Non edible oil sources have the potential to lower the cost of biodiesel. However, they usually contain significant high amounts of free fatty acids (FFA) that make them inadequate for direct base catalyzed transesterification reaction (where the FFA content should be lower than 3%). The present work reviews chemical re-esterification as a possible method for the pre-treatment of high FFA feedstock for biodiesel production. The effects of temperature, amount of glycerol, type and amount of catalyst have been discussed. Chemical re-esterification lowers FFA to acceptable levels for transesterification at the same time utilizing the glycerol by product from the same process. Further researches have been proposed as a way forward to improve the process kinetics and optimization so as to make it more economical.

A novel low temperature glycerolysis process for lowering free fatty acid (FFA) in crude jatropha oil for alkali catalyzed transesterification has been developed. The response surface methodology (RSM) based on central composite design was used to model and optimize the glycerolysis efficiency under three reaction variables namely; reaction time, temperature and glycerol to oil mass ratio. The optimum conditions for highest glycerolysis efficiency of 98.67% were found to be temperature of 65˚C, reaction time of 73 minutes and 2.24 g/g glycerol to oil mass ratio. These conditions lower the high free fatty acid of crude jatropha oil from 4.54% to 0.0654% which is below 3% recommended for alkali catalyzed transesterification. The pre-treated crude jatropha oil was then transesterified by using homogeneous base transesterification resulting to a conversion of 97.87%. The fuel properties of jatropha biodiesel obtained were found to be comparable to those of ASTM D6751 and EN 14214 standards. The process can also utilize the crude glycerol from the transesterification reaction, hence lowering the cost of biodiesel. The glycerolysis is easier implemented than acid esterification thereby avoiding the need for neutralization and alcohol removal step.

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The achievement of sustainable development goals (SDGs) depends on the access of modern, sufficient, and efficient energy to all people. Currently, developing countries including sub-Saharan Africa (SSA) are the most vulnerable to the environmental problems associated with the use of non-renewable energy. All countries are striving to develop and use sustainable renewable energy (RE) with zero, low, or neutral greenhouse gas emissions. However, there are a lot of challenges that hinder effective utilization of RE resources in SSA. Therefore, this paper attempts to explore RE potentials for sustainable development in sub-Saharan African countries and provides an in-depth discussion on the challenges facing the exploitation of renewable energy resources. Additionally, it examines ways forward to improve the situation. This study systematically reviews the RE and sustainable development sector in SSA based on the relevant studies published between 2012 and 2020. Relevant data and information from various bibliographic sources such as Web of Science were collected, selected, organized, analyzed, interpreted, and presented in themes, graphs, and tables. The study revealed that despite the abundance of RE resources such as hydropower, wind and solar energy, and bio and geothermal power in SSA, there are various drawbacks curtailing their exploitation. These include inadequate technical, financial, and human resources, weak institutional and regulatory frameworks, and sociopolitical barriers. Thus, the study recommends the strengthening of the institutional and regulatory framework, capacity building, and harmonization of financial resources and enhancement of security and political environments to attract investors.

The agenda to utilize and efficiently convert biomass has been raised to alleviate environmental problems and pressure on the reliance on fossil fuel. Intermediate pyrolysis has the ability to treat different biomasses and coproduction of biooil and adsorption biochar. This review article aims to evaluate the appropriateness of intermediate pyrolysis for the coproduction of biooil and adsorption biochar. It was observed that coproduced biooil is of high quality, stable, and miscible that can be used directly to existing engines or be easily blended. The biochar coproduced is good for adsorption but is not stable for microbial attack and hence unsuitable in soil treatment but for hydrometallurgy. Since the process is capable of treating waste biomass, it is an opportunity for further investigations in areas where wastes are plenty and less utilized. To increase the effectiveness of this technology for coproduction, optimizing parameters, design of efficient reactors, and use of catalyst must be worked upon.