M and 1 M HCl respectively. The corrosion rate was reduced with an increase in concentration of HSLE and almost approached zero. The mechanism of corrosion inhibition was physiosorption. Electrochemical result showed HSLE as a mixed-type inhibitor, shifting the cathodic and anodic arms of the curve.

This work investigated six heavy metals (Pb, Hg, Cd, Mn, Fe and As) in sediment samples of the Anambra River collected from five sampling points at 1km from each other. The Anambra River cuts across several towns and flows into River Niger in Anambra State Nigeria. A total of forty sediment samples were used for the study. The samples were collected from November 2017 to Feb 2018 (dry season sampling) then from May 2018 to August 2018 (wet season sampling). Metal ion concentration in the sediments was determined using Atomic Absorption Spectrophotometer (AAS). Experimental results showed the concentration of metals in the order of Fe > Mn > As > Cd > Hg > Pb (Dry season) and Fe > Mn > As >Hg > Pb >Cd (wet season). In both seasons iron, manganese and arsenic recorded higher values than other metals. Results from Contamination Factor (CF) calculation showed that all the metals analyzed (except for arsenic) exert low contamination effect on the sediment samples in both seasons. Arsenic exerts considerable contamination in dry season. This study provided information on heavy metal concentration in sediment, magnitude of contamination, likely ecological risk to man and other living organisms within the Anambra River catchment area.