Int. J. Environment And Waste Management

 Journal

 Conversion Of Siam Weeds And Rice Straws To Energy Products And Valuable Chemicals Via Pyrolysis

 Joseph K. Ogunjobi*, Labunmi Lajide And Bodunde J. Owolabi

 2016

Increasing global warming has necessitated reduction in combustionof waste and encouraged their conversion into useful materials. Rice straw andSiam weed were valorised via pyrolysis in a laboratory-scaled modified slowpyrolysis reactor and products collected and characterised. The major productobtained was bio-char for both wastes with 12.3% and 27.8% viscous bio-oilrecovered from the pyrolytic condensates of rice straw and Siam weedrespectively. The resulting bio-oil is less acidic compared to most knownpyrolytic oils. Separation of condensates reduced acidity and retarded ageing ofbio-oils. The most abundant compound found in Siam weed viscous bio-oilfrom GC-MS analysis was phenol (16.93%) while it was pentadecyl-2-propylester sulphurous acid (30.37%) in rice straw. Bio-chars from these residuesshowed a higher heating value of ~21 MJ/kg and pH values of ~9.00. 

 Royal Society Of Chemistry

 Journal

 Post-polymerisation Modification Of Bio-derived Unsaturated Polyester Resins Via Michael Additions Of 1,3-dicarbonyls

 T. J. Farmer, J. H. Clark, D. J. Macquarrie, J. K. Ogunjobi And R. L. Castle

 2016

Post-polymerisation modification of α,β-unsaturated polyesters (UPEs) is useful to deliver polymers withtuneable properties and applications different from their parent backbone. Bio-derivable itaconate unsaturatedpolyesters, with a range of co-monomers, were modified via a heterogeneously catalysedmicrowave-assisted Michael addition of pendants, acetylacetone (Hacac) and dimethyl malonate (DMM),to the polymer backbones with very short reaction times. Differential scanning calorimetry analysisshowed an increase in the glass-transition temperatures of most of the saturated polyesters considered.Solubility and complexation studies demonstrated metal chelating abilities of the acetylacetone pendantcan be retained, even following tethering to a polyester backbone. Additionally, it is demonstrated for thefirst time that Michael addition with Hacac and DMM can be used to reverse Ordelt saturation, anunwanted side-reaction in the synthesis of UPEs. 

 Taylor & Francis Group, LLC

 Journal

 The Potentials Of Cocoa Pods And Plantain Peels As Renewable Sources In Nigeria

 Ogunjobi J. K. And Lajide L.

 2015

The use of thermochemical processes to convert biomass into energy products has continued to allay apprehensions arising from increasingdepletion of fossil fuels and growing energy demand. Pyrolysis products (bio-oils and bio-chars) from cocoa pods and plantain peels havebeen characterized. Products distribution for cocoa pod and plantain peel was 29.4% and 38.1% condensate; 46.5% and 38.5% bio-char;and 24.1% and 23.4% noncondensable gas respectively. Bio-oils from the wastes were found to possess low acidity and improved stabilityupon storage. Over 70% oleic acid was obtained in cocoa pod bio-oil, which could serve as a raw material for many chemical industries.Bio-chars from both residues have higher heating value (HHV) as ∼22 MJ/kg and pH as ∼10 and could serve as renewable fuels in thecountry. SEM-EDS morphology and elemental composition revealed that these bio-chars contain about five elements essential for plantgrowth. 

 Journal Of American Science

 Journal

 Investigation Of The Inhibitive Properties Of Alchornea Laxiflora Leaves On The Corrosion Of Mild Steel In HCl: Thermodynamics And Kinetic Study

 Olasehinde, E.F, Ogunjobi, J. K., Akinlosotu, O. M., Omogbehin, S. A.

 2015

The use of naturally occurring compounds as corrosion inhibitors is of potential interest because of theircost effectiveness, abundant availability and environmental acceptability. Therefore, the study investigates theinhibition efficacy of acid extract of Alchornea laxiflora leaves on mild steel in acidic medium using gravimetricmethod. Experiments were performed by varying the immersion time, concentration of extract and the temperature.The results showed that acid extract of Alchornea laxiflora leaves is a potential inhibitor for the corrosion of mildsteel in acidic medium. The corrosion rate of mild steel in 1M HCl decreases with increase in the concentration ofthe extract. The inhibition efficiency increases progressively as the concentration of the extract increases butdecreases with rise in temperature and the exposure time. The highest inhibition efficiency observed in the presenceof the extract was 96 %. Activation energy was found to be 21.81 kJ mol-1 for the blank and increases to 82.57 kJmol-1 in the presence of the extract. Thermodynamic parameters such as enthalpy change, entropy change andGibb’s free energy were evaluated. Kinetics of the reaction in the presence of the extracts revealed that it follows afirst order reaction and the half-lives increase as the concentration of the extract increases. Adsorption studiesrevealed that Langmuir adsorption isotherm is the best adsorption model applicable to the adsorption of the extracton mild steel surface. Preliminary investigation of the phytochemical constituents showed that the extract containstannin, flavonoid, terpenoid and some other compounds in trace constituents. 

 Nil

 Journal

 Characterisation Of Bio-Oil And Bio-Char From Slow-Pyrolysed Nigerian Yellow And White Corn Cobs

 Ogunjobi J. K. And Lajide L.

 2013

Cobs from yellow and white corn were slow pyrolysed at 450°C in a laboratory-scaled fixed bed reactor. Product distribution obtained was: 42.6% and 44.8% condensate, 33.3% and 33.5% bio-char, and 24.1% and 21.7% non-condensable gas for white and yellow corn cobs respectively. 13.6% bio-oil was recovered from white cob condensate and 10.12% for yellow cob. The resulting bio-oil with pH of around 5 and density of ~1.1 g/cm3 was found to be stable on storage over a period of 10 months. Ash level and viscosity at 50°C were (0.12% and 0.10%) and (41.2 cSt and 20.8 cSt) in bio-oils from the cobs of yellow and white corn respectively. Characterisation with gas chromatography revealed that the bio-oil contained cellulose and lignin-derived compounds. Bio-chars from these residues have higher heating value of ~30.00 MJ/kg, pH of ~8, bulk density of ~0.220 g/cm3 and ash level of ~1.7%. Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectrometry (EDS) was used to examine the morphology and elemental composition of these bio-chars. The bio-char produced is capable of contributing 83.6 billion MJ to energy demand in Nigeria and preventing about 6.8 million tonnes of CO2 emission into the environment.

 

 Nil

 Disertations

 Production And Characterisation Of Bio-oils And Bio-chars From Slow-Pyrolysed Plant-Based Agricultural Wastes

 Ogunjobi J. K.

 2012

nil

 

 Nil

 Disertations

 Production And Characterisation Of Bio-oils And Bio-chars From Slow-Pyrolysed Plant-Based Agricultural Wastes

 Ogunjobi J. K.

 2012

Yellow and white corn cobs (Zea mays), cocoa pods (Theobroma cacao), plantain peels (Musa paradisiaca), rice straw (Oryza sativa) and Siam weed (Chromolaena odorata) were subjected to thermochemical conversion technology. The residues were pyrolysed at 450oC in a laboratory-scaled modified slow pyrolyser for 1 hour. The product distribution obtained was:  42.6%, 44.8%, 36.8%, 38.1%, 37.8% and 29.4% condensates; 33.3%, 33.5%, 46.9%, 38.5%, 42.9% and 46.5% bio-chars; and 24.1%, 21.7%, 16.3%, 23.4%, 19.3% and 24.1% non-condensable gases for white corn cob, yellow corn cob, rice straw, plantain peel, Siam weed and cocoa pod respectively. Percentages of viscous bio-oil reclaimed from the feedstock were 13.6%, 10.12%, 12.3%, 13.3%, 27.8% and 9% from white corn cob, yellow corn cob, rice straw, plantain peel, Siam weed and cocoa pod respectively. GC/MS analysis revealed that the most abundant compounds in the biomass feedstock bio-oils were: phenol (16.93%) in Siam weed; 3, 5- di-tert-butyl phenol (13.88%) in plantain peel; 4-ethyl phenol (29.33% and 25.53%) in yellow and white corn cobs respectively; and oleic acid (72.90%) in cocoa pod. Pentadecyl-2-propyl ester sulfurous acid (30.37%) and 1-mono-linolein (29.88%) were found to be the most abundant compounds in rice straw bio-oil. While aqueous bio-oils from nearly all the feedstock were acidic, viscous bio-oils from plantain peel, Siam weed and cocoa pod were slightly alkaline.  Viscosities of bio-oils at 50oC were in the range of 10-117cSt and densities greater than 1.0 g/cm3.Higher heating value in the range of 20- 32 MJ/kg was obtained for bio-chars from the residues. Elemental analysis using Energy Dispersive X-ray Spectrometry (EDS) indicated that these bio-chars contain more than five plant nutrients in appreciable quantity while Scanning Electron Microscopy (SEM) revealed their porous structural nature. pH study showed that bio-chars from all the biomasses were slightly alkaline with value ranging from 7.80-9.70. These products have potentials as solid fuels to meet the increasing energy demand and as valuable raw materials for local industries and agricultural purposes in Nigeria. 

 

 Nil

 Disertations

 Syntheses Of Bromo, Chloro And Nitro Piperonal Derivatives And Their Antimicrobial Activities

 Ogunjobi J. K.

 2008

nil