No abstract

The kinetic modelling of thin layer drying is performed with various agricultural products such as seeds, grains, fruits and some plant species with economic importance. Sweet Potato (Ipomoea batatas L) is a widely consumed, and its industrialization is on the increase. The thin layer drying kinetics of sweet potato were experimentally investigated in a convective hot air dryer. Comparison was made between the experimental and model predicted moisture ratio by nonlinear regression analysis. Furthermore, the effect of drying temperature and slice thickness on the selected model constants was evaluated. From the experimental data obtained, it was observed that moisture ratio of the potato sample was directly proportional to the mass of the sample while the time of drying was inversely proportional and these two parameters (mass and time) were used to develop a mathematical model for the thin layer drying of sweet potatoes using a convective hot air dryer. The mathematical model developed was validated. The experimental data fitted the developed mathematical model and gave the Sum of Squares (SSE) value of 0.0001296 and coefficient of determination (R 2 ) as unity. The parameters obtained from the kinetic modelling of the selected models studied could be used in designing low cost dryers for optimum drying conditions.

Crude oil spills have tremendous effects on our environment and poses severe pollution problems around the world as hazardous chemicals such as polycyclic aromatic hydrocarbons are released into the ecosystem. The clean-up of these spills using natural adsorbent is considered as an eco-friendly and cost effective method of handling the oil spills due to its high oil sorption capacity and biodegradability. Coconut coir predominantly found in the Niger Delta area of Nigeria was carbonized and chemically activated using Potassium Hydroxide (KOH) for the removal of crude oil spill. The kinetic data were fitted into various kinetic models with Pseudo-second order model showing best fit with a correlation coefficient R 2 =0.999 and the Boyd model revealed that the adsorption was controlled by internal transport mechanism and film-diffusion was the major mode of adsorption. Thus, Coconut Coir Activated Carbon (CCAC) showed significant capability to be used as a low-cost, re-generable and eco-friendly adsorbent in oil spill clean-up. A mathematical model was also developed using multivariate numerical optimization method and was validated by fitting it into the experimental data which gave a correlation coefficient R 2 =0.997. Hence, the empirical model developed using multivariate numerical optimization method can be used for the design of industrial treatment plant.