Sorption of synthetic dyes on low-cost solid sorbents is a simple technique for their removal from wastewater. Recent initiatives in the sorption process have sought the use of activated carbon derived from agricultural wastes as it provides an attractive and cheaper alternative to commercial activated carbon, which is usually expensive. This research investigates the sorption kinetics and equilibrium of two synthetic cationic dyes, crystal violet and methylene blue from aqueous media using activated carbon prepared from an agro-waste, Millettia thonningii seed pods. Sorption experiments were carried out using the batch process. The kinetic data were analyzed using the pseudo-first-order, pseudo-second-order, and intraparticle diffusion models while the equilibrium data were analyzed using the Langmuir, Freundlich, and Redlich–Peterson isotherm models. Nonlinear regression method was used to fit the data to the isotherm models in order to determine model parameters and the best-fit isotherms. Thus, three error functions; coefficient of determination, Chi-square statistic test, and the sum of error squares were applied to evaluate the sorption data. The pseudo-second-order model best described the sorption kinetics of both dyes while the Redlich–Peterson model described the equilibrium data the most, followed closely by the Freundlich isotherm model indicating a heterogeneous sorbent surface. The experimental results indicate that the agro-waste derived activated carbon is a viable adsorbent for the remediation of dye-contaminated water.

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The dependence of Nigerian Government on foreign technology for oil spill cleanup in its water bodies does not add local content value in the development of the Nation's economy. Acetylation of natural cellulose gives a material with high sorption capacity for oil in water. This research investigates crude oil sorption from water using acetylated and unacetylated lignocellulose. Oil palm empty fruit bunch (OPEFB) and cocoa pod (CP) were acetylated under mild conditions. The acetylated (modified) and unacetylated (unmodified) sorbents were used to sorb oil from water, and their sorption capacities and mechanisms were compared. Paired t test showed there was significant difference in the sorption capacities of modified and unmodified sorbents. Sorption of oil from water was found to be time and concentration dependent. Equilibrium studies showed that CP has higher sorption capacity than OPEFB and acetylation enhanced the crude sorption capacities of the sorbents. Crude oil sorption from water is a monolayer process that might have progressed from multilayer processes. Kinetic studies showed that sorption of crude oil by the sorbents was diffusion-controlled with the aid of physisorption and chemisorption mechanisms. Fourier transform infrared and scanning electron microscope analyses showed clear evidence of successful acetylation and oil sorption.

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The impact of acute exposure of Clarias gariepinus juveniles to commonly used herbicides, glyphosate and paraquat was evaluated through changes in fish mortality and biochemical indeces. Juveniles of the African catfish were exposed to varying acute concentration of glyphosate and paraquat. After 96 h of exposure, the 96 h LC 50 for paraquat was found to be 0.07 mg/l while that of glyphosate was found to be 0.530 mg/l. After the exposure period, some enzymes were assayed for in fish liver using a combination of conventional methods and commercially available kits. Comparing with the control, ANOVA analysis revealed that there were significant (p < 0.05) increases in the activities of all enzymes assayed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP). There were also significant (p < 0.05) increases in the activities of the antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and in lipid peroxidation, which was measured by thiobarbituric acid substances (TBARS). The result revealed that glyphosate and paraquat have the ability to modulate certain fish biochemical parameters and can therefore serve as reliable indicators of toxicity in environmental impact assessment programmes.

Because of increasing cost and environmental pollution effects of fossil fuels, palm oil, its methylester and ester-diesel blends were analyzed comparatively with diesel for their fuel properties that will make them serve as alternatives to diesel in diesel engines. Equally, the samples were comparatively analyzed for their trace metal composition in relation to corrosion. Also the bond structure/stability of the samples in relation to diesel were monitored with a Fourier transform infrared spectrometer. Results confirmed that most methylester blends with diesel fell within the grade 2D while the oil, methylester and 90:10 blend fell into 4D grade diesel fuels. From bond structure/stability comparison, all the samples were stable at 28 o C and had similarity in structure with diesel. All samples are commercializable. The trace metal composition of most samples was below that of the diesel with exception of Mn, Pb and Zn. The total acid numbers of all samples were below that of diesel and would not cause corrosion. It is recommended that processing of these samples should be done to conserve fossil fuel and as alternative diesel fuels in diesel engines.

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Direct and indirect contamination of the aquatic environment by pesticides results in a decrease in fish productivity and may elevate concentrations of undesirable chemicals in edible fish tissues. The effects of long-term exposure of Clarias gariepinus juveniles to sublethal concentrations of glyphosate and paraquat, two commonly used herbicides, for eight weeks were investigated using three concentrations of the 96 h LC 50 of each herbicide: 3.5, 7 and 14 µg l −1 for paraquat, and 26.5, 53 and 106 µg l −1 for glyphosate. Enzyme assay and histological analysis were conducted every fortnight. Significant increases in the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and hepatocyte vacuolation in the livers of the exposed fish confirms the toxicity of the herbicides, and thus could be useful tools in environmental monitoring.