CHARACTERIZATION

Chemical industries increasingly rely on catalytic processes, and more than 90% of large scale chemical transformations depend on catalysts. Some of the commonly used homogeneous catalysts in Fridel Crafts alkylation reaction are; BF3, H2SO4, HF, AlCl3. Though, readily available at low cost, they have several limitations and these include toxicity, difficulty in separation and recovery and disposal problems. These limitations have intensified the demand for sustainable, efficient, and environmentally benign heterogeneous catalysts. This study focuses on the development of metal-doped coconut-shell biochars as robust heterogeneous catalysts for the Friedel Crafts benzylation of toluene. Biochars derived from the coconut shell produced at different pyrolysis temperatures (350, 400, 450, 500, 600 and 700 °C) were characterized in terms of their physicochemical and textural properties, surface oxygen functional groups and surface morphology using standard methods. The coconut shell biochar (CSB) sample with the optimal textural properties (CSB450) was then co-pyrolysed with Fe³⁺, Zn²⁺, and Fe³⁺/Zn²⁺ ions to produce metal doped biochars (Fe³⁺ - doped, Zn²⁺- doped, and Fe³⁺/Zn²⁺-doped biochar). Central Composite Design (CCD) of the Response Surface Methodology (RSM) was employed to optimize the process variables (metal loading, pyrolysis temperature and pyrolysis time) for the co-pyrolysis reaction. Similarly, RSM was used to optimized the process variables (mole ratio of toluene: benzyl chloride (T:BC), reaction temperature and reaction time) on benzyl chloride conversion to benzylated toluenes with the metal doped biochars. RSM-derived optimal conditions resulted in enhanced specific surface areas of 2098.04 m2 .g-1 for the Fe³⁺-doped biochar, 1721.40 m2 .g-1 for the Zn²⁺-doped biochar, and 2124.5 m2 .g-1 for the Fe³⁺/Zn²⁺-doped biochar. Compared with the pristine biochar (CSB450), the metal doped biochars (MBCs) showed improved physicochemical properties and textural properties. In addition, surface elemental analysis confirmed the successful incorporation of the Fe (10.09%), Zn (5.17%) and Fe/Zn (9.44/6.51%) on the MBCs. The results of the conversion process showed that the reaction temperature, mole ratio, and reaction time significantly affected benzyl chloride conversion with the metal doped biochar. Three novel models were developed for benzyl chloride conversion process. From the models, we predicted optimized process conditions; optimum benzyl chloride conversion of 93% was found for Fe3+/Zn2+ - doped biochar, with values of 87 and 81% for the Fe3+ - and Zn2+ - doped biochar respectively. This research established metal doped coconut shell biochar as an effective, low-cost, and environmentally friendly heterogeneous catalysts for organic transformations, presenting a viable alternative to conventional corrosive and non-recyclable catalysts in industrial alkylation processes.

Chemical industries increasingly rely on catalytic processes, and more than 90% of large scale chemical transformations depend on catalysts. Some of the commonly used homogeneous catalysts in Fridel Crafts alkylation reaction are; BF3, H2SO4, HF, AlCl3. Though, readily available at low cost, they have several limitations and these include toxicity, difficulty in separation and recovery and disposal problems. These limitations have intensified the demand for sustainable, efficient, and environmentally benign heterogeneous catalysts. This study focuses on the development of metal-doped coconut-shell biochars as robust heterogeneous catalysts for the Friedel Crafts benzylation of toluene. Biochars derived from the coconut shell produced at different pyrolysis temperatures (350, 400, 450, 500, 600 and 700 °C) were characterized in terms of their physicochemical and textural properties, surface oxygen functional groups and surface morphology using standard methods. The coconut shell biochar (CSB) sample with the optimal textural properties (CSB450) was then co-pyrolysed with Fe³⁺, Zn²⁺, and Fe³⁺/Zn²⁺ ions to produce metal doped biochars (Fe³⁺ - doped, Zn²⁺- doped, and Fe³⁺/Zn²⁺-doped biochar). Central Composite Design (CCD) of the Response Surface Methodology (RSM) was employed to optimize the process variables (metal loading, pyrolysis temperature and pyrolysis time) for the co-pyrolysis reaction. Similarly, RSM was used to optimized the process variables (mole ratio of toluene: benzyl chloride (T:BC), reaction temperature and reaction time) on benzyl chloride conversion to benzylated toluenes with the metal doped biochars. RSM-derived optimal conditions resulted in enhanced specific surface areas of 2098.04 m2 .g-1 for the Fe³⁺-doped biochar, 1721.40 m2 .g-1 for the Zn²⁺-doped biochar, and 2124.5 m2 .g-1 for the Fe³⁺/Zn²⁺-doped biochar. Compared with the pristine biochar (CSB450), the metal doped biochars (MBCs) showed improved physicochemical properties and textural properties. In addition, surface elemental analysis confirmed the successful incorporation of the Fe (10.09%), Zn (5.17%) and Fe/Zn (9.44/6.51%) on the MBCs. The results of the conversion process showed that the reaction temperature, mole ratio, and reaction time significantly affected benzyl chloride conversion with the metal doped biochar. Three novel models were developed for benzyl chloride conversion process. From the models, we predicted optimized process conditions; optimum benzyl chloride conversion of 93% was found for Fe3+/Zn2+ - doped biochar, with values of 87 and 81% for the Fe3+ - and Zn2+ - doped biochar respectively. This research established metal doped coconut shell biochar as an effective, low-cost, and environmentally friendly heterogeneous catalysts for organic transformations, presenting a viable alternative to conventional corrosive and non-recyclable catalysts in industrial alkylation processes.

In today's world, the rise of modernization and industrialization has quietly reshaped ecosystems—the rapid expansion of industries and unchecked urbanization continue to disrupt fragile environments, leading to the persistent challenge of heavy metal contamination in soil. This study investigates the green synthesis and characterization of an MgO-MnO-biochar ternary nanocomposite as well as the MgO-MnO Nanopparticle using an eco-friendly co-precipitation method, and highlightening its potential heavy metal remediation applications. The synthesis involved the bottom- up fabrication of magnesium and manganese oxides in a green solvent system, followed by integration with biochar. The characterization of the MgO-MnO-biochar nanocomposite and MgO-MnO nanoparticle system revealed significant structural, compositional, and morphological differences. FTIR analysis showed the nanocomposite had prominent O–H stretching at 3951.1, 3641.1, and 3790.2 cm⁻¹, C–H stretching at 2907.3 cm⁻¹, CO₂ adsorption at 2110.3 cm⁻¹, C=C stretching at 1611.8 cm⁻¹, and Mg–O and Mn–O bonds at 946.3 and 864.7 cm⁻¹, while the nanoparticle system exhibited fewer functional groups, with CO₂ adsorption at 2102.2 cm⁻¹ and C=C stretching at 1598.5 cm⁻¹. EDX analysis revealed high carbon content (48.72 wt%) in the nanocomposite, absent in the nanoparticle system, alongside higher Mn (61.62 wt%) and Mg (32.24 wt%) concentrations in the nanoparticle system compared to 24.47 wt% Mn and 11.34 wt% Mg in the composite. XRD analysis identified Lindergerbite (59.00%) and Periclase (13.00%) in the nanoparticle system, while the nanocomposite featured Flagstaffite (52.40%), Graphite (1.84%), and Cryoptohalite (7.96%). BET analysis showed the nanoparticle system had a higher surface area (282.000 m²/g vs. 216.400 m²/g), pore volume (0.173 cm³/g vs. 0.128 cm³/g), and BJH surface area (354.200 m²/g vs. 265.400 m²/g), though pore diameters were similar (2.132 nm vs. 2.129 nm). SEM analysis revealed the nanocomposite's porous, fibrous structure with well-dispersed nanoparticles, while the nanoparticle system exhibited a denser, more aggregated morphology with reduced porosity. The characterization results revealed that the MgO-MnO-biochar ternary nanocomposite possesses significant structural and compositional properties, suggesting its potential as a sustainable, cost-effective material for future heavy metal remediation applications.

Groundnut sauce (Ose-Oji) is a popular traditional condiment widely consumed in many parts of Nigeria. Due to its high nutrient content and methods of preparation and storage, it is susceptible to microbial contamination, particularly by fungi. This study was carried out to isolate and characterize fungi present in Ose-Oji obtained from selected local government areas in Edo State. Samples of the sauce were collected from different vendors and transported to the laboratory under sterile conditions for analysis. Standard microbiological techniques were employed for the isolation of fungal organisms using suitable culture media. The isolates were further characterized based on their macroscopic and microscopic features. The study revealed the presence of several fungal species, including Aspergillus, Penicillium, Rhizopus, and Mucor. The occurrence of these fungi indicates possible contamination arising from poor handling practices, environmental exposure, and improper storage conditions. Some of the identified fungi are known to produce mycotoxins that may pose health risks to consumers. The findings highlight the need for improved hygienic practices during the preparation, handling, and storage of groundnut sauce. Public awareness and proper food safety measures are therefore recommended to reduce fungal contamination and ensure the safety of this widely consumed food product.