S.E UWADIAE

The increasing global demand for renewable and sustainable energy sources has intensified research into bioethanol production from non-food lignocellulosic biomass. This study investigates the production of bioethanol from oil palm trunk (OPT), an abundant agricultural residue generated during replanting cycles in oil palm plantations in Nigeria, to optimize pretreatment and fermentation conditions to maximize fermentable sugar yield and ethanol production efficiency.
Oil palm trunk samples were collected from Idogbo, Benin City, Nigeria, and processed through size reduction, drying, and sieving to a 500 µm particle size. Chemical composition analysis confirmed that OPT contains 29 to 45% cellulose, 12 to 29% hemicellulose, and 18 to 23% lignin, validating its suitability as a second-generation bioethanol feedstock. Pretreatment was carried out using dilute sodium hydroxide (NaOH) at a concentration of 20% to disrupt the lignocellulosic matrix and enhance cellulose accessibility for enzymatic hydrolysis. Response Surface Methodology (RSM) based on a Box-Behnken design was employed to optimize three key pretreatment variables, namely acid concentration (1 to 6%), reaction time (10 to 120 minutes), and temperature (30 to 120°C), with fermentable sugar yield as the response variable. A total of 17 experimental runs were conducted, and the results were fitted to a quadratic model. Analysis of variance (ANOVA) confirmed the statistical significance of the model, with an F-value
of 115.99 and a p-value of less than 0.0001. The model demonstrated excellent predictive accuracy,
with a coefficient of determination (R²) of 0.9933, an Adjusted R² of 0.9848, and an Adequate Precision ratio of 28.27, confirming a strong signal-to-noise ratio and reliable navigability of the design space. Acid concentration (A), reaction time (B), temperature (C), their interaction terms (AB and BC), and quadratic terms (A², B², and C²) were all identified as statistically significant factors influencing sugar yield (p less than 0.05).
The optimum pretreatment condition was established at an acid concentration of 3.5%, a temperature of 120°C, and a reaction time of 120 minutes, yielding a maximum fermentable sugar concentration of 553.54 mg/g. Three-dimensional response surface plots demonstrated that sugar yield increased progressively with moderate acid concentration and rising temperature, but declined at extreme values due to thermal and acid-induced sugar degradation and the formation of inhibitory compounds, including furfural and hydroxymethylfurfural (HMF). Enzymatic hydrolysis of the pretreated OPT biomass was performed using commercial cellulase enzymes, followed by fermentation with Saccharomyces cerevisiae. Fermentation performance was monitored over four days using the 3,5-dinitrosalicylic acid (DNS) colorimetric method at 610nm. Sugar concentration decreased progressively from 3.8 mg/g on day one to 0.405 mg/g by day four, confirming active microbial metabolism and efficient conversion of released fermentable sugars into ethanol.
The findings of this study demonstrate that oil palm trunk is a technically viable and sustainable lignocellulosic feedstock for second-generation bioethanol production. The optimized pretreatment conditions effectively balanced lignin disruption and cellulose preservation, maximizing sugar recovery while minimizing inhibitor formation. The results support the potential of OPT waste valorization as a pathway toward renewable energy generation, reduced agricultural waste burden, and enhanced energy security in palm oil-producing regions of Nigeria. Future work
should focus on co-culture fermentation systems capable of utilizing both hexose and pentose sugars, detailed techno-economic analysis, and life-cycle assessment to establish the commercial and environmental viability of large-scale OPT-based bioethanol production.

Heavy metal pollution has become a critical environmental challenge, particularly due to the persistence and toxicity of metals such as copper in aquatic ecosystems. Conventional treatment methods for metal removal, including chemical precipitation, ion exchange, and membrane filtration, are often costly, inefficient at low metal concentrations, and produce secondary waste. In response, biosorption has emerged as an eco-friendly and sustainable alternative. This study investigates the potential of corn cobs, an abundant agricultural by-product, as a low-cost biosorbent for the removal of Cu2+ ions from aqueous solutions. The biosorbent was prepared through collection, washing, drying, crushing, and sieving of corn cobs to obtain uniform particle sizes. A Box-Behnken Design (BBD) under the Response Surface Methodology (RSM) framework was employed to optimize process parameters such as adsorbent dosage, contact time, and metal concentration. Experimental data were fitted to a quadratic model, and statistical analysis through ANOVA revealed that the model was highly significant (F-value = 116.31 , P < 0 .0001) with strong correlation coefficients (R2 = 0.9934, Adjusted R2 = 0.9848, Predicted R2 = 0.9135). Optimization results indicated maximum copper ion removal of 94.73% at the optimal conditions of 5.5g/L adsorbent dosage, 67.5 minutes contact time, and 6 mg/L initial metal concentration. The model validation confirmed close agreement between predicted and experimental results, demonstrating the reliability of the developed model. Thermogravimetric and differential thermal analyses (TGA/DTA) suggested that the corn cob biosorbent possessed good thermal stability, which supports its suitability for adsorption applications. The study concludes that corn cobs are an effective, sustainable, and economical biosorbent for copper ion removal from wastewater. It further recommends their potential application in small- to medium-scale industrial effluent treatment systems. Future research should focus on kinetic and isotherm modeling, column adsorption studies, and biosorbent modification to enhance adsorption efficiency and extend applicability to other heavy metals.

Chromium is one of the most notorious heavy metals released by various industries such as tanning and leather industries, manufacturing industries, catalyst and pigments, fungicides, ceramics, crafts, glass, photography, electroplating industry and corrosion control application. This study was aimed at sorption of chromium(VI) ion from aqueous solution by adsorbent derived from used tyres. Waste tyre was collected from Uwelu spare part market in Edo state. The collected tire was washed and rinsed with distilled water to remove debris, oven dried for 3hours at 180oC and ground into powder. This dried powder was carbonized and activated by charging into a muffle furnace for 2hrs at 500oC and then treated with 4M nitric acid. The efficacy of chromium removal of the adsorbent is determined by investigating the various parameters such as adsorbent dose, agitation time and shaking speed. The adsorbent was characterized by Scanning Electron Microscopy (SEM), Energy dispersive X-ray (EDX) and Fourier Transform Infra-Red (FTIR) spectroscopy. The total pore volume of the adsorbent was observed to bet P/P0=0.988646762:0.624668 cm3/g. The percentage of C and O was found to be 30.50% and 20.23%. Analysis of Variance for the response surface quadratic model showed that the Model F-value of 75.25 implies that the model is significant. The Lack of Fit F-value of 0.9763 implies that the Lack of Fit is not significant relative to the pure error. The high R-square value (coefficient of determination) of 0.9898 indicates that the fitted model predicts the metal ion removal with reasonable precision