This chapter gives an overview of polymer-based nanocomposites (PMNC), focusing on the processing. Polymers such as condensation polymers, vinyl polymers, polyolefins, specialty polymers including biodegradable are used in production of PMNC. It is the reinforcement that is in the nanorange size in nanocomposites generally. Reinforcements used are metal powders, silica, clays, and metal oxides. The most important methods of preparing PMNC are intercalation of the polymer or pre-polymer from solution, in-situ intercalative polymerization, melt intercalation, direct mixture of polymer and particulates, template synthesis, in-situ polymerization; and sol-gel process. The structure of polymer-based nanocomposites consists of the matrix material containing the nanosized reinforcement components in the forms of whiskers, particles, nanotubes, fibers, etc. It is clear that polymer-based nanocomposites provide many benefits such as improved properties, minimization of solid wastes films, and lower and improved manufacturing capabilities.
Sewage sludge is a very harmful waste when improperly discharged into the environment because of its inherent abundant pathogens, organic pollutants, and heavy metal constituents. The pyrolysis of sewage sludge is viewed not only to reduce pollutants associated with it but also one of the viable alternative sources for renewable energy or biofuel production. In this study, the effect of catalyst and temperature on the yield and composition of bio-oil obtained from the catalytic and non-catalytic pyrolysis of desludging sewage samples (DSS) was investigated. Modified pyrolysis reactor was used to pyrolyze the DSS at temperature ranges of 300–400,400–500,500–600 and 600–700 ℃ with and without the use of zeolite-Y catalyst. The 'heterogeneous' catalysis reaction yielded 20.9 wt% bio-oil, while the reaction without catalyst yielded 18.2 wt% bio-oil. Pyrolysis of the DSS favored char yield of between 55.4 and 76.6 wt%. The X-ray Fluorescence (XRF) analysis showed high silica (46 and 56.1 wt%), calcium (20.9 and 15.50 wt%), and low organic matter (12 and 12.87 wt%) contents present in the desludging feedstock before and after pyrolysis respectively. The gas chromatography–mass spectrometry (GCMS) analysis indicated the presence of nitrogen-containing compounds (between 20 and 50 wt%), mono-aromatics (18 and 28 wt%) and oxygenated compounds, in the form of carboxylic acids, aliphatics, ketones, ethers, esters and aldehydes in the bio-oils. Pyrolysis process development is, therefore, essential to clean the environment of pollutants from sewage sludge, by its conversion to more useful chemicals. In contrast, sewage sludge with high silica content may be tailored to the production of building materials.
Data from literature and a stoichiometric material balance model were employed to estimate associated emissions with flaring of sweet gas in Nigerian oil and gas companies. Emission factors were obtained using AP 42 formula. Results showed that thousands of tonnes, ranging from 6500 to 22,000 tonnes of natural gas were flared from 1997 to 2016. At flaring stack efficiencies of 97% and 98%, the associated emissions are: CH4, C2H6, C3H8, iC4H10, nC4H10, iC5H12, nC5H12, C6H14, C7H16, C8H18, C9H20, CO2, and N2 from unburnt natural gas and in addition to CO2, CO, N2, NO, NO2, H2O and H2 from incomplete combustion. At both flaring stack efficiencies, the amount of emissions from unburnt condition ranged from1,608 tonnes N2 to 9,146 tonnes CO2 all higher than any emission standards in the world, while the amounts of emissions from incomplete combustion ranged from 467,964 tonnes for CO2 the lowest to 2,476,011 tonnes for N2 the highest all higher than any emission standards in the globe. Emission factors of emissions from unburnt natural gas ranged from 0.000090 tonne/tonne for C10H22 to 0.026235 tonne/tonne for CH4 while those of the emissions from incomplete combustion ranged from 0.10285 tonne/tonne for H2 to 1.13137 for CO2 tonne/tonne. It was observed that thousands of tonnes of emissions are released into the atmosphere during flaring of sweet natural gas either at complete or incomplete combustion. It is recommended that flaring of natural gas should be reduced to a minimal level to safeguard the environment.
Shea tree sawdust delignification kinetic data during alkaline peroxide pretreatment were investigated at temperatures of 120 °C, 135 °C, and 150 °C. The activation energy during delignification was 76.4 kJ/mol and the Arrhenius constant was calculated as 8.4 x 106 per min. The reducing sugar yield for the treated to the untreated biomass was about 22-fold. Enzymatic hydrolysis conditions studied were; time (72 h and 96 h), substrate concentration (20, 30, 40, and 50 g/L), and enzyme loadings (10, 25, 40, 50 FPU/g dry biomass), which showed the optimum conditions of 96 h, 40 g/L, and 25 FPU/g dry biomass at 45 °C hydrolysis temperature. At the optimized enzymatic hydrolysis conditions, the reducing sugar yield was 416.32 mg equivalent glucose/g treated dry biomass. After 96 h fermentation of treated biomass, the ethanol obtained at 2% effective cellulose loading was 12.73 g/L. Alkaline peroxide oxidation pretreatment and subsequent enzymatic hydrolysis improved the ethanol yield of the biomass.
In this study, alkaline peroxide oxidation pretreatment was evaluated for sugarcane bagasse, a lignocellulosic biomass. By comparing the effects of NaOH- H2O2 and Ca(OH)2 on pretreatments at specified reaction time periods (3, 6, 9, and 12 h) and reaction temperatures (60, 70, 80, and 90 h), optimum responses in term of cellulose content, hemicellulose solubilization, and lignin removal were established. Optimum pretreatment conditions of 80 o C reaction temperature, 3 h reaction time, and 30 mL/L of water hydrogen peroxide concentration (1%H2O2) solubilized 69.5%(w/w) hemicellulose for the sodium hydroxide peroxide (SHP) pretreatments, 75.8%(w/w) lignin removal was also achieved with 59.2%(w/w) cellulose retained in the solid fraction. In addition, the responses for the optimum conditions for the calcium hydroxide peroxide (CHP) pretreatments, the cellulose content, hemicellulose solubilization, and lignin removal were 50.3%, 66.6%, and 65.4%(w/w) respectively. Pretreatments showed both NaOH- H2O2 and Ca(OH)2-H2O2 to be useful pretreatment agents for the disruption of the polysaccharide complex. The study also revealed that NaOH-H2O2 pretreatment stands as a better choice to Ca(OH)2-H2O2 pretreatment.
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