Effect of Thermal Pretreatment on the Yield of Biogas from Microcoleous Vaginatus

Biomass is being looked upon as one of the promising renewable energy sources for the future, with growing interest in microalgae conversion into biogas through anaerobic digestion. Recently, the ability of microalgae to treat waste water has doubled its potentials material today. However, in spite of the progress made in that regards, there are still challenges of algae conversion to biofuel, due to the presence of complex cell wall in some algae. Cell wall inhibits bacteria growth during degradation. In this research work 10 grams of Microcoleous vaginatus was treated in an oven at varying temperatures of 70, 75 and 80 oC for an hour, out of which 4 g was measured into 250 ml serum bottle for digestion at mesophilic temperature of 37 oC. Based on the results of proximate analysis, 69%increase in carbohydrate was attained with 72.7 – 148% reduction in moisture content. The biogas yield of untreated sample was 4.36 mLg−1 VS, while, pretreated samples at 70, 75 and 80 ℃ produced 8.39, 9.07 and 9.38 mLg−1VS (volatile solid) of biogas. This  corresponds to 92, 108 and 115% higher than that of untreated samples. However, thermal treatment of M. vaginatus prior to digestion show positive effect on carbohydrate extraction and enhanced biogas and methane yield as well. Therefore, this makes the substrate a good feedstock for biogas production. Keywords: Biomass, pretreatment, thermal, anaerobic digestion, degradation, Microcoleous vaginatus

Improving rheological properties of Gambe clay for drilling fluid application using fermentable polymers

There are abundant bentonitic clay deposits in Nigeria. However, it does not meet commercial standard for drilling mud formulation, because it is composed of calcium montmorillonite. Therefore, there is need for the clay to be enhanced and polymers have been identified as enhancement agents. The work was aimed at improving the rheological properties of Gambe clay for drilling fluid formulation using the fermentable polymers (xanthan gum, locust bean gum and tamarind seed gum). The clay was obtained from Gambe town in Adamawa State, Nigeria. The clay was beneficiated for quartz removal and chemical beneficiated with 6 wt% of Na2CO3. The mineral composition and the cation exchange capacity of the clay was determined using X-ray diffraction analysis and ammonium acetate saturation method, respectively to find out its quality for drilling mud formulation. Drilling mud was formulated by mixing of 22.5 g of the clay to 350 ml of water with a high speed mixer to obtain a homogenous mixture. The polymer enhancers were also added to the mixture. The effect of the fermentable polymer at different concentration on the rheological properties of the formulated drilling fluid was investigated employing FANN 35SA viscometer. It was found that 0.93 wt% of the tamarind seed gum, locust bean gum and xanthan gum in the formulated drilling fluid enhanced the yield point from 0.72 Pa to 7.2 Pa, 12.48 Pa and 16.36 Pa, and the gel strength from 0 Pa to 8.35 Pa, 10.44 Pa and 68.92 Pa of the formulated mud respectively. The mud enhanced with 0.80 wt% of the enhancers had high rheological properties than imported clay.Keywords: Drilling mud, Gambe clay, tamarind seed gum, locust bean gum, rheological propertie

Production and Characterization of Carbon Molecular Sieves from Bituminous Lafia-Obi Nasarawa Coal by Pore Size Modification with Spent Engine Oil

In this work, a carbon molecular sieve (CMS) was produced from a  bituminous Lafia-Obi Nasarawa coal. An initial activated carbon (AC) sample was prepared via chemical activation from the coal, from which the CMS samples were then produced through heat treatment processes and carbon deposition fromspent engine oil. Spent engine oil was pyrolyzed in order to deposit carbon at the pore mouth of coal-based AC to yield CMS. The effect of reaction temperature and holding time variation on the surface area, micropore pore volume and pore size of CMS was studied. Reaction  temperature was varied at 400, 550 and 700 °C while holding time was varied at 30 and 60 min. The Brunauer–Emmett–Teller (BET) method was used to calculate the surface areas, while the Dubinin–Radushkevich (DR) and Horváth-Kawazoe (HK) methods were used to determine the microporevolumes and pore sizes of the AC and CMS, respectively. The CMS sample with the largest BET surface area (5.824 m2 g–1), DR micropore volume (0.172 cm3 g–1) and HK pore size (6.317 Å) were obtained at 700 °C reaction temperature and 60 min holding time. In addition to this, a molecular sieving ability test to separate benzene from a mixture of benzene and o-xylene in solution was carried out on the AC and CMS, with the CMS having a selective benzene percentage uptake of 61.36 %.Keywords: Activated carbon (AC), carbon molecular sieves (CMS), carbon deposition, reaction temperature, holding time

Determination of morphological features and molecular interactions of Nigerian bentonitic clays using Scanning Electron Microscope (SEM)

This research focused on identifying the morphological features and molecular  interactions of the Nigerian Bentonitic clays using Scanning Electron Microscope (SEM) characterisation technique. The SEM microstructure images indicated that the bentonite samples are generally moderately dispersive to dispersive with some large flocs which were apparently separate and dispersed from one another rather than located on the totality of the image. This property is more pronounced on the sodium (Na) activated and the treated samples than in the raw samples, which could be due to quartz removal and Na activation on the raw Bentonitic samples. Dispersive sample surfaces consist of loose flakes with no definitive mass structures observed on the treated samples due to added poly anionic cellulose (PAC) to the samplesKey words: SEM, microstructure, images, bentonite, flocs and PA