Journal of The Nigerian Society of Chemical Engineers

The sorption process of lead (II) ions from textile effluent was investigated using chitosan obtained from a snail shell (SSC). The effects of various experimental parameters on Pb (II) ions adsorption were studied, and optimal conditions were determined. The equilibrium data were analyzed with Langmuir, Freundlich, Temkin, Elovich, Florry Huggins, Jovanovic, Harkin Jura, and Dubinin–Radushkevich (DRK) adsorption models. The high correlation factor of Langmuir isotherm indicates the monolayer coverage of the adsorbent. Freundlich isotherm fitted the adsorption data excellently. The adsorption intensity (n) is 1.68. This means the suitability of the adsorption process. The adsorption process is beneficial when the adsorption intensity is between 1 and 10. Adsorption kinetics data for sorption of Pb2+ ion unto chitosan were analyzed using the pseudo-first order, pseudo-second order, and intraparticle diffusion models. The results indicated that the pseudo-second-order model best described the adsorption kinetic data. For the thermodynamic studies, the enthalpy change, ΔH°, and the entropy change, ΔS°, for the adsorption processes are -18.10 kJ/mol and -0.0652 KJ/mol K respectively. The free energy, ΔG° for the process are 2186.39 J/mol, 3071.761 J/mol, 3689.615J/mol, and 4153.032 J/mol at 303K, 313K, and 323K respectively. The thermodynamic parameters showed that the adsorption of lead into SSC was exothermic and non-spontaneous.

Phenol is considered to be a very toxic pollutant in refinery wastewater which poses danger to man and its environment. This study target was to establish the effective assessment of phenol removal using chitosan, nano-chitosan obtained from crab shells and their generative potentials. The crab shells were prepared and converted to chitin. The experiment conducted was at different conditions for both chitosan (CTS) and nano-chitosan (NCTS) to achieve basic polysaccharide of low molecular weight chitosan (LMWC) and low molecular weight nano-chitosan (LMWNC) for removal of phenol from the refinery wastewater. Various techniques were used to characterize both chitosan, nano-chitosan and refinery wastewater, such as Double beam UV- spectrophotometer, Fourier Transforms Infrared Spectroscopy (FTIR), X-Ray Fluorescence (XRF) and Dynamic Light Scattering (DLS). The characterization of obtained chitosan and nano-chitosan absorbents showed good surface area, high pore sizes, effective size reduction yield of over 80% with good content of macro elements and good molecular weight. The values of calcium were 6.6972%, 5.6422% for CTS and NCTS respectively. The results of interaction revealed at factors of 35% sodium hydroxide, 3 h and 75 oC gives the degree of deacetylation (DD) to be 81.75%. The percentages of phenol removal were 87.88% and 98.77% for both CTS and NCTS respectively. The maximum regeneration obtained was 93.65 % which occurred at 50 mins. Hence, this showed that the synthesized nano-chitosan polysaccharide from white shrimp shells had the potential for phenolic compounds removal from refinery wastewater and the NCTS enhances the adsorption capacity due to higher surface areas.

Three vegetable oils, palm oil, shea butter, and groundnut oil, were investigated for use as lubricants in the orthogonal turning of mild steel. The cutting speed was varied while the depth of cut and feed was kept constant; the surface finish was determined using a roughness checker, and the interface temperature was measured using a k-type thermocouple. Tool life and coefficient of friction were determined. Results show improved tool life and good surface finish were obtained at low and medium cutting speeds. Findings show the satisfactory performance of groundnut oil with chip compression of 0.83 at the speed of 300 rpm and that of the shear butter with a maximum temperature of 62oC within the speed range. The cooling effect of the vegetable oils compared favourably with that of the standard soluble oil. The order of performance of the oils was palm oil, shear butter, and groundnut oil, which decreased in order, a performance attributed to their oiliness. The result of this work can be used to source new cutting fluids in cutting operations.

This study aims to optimize the removal efficiency of melon husk as a bio-adsorbent for lead ions in water. Response Surface Methodology (RSM) and Pyomo were employed to analyze experimental data from literature and identify optimal operating conditions. The independent variables used were dosage of melon husk and contact time. It was observed that time had a more positive influence on removal efficiency than dosage. Using the Stat-Ease 360 software, a quadratic model, exhibiting an excellent fit with an adjusted R-squared of 0.6862, was developed to describe the relationship between dosage and contact time on lead removal efficiency. RSM identified an optimal melon husk dosage of 0.64 g and a contact time of 49 minutes. However, Pyomo optimization revealed a slightly more efficient configuration with an optimal dosage of 0.63 g and a contact time of 44.8 minutes. This suggests that Pyomo may be a more effective tool for predicting the optimal conditions in this particular application.

Acetylation enhances the hydrophobicity of lignocellulosic biomasses by replacing their dominant hydrophilic hydroxyl groups with hydrophobic acetyl groups, thereby increasing their suitability for oil sorption. This modification typically results in weight gain due to the higher molecular mass of the introduced functional groups. This study employed the Central Composite Design (CCD) Response Surface Methodology (RSM) to optimise cotton fibre acetylation to enhance its weight percent gain (WPG) and improve its suitability for oil sorption. Reaction time, temperature, and the fibre mass-to- volume ratio of acetic anhydride were investigated, with WPG as the response parameter. Among the 20 experimental runs, the highest weight gain of 4.782% was achieved at 2 hours, 137°C, and a mass- to-volume ratio of 0.011 (0.550 g/50 ml). However, optimisation of the experimental conditions yielded a predicted WPG of 4.950% at 2.584 hours, 129.964°C, and 0.258 g of fibre per 50 ml of acetic anhydride. Validation of the predicted optimum response resulted in an experimental WPG of 4.896%, closely matching the predicted value of 4.950%. The minimal deviation of 0.054 demonstrated the model's high accuracy and reliability. Additionally, the desirability score of 1.000 indicated that the optimised conditions perfectly aligned with the study’s objectives. Successful acetylation was confirmed through FTIR analysis, which provided evidence of the introduction and enhancement of peaks associated with acetylated products.

The search for alternative building and road construction material in a strained economic situation is critical for socio-economic activities to thrive. The Nigerian Building and Road Research Institute (NBRRI) has keyed into the technology of making interlocking compressed stabilized earth block (ICSEB), as an alternative building materials. Nevertheless, parameters such as decomposition process and its microscopic properties have not been studied for the user comfort as friendly building material. This paper, examine “the time dependency thermogravimetric and differential thermal analysis (TGA- DTA), scanning electron microscope (SEM) and Fourier transform infrared (FTIR) of the already made ICSEB” based on the 95% laterite and not less than 5% cementing stabilization, with compaction pressure of 3 KN/mm2. Results revealed that, the ICSEB TGA takes 41.45 minutes, 33.33 minutes and 29.58 minutes to decompose at 10 oC/min, 15 oC/min and 20 oC/min heating rates and the combined TGA-DTA is endothermic process decomposition. SEM morphology showed heterogeneous phase formation with visible cracks, EDX detected 15 elements at 537 µm, having 41.37% carbon, 24.06% silicon, 21.35% aluminium, 5.14% Iron, 3.04% calcium, while others are in traces. These results imply that low aluminium and silicon content with greater carbon was responsible for early decomposition of the block in less than 1 hour heating. This therefore, suggests that the block has low-bearing capacity which requires optimization for its sustainability being an affordable and economical material within the reach of low-income earners.

Organic corrosion inhibitors, which are commonly used in the petroleum, refinery, pipeline, and automobile applications, are toxic and have negative environmental consequences. A cost-effective green inhibitor is undoubtedly a better option. The aim of this study is to use banana stem extract as a viable green inhibitor to mitigate corrosion in marine environment using an optimization approach. The extract was phytochemically analyzed to find out if it contained any bioactive constituents capable of preventing metal corrosion. Box-Behnken design was used to investigate the effects of process variables: temperature (30°-60°C), immersion time (3-9 days), extract amount (0.2-0.8 g/l). Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) were employed for characterization. The extract was found to be a good inhibitor because it contains alkaloids, phenols, tannins, saponins, terpenoids, steroids and flavonoids, according to the results of the phytochemical analysis. The experimental design's optimal process levels were found to be 45°C, 6 days of immersion, and 0.5 g/l of inhibitor. It was observed that more white patches were present on the SEM and EDS results of the mild steel from validated experiment via adsorption. It confirmed that banana stem extract is a good inhibitor in 0.1M H2SO4 solution.

Chitosan/clay materials from periwinkle shells and clay soil at a 50:50 ratio was made adsorbent and characterized, used for the adsorption of CO2 from flue gas at elevated temperatures (50 oC – 500 oC) in a fixed bed column (length 1.5m, and internal diameter 0.02m). Flue gas with composition of Methane (0.003), Ethane (0.002), Hydrogen (0.05), CO2 (0.15), Water Vapour (0.02), and Nitrogen (0.76), of pressure 49KPa, temperature of 500 oC, and flow rate of 75min/L from the exhaust tank; enters the fixed bed column for the adsorption process where the adsorbent is already placed. The results of the characterization of the adsorbent showed that 5.283nm, 2.64nm, 434.7m2/g, 704.2m2/g, 0.202cc/g, and 56.73% were best the values for the adsorbent’ pore width, pore diameter, microspore surface area, pore volume, and porosity, obtained using Dubinin-Raduskevich (DR), density functional theory (DFT), hydraulic diameter (DH), Langmuir, DH, and scanning electron microscope (SEM) analysing techniques respectively. The Fourier transform infrared (FTIR) Spectrum showed the presence of halogen (C-Cl), 20 alcohol (C-O), Nitro (N-O), and amine (N-H) compounds in the nanoparticles, revealing a strong affinity for CO2 particles in the flue gas. Another analysis showed the presence of elements (Ca, Si, Al, and Sr) in high compositions (0.470, 0.202, 0.186, and 0.092, respectively), revealing that the adsorbent is resistant to high temperatures. X-ray diffraction (XRD) analysis of the adsorbent gave Ca (OH)2, CaCO3, and TiO2 with compositions of 0.78, 0.19, and 0.026, respectively which revealed the strong affinity of the adsorbent for CO2. The Surface morphology of the adsorbent revealed that the surface was very rough and contains variety of pores or holes with wide capacities, indicating that more CO2 was captured and accommodated within the surface. Thermal analysis using the Barrett-Joyner-Halenda (BJH) method revealed that the adsorbent could withstand high temperatures up to 9000C, at this temperature, the adsorbent is only about 18% of the amount that enters the fixed-bed column for adsorption, but 100% of it can remain in the process for temperatures ranging from 0 oC – 300 oC. Finally, it was revealed that 95% of CO2 was adsorbed at the maximum value for the temperature (50 oC – 350 oC), time (0.5 - 5hr), and bed height (1 - 6cm).

Acha (Digitaria exilis) is a cereal crop, rich in carbohydrates, dietary fibre, minerals, and amino acids. Acha sourdough in powder form has several advantages including longer shelf life, constant product quality, and low cost of maintenance and transportation. This study aims to investigate the impact of feed rate on the spray drying process of acha (Digitaria exilis) sourdough into powder form. A fresh acha sourdough was prepared and spray-dried into powder at different feed pump rates (3, 3.5. 4, 4.5, and 5 Hz). Performance indicators of the process were analyzed. The spray dryer exit air temperature ranged from 70 ℃ to 55℃, while the relative humidity varied from 7% to 21%. The thermal efficiency and evaporation rate ranged from about 67% to 79% and 4.5 g/min to 13.0 g/min respectively. Powder yield and moisture, respectively varied from 45% to 50% and 8 % to 5%. The maximum powder yield of 50% was achieved at a feed pump rate of 4Hz. The viability of Lactic acid bacteria and yeast ranged from about 4.9 log (CFU/g) to 6 log (CFU/g) and 4.6 log (CFU/g) to 5.8 log (CFU/g) respectively. The total titrable acid ranges from 1.5 ml to 1.6 ml, while the pH varied from 4.3 to 4.2. The bulk density varied from about 4.6 g/ml to 6.0 g/ml. The results showed that the spray-drying approach produced stable sourdough powder with standard functional properties for production of gluten-free baked foods.

This study dwell on the removal of color of two different dye types namely Acid Red-27 (AA27) and Brilliant Green (BG) in a simulated waste dye water. An adsorption process in which the parameters were optimized with response surface methodology was adopted. Numerical optimization was determined at optimum conditions for BG and AA27, respectively and was used in carrying out a batch equilibrium studies while studying the effect of contact time, initial concentration and adsorbent dosage. The outcome of the experimentation indicate that the adsorbent dosage of the dye solution had a significant impact on adsorption. The result also showed that Freundlich isotherm fit the isotherm model for AA27, and Langmuir isotherm fit that of BG. The overall experimental data indicate a maximum removal of 96.24 % and 83.10 % was found for Brilliant Green and Acid Red 27 respectively while the maximum dye adsorption capacity of BG and AA27 was obtained at 68.02 and 3.43 mg/g, respectively. Activated Nigerian Laumontite zeolite has capability for adsorption and hence can be used for effective removal of dyes from wastewater.