Chemistry

In this study, the synchronous removal of Pb and Cd ions from aqueous solutions by colloidal particles made from rice husk ash (RHA) in aqueous sodium dodecyl sulfate (SDS) solution was investigated. The RHA derived from rice husk waste generated from the rice mills in Wukari, north-eastern Nigeria was combined with sodium dodecyl sulfate (SDS) for the metal ions adsorption. The adsorption studies under different experimental conditions were optimized and the removal of Pb and Cd ions was highly pH dependent. The results indicated that pH 8.0 was the optimum for the removal of the metal ions. Adsorption equilibration time was achieved in 2 hours with maximum removal efficiency of the metals ions attained at 71.8 and 88.9 % for Pb and Cd respectively. The equilibrium data were satisfactorily fitted to Langmuir and Freudlich isotherms. The Langmuir isotherm models gave a better representation of the data than the Freudlich isotherms. The RHA-SDS combination showed higher adsorption ca...

Heavy metal pollution is a major environmental problem, especially around highways with high traffic density. This study investigates the levels of Pb, Cd, Zn and Cu in roadside soils of Wukari section of the Wukari-Jalingo highway, Taraba state, Nigeria. Samples were randomly collected and analyzed using standard methods. The mean concentrations (µg/g) of Pb, Cd, Zn and Cu from all sample sites ranged: 89.6-247.0, 0.15-5.3, 26.8-163.0 and 7.1-61.2 respectively. The extent of the heavy metals contamination was assessed, as analytical data were subjected to pollution calculation methods. The contamination factors (CF) reveal extreme contamination of the sites and an increasing trend in the heavy metals concentrations was observed in sites with more human activities. The pollution load index (PLI) showed that the sites are severely polluted as the PLI of the metals from each sample site exceeded the PLI of the background (control) sample (0.7). Spearman’s rank correlation analysis sho...

This study assesses gas flaring and venting impacts in some oil producing areas in the Niger-Delta of Nigeria. The research instrument adopted for this study was the questionnaire survey and laboratory analysis, both microbiological and physico-chemical. The analysis of the data was done using simple descriptive analysis of frequency distribution of the relevant statistical information, supplemented by Chi-Square (X2) statistical method. Soil samples obtained from selected flare sites were analyzed and they indicated a negative impact on the microbial content of the soil. Rain water samples collected from different locations at different times and analyzed revealed a significant level of acidity (4.5-6.9) which causes damage to property and affect crops yield. Nitrates produced by the gas flare which varied from 0.12 to 0.47 mg/L result in the production of dilute nitric acid which is also corrosive. A survey carried out in this study revealed that the majority of Nigerians believe ...

Acidic cleaning solution formulated with HCl (5–15%) corrodes pipeline steel when used for descaling in oilfields. Two isonicotinohydrazide Schiff bases namely, N-(2-hydroxybenzylidene)isonicotinohydrazide (N-2HBI) and N-(5-nitro-2-hydroxybenzylidene)isonicotinohydrazide (N5N-2HBI) were synthesized and tested as alternative eco-friendly and non-toxic corrosion inhibitors for J55 steel in 5% (w/v) HCl at various temperatures. Different experimental techniques were employed to examine the inhibitive performance of N-2HBI and N5N-2HBI on the steel corrosion. Obtained results indicated effective corrosion inhibition by the synthesized Schiff bases on J55 steel dissolution in 5% HCl. Electrochemical impedance spectroscopy (EIS) data reveal that the charge transfer did not only increase on addition of the Schiff bases but the double layer capacitance and the corrosion current decreased as well. Potentiodynamic polarization (PDP) data show the mixed-type behavior of N-2HBI and N5N-2HBI with some dominant anodic effect. The adsorption of N-2HBI and N5N-2HBI on J55 steel surface followed Langmuir’s adsorption isotherm. The thermodynamic adsorption parameters at different inhibitor concentrations were calculated and discussed. Scanning electron microscopy (SEM) analyses revealed a much better morphology of the J55 steel surface in the presence of N-2HBI and N5N-2HBI.

The solvatochromic behaviour of three heterocyclic Schiff bases derived from isonicotinic acid hydrazide (INH) and pyrrole-2-carboxaldehyde (L1), furan-2-carboxaldehyde (L2) and thiophene-2-carboxaldehyde (L3) was studied in nine solvents of different polarities. The electronic transition properties were investigated using the Kamlet-Taft parameters, dielectric function, refractive index function and Catalan parameters. The results indicate that the hydrogen bond acceptor properties of the solvent are more effective in directing the solvatochromic behavior of the Schiff bases.