Microwave-assisted and conventional hydrothermal carbonization of lignocellulosic waste material: comparison of the chemical and structural properties of the hydrochars

This study compares the chemical and structural properties of the hydrochars prepared from microwave-assisted and conventional hydrothermal carbonizations of Prosopis africana shell, a waste plant material. The preparation involved heating the raw material in de-ionized water at 200 °C for 5-20 min, and 120-240 min in the microwave and conventional oven respectively. The prepared hydrochars were characterized using the scanning electron microscope, nitrogen sorption measurement, Fourier transform infrared spectroscopy, CHN analyzer, thermogravimetric analysis, and nuclear magnetic resonance. The results showed that the microwave-assisted hydrothermal carbonization process is fast in the carbonization of the Prosopis africana shell as shown by the level of conversion attained within the short time. This study presents new data on the comparison of the hydrochars from microwave-assisted and conventional hydrothermal carbonization processes of the same lignocellulosic material in terms of their properties

Biomass derived mesoporous carbon monoliths via an evaporation-induced self-assembly

Evaporation-induced self-assembly has been applied in the synthesis of crack-free mesoporous carbon monolith with good mechanical stability using a waste plant material as carbon precursor and triblock copolymer F127 as template. The carbon monolith was characterized using transmission electron microscopy, scanning electron microscopy, nitrogen adsorption–desorption measurement, X-ray diffraction and Fourier transform infrared spectroscopy. The results showed that the carbon monolith is mesoporous, has a surface area of 219 m²/g, and a narrow pore size distribution of 6.5 nm

Microwave-assisted hydrothermal carbonization of rapeseed husk: A strategy for improving its solid fuel properties

Hydrothermal carbonization of a waste biomass material is a green and promising technique for improving its solid fuel properties, which does not require pretreatment procedure such as drying of the biomass. In this study, hydrothermal carbonization of rapeseed husk, a waste plant material was carried out under microwave heating and the effect of process parameters, such as reaction temperature and residence time on the mass yields and energy properties of the hydrochars was studied. The procedure involved the heating of the feedstock in deionized water in a microwave oven at temperatures of 150 to 200 °C for a specified period of time. The results indicated that the mass yields decreased, as the reaction temperature and residence time were increased, which led to improvement in the energy properties of the prepared hydrochars. The reaction was rapid within the first 20 min, and stabilized afterwards. The energy properties of the prepared hydrochars are consistent with previous studies, showing that the hydrochars have the potential of being used as solid fuel. The structural and morphological analysis carried out revealed that the feedstock was transformed during the process

Pollution reduction with processed waste materials

This research aimed at providing an understanding into the waste management options available for developing countries and also to provide insight into the possible application of the processed materials during the waste management processes, thereby helping in converting the waste materials which would have been a nuisance into useful products. Pyrolysis and composting were utilized as the waste management techniques for processing the waste materials for use in pollution reduction.Carbon materials (biochar and hydrochar) were prepared in the pyrolysis aspect of this research through dry and wet (hydrothermal carbonization) pyrolysis respectively. Under the wet pyrolysis, comparisons were made between the conventional and the microwave-assisted hydrothermal process for carbonisation of waste materials. Three waste materials were investigated Prosopis africana shell (from Nigeria), rapeseed waste (from the UK) and coconut husks (a well-studied material in carbon science). The result shows that the microwave-assisted hydrothermal carbonization process reduced the processing time from 4 hours to 20 minutes for the same level of carbonisation. The biochar and the hydrochar from the pyrolysis and microwave-assisted hydrothermal carbonization of one of the waste materials (Prosopis africana shell) were applied in the adsorption of Pb²⁺ and Cd²⁺ from aqueous solution. In terms of adsorbing the heavy metal ions from aqueous solution, the materials proved to have high adsorption capacities than some previously studied adsorbents. Maximum adsorption capacities for the hydrochar and biochar were 45.3 and 31.3 mg/g for Pb²⁺ and 38.3 and 29.9 mg/g for Cd²⁺ respectively. Interestingly, the hydrochar from microwave-assisted hydrothermal carbonization, which is a green chemistry approach, was capable of adsorbing the metal ions more than the biochar from aqueous solution. The adsorption process was dominated by chemisorptions as it followed the pseudo-second-order kinetics and the adsorption data fitted the Langmuir isotherm model. The thermodynamics study of the adsorption processes showed that it was spontaneous and endothermic.Microwave-assisted hydrothermal process and evaporation-induced self-assembly (EISA) were also used to synthesize carbon monoliths, using a waste plant material as the carbon precursor. The microwave-assisted hydrothermal process was not successful in the synthesis of the carbon monolith; however novel carbon monolith was produced using the EISA approach. The carbon monolith in comparison to the biochar and hydrochar from the same material is not powdered, has higher surface area and porosity which could enhance its adsorption capacities for heavy metal ions.In the composting aspect of the research, the Prosopis africana shell showed that it can be composted. The effect of an organic pollutant, in this case anthracene during a starch amended co-composting process was evaluated through total dry matter and extracellular enzyme activities of both starch specific (α-glucosidase) and non-specific (β-glucosidase) substrate. The result showed that the effect of anthracene amendment alone was not highly significant on the process. However, the interaction between the anthracene and starch have consistent effects on the process, which is novel and should be studied further to know the magnitude of sure interaction.This research showed that the waste material (Prosopis africana shell) from Nigeria can be processed into useful products using pyrolysis and composting. Further work will be required in Nigeria outside the laboratory to see the real applicability of these processed materials

Microwave-assisted hydrothermal synthesis of carbon monolith via a soft-template method using resorcinol and formaldehyde as carbon precursor and pluronic F127 as template

A new microwave-assisted hydrothermal synthesis of carbon monolith is reported in this work. The process uses microwave heating at 100 °C under acidic condition by employing a triblock copolymer F127 as the template, and resorcinol–formaldehyde as the carbon precursor. Scanning electron microscopy, Fourier transform infrared spectroscopy, nitrogen sorption measurements, transmission electron microscopy, X-ray studies and thermogravimetic analysis were used to characterize the synthesized material. The carbon monolith is crack-free, mesoporous and has a high surface area of 697 m²/g. The results demonstrate that the microwave-assisted hydrothermal synthesis is a fast and simple approach to obtain carbon monoliths, as it reduces effectively the synthesis time from hours to a few minutes which could be an advantage in the large scale production of the material

Implication of Economic and Financial Crimes Commission and Corruption on the Consolidation of Democracy and Sustainable Development and Growth in Nigeria from 2004-2008

Nigeria’s inability to consolidate her democracy is blamed largely on the high level of corruption in the country. Corruption is efforts to secure wealth or power through illegal means for private gain at public expense; or a misuse of public power for private benefit. Corruption like cockroaches has coexisted with human society for a long time and remains as one of the problems in many of the world’s developing economies with devastating consequences. Corruption as a phenomenon, is a global problem, and exists in varying degrees in different countries (Agbu, 2001). Corruption is not only found in democratic and dictatorial politics, but also in feudal, capitalist and socialist economies. Christian, Muslim, Hindu, and Buddhist cultures are equally bedeviled by corruption (Dike, 2005). Corrupt practices are not an issue that just begins today; but the history is as old as the world (Lipset and Lenz, 2000). Corruption not only distorts competition, hinders economic growth and endangers the stability of democratic institutions; it pulls down the moral foundation of society (Inokoba and Ibegu, 2011). In Nigeria, it is one of the many unresolved problems (Ayobolu, 2006) that have critically hobbled and skewed development. It remains a long-term major political and economic challenge for Nigeria (Sachs, 2007). It is a canker worm that has eaten deep in the fabric of the nation. It ranges from petty corruption to political / bureaucratic corruption or Systemic corruption (International Center for Economic Growth, 1999). World Bank studies put corruption at over $1 trillion per year accounting for up to 12$188 million, up from $15 million, with a deadline for compliance at the end of December 2005. This resulted in a record number of bank mergers and acquisitions. As a result, the number of banks in Nigeria has shrunk from 89 in 2004 to 25 in December 2005. The institutions charged to fight corruption in Nigeria have not done enough to contain the upsurge of his this menace up to expectation. Thus, the paper is tempted to ask the following questions: Why have the various anti-corruption agencies of various administrations failed to reduce the menace of corruption? Are the methods applied to confront corruption inadequate? Can the present anti-corruption commission (EFCC) effectively confront corruption as a step to the consolidation of democracy? Lastly, does the role played by the EFCC justify why it was established? It is against this background that this study seeks to investigate the implication of Economic and Financial Crimes Commission (EFCC) and corruption on the consolidation of democracy and sustainable development and growth in Nigeria from 2004-2008

Storage Mycoflora in Sesame Seed Production in Benue State, Nigeria

Sesame (Sesamum indicum) is usually contaminated with many fungi where some of them are mycotoxigenic causing economic and health problems. This study investigated the percentage composition of fungi contamination of sesame seeds in Benue state Nigeria. Using direct plating technique; the study revealed twelve species of fungi contamination in sesame seed obtained in Benue State. The percentage occurrence of fungal isolates shows that Aspergillus flavus and A. niger were found in all the locations and their occurrence was significantly different (P≤0.05). The percentage contamination of Sesame samples collected from Otukpo LGA has the highest fungal (23.35%) contamination and was significantly higher (P≤0.05) from samples of other places whereas Sesame contamination from Gboko was the least with total percentage of (12.05%). In conclusion, considering the benefits of sesame, it is recommended that several treatments should be applied to reduce the levels of contamination in sesame seeds before consumption utilization such as environmental conditions leading to fungal proliferation (a high temperature, humidity, poor soil fertility, drought and insect damage). Also poor harvesting practices, unsuitable storage conditions, improper transportation, marketing and processing should be discouraged

Characterization of energy-rich hydrochars from microwave-assisted hydrothermal carbonization of coconut shell

In this study, microwave-assisted hydrothermal carbonization of waste coconut shell (feedstock) is reported. It is a thermo-conversion technique in which the feedstock was transformed into energy-rich carbonaceous material under mild conditions. The process was conducted in a microwave oven by heating the waste coconut shell in deionized water inside a pressurized vessel. The effects of different process conditions on the product yields, and the energy properties of the hydrochars were studied by varying the reaction temperature from 150 to 200 °C and residence time from 5 to 30 min. The results showed that there was transformation of the feedstock in the process due to the decarboxylation, dehydration, and demethanation reactions. This led to changes in the chemical and structural compositions, as well as increase in the energy properties of the prepared hydrochars. The higher heating value increased from 15.06 MJ/kg in the feedstock to 19.76 MJ/kg in the hydrochar. The energy properties of the hydrochars prepared in this study showed that microwave-assisted hydrothermal carbonization process could be a technique for converting waste coconut shell into high value-added product

Tax Return and Economic Growth: Evidence from Nigerian Experience (2000-2017)

This paper determined the effect of tax return on gross domestic product. Data were collected using secondary source only. The technique employed was multiple regressions as tool of analysis for the study. The findings of the study show that Tax Returns on Customs and Excise Duty, Value Added Tax and Aggregate Tax Revenue have positive significance growth rate on Gross Domestic Product. Based on this, the paper recommended among others that government should also ensure that they remove impediments to investment in form of legal and regulatory barriers. There is need to ensure stable macroeconomic environment. The Government should ensure that Value Added Tax Growth Rate is boosted in order to improve the economy. Keywords:Tax return, Customs and Excise Duty (CED), Value Added Tax (VAT), Aggregated Tax revenue, Gross Domestic Product (GDP) and Nigerian tax DOI: 10.7176/RJFA/11-18-16 Publication date:September 30th 202

Performing the Border as a Zone of Contestations: A Critical Analysis of Root Map

The plethora of meanings associated with the term “border” not only accentuates the frequent use of the word, but also implicates the border as a zone of contestations. These contestations underscore how borders covertly or overtly continue to affect the lives of millions of people across the globe. By “zone of contestations,” I situate the border as both a tangible and an intangible site that is replete with competing narratives about migration and migrants themselves. As a zone of contestations, the border eschews the idea of a monolithic story of migration; instead, it presents us with layers of stories by relocating border discourses to the realm of both the personal and the interpersonal lives of those interfacing with the border. Keywords: migration, performance, theatre, border, migrants, deontology, consequentialism DOI: 10.7176/RHSS/9-24-10 Publication date: December 31st 201