Edu Inam

Chemical and spectrophotometric studies of naphthol dye as an inhibitor for aluminium alloy corrosion in binary alkaline medium

The inhibition of a substituted naphthol compound, 4-(4-nitrophenylazo)-1-naphthol (44NIN), on the corrosion of aluminium (Al) in a basic medium was studied by classical chemical (gravimetric) and spectrophotometric (UV–Vis and FTIR) methods at 303–333 K. 44NIN demonstrated an excellent inhibiting property to Al corrosion in the aerated binary alkaline solution as shown from the results. The inhibition efficiency was found to increase with the azo dye concentration but not with temperature. Thermodynamic and adsorption evaluation for this inhibition process were accessed and thoroughly discussed. The UV–visible absorption spectra of the solution containing this dye after the immersion of Al specimen indicate the possible formation of a 44NIN–Fe type complex. The FTIR was carried out of the dye and protective film formed on the surface of the metal in the electrolyte containing the dye after a 72 h immersion period. These results show a correlation between the inhibitive effect and molecular structural information of 44NIN in this typical heterogeneous alkaline system.

Process optimization for the application of carbon from plantain peels in dye abstraction

Abstract Activated carbon obtained from plantain peels was applied to the optimization of the adsorption process parameters for abstraction of colour from simulated dye effluent. The activated carbon was prepared and characterized using nitrogen adsorption, X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR). Equilibrium isotherms were modelled using the Langmuir, Freundlich, Dubinin–Radushkevich and Temkin models; the Temkin and Dubinin–Radushkevich models provided the best fit for the sorption process, with a correlation coefficient greater than 0.95. The D–R model suggested a chemical process. The pseudo second-order kinetic model agreed well for fitting experimental data with the calculated adsorption capacity, qe, (46.5 mg/g), which was reasonably close to the experimental value (47.3 mg/g). Optimization of the process parameters was achieved using response surface methodology (RSM) – Box–Behnken design, where factors considered are represented on three levels: (−1), (0) and (+1) for high, mean and low levels, respectively. ANOVA fits a quadratic model with prob > F less than 0.05 (<0.0001) at 95% confidence level. From this modelling, significant factors for dye removal have been identified.

Assessment of the Occurrence and Risks of Emerging Organic Pollutants (EOPs) in Ikpa River Basin Freshwater Ecosystem, Niger Delta-Nigeria

Abstract The levels of some emerging organic pollutants (EOPs) including endocrine disrupting compounds, pharmaceuticals and personal care products were quantified in surface water of a freshwater ecosystem, the Ikpa River Basin, Nigeria using liquid chromatography/high resolution tandem mass spectrometry (LC–MS/MS). In addition, leachates and storm water samples collected from nearby dumpsites were also analysed to assess the effect on water quality. Seventeen compounds were detected at the nanogramme-per-litre levels and the ecological risks of selected compounds assessed based on predicted no-effect concentrations derived from comparison of toxicity data recorded for green algae, fish and invertebrate with the maximum measured environmental concentrations, to obtain risk quotients. Some of the compounds showed some level of widespread occurrence or persistence. Also, bisphenol A, chloramphenicol, erythromycin, triclocarban and triclosan were the most important EOPs detected in the study area that may pose detrimental effects to the aquatic organisms based on the outcome of the risk assessment.

Petroleum hydrocarbons and trace metal loads in the mangrove oyster (Crassostrea rhizophorae) from the Qua Iboe Estuary and adjoining creeks in Nigeria

The mangrove oyster Crassostrea rhizophorae was harvested from clutches associated with mangroves in the Qua Iboe Estuary and adjoining creeks to determine the concentrations of total petroleum hydrocarbons (TPH) and trace metals (Fe, Ni, Pb, Cr, V, Cu and Zn) and to understand their bioaccumulation status. The mean concentrations of trace metals in C. rhizophorae were 36.06 mg·kg− 1 for Fe, 0.58 mg·kg− 1 for Ni, 0.05 mg·kg− 1 for Pb, 0.66 mg·kg− 1 for Cr, 0.32 mg·kg− 1 for V, 6.70 mg·kg− 1 for Cu and 3.93 mg·kg− 1 for Zn. The oysters demonstrated relative affinity for accumulation of Fe, Cu and Zn and the relative status of the metals accumulated, in comparison with the background trace metal load, revealed bio-concentration factors of 0.024, 0.016, 0.004, 0.213, 0.037, 0.302 and 0.036 for Fe, Ni, Pb, Cr, V, Cu and Zn, respectively. The concentrations of TPH in the oyster were highly variable and ranged between 6.37 and 8.44 mg·kg− 1 dry weight of C. rhizophorae. Although the correlation between TPH levels in intertidal (epipelic) sediment and oyster specimens was positive (r = 0.097), it was not significant (p>0.05). However, the relationship between TPH and trace metal levels in C. rhizophorae revealed well-fitting linear models that indicated that the trace metals originated from petrogenic sources. Although the levels of TPH and trace metals in the oyster were within permissible levels, they might affect calcium metabolism and the general productivity of the shellfish. The recorded levels are also indicative of long-term and chronic accumulation of hydrocarbons in the estuarine ecosystem and potential risk to human health.

Humic Acid from Livestock Dung: Ecofriendly Corrosion Inhibitor for 3SR Aluminum Alloy in Alkaline Medium

Humic acids (HAs) extracted from cow, goat, and poultry dung were studied. Extraction was performed by treating the source materials with acid hydrolysis using hydrochloric acid (HCl) before alkaline extraction with sodium hydroxide (NaOH). Yields of 3.33, 2.67, and 1.28% dry weight were obtained from cow, goat, and poultry dung respectively. The extracted humic acids were characterized using Fourier transform-infrared (FT-IR) and ultraviolet-visible (UV-vis) spectroscopy techniques. The results obtained were in good agreement with commercial HA (Sigma-Aldrich). The humic acid extracted from cow dung was used to evaluate its corrosion inhibition potential for alkaline-induced corrosion of 3SR aluminum alloy using weight loss and electrochemical (potentiodynamic polarization) techniques at 30°–60°C. Results obtained show that the humic acid functions as an excellent corrosion inhibitor for aluminum alloy in 0.1 M NaOH solution. Corrosion inhibition efficiency increased with increase in humic acid concentration but decreased with rise in temperature. Results from potentiodynamic polarization measurements show that the HA behaved mostly as a mixed-type inhibitor. Adsorption of the humic acid was found to obey the Langmuir adsorption isotherm at all concentrations and temperatures studied. The mechanism of physical adsorption has been proposed based on the trend of inhibition efficiency with temperature. The proposed mechanism was also corroborated by kinetic and thermodynamic parameters obtained.

The role of pH in metal ion removal using coir dust and its modified extract resins

The role of pH on metal ion adsorption by unmodified coir dust and its modified extract forms (namely carboxylated and sulphonated coir extract resins) was studied in a batch system. The zero point charge pH (pH pzc) of the adsorbents was determined and the results demonstrated that the amount of metal ions adsorbed by the adsorbents was dependent on pH(pzc). The adsorption of these metal ions by the adsorbent increased with increasing pH. The unmodified coir dust, being a lignocellulosic material, removed more metal ions than the modified coir extract resins derived from a tannin-polyhydroxy compound. Hydroxyl, carboxylic and sulphonic functional groups are responsible for the metal ion binding in these adsorbents, as revealed by infra-red spectroscopic analysis. Coir dust, carboxylated coir extract (CTR) and sulphonated coir extract resin (STR) are effective adsorbents for removal of metal ions from aqueous solution and industrial effluents/wastewater.

Bioconversion of Crude Oil Production Sludge into Soil Conditioner Using Sawdust as Organic Amendment

ABSTRACT Nigeria is a major oil producer in Africa and the World, with significant oil exploration and production activities. These vast oil activities pose a challenge in disposal of oily sludge. The objective of this study was to adopt the principles of biotechnological wastes—to—wealth conversion for the utilization of abundant oily sludge waste. Various sawdust/oily sludge (SD/OS) ratios were used for composting for 21 weeks with sawdust (SD), oily sludge (OS) and untreated soil used as controls. Total heterotrophic bacterial count for SD/OS ratios used ranged between 7.4 and 17.4 x 106 cfu/g and between 6.2 and 18.4 x 106 cfu/g for controls. Hydrocarbon utilizing bacterial counts ranged between 5.9 and 9.0 x 106 cfu/g for SD/OS ratios and between 5.4 and 5.8 x 106cfu/g for controls while total fungal counts for SD/OS ratios used ranged between 4.5 and 5.0 x 107cfu/g and between 3.25 and 5.50 x 107 cfu/g for controls. Hydrocarbon utilizing fungal counts ranged between 3.50 and 4.25 x 107 cfu/g for SD/OS ratios and between 3.00 and 5.25 x 102cfu/g for controls. Predominant bacterial genera isolated were Micrococcus, Flavobacterium, Pseudomonas, Acinetobacter and Staphylococcus while fungal genera were Aspergillus, Penicillium, Saccharomyces and Candida. Nutrient levels for nitrogen, potassium, phosphorus, magnesium, iron and zinc reduced between weeks 0—21. Microbial counts increased between weeks 0 and 7 and decreased between weeks 14 and 21 of composting for SD/OS ratios, SD and OS. SD/OS ratios 1:1, 4:1, 8:1, 16:1 caused the most positive significant effects on plant growth. This research shows that oily sludge from oil activities can be converted to soil conditioner to enhance agricultural productivity and thus ensure food security.

Condition factor, hydrocarbons and bacterial burdens of shellfishes from mudflats in the Qua Iboe Estuary, Nigeria

In this article, the condition factor (CF; health status), bacterial burdens and total petroleum hydrocarbons (TPH) accumulating potential of shellfishes harvested from tidal mudflats in the Qua Iboe Estuary mangrove ecosystem, Nigeria, were investigated. The results revealed that most species of shellfishes from the estuary were not healthy. Tympanotonus fuscatus had a healthy status (CF) of 54.6%, while Mytilis edulis, Thais haemostoma and Callinectes latimanus from hydrocarbon-impacted mudflats exhibited poor health statuses with CF values less than 40%. Though unhealthy, they exhibited great propensity to bioaccumulate hydrocarbons and bacteria including hydrocarbonoclastic bacteria from the environment. The mean levels of TPH in the shellfishes were 4.68 mg/g, 7.92 mg/g, 4.86 mg/g and 3.97 mg/g dry weight of T. fuscatus, M. edulis, Th. haemostoma and C. latimanus, respectively, as against 30.36 mg/g dry weight detected in the intertidal sediment. Correlation between levels of TPH accumulated and CF of the shellfishes (at p < 0.05) revealed weak and not definite relationships in T. fuscatus (r = 0.080), M. edulis (r = 0.102) and Th. haemostoma (r = 0.214), while a positive significant relationship was observed for C. latimanus (r = 0.583). The bacteria densities of freshly collected samples varied between the diverse species of shellfish. The relationship between bacterial load and CF was negative and insignificant in C. latimanus (r = − 0.123) but insignificantly positive in M. edulis (r = 0.011), Th. haemostoma (r = 0.347) and T. fuscatus (r = 0.347). These findings have shown that shellfishes from mudflats in the Qua Iboe Estuary are not healthy but have great capability to bioaccumulate hydrocarbons and bacteria. Their bioaccumulating potential is not definitive and health (CF) dependent, but plausibly determined by the availability and nature of contaminants and their feeding mode. Though the role of oil-degrading bacteria within the viscera of shellfishes is uncertain, it is obvious that the commercially valid species investigated could serve as possible bio-indicators of hydrocarbon and bacterial contaminants in the fishing waters.