Adama University

About: Adama University is a education organization based out in Nazrēt, Ethiopia. It is known for research contribution in the topics: Population & Adsorption. The organization has 840 authors who have published 1010 publications receiving 5547 citations. The organization is also known as: Adama Science and Technology University & ቴክኖሎጂ ዩኒቨርሲቲ, አዳማ ሳይንስና ቴክኖሎጂ ዩኒቨርሲቲ.

Color pollution control in textile dyeing industry effluents using tannery sludge derived activated carbon

Abstract: Effective treatment of dyestuff containing textile dyeing industry effluents require advanced treatment technologies such as adsorption for the removal of dyestuffs. Powdered commercial coal based activated carbon has been the most widely used adsorbent for the removal of dyestuffs from dyeing industry effluents. As an alternative to commercial coal based activated carbon, activated carbon prepared from dried tannery sludge was used as an adsorbent for dyestuff removal from simulated textile dying industry effluent in this study. The color removal performance of tannery sludge derived activated carbon and commercial coal based activated carbon has been investigated using parameters such as adsorbent dosage, initial dye concentration, pH and temperature. It was found that tannery sludge derived activated carbon exhibits dye removal efficiency that is about 80–90 % of that observed with commercial coal based activated carbon. The amount of dye adsorbed on to tannery sludge derived activated carbon is lower compared with commercial activated carbon at equilibrium and dye adsorption capacity increased with increase of initial dye concentration and temperature, and deceasing pH. It was found that the Langmuir isotherm appears to fit the isotherm data better than the Freundlich isotherm. The leachate of heavy metals from tannery sludge derived activated carbon to the environment is very low, which are within the standard limit of industrial effluent and leachable substances. KEY WORDS: Adsorption, Tannery sludge derived activated carbon, Commercial coal based activated carbon, Adsorption isotherms, TCLP Bull. Chem. Soc. Ethiop. 2008 , 22(3), 369-378.

Investigation of the Adsorption Performance of Acid Treated Lignite Coal for Cr(Vi) Removal From Aqueous Solution

Abstract: Several methods have been used to reduce the negative contribution of heavy metal contaminants effluents in the environment. The method studied in this research was the use of activated carbon derived from Ethiopian lignite for hexavalent chromium adsorption from aqueous solution. The adsorption study was evaluated as the function of initial Cr (VI) concentration, adsorbent dosage and pH. All the batches' tests were conducted by using synthetic wastewater in this study. General Factorial Design (GFD) of Response surface methodology (RSM) was used in this batch test for analysis of experimental. The effects of independent variables on various initial Cr (VI) concentrations between 20 ppm and 100 ppm were evaluated. According to ANOVA analysis, each and combined term is statistically significant. A Cr (VI) removal efficiency of 98 % was achieved at pH 1 with 3.5 g of LAC in 200 ml of solution at 4 h of contact time using initial Cr (VI) concentration of 20 ppm. Removal increased up to 96.54% when Cr (VI) concentration decreased to 20.5 ppm, and adsorbent dose increased to 3.01 g at pH 1. 49.94% chrome removal was achieved at Cr (VI) concentration of 100 ppm and pH 5 with an adsorbent dose of 3.5 g for the combined effect of initial Cr (VI) concentration and pH, which was decreased with increased both initial Cr (VI) concentrations and pH value. With the combined effect of pH and adsorbent dosage the maximum percentage removal of Cr (VI) ion was obtained at lower pH and higher adsorbent dosage (96.5%). The adsorption of Cr (VI) was evaluated using batch adsorption equilibrium isotherms (Langmuir and Frendlich) and kinetics reaction rate (first and second order). The Frendlich isotherm model was the best one for the description of adsorption of Cr (VI) onto LAC heterogeneous surface energy. The adsorption kinetics of Cr (VI) onto LAC followed the second order kinetic model, suggesting that the adsorption reaction rate depends on two parameters, which might be the Cr (VI) concentration and adsorbent dosage. These results support similar conclusions mentioned by several authors in the literature.

Globalization and Its Impact on the Performance of the Nigerian Economy

Abstract: This paper investigates the impact of globalization on the performance of the Nigerian economy ‘between’ 1962-2009 through the application of simple Annual Average Growth Rate (AAGR) technique. The comparative analysis of growth of key sectors of the Nigerian economy (agriculture, petroleum, manufacturing, solid minerals, transport and communication sectors) between Pre-globalization (Pre-SAP; 1962-1985) and Post globalization periods (Post-SAP; 1986-2009). The study reveals that ‘‘globalization’’ had had positive impact on some sectors of the economy especially, agriculture, transportation and communication; while negative impact on some sectors especially petroleum, manufacturing, and solid minerals. Globalization had had positive impact on the overall performance of the economy which is measured by GDP. This implies that despite its negative impact on some sectors of the economy; still is beneficial to the growth of the economy. This paper therefore, recommends that concerted effort need to be taken by government and policy makers to boost the performance of the sectors negatively impacted by globalization especially petroleum which is the largest contributor to GDP in recent time in the country, followed by manufacturing and solid minerals with the view to diversifying the economy. The paper also recommends that crude petroleum should be refined before exporting in order to benefit more from globalization. Another policy implication of this study is that inflation and unemployment may be successfully control if the rate at which Nigerian economy is globalized reduces to some level (i.e. openness of the economy be reduce).