Heterogeneous catalytic conversion of carbon dioxide to chloromethyl ethylene carbonate and styrene carbonate using a novel Zr/ZIF-8 catalyst

In the last two decades, several attempts have been made to develop new catalytic systems for the chemical fixation of CO2, both homogeneous and heterogeneous catalysis. However, these attempts have failed to yield satisfactory results as most of these catalysts requires high temperature and/or pressure (usually around 453 K and pressure higher than 8 atm), further separation and purification steps, many of these catalysts deactivate after few recycle experiments and worse of all, low product yield. Hence, this research is focused on the use of metal-organic frameworks (MOFs) catalysts as a relatively new and promising candidate that addresses these aforementioned shortfalls. The development of a novel Zr/ZIF-8 catalyst via a simple low-cost solvothermal method, easy separation by centrifugation, and its excellent recyclability properties have demonstrated that the catalyst could be viable for large-scale industrial applications. The heterogeneity of the catalyst has been proven by recovering and reusing the catalyst for up seven times without any significant loss in catalytic activity. The powder x-ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) of the recycled catalyst shows that its framework is quite stable after reusability performance. Furthermore, the catalyst shows high substrates tolerance towards different epoxides including epichlorohydrin (ECH), styrene oxide (SO) and butylene oxide (BO). The reaction has been carried out under solvent-free and cocatalyst conditions. The catalytic properties of the novel catalyst have been satisfactorily consistent with pristine ZIF-8 catalyst using multiple physicochemical characterisation techniques. We believe that this work could provide a new direction for designing more sustainable, non-toxic catalysts for the transformation of CO2 and other substrates. The comparison of catalytic activity of both the pristine ZIF-8 and the novel Zr/ZIF-8 catalysts have been drawn based on the effect of various reaction conditions such as reaction temperature, CO2 pressure, catalyst loading, reaction time, stirring speed and reusability studies. Zr/ZIF-8 catalyst has been assessed as a suitable heterogeneous catalyst outperforming the catalytic activity of pristine ZIF-8 catalyst with respect to the conversion of epoxide, selectivity and yield of the desired carbonates. In addition, experimental design, modelling and optimisation techniques via response surface methodology (RSM) have also been implemented for different process responses. The experimental results have been employed to design and simulate chloromethyl ethylene carbonate (CMEC) and styrene carbonate (SC) using batch experimental studies. The adequacy of the models has been validated by the correlation between the experimental and predicted values of the responses using an Analysis of Variance (ANOVA) method. Therefore, statistical modelling using RSM can be used as a reliable prediction tool for system optimisation for greener synthesis of both chloromethyl ethylene carbonate and styrene carbonate. In conclusions, the catalyst has displayed high epoxide conversion and high carbonate selectivity. The optimum experimental conditions and results for the synthesis of chloromethyl ethylene carbonate were found to be 353 K, 8 bar of CO2 pressure and 8 h using fresh 10% (w/w) Zr/ZIF-8 catalyst loading for a 93% ECH conversion, 86% and 76% of CMEC selectivity and yield, respectively. While the optimum experimental conditions and results for the synthesis of styrene carbonate were found to be 353 K, 6 bar of CO2 pressure and 8 h using fresh 6% (w/w) Zr/ZIF-8 catalyst loading for a 98% SO conversion, 72% and 68% of SC selectivity and yield, respectively. Similarly, the optimised reaction conditions and results using RSM techniques for the synthesis of chloromethyl ethylene carbonate were found at 353 K, 11 Bar of CO2 pressure 12 h using 12% (w/w) fresh catalyst loading for a 96% ECH conversion and 68% CMEC yield while 353 K, 6.1 Bar of CO2 pressure and 8.2 h using fresh 6% (w/w) Zr/ZIF-8 catalyst loading for 98% SO conversion and 68% SC yield for the synthesis of styrene carbonate

N Dama Cattle Conservation: The Potential Roles of Artificial Insemination and the National Policy

Regular access to genetically superior bulls from an open nucleus breeding system is an impetus for N’Dama cattle utilization and conservation. However, shortage in the number of bulls that could be distributed to the farmers for subsequent breeding remains a challenge in some countries of West Africa. In this regard, the potential benefit of artificial insemination (AI) and the roles of national policy were assessed. The open nucleus-breeding scheme of International Trypanotolerance Center (ITC) in the Gambia was used as a case study and the research questions were answered with literature review, focus group discussion, and Likert-scale questionnaire. Introduction of AI into the breeding scheme of N’Dama cattle can create higher selection intensity and promote a wider dissemination of genetic gain made at the nucleus. With improved AI techniques, a better use of improved N’Dama bulls can be achieved. Notwithstanding, there are concerns about low pregnancy rate, quality of the semen, inadequate knowledge of AI technicians, and the regular availability of quality bulls. For the Gambian national policy, the environmental component is the most relevant for conservation of N’Dama cattle. This can be buttressed with more flexibility and a clearer communication of the objectives through workshops and local media

Implications of Gender Disparity in Concepts of Conflict Resolution for Peace and Stability among Residents of Gombe Town

This paper examined the implications of the concept of conflict resolution which male and female residents of Gombe town have on peace and stability.  In attempt to provide solution to the problem raised by the topic, an instrument was designed that consists of twelve items.  One hundred and fifty residents of Gombe were served the instrument to which they responded.  Seventy five of them were males and seventy five were female.  Their responses were subjected to t-test analysis. Generally, there was no significant difference in the way they think of conflict resolution.  However, on examination of each of the responses using their mean scores to determine how they rank the items, differences were observed.  Based on this analysis, five implications were drawn out.  Recommendations were made at the end of the paper.   Keywords: Implications, Gender Disparity, Concepts, Conflict Resolution, Peace and Stabilit

The Challenges and Prospects of Teaching and Learning Dramatic Arts in Tertiary Institutions in Nigeria

Dramatic education is an all-inclusive academic discipline which uses as tools branches of learning that bear upon the dramatic impulse. It utilizes eclectically each and every single discipline into one unified body of knowledge, so that it can help man to comprehend the nature of experience. Educational drama or Dramatic education is as old as education itself. In the course of history, both have been periodically reviewed, refined and ultimately codified into a set of principles for use in formal learning environments. However, education is yet to tap the full resources that drama is capable of providing because of some lapses inherent in the teaching and learning Dramatic Arts. Hence, this research investigates the challenges and prospects of teaching and learning of Dramatic Arts in tertiary institutions in Nigeria. It identifies such problems as apathy, lack of basic instructional and infrastructural facilities, inadequate funding by the government and non-inclusion of drama in the curricula of primary and post-primary schools, as the major challenges impeding the effective teaching and learning of the course. It was discovered however, that graduates of the course have a very bright prospect in the labour market after leaving school, aside the fact that dramatic education can help inculcate moral discipline and confidence in the entire society. The paper therefore concludes by recommending that government and all stake-holders in the educational sector should improve upon the funding of Dramatic Arts in our tertiary institutions so as to provide the necessary instructional and infrastructural facilities needed for the effective teaching and learning of the course. Primary and post-primary schools’ curricula should also be reviewed and expanded to include the teaching of drama, if the dream of the much-sought golden educational future must be realized.Key words: Dramatic Arts, Learning, Teaching, Theatre and Tertiary, Institutio

The pattern of the frequency of hbsag, hbeag, anti-hcv and anti-hbe in patients with haemoglobin genotype HbSS and HbSC in a rural community.

Sixty HbSS sickle cell anaemic patients aged 17.45 ±10.1years (Female=30, Male=30) and sixty HbSC sickle cell disease patients aged 20.6±11.0years(Female=30,Male=30) were recruited for the investigation. Haemoglobin genotype of each of the patient was determined by electrophoresis. HepatitisB‘s' antigen, HBeAg,anti-HBe, and anti-HCV in patients' plasma were determined by Enzyme Immunoassay. The frequencies of HBsAg, anti-HBe, HBeAg +HBsAg, HBsAg + antiHBe, in HbSS(6.7% , 20%,13.3%, and 20% respectively) were higher than those of HbSC( 5% ,8.3%, 5% , and 3.3% respectively). The frequency of anti-HCV + anti-HBe in HbSC was higher compared with that of HbSS patients ( 3.3% Vs 0%).The frequency of HBeAg in female HbSS and HbSC patients was higher than their male counterparts.( HbSS:16.7%Vs 10%;HbSC:6.7% Vs 3.3%).Higher frequency of HBsAg was found in HbSS male patients than the females (26.7% Vs 13.3%).The frequency of anti-HBe in HbSS male patients and HbSC female patients was higher than those of HbSS female patients and HbSC male patients respectively( HbSS:10% Vs 3.3%; HbSC: 10% Vs 6.7%).The frequency of HBeAg+ HBsAg obtained in HbSS male patients and HbSC female patients was higher than the results obtained from HbSS female patients and HbSC male patients (HbSS: 16.7% Vs 10%; HbSC:6.7% Vs 3.3%).The frequency of HBsAg + anti-HBe in HbSS female patients was higher than in HbSS male patients.(23.3% Vs 16.7%).None of the patients plasma was found to contain both HBeAg + anti-HBe. This research work has therefore been used to examine the pattern of HBeAg, HBsAg, anti-HCV, and anti-HBe in the plasma of patients with haemoglobin genotype HbSS and HbSC in rural community. Keywords: Pattern, Frequency, HepatitisB, Hepatitis C, Antibody, Surface (‘s') and Envelope (‘e') antigens. African Journal of Clinical and Experimental Microbiology Vol. 9 (2) 2008 pp. 82-8

Imposing Liability for Oil Spill Clean-Ups in Nigeria: An Examination of the Role of the Polluter-Pays Principle

Oil spills lead to pollution of water and land in the surrounding environment. The health and the farmland of the people living around the area of the spills are also adversely affected. Numerous laws are usually in place to deal with the issue of oil spills but often times some of these laws are not totally enforced or the institutions set up to deal with the spills are inefficient. Oil spills cannot be left unabated. The problem of oil spills have to be dealt with in order to avoid the devastating effects of oil spills on the environment. In a place like the Niger-Delta in Nigeria where oil spills are rampant, an effective means of curbing the menace have to be thought out to deal with spills. Oil theft, pipeline vandalism and sabotage are the order of the day and thus, oil spills are a recurring decimal in the Niger-Delta. The question then is can the polluter-pays principle play a role in the prevention and control of oil spills especially in Nigeria? This article seeks to answer this question by examining whether the Polluter Pays Principle, an international environmental law principle, can act as a deterrent to oil spills especially deliberate oil spills. This paper examines the tenets of the polluter-pays principle, the deterrence theory, challenges militating against the prevention and control of oil spills in Nigeria and then relevant recommendations and conclusion as regards the role of the polluter-pays principle in preventing and controlling oil spills are put forward. Keywords: Polluter Pays-Principle, Oil Spills, Liability for Oil spills, Niger-Delta, Nigeri

Multiobjective optimization for the greener synthesis of chloromethyl ethylene carbonate by CO2 and epichlorohydrin via response surface methodology

© 2020 by the authors. In this paper, a statistical analysis with response surface methodology (RSM) has been used to investigate and optimize process variables for the greener synthesis of chloromethyl ethylene carbonate (CMEC) by carbon dioxide (CO2) and epichlorohydrin (ECH). Using the design expert software, a quadratic model was developed to study the interactions effect between four independent variables and the reaction responses. The adequacy of the model was validated by correlation between the experimental and predicted values of the responses using an analysis of variance (ANOVA) method. The proposed Box-Behnken design (BBD) method suggested 29 runs for data acquisition and modelling the response surface. The optimum reaction conditions of 353 K, 11 bar CO2 pressure, and 12 h using fresh 12% (w/w) Zr/ZIF-8 catalyst loading produced 93% conversion of ECH and 68% yield of CMEC. It was concluded that the predicted and experimental values are in excellent agreement with ±1.55% and ±1.54% relative errors from experimental results for both the conversion of ECH and CMEC yield, respectively. Therefore, statistical modelling using RSM can be used as a reliable prediction technique for system optimization for greener synthesis of chloromethyl ethylene carbonate via CO2 utilization

Comparison of catalytic activity of ZIF-8 and Zr/ZIF-8 for greener synthesis of chloromethyl ethylene carbonate by CO2 utilization

© 2020 by the authors The catalytic activity of both ZIF-8 and Zr/ZIF-8 has been investigated for the synthesis of chloromethyl ethylene carbonate (CMEC) using carbon dioxide (CO2) and epichlorohydrin (ECH) under solvent-free conditions. Published results from literature have highlighted the weak thermal, chemical, and mechanical stability of ZIF-8 catalyst, which has limited its large-scale industrial applications. The synthesis of novel Zr/ZIF-8 catalyst for cycloaddition reaction of ECH and CO2 to produce CMEC has provided a remarkable reinforcement to this weak functionality, which is a significant contribution to knowledge in the field of green and sustainable engineering. The enhancement in the catalytic activity of Zr in Zr/ZIF-8 can be attributed to the acidity/basicity characteristics of the catalyst. The comparison of the catalytic performance of the two catalysts has been drawn based on the effect of different reaction conditions such as temperature, CO2 pressure, catalyst loading, reaction time, stirring speed, and catalyst reusability studies. Zr/ZIF-8 has been assessed as a suitable heterogeneous catalyst outperforming the catalytic activities of ZIF-8 catalyst with respect to conversion of ECH, selectivity and yield of CMEC. At optimum conditions, the experimental results for direct synthesis of CMEC agree well with similar literature on Zr/MOF catalytic performance, where the conversion of ECH, selectivity and the yield of CMEC are 93%, 86%, and 76%, respectively

Enhancing the Nigerian Educational System through Creative Dramatics

In every organized society, there exists certain belief as to what its educational philosophy should satisfy. These beliefs are hinged on the objectives which the society intends to achieve through its process of education and training. The main focus of this paper is to make a strong case for the need for the educational authorities in Nigeria to recognize the fact that the country’s professional theatre requires to be nurtured and sustained through a vibrant pedagogical drama. This is because, as with all human preoccupations, the love and appreciation of drama is a habit that requires to be cultivated, nurtured and sustained right from adolescence. The paper discusses creative dramatics as a symbolic tool for educational development. It also clarifies the meaning and objectives of creative dramatics as well as the functions of drama. It reviews the current deplorable educational system in Nigeria and concludes that if our educational policy-makers are able to muster political will, a feasible blue-print for the ultimate realization of the long-awaited dream of educational drama in Nigerian school and colleges would soon emerge. The paper therefore recommends that drama education should be considered part of the total education of the average Nigerian since it stresses the cultural enrichment of the nation. Consequently, Nigeria’s educational institutions should place greater emphasis on the creation of institutional strategies that will enhance life-long national development through educational drama or creative dramatics.Key words: Adolescent, Creative Dramatics, Development, Education, Enhancement