http://ir.haramaya.edu.et//hru/handle/123456789/225 Mon, 20 Apr 2026 12:41:01 GMT 2026-04-20T12:41:01Z http://ir.haramaya.edu.et//hru/handle/123456789/8208 ADSORPTIVE REMOVAL OF Pb2+, Cd2+, AND Cr6+ FROM AQUEOUS SOLUTION USING CACTUS OPUNTIA Girma Abebe Bedo; (PhD) EndaleTeju; (PhD) DeribachewuBekana Industrial processes regularly discharge harmful metal compounds into the environment. Even in low quantities, hazardous metals in the environment can affect humans and other creatures. Toxic metals cannot breakdown into innocuous end products, thus they can collect in living bodies and become concentrated throughout the food chain.The main objective of this study is to investigatesorption behavior of Cactus Opuntiaficus-indicus (OFI) powder in the removal of selected metal ions (Cd2+, Cr6+and Pb2+) from aqueous solution using adsorption techniques. Characterization of the prepared adsorbent was performed using only Fourier Transform Infrared spectroscopy (FTIR) to identify the functional groups of the adsorbent before and after the adsorption and the metal contents were analyzed by Flame Atomic Absorption Spectroscopy (FAAS). Batch experiments were carried out to determine the effect of pH, initial metal ions concentration, adsorbent dose, adsorbent particle size, contact time,andagitation speed on the adsorptive removal of the selected metals by the prepared adsorbent.The FTIR assessment revealed that the hydroxyl (-OH),carboxyl(-COOH),Ester group –COO- and carbonyl (C=O), functional group intensities shifted following the adsorption of the selected metal ions, demonstrating that Opuntiaficus-indica successfully adsorbs metal ions.After optimization, both the Langmuir and Freundlich isotherm models were used; nevertheless, the Langmuir isotherm model R2valueis equal to 0.999,0.999and 0.998 ,for Pb2+,Cd2+and Cr6+respectively .Soit fits the experimental data better. On the other hand, pseudo-first and pseudo-second-order kinetic models were also evaluated. The experimental data fitted with the pseudo-second-order kinetics modelwith R2values0.9997,0.9997and 0.9999 for the adsorption of the selected heavy metal ions byOFI.The percentage removal was found to be99, 98.1, and 99.1% for Pb2+, Cd2+, and Cr6+, respectively,by OFI, at pH = 10 (for Pb2+and Cd2+) and 2 for Cr6+),initial concentration of 25 mg/L, dose 0.5 g, contact time 120 minutes,and particle size 300 μm. The batch adsorption experiments showed that the adsorbent could remove the majority of the Pb2+, Cd2+, and Cr6+ from the aqueous solution under optimal conditions.Based on the results observed in the present study, OFI can be taken as a promising adsorbent for the removal of heavy metals from aqueous solution.The adsorption of Pb2+, Cd2+ and Cr6+.using OFI from rale sample or waste water was conducted and the percent of adsorption result obtained were 97.1,92.68 and 97.3 for Pb2+,Cd2+ and Cr6+ respectively.The result confirming Cactus Opuntia’s effectiveness in waste water sample selected heavy metal ions removal . 82p. Sun, 01 Dec 2024 00:00:00 GMT http://ir.haramaya.edu.et//hru/handle/123456789/8208 2024-12-01T00:00:00Z http://ir.haramaya.edu.et//hru/handle/123456789/7374 DIAGNOSIS OF STUDENTS’ MISCONCEPTION ON THE CONCEPT OF ACID-BASE IN TWO SECONDARY SCHOOLS OF BISHOFTU, ETHIOPIA KASSU BIRATU BEDASSA; Ayalew Temesgen (PhD); Yiheyis Bogale (PhD) Acid-base chemistry is the dominant chemical reactions in the chemical industry. However, most of the high school students are considered it as difficult topic and usually they had misconception about the reaction products and their properties, pH value, H + ion, and OH ion, neutralization reactions and others. Therefore, the aim of this study was to identify the common misconceptions, source of misconceptions, and the level of misconceptions grade 10 and 12 of Bishoftu secondary school and Babugaya preparatory school students faced on acid-base. The nature of the study was descriptive setting. The participants of the study were 82 grade 10 students and 60 grade 12 students of Bishoftu secondary school and Babugaya preparatory school, respectively. Data were collected using four tiers multiple choice test (4TMCT), open ended questionnaires, and interview. The collected data were analyzed using Statistical Package STATA. The results of reliability alpha general coefficient were 0.6214 implies the data collection instrument was internally consistence and reliable. The value of the validity test correlation between first and second tiers, third tiers and fourth-tiers, second-tier and both confidence tiers were 0.98, 0.95, 0.94, 0.9 of grade 10 students and 0.97,0.92, 0.94, 0.88 of grade twelve students, respectively. The difficulty coefficient ranges between 0.2 and 0.8 indicates that the used questions were moderate. The result of the analysis showed that 13 and 12% of grade 10 and 12 students had misconception, respectively. Furthermore, among the sample student, the pooled result showed that 7.5% of the students were scientifically conceived, 80% of the student showed lack of knowledge and 12.5% had misconception. Therefore, any governmental and nongovernmental organization concerned on education quality in chemistry related to acid base reaction to enhance the understanding of the students. 74 Sun, 01 Jan 2023 00:00:00 GMT http://ir.haramaya.edu.et//hru/handle/123456789/7374 2023-01-01T00:00:00Z http://ir.haramaya.edu.et//hru/handle/123456789/7373 PHYTOCHEMICAL INVESTIGATION AND EVALUATION OF ANTIMICROBIAL ACTIVITIES OF ROOT BARK EXTRACTS OF CALPURNIA AUREA (AITON) BENTH ASLEDIN AHMED MUME; Neelaiah Babu G. (PhD); Teshome Gonfa (MSc) All parts of Calpurnia aurea are traditionally used for the treatments of diarrhea,live stock ticks and antiinflammentery.The present study was carried out to investigate phytochemicals constituents and evaluation of antimicrobial activities of the root bark extract of calpurnia aurea. Accordingly, the chloroform and methanol extacts were subjected to preliminary phytochemical screening was tested by using standard procedures and methods and the result showed the presence of alkaloids, terpenoids, saponnins, tannin and flavonoid in both chloroform and methanol extcat of Calpurnia aurea. Fractionation of chloroform extract by column chromatography led to the isolation of two compounds namely; CA-1,Calpurnine and CA-2,(10E,13Z)-2,3-dihydroxypropyl 9-methylheptadeca-10,13-dienoate). Among which the constituents of root bark extract includes Calpurnine were considered as major constituents. The two isolated compounds the antimicrobial activity test were carried out and the highest activity was exhibited by fraction CA-1 against three bacteria such as S.typhi, S.aureus and S.pyogen, respectively and the highest antifungal activity test were recorded by CA-2 against A.Niger,A,Verticola and C.Albica. Isolated fraction ,exhibited medium antimicrobial activity against E. coli and having high activity against S.typhi.The structure of the two compounds were established by UV-Vis, IR and 1D-NMR spectroscopy.Thus the present study supported the traditional claims of the plant. 67 Wed, 01 Nov 2023 00:00:00 GMT http://ir.haramaya.edu.et//hru/handle/123456789/7373 2023-11-01T00:00:00Z http://ir.haramaya.edu.et//hru/handle/123456789/7111 ZEOLITE SUPPORTED V2O5: POTENTIAL CATALYTIC APPLICATION IN OXIDATIVE ESTERFICATION OF AROMATIC ALDEHYDES BIRHAN HAILIE SITOTAW; Neelaiah Babu G (PhD); Prof. Abi Taddesse (PhD) The direct oxidative esterification reaction of aldehydes is a conceptually and economically attractive approach and, therefore, has received increasing attention. The improvement of a one pot oxidative esterification of aldehydes under heterogeneous catalytic conditions that reduce jeopardy wastes is extremely required from both commercial and environmental points of view. Amongst the reported schemes heterogeneous catalysts are favored due to their simplistic reclamation, less contagion of the product and effective reusability. Recently, extensive and intensive studies have been made on the heterogeneously catalyzed oxidative esterification of aldehydes. Furthermore, V2O5/CBV400 complexes catalyzed esterification of aromatic aldehydes under heterogeneous conditions with H2O2 has been explored in this study. In this research, preparation of the catalyst in different weight ratios, screening it, characterized it using XRD, BET, FT-IR, SEM, TGA techniques, application of the catalyst including optimization, substrate scope, and reusability of the catalyst have been investigated. Methods used for both catalyst synthesis and organic transformation were reflux method and the product obtained from the transformation of aldehyde was 95% at optimized level of reaction condition (at 85℃, 20% catalyst, 16ml methanol solvent, 0.4ml H2O2 oxidant and 3 & half hours). Also recycled the catalyst five rounds and the last cycle has produced 84% yield. FT-IR and NMR characterization of the as synthesized organic compound (methyl benzoate) was investigated. 79 Mon, 01 May 2023 00:00:00 GMT http://ir.haramaya.edu.et//hru/handle/123456789/7111 2023-05-01T00:00:00Z