Enzymatic Hydrolysis and Fermentation of Plantain Peels: Optimization and Kinetic Studies

Abstract The aim of this work was to optimize the hydrolysis and fermentation of plantain peels. Kinetic study was also carried out. Proximate analysis of plantain peels was carried out and the result showed that it contains 46% cellulose. Aspergillus niger isolated and screened for cellulase activities was used as the crude enzyme for the hydrolysis and commercial available Saccharomyces cerevisae was used for the fermentation. The optimization was done using quadratic model of central composite rotatable design for both hydrolysis and fermentation. Analysis of variance ANOVA was used to test for the significance of the model and the factors. The results of the analysis showed that temperature, time, pH and the substrate concentration significantly affected the yield of simple sugar in the hydrolysis of plantain peels. The result equally showed that temperature, time and pH were significant factors of fermentation. The optimum conditions for the hydrolysis were 35˚C, 5 days, and pH of 5.5, substrate concentration of 8 g/30ml and glucose yield of 49%. Also the optimum conditions of fermentation were obtained as 30˚C, pH of 4.0, 9 days and ethanol yield of 19%. The Michaelis-Menten model adequately fit both the hydrolysis and fermentation kinetics

The Effect of H2PO4 Catalyst on Biodiesel Production from Castor Seed Oil

This research work studied the effect of H2PO4 catalyst on biodiesel production from castor seed oil. The Castor seed oil was mix with methanol and H2PO4 catalysts to undergo a tranesterification reaction. The characterization of the castor seed oil was done using American Society Testing Methods (ASTDM). The transesterification reaction was repeated with varying catalyst weight, oil to methanol ration, reaction time and reaction temperature. The biodiesel produced was characterized and compared with fossil Diesel fuel. High-Performance Liquid Chromatography (HPLC) was used to analyze the various biodiesel samples produced to identify the level of conversion to methyl ester and also identify the component mixture of the fatty acid methyl esters (FAMEs). Kinetics study revealed by the experimental data from the transeterification reactions, showed best conformity to a pseudo second-order kinetic model. Central Composite Design (CCD) was used to optimize the reaction process. Optimal value of the reaction shows a conversion of 62.60%. H2PO4 catalyst was found to be an effective transesterification catalyst

Removal of Solids from Palm Oil Mill Effluent and Paint Wastewater Using Electrocoagulation Technique

Electrocoagulation has been employed as a treatment technique for treating various wastewaters. This study focuses on the performance of electrocoagulation process for the treatment of Palm Oil Mill Effluent (POME) and Paint Wastewater (PW) using iron electrodes. POME obtained from local palm oil producers and PW from a paint industry, both in Enugu state of Nigeria, were treated by electrocoagulation using two iron electrodes. Effects of current density, electrocoagulation time, pH, and temperature were studied. Results revealed that this process could reduce the concentration of Total Suspended and Dissolved Solids (TSDP), in both POME and PW. The highest removal efficiencies of 65% and 76% were obtained for POME and PW, respectively, at 3 Amps, 60min, pH of 10, and 50°C for POME and 3 Amps, 60min, pH of 6, and 60°C for PW. Of the two kinetic models studied, second-order kinetic model fitted best to the obtained experimental kinetic data. From this study, it can be concluded that electrocoagulation is effective in the treatment of POME and PW

Packed bed column adsorption of oil and grease from refinery desalter effluent, using rice husks derived carbon as the adsorbent: Influence of process parameters and Bohart–Adams kinetics study

Oil and grease (O&G) adsorption in a packed bed column, using adsorbent prepared from rice husks wastes, was investigated. The effects of adsorbent particle size (150, 300, and 600 µm), initial adsorbate concentration (200, 300, and 400 mg/L), and bed height (100, 200, and 300 mm) on the performance of column adsorption for O&G removal and breakthrough time were investigated in the packed column experiments at a constant flow rate of 10.5 mL/min. The kinetic behavior of the column adsorption process was analyzed using the Bohart–Adams model. The kinetic data fitted the model very well. The rate constant (mass transfer coefficient) for Bohart–Adams model (KAB) increased with the decrease in adsorbent particle size and initial ion concentration but was higher at the bed height of 200 mm. The maximum adsorption capacity (No) increased with a decrease in particle size and initial ion concentration but increased with an increase in the bed height. The rate constant for Bohart–Adams model decreased with an increase in adsorbent size and initial concentration, and was higher at the bed height of 200 mm. The time required for 90% breakthrough decreased with increase in the flow rate, bed height, and initial ion concentration. The model results of the O&G breakthrough curve concentration have shown a fairly good agreement with experimental results. This analysis, considering the adsorbent’s particle size, feed concentration, and bed heights indicated that the packed bed unit could be used for the treatment of O&G effluent to reduce the difficulties of oil refineries in Nigeria and other countries

Cissus Populnea Fiber - Unsaturated Polyester Composites: Mechanical Properties and Interfacial Adhesion

Mechanical (flexural, hardness, and impact) properties and interfacial adhesion of acetic anhydride (AC) and ethylene diamine tetraacetic acid (EDTA) treated Cissus populnea fiber-unsaturated polyester (UPR) composites was investigated because of poor durability of the natural fiber-UPR composite applications. UPR composites were prepared with untreated and optimally treated fiber using hand-lay-up technique. Optimization of mechanical properties and interfacial adhesion between the fiber and UPR were determined using response surface methodology and fiber pull-out method, respectively. AC and EDTA treated fibers improved the flexural and hardness properties and interfacial adhesion at reduced impact strength. This is corroborated with morphology of the composites

Adsorptive Dephenolization of Aqueous Solutions Using Thermally Modified Corn Cob: Mechanisms, Point of Zero Charge, and Isosteric Heat Studies

The sorption mechanisms, point of zero charge, and isosteric heats involved in the adsorptive dephenolization of aqueous solutions using thermally modified corn cob (TMCC) were studied at different initial phenol concentrations (100–500 mg/l), TMCC dosage (0.4–2.0 g), contact time (5–60 min), pH (2–10), and temperature (30–60°C). Analysis of the adsorbent material showed that it possessed the properties typical of a good adsorbent. The adsorption experiments revealed that phenol uptake is favored by an increase in TMCC dosage and contact time and a decrease in temperature and concentration of phenol in the solution. The experimental data were well-fitted to the Sips, Langmuir, Toth, and Redlich–Peterson isotherm models. Thermodynamic studies suggested that the sorption of phenol onto TMCC is feasible, spontaneous, and endothermic. The isosteric heats of adsorption obtained are in the range 47.43-79.38 kJ/mol, confirming that the adsorption process is predominantly a physical process depicting the van der Waals interactions, and it is inversely proportional to surface loading. The analysis of the adsorption mechanisms showed that the intraparticle, film, and pore diffusion mechanisms were significantly involved in the phenol adsorption process. The involvement of electrostatic attraction, π‐π electron-donor interaction, and hydrogen bonding was also demonstrated. The point of zero charge (pHpzc) was obtained at a pH of 5.83; being slightly lower than the optimum pH of 6 indicates that the sorbent surface is obviously not negatively charged at pHpzc. The discoveries of this study have shown that the dephenolization process is feasible, spontaneous, endothermic, dominated by a physical process, and governed by intraparticle, film, and pore diffusion mechanisms