No abstract

Optimization of process parameters for the regeneration of used mobil oil by acid/clay method using sulphuric acid as washing agent was successfully carried out. Used mobil oil was characterized before and after regeneration to determine the changes in the physicochemical properties of the oils. The viscosity, flash point and fire point of the oil increased after regeneration while the specific gravity and sulphur content decreased. The Atomic Absorption Spectrometry (AAS) carried out revealed the presence of eight different metals in the fresh mobil whose concentration increased during use but reduced after regeneration. The FTIR instrumentation analysis revealed that the used mobil oil has high concentration of some ester groups, aromatic materials, glycol and sulphur oxidation products while the proportion of these materials plunged significantly after treatment. Changes in the process conditions like acid concentration, settling time and bleaching temperature affected the effectiveness of the regeneration process by affecting the desired changes in the physicochemical properties. The process parameters were optimized using Central Composite Rotatable Design (CCRD) of Response Surface Methodology (RSM), with the aid of design expert. The design, which use purity as the response of the experiment, considered three independent factors of acid concentration, settling time and bleaching temperature; and the effects of these factors on the response are significant since their P-values are less than 0.05. An optimum theoretical purity of 0.86 was obtained at 6.5mol/lit acid concentration, 5.5hours settling time and 95.5 °C bleaching temperature, which agreed excellently with 0.85 actual purity obtained at the same conditions. Therefore, the regenerated mobil oil at these optimal conditions is capable of meeting commercial expectations.

The aim of this study was to develop a process of extraction oxyresveratrol from Artocarpus lakoocha heartwood using a maceration method. The influences of types of solvent, a concentration of solvent, and time to extract on the yield of oxyresveratrol were studied. In addition, the antioxidant capacity of the extract was investigated. The quantitation of oxyresveratrol was measured by high-performance liquid chromatography (HPLC) analysis, and antioxidant activity was analyzed by 1,1'-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. The results indicated that 70-percent ethanol solvent by volume for 6 hours could extract the optimum oxyresveratrol at 13.09 percent of the dry weight of Artocarpus lakoocha, and antioxidant efficiency had an IC 50 of 47.70 μg/ml.

This work focuses on the removal of oil from polluted water surface using activated biomass such as ogbono shell. The shell was carbonized at a temperature of 600 o C for 4h and then further modified with stearic acid. Characterization of the adsorbent produced was carried out using Scanning electron microscopy (SEM) to study the surface morphology of raw and grafted ogbono shell. Fourier Transform Infra-red Spectroscopy (FTIR) was used to investigated the functional group of different minerals. Proximate analysis was carried out to determine the surface area of the agro wastes before and after modification. Batch experiments were carried out to investigate the effects of the oil water ratio, temperature, pH and contact time on the sorption capacities of the adsorbents. Physiochemical characterization of the adsorbents revealed that surface area increased from 114 cm 2 to 190.5 cm 2 after modification. SEM and FTIR results revealed that more micro porous surfaces were created on the surface of the adsorbent after modification. Batch adsorption experiments with esterified ogbono shell revealed that 96% of crude oil was removed at a pH of 5 with oil water ratio of 1.4/100 cm 3 after 50 min at a temperature of 90 o C. Esterified ogbono shell was found to be a good adsorbent for the removal of oil layer from polluting water surface.

Fluted pumpkin seed shell, an abundant and inexpensive natural resource in Nigeria, was used as a precursor to adsorbent production for the removal of suspended and dissolved particle (SDP) from initially coagulated coal washery effluent (CWE). Key parameters such as contact time, adsorbent dose, pH and temperature were investigated using batch mode. The adsorption equilibrium, thermodynamics and kinetics of SDP on H3PO4 treated shell (FPA) and NH4Cl treated shell (FPS) were examined at specified temperatures. Equilibrium data sufficiently fit the Langmuir isotherm model (R2 > 0.99; SSE < 0.09). The pseudo-second order kinetic model provides the best correlation (R2>0.99;SSE<0.1) with the experimental data. The evaluated ΔG○ and ΔH○ indicate the spontaneous and endothermic nature of the process. This study demonstrates that pumpkin seed shell could be utilized as low cost, renewable, ecofriendly bioadsorbent for the removal of SDP from CWE.