Departments of Chemistry

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1,4-BENZOQUINONE MODIFIED CARBON PASTE ELECTRODE FOR VOLTAMMETRIC INVESTIGATIONOF DOPAMINE
(HAWASSA UNIVERSITY, 2025-04) KASSA BEKO
Dopamine (DA) is one of electrochemically active molecule; electrochemical techniques currently have received great interest for their investigation due to their simplicity, cost effective, low detection limit, and fast response time. This study investigates the electrochemical oxidation of dopamine using a low-cost and sensitive voltammetric method based on a 1,4-Benzoquinone modified carbon paste electrode. Cyclic voltammetry revealed significant enhancements in the oxidative peak current for dopamine at the modified electrode compared to unmodified carbon paste electrode, indicating its electrocatalytic properties. Scan rate, pH, differential pulse amplitude, and concentration of dopamine were optimized for the investigation of dopamine. The optimized values were 100 mV/s, 7, and 240mV, respectively. The voltammogram resulted from those parameters showed that quasireversible nature of the analyte towards modified electrode with the transfer of two electrons per molecule of the analyte. The dependence of anodic peak current on the square root of scan rate with high correlation coefficients (R2 =0.99907 and scan rate (R2 =0.99103) indicated that, the diffusion control is dominant, but adsorption also plays a role. Key kinetic parameters were calculated: anodic transfer coefficient (α =0.798), diffusion coefficient (D=2.18×10−7 cm 2 /s), and heterogeneous electron transfer rate constant (Ks,h=2.26×10−4 cm/s). Anodic transfer coefficient (α =0.798) value is closer to one this suggests that anodic process is more favorable. Optimization of experimental conditions led to be a linear response for DA concentration ranging from 1.0 × 10−3 M to 3.5 × 10−3 M, with a detection limit of 1.39 × 10−4 M using cyclic voltammetry and 7.64 × 10−5 M with differential pulse voltammetry. The result suggests that 1,4-BQMCPE is a promising electrode material for the development of electrochemical sensors for DA detection.
A COMPARATIVE ANALYSIS OF PHYSICOCHEMICAL PARAMETERS AND MINERAL CONTENT IN COW AND CAMEL MILK FROM AGA WAYU DISTRICT, GUJI ZONE, OROMIA, ETHIOPIA
(HAWASSA UNIVERSITY, 2025-06) DINAOL BAYU
This study aims to analyze and compare the physicochemical properties and mineral composition of cow’s and camel’s milk. Milk samples were collected from the Aga Wayu district in the Guji zone of the Oromia region, Ethiopia, using a proportional random sampling method. The physicochemical parameters analyzed included pH, titratable acidity, ash content, specific gravity, protein content, fat content, moisture content, total solids, and boiling point. Additionally, the concentrations of selected minerals (phosphorus, sodium, calcium, and potassium) were measured. The results showed that cow’s and camel’s milk exhibited similar physicochemical properties, with comparable pH (5.8 ± 0.5), titrateble acidity (0.20 ± 0.01), ash content (0.84 ± 0.12%), specific gravity (1.04 ± 0.11), protein content (3.32 ± 0.43%)for cow, fat content (3.6 ± 0.48%) and boiling point (92.66°C)for camel. The concentrations of sodium (3.63 ± 1.23 mg/L) and phosphorus (2.43 ± 0.39 mg/L) were also similar in both types of milk. However, cow’s milk had higher moisture content (85.13 ± 2.65%) and calcium levels (22.44 ± 2.41 mg/L) compared to camel’s milk, which had lower moisture (82.83 ± 1.22%) and calcium (17.07 ± 1.38 mg/L). Conversely, camel’s milk contained higher total solids (18.26 ± 0.50%) than cow’s milk (14.82 ± 2.11%). In conclusion, camel’s milk was found to have higher protein and lactose content than cows’s milk, while cow’s milk had a greater fat content. These findings highlight the distinct nutritional profiles of the two types of milk, which may have implications for their dietary applications.
ADSORPTIVE REMOVAL OF LEAD ION FROM AQUEOUS SOLUTION USING CRYSTALINE NANOCELLULOSE PREPARED FROM MAIZE COBS
(2024-03) GETAHUN ESHETU
Heavy metals significantly impact the environment due to their non-biodegradable, toxic, and carcinogenic behaviors. Lead contaminants impose severe health impacts on humans and the water environment. Therefore, eco-friendly and efficient lead ion removal practices such as nanotechnology are an urgent requirement for the abatement of lead pollution. The aim of this study was to evaluate the removal of lead from an aqueous solution using maize cob cellulose Nano crystals. In the present study, crystal Nano cellulose was synthesized from maize cob. The crystal Nano cellulose synthesized was characterized by using FTIR, XRD and SEM. FTIR analysis reveals presence of functional groups with a high chelating capacity, as identified via FTIR. From SEM analysis the crystal Nano cellulose was noticed to be disordered and irregular in shape. The adsorption capacity of the crystal Nano cellos was 3.85 mg/g. The adsorption process was evaluated by adjusting the pH, dose, initial concentration and temperature. Optimum conditions were dose of 0.16 gram initial concentration of 10 ppm, contact time of 115 minute, pH of 6 and temperature of 450 c. Based on the optimal parameters, the kinetics were evaluated using the pseudo first and pseudo second order models based on that pseudo second order more fit than pseudo first order model. Equilibrium data were represented better by the Freundlich model than the Langmuir model which describes multilayer adsorptions. The adsorbent-formulated from crystalline Nano cellulose presented a good capacity to remove lead from aqueous media.
ASSESEMENT OF THE LEVEL OF HEAVY METALS IN DIFFERENT VARIEETIES OF KHAT (CATHA EDULIS) AND SUPPORTING SOIL SAMPLES COLLECTED FROM TULLA AREA, SIDAMA REGION; ETHIOPA
(2024-11) GETAHUN MENGIST GELLA
Heavy metal pollution of the environment has been a global concern due to its acute and chronic health effects. The consumption of contaminated food and beverages is among the major route of exposure. Khat (Catha edulis) is one of the major cash crops that are widely cultivated and consumed as stimulant in the study area (Tulla Sidama regional state).This work focuses on the physicochemical analysis and determination of selective heavy metals (Cu, Co, Ni, Cr and Pb) concentration in chewable parts of the leaves of the selected Khat varieties (Nole, Dume and Megala) and its support soil samples. Samples were randomly collected from the selective kebeles of the study area and digested using mixture of acids. Analysis of the physicochemical parameters (pH, electrical conductivity and ash content) was carried out by standard method. The determination of the heavy metals was carried out using Flame Atomic Absorption Spectroscopy (FAAS). The physicochemical analysis showed pH (6.21-6.82), electrical conductivity (1.42-1.86), and ash content (1.72-2.17) in soil samples and pH (5.93-6.43), electrical conductivity (1.17-1.54), and ash content (0.63-0.93) in khat samples. The heavy metal analysis showed concentration of Cu, Ni and Co to be 4.33-4.93mg/kg, 2.52-3.26mg/kg and 1.84-2.85mg/kg respectively in khat samples. The levels of these metals in the corresponding soil samples were (8.54-9.96mg/kg), (3.67-4.95mg/kg) and (3.37-4.85mg/kg for Cu, Ni and Co respectively. Pb and Cr were not detected in soil and khat varieties samples. Among the analyzed heavy metals Cu was detected relatively at the highest concentration followed by N and Co in both soil and Khat samples. These findings indicated a positive correlation between the levels of the heavy metals in the soil and the Khat samples. Although Pb, Cr, Cu and Ni were detected below the permissible level, Co was detected above the permissible level stipulated by WHO. Therefore, it can be concluded that continuous consumption of Khat as stimulant might lead to health risks associated with heavy metals.
ASSESSMENT OF THE PHYSICOCHEMICAL QUALITY AND MINERAL COMPOSITIONS OF RAW COW’S MILK COLLECTED FROM MILK PRODUCER IN HAWASSA, SIDAMMA REGION, ETHIOPIA
(Hawassa University, 2025-03) ASHENAFI LORENSO
Milk is a wholesome food as it contains various nutrients. Milk should be free from contaminants and adulterant materials that can directly or indirectly affect the consumer‘s health. It is, therefore, necessary to check the safety and quality of milk available in the domestic market. Therefore, this study was aimed at determining the levels of selected physicochemical quality parameters and metals in raw cow‘s milk samples collected from milk producer, in Hawassa city, Sidamma Region, Ethiopia. The determination of fat, Solids-Non-Fat, milk density and added water to milk were carried out using EKOMILK Ultrasonic Milk Analyzer, in Hawassa University, and the total moisture and total ash content in raw cow milk samples were done using the Gravimetric Method. The values of total protein, total solids, and lactose content of the raw cow‘s milk samples were calculated using formulae that used the measured value of Solids-NonFat, while the metal content were determined by flame atomic absorption spectrometry (FAAS). The average values of the physicochemical parameters investigated in this study were found to be in the range pH (6.59–6.73), water added (5.54–10.33)%, density (1.023–1.029) g/mL, titratable acidity (0.153–0.213)%, total solids (10.566–13.800)%, total ash (0.603–0.636)%, Solids-not-fat (SNF) (7.266–7.666)%, total fat (3.266– 6.230)%, total protein (2.666–2.813)%, and lactose (3.996– 4.216)%. The average concentrations of the metals were found to be in the range Ca (1124.770–1505.110) mg/L, Mg (102.330–109.000) mg/L, Cu (0.0536–0.0817) mg/L and Mn (0.052–0.072). Metals such as Ni, Co, Cr, and Pb were found to be below the detection limit of the instrument. The accuracy of the method of the analysis was evaluated by analyzing the digest of the spiked samples and the recoveries of the metal were in the range of 99.810– 104.220%. One-Way-ANOVA analysis showed that there were significant variations (p < 0.05) in the physicochemical quality parameters, and metal content except for total ash, solids-non-fat, total protein, and lactose among the raw cow‘s milk samples. In general, pH, specific gravity, titratable acidity, total ash, and lactose were found to be within the maximum permitted level set by Ethiopian Standard, and EU guidelines, while total fat, total protein, and solid-not-fat were found to be below the recommended limits.
BIOSYNTHESIS OF Fe3O4/Co3O4 NANOCOMPOSITE FOR PHOTOCATALYTIC DEGRADATION OF CONGO RED AND MALACHITE GREEN DYES UNDER SOLAR IRRADIATION
(HAWASSA UNIVERSITY, 2024-11) AKINAW AGALU TAYE
The global concern regarding environmental pollution caused by organic pollutants, as population growth and industrial expansion, has increased the demand for the development of efficient nanomaterials for pollution control. In this study, Fe₃O₄, Co₃O₄ NPs, and Fe₃O₄/Co₃O₄ NCs were synthesized using a green method involving the extract of B. spectabilis flowers. Characterization of the synthesized nanomaterials was conducted using UV-Vis, FT-IR, SEM, and XRD. UV-Vis analysis confirmed the successful synthesis and optical properties of Fe₃O₄, Co₃O₄ NPs, and Fe₃O₄/Co₃O₄ NCs at the nanoscale via green methods, with energy band gaps measured at 2.18 eV, 2.2 eV, and 1.98 eV respectively. FTIR analysis indicated the presence of peaks corresponding to Fe-O 484 cm-1 and Co-O 558 cm-1 bonds. SEM images revealed that the Fe₃O₄, Co₃O₄ NPs, and Fe₃O₄/Co₃O₄ NCs exhibited a smooth surface with non-uniform, rough, and closely packed irregular granular structures. A sponge-like morphology characterized by numerous irregular pores was observed, combined with surface functionalization of Fe₃O₄ due to Co₃O₄ nanoparticle agglomeration, which displayed a smooth and uniform morphology. The average particle size distributions were determined to be 1949 nm, 1437 nm, and 1622 nm respectively. XRD analysis confirmed the successful synthesis of Fe₃O₄, Co₃O₄ NPs, and Fe₃O₄/Co₃O₄ NCs, revealing planes indicative of a high degree of crystallinity in the iron oxide phase and a cubic spinel structure for cobalt oxide. Multiple diffraction peaks corresponding to the spinel structures of both Fe₃O₄ and Co₃O₄ were observed, with crystallite sizes determined to be 31.02 nm 19.05 nm, and 24.2 nm respectively. Photocatalytic activity towards CR and MG using Fe₃O₄/Co₃O₄ NCs, maximum degradation efficiencies of 96.13% for CR (catalyst dose of 0.09 g, initial concentration of 20 ppm, exposure time of 75 min, pH of 6) and 94.40% for MG (catalyst dose of 0.06 g, initial concentration of 15 ppm, exposure time of 90 min, and pH of 8). The degradation efficiencies of 93.65% for CR and 91.39% for MG by Fe₃O₄ NPs, as well as Co₃O₄ NPs, which demonstrated efficiencies of 92.57% for CR and 90.57% for MG were achieved under optimal conditions. Kinetic studies revealed that the Fe₃O₄/Co₃O₄ NCs follow a pseudo-first-order kinetic model for the degradation of CR, exhibiting the highest correlation coefficient (R² = 0.988). In contrast, the degradation of MG follows a pseudo-second-order kinetic model, with the highest correlation coefficient (R² = 0.997)
BIOSYNTHESIZED NITROGEN-ZINC-CODOPED COPPER OXIDE NANOPARTICLES FOR PHOTOCATALYTIC DEGRADATION OF METHYLENE BLUE
(HAWASSA UNIVERSITY, 2024-06) YOHANNES SHUKA JARA
Herein, nitrogen-zinc-codoped copper nanoparticles (N-Zn-CuO NPs) was successfully synthesized by using Pycnostachys Abyssinica Fresen plant leaf extract as a bioreducing and capping agent for the photocatalytic degradation of methylene blue under natural sunlight irradiation. Additionally, pure CuO NPs, N-CuO NPs, and Zn-CuO NPs were also biosynthesized for comparison. Characterization techniques of UV-Vis, XRD, SEM, FT-IR revealed that N-Zn-codoping narrowed the band gap (1.72 to1.07 eV), reduced the crystallite size (25 to11.23 nm), distortion of monoclinic crystal lattice (rhombus and diamond like shape with an average diameter of 2.25 µm to irregular shape with an average size of 2.75 µm), and towards redshift of the Cu-O characteristic peaks (617 to 529 cm-1 ) of CuO NPs, respectively, confirmed the successful incorporation of dopants into CuO NPs. The effects of key parameters on the photocatalytic degradation efficiency of all biosynthesised NPs were investigated. The optimal conditions with maximum degradation for N-Zn-CuO NPs were determined to be 3% dopant concentration for both N and Zn, 120 mg of photocatalyst dosage, pH of solution at 11, 20 ppm of Initial dye concentration and 30 minutes of reaction time. Photocatalytic activity towards methylene blue (MB) dye degradation under 30 minutes exposure to sunlight was 99.75% for N-ZnCuO NPs, outperforming pure CuO NPs (95.76%), N-CuO NPs (97.93%), and Zn-CuO NPs (98.26%) under optimal conditions. The enhanced photocatalytic performance of NZn-CuO NPs is attributed to their tailored optical properties, leading to improved charge separation and reduced recombination. Kinetic studies revealed a strong fit (R2=0.99799) with the BMG kinetic model for N-Zn-CuO NPs, indicating surface-mediated degradation of MB. Furthermore, the nanocatalysts exhibited excellent reusability and stability over four cycles. This finding highlights the potential of biosynthesized N-Zn-CuO NPs as highly efficient, simple, eco-friendly and sustainable solutions for the degradation organic pollutants.
DESIGN AND SYNTHESIS OF SOME NOVEL HYBRID MOLECULES CONTAINING INDOLE AND OXADIAZOLE RING FOR EVALUATION OF ANTIBACTERIAL AND ANTIOXIDANT ACTIVITIES
(HAWASSA UNIVERSITY, 2024-05) AMANUEL ABRIHAM BUDE
Indole-containing oxadiazole compounds have emerged as a versatile class of nitrogencontaining heterocyclic compounds with a wide range of biological activities. These compounds and their derivatives exhibit a diverse array of properties such as antiviral, anticancer, anti-HIV, antioxidant, antimicrobial, antidiabetic, and antimalarial activities. The aim of the study was to design and synthesize some novel hybrid molecules containing an indole and oxadiazole rings, followed by partial characterization of the synthesized compounds using UV-vis and FT-IR spectroscopic techniques, and assessment of their antibacterial and antioxidant activities. The synthetic methodology was initiated by esterification of 2-(1H-indol-3-yl) acetic acid (105aʹ) and 4-(1H-indol-3-yl) butanoic acid (105bʹ) using a catalytic amount of sulfuric acid and excess methanol. This process resulted in the formation of methyl 2-(1H-indol-3-yl)acetate (106aʹ) and methyl 4-(1H-indole-3-yl)butanoate (106bʹ) respectively. These esters were further converted to 2-(1H-indol-3-yl)acetohydrazide (107aʹ) and 4-(1H-indole-3-yl)butaneydrazide (107bʹ) respectively. Finally, the compounds (107aʹ) and (107bʹ) underwent a reaction with substituted carboxylic acids in the presence of POCl3 to produce the desired targeted compounds: 110aʹ, 111aʹ, 110bʹ, and 111bʹ. The synthesized compound yields were as follows: 110aʹ (62%), 111aʹ (55%), 110bʹ (57%), and 111bʹ (53%). The chemical structures of these synthesized compounds were partially characterized by using spectroscopic techniques like UV-Vis and FT-IR. The synthesized compounds were evaluated for their in vitro antibacterial activity test against four bacterial strains: E. coli, P. aeruginosa, S. pyogenes and S. aureus by the disk diffusion method. Among synthesized compounds, compound 111bʹ showed potent inhibitory activity against Gram-negative, E. coli with 11.57 ± 0.15 mm zone of inhibition compared to the standard drug tetracycline (13 ± 0.5 mm) at 150 mg/mL. The RSA of synthesized compounds were assessed through DPPH radical assay, revealing that compounds 111aʹ and 110aʹ demonstrated higher %RSA (91.83% and 89.9%, respectively) with IC50 values of 4.95 and 5.03, respectively, compared to the standard ascorbic acid of %RSA (87.5%) with an IC50 of 31.44 and than other synthesized compounds. Hence, the studies have indicated that all the synthesized compounds could be considered as potential candidates for further investigation in antibacterial and antioxidant research.
DETERMINATION OF PHYSICO-CHEMICAL PARAMETERS AND SELECTED HEAVY METALS FOR DRINKING WATER SUITABILITY OF LAKE ZENGENA,AWI ZONE,AMHARA REGION,ETHIOPIA
(HAWASSA UNIVERSITY, 2024-11) ZEMENU KASSA ADELA
The determination of the physico-chemical parameters & heavy metals of any lake is important. The water quality test will identify weather the water is suitable for different purposes. This study aimed to determine the levels of some physico-chemical parameters and elements in Lake Zengena, Awi zone, Amhara regional state, Ethiopia using Atomic Absorption Spectrophotometer (AAS) & Palintest Photometer. For this study, six water samples were collected from two Lake Sites. Samples of the water from Lake Zengena were collected according to standard laboratory guideline for the analysis of water quality parameters & metals. The following water quality parameters were measured in the laboratory and in the field: temperature; pH; Electrical conductivity; TDS; turbidity, total hardness, dissolved oxygen, & BOD. There are two field sites and they were selected due to their differences in their position of the chance the contaminant can enter. The mean & standard deviation of the results obtained were - pH (6.82±0.057) for site one & (6.62 ± 0.00816) for site two, electrical conductivity (203.3 ±0.15 μs/cm) for site one & (199.1 ± 0.471 μs/cm) for site two, temperature (20.63± 0.057 0C) for site one & (20.13 ± 0.0416 0C) for site two. Total dissolved solids (20.5 ± 0.1 mg/l) for site one & (18.23 ± 0.124) for site two, turbidity (0.52 ±0.015 NTU) for site one & (0.41± 0.00816NTU) for site two, total hardness (44.5 ±0.1 mg/l) for site one & (41.4 ± 0.081mg/l). Dissolved oxygen (7.16 ±0.11) for site one & (6.3 ± 0.0816) for site two, biological oxygen demand (22.46± 0.05) for site one & (20.3 ± 0.0816) for site two. In addition, chemical oxygen demand (104.56 ± 0.057) for site one and (102.16 ± 0.0471) for site two, alkalinity (90.16 ±0.11 mg/) for site one & (80.26 ± 0.124) for site two. In addition, the results of metals in water sample were as follow:-Pb, Cr & Ni were bellow detection limit. Ca (0.63 ± 0.02) for site one & (0.83 ± 0.016) for site two, Mg (0.31 ± 0.02) for site one & (0.43 ± 0.0.0081) for site two, Zn (1.65 ±0.01) for site one & (1.85 ± 0.0081) for site two, K (5.8 ± 0.1) for site one & (4.66 ± 0.047) for site two. Fe (0.13 ± 0.02) for site one & (0.12 ± 0.0081) for site two, Cu (0.67 ± 0.015) for site one & (0.76 ± 0.0244) for site two. The statistical data analysis by using t-test shows that there was no significance difference between analyzed metals in site one and site two at (p < 0.05). The results of physico-chemical parameters & metals indicate that Lake Zengena is safe for the use of human being according to WHO
DETERMINATION OF SELECTED ESSENTIAL AND NON- ESSENTIAL METALS IN TEFF GRAIN SAMPLES COLLECTED FROM YILMANA DENSA WOREDA, WEST GOJAM ZONE, ETHIOPIA
(HAWASSA UNIVERSITY, 2024-11) ZELALEM TALACHEW
Teff [Eragrostis teff (Zuccagni) Trotter] is one of the major and indigenous cereal crops in Ethiopia. Teff is a staple food in Ethiopia, consisting of two-thirds of their cereal diet and is mainly used to make human food. Although Teff is farmed for its grain, the straw is also used to build homes in both rural and urban areas, to reinforce mud or plaster, and as feed for cattl. The levels of selected essential and non-essential metals in the white, red, and mixed teff grains collected from Yilmana Densa Woreda, West Gojam Zone (Ethiopia) were determined by AAS equipped with deuterium background corrector and air-acetylene flame atomizer. After a suitable sample pretreatment, the powdered teff was wet digested with the acid mixture (8 mL HNO3:2 mL H2O2) at 180 oC for 3:00 h over wet digestion block. The accuracy of the optimized procedure was evaluated by analyzing the digest of the spiked samples with a standard solution of metals, and the percentage recoveries varied from 99 % to 113%. The mean concentrations of metals determined (mg/kg, dry weight) were in the ranges of Fe (632-761) > Mn (191-516) > Zn (87-168) > Cu (75-112) > Ni (4.15-10.81) > Co (5.36-7.15) > Cr (3.93-5.15) > Pb (1.14-2.26). A statistical analysis of variance indicated that there is significant difference between the mean concentrations of all metals (Co, Cr, Pb Ni, Fe, Mn, Cu and Zn) with (P < 0.05 at 95% confidence interval) between the different types of teff samples. . The concentrations of the metals showed that the red teff samples collected from fetlo kuskaum have higher amounts of Fe and Cu, compared to that of the white and mixed teff samples. The mixed teff samples collected from Kililt has higher amounts of Fe, Mn and Zn, compared to that of the red and white teff samples.The amount of essential metals is high in red teff samples at Fetillo Kuskuam and in mixed teff at Kililt. The presence of significant differences may be due to the presence of different geographical distribution, rainfall, soil composition, harvesting, and storing methods.
DETERMINATION OF SELECTED HEAVY METALS (Cu, Cr, Pb. Ni, Mn AND Co) IN SOIL SAMPLES AROUND MIDROC GOLD MINING IN SHAKISO DISTRICT, GUJI ZONE, OROMIA REGION ETHIOPIA.
(2025-06) DEJENE GENENE ASHENAFI
Soil supports all terrestrial life, and it is a medium in which nearly all food-producing crops grow. However, soil pollution, mainly due to anthropogenic origin, is a significant problem worldwide, affecting soil fertility, plant growth, and human health. Heavy metal contamination of soils is mostly due to mining and smelting of metal ores. Therefore, in this study, soil samples were taken from three sampling sites, such as Dadola, Reji, and Legedembi, around the MIDROC gold mining company to assess the levels of heavy metal contamination of the sampling sites. The soils samples (0 to 15 cm deep) were collected from across 9 sites within three selected areas by using stainless steel applying a random sampling technique. After proper samples pretreatment of dried, crushed and homogenized, known weight of Soils sample was wet digested using 3:2mL of HNO3, of HClO4 for 2:00 hr at 250 oC and Soil samples were prepared through an optimized wet digestion procedure is a material to ensure safety and accurany., and the concentrations of the selected heavy metals (Cu, Cr, Co, Pb, Mn, and Ni) were determined by using FAAS. All these heavy metals statically analyzed by using one way ANOVA are significantly difference (p<0.05). The average concentrations of the heavy metals were found to be in the range of Cu (161.5–312) mg/kg, Cr (127–276.66) mg/kg, Mn (446.27–644.44) mg/kg, Pb (52–77) mg/kg, Ni (25.5–42.83) mg/kg, and Co (13.18–18) mg/kg. The levels of the heavy metals in the soil samples were found in the decreasing order Mn > Cu > Cr > Pb > Ni > Co, and the concentrations of Cu, Cr, Pb, and Mn were above the WHO-recommended limits. This result showed the sampling sites were polluted with heavy metals, and this could affect soil quality, the environment, and human health. Therefore, the concerned bodies should take necessary measures to reduce the effect of soil pollution from MIDROC gold mining companies in the host community.
DETERMINATION OF SELECTED METALS AND NUTRITIONAL COMPOSITION IN PAPAYA (CARCIA PAPYA) AT SAJA DISTRICT, YEM SPECIAL WOREDA, SOUTHERN ETHOIOPIA
(HAWASSA UNIVERSITY, 2023-07) ZEKARIAS ZERFU
Papaya is commonly known for its food and nutritional values throughout the world. The study was aimed to determine the level of selected metals as well as nutritional value of Papaya samples collected from six kebeles of Yem Special Woreda, SNNPRS. The optimized wet digestion method was used in the analysis. The results revealed that papaya has the ability to accumulate relatively higher amounts of Ca and Mg among the determined essential metals. The result of metal analysis revealed that papaya contains appreciable level of essential metals and the level of toxic heavy metals (Pb and Cd ) were below maximum permissible value set by WHO/FAO indicating that the given fruit was safe to use The concentration ranges in dry weight basis in decreasing order were: Ca (7.13 -24.51) >Mg (9.76-10.87) > K (3.83 – 4.64) > Fe (1.18 – 5.76) >Mn (0.19-0.49) > Zn (0.14-0.45)>Pb(0.16-0.24) > Cu (0.14-0.16) >Cd (0.01) mg/kg. The proximate compostion results indicated that the percentage of nutritional value in papaya ranges from (5.90 to 6.37), (70.56 to 72.42), (6.47 to 13.90), (2.08 to 2.85), (1.40 to 2.20), (6.21 to 11.45), (85.44 to 105.28); for ash, moisture, crude protein, crude fat, crude fiber, carbohydrates and total energy respectively. The efficiency of digestion methods was revealed that the excellent recoveries obtained which were found within the acceptable range for the analyzed metals. Regarding the proximate analysis, papaya was a good source of carbohydrate, fat, protein, and fiber and energy contents.
DETERMINATION OF SELECTED PHYSICOCHEMICAL AND MINERAL CHARACTERISTICS OF DRINKING WATER IN ANASORA DISTRICT, GUJI ZONE, OROMIA REGIONAL STATES, ETHIOPIA
(HAWASSA UNIVERSITY, 2024-10) DEREJE JANBOARARSO
Drinking water should be free unwanted constituent, contaminant, or impurity and fulfil quality requirements (desirable and permissible limits) recommended national and international organizations. This study was done to determine the levels of selected physicochemical parameters (temperature, pH, Electrical Conductivity, Total hardness, Total Alkality, and chloride), and minerals such as (Ca, Mg ,Cr and Pb), trace elements (Cu, Mn, Ni, and Co) in drinking ground water samples sampled from selected Kebeles such as Bube Korsa, Hiyo Komele, and Irba Buliyo of Ana Sora district, Guji zone, Oromia regional state, Ethiopia. The temperature, pH, electrical conductivity, and TDS were measured using an AD8000 pH/mV/EC/TDS/Temp meter; TH, TA, and chloride were determined by titration method, while the mineral content was determined by flame atomic absorption spectrometry (FAAS). The average values of the physicochemical parameters investigated in this study were found to be in the range: temperature (20.8 – 23.1) °C, EC (3.7 – 23.7) 𝜇S/cm, TDS (8.5 – 12.8) mg/L, TH (14.7 – 42.4) mg/L, TA (23.3 – 38.3) mg/L and chloride (2.3 – 3.8) mg/L. The average concentrations of the minerals were found to be in the range of temperature: Ca (2.32 – 9.62) mg/L, Mg (11.9 –24.6) mg/L, and Cu (0.13 – 0.30) mg/L. Metals such as Mn, Ni, Co, Cr, and Pb were found to be below the detection limit of the instrument. The accuracy of the method of recovery experiment the analysis was evaluated by analyzing the digest of the spiked samples. The recoveries of the metal were in the range of 96.0to 110.0%.OneWay-ANOVA analysis showed that there were significant variations (p < 0.05) in the physicochemical parameters and metals investigated among the drinking groundwater samples. However, all the values of the physicochemical parameters investigated were found to be within the acceptable standard specified in Compulsory Ethiopian Drinking Water Specifications. Therefore, the drinking ground water supplied to the community in Ana Sora district was deemed to be safe for human consumption according to the selected parameter and, mineral set as standard.
GREEN SYNTHESIS OF CO3O4/POLYANILINE NANOCOMPOSITES USING VERNONIA AMYGDALINA LEAF EXTRACT FOR PHOTOCATALYTIC DEGRADATION OF METHYLENE BLUE AND CONGO RED UNDER SOLAR IRRADIATION
(Hawassa University, 2024-11) BEZABIH KASAHUN KAYIMO
PANI, Co3O4 NPs, and Co3O4/PANI nanocomposites were successfully synthesized using a green synthesis method and applied for the photocatalytic degradation of Methylene blue (MB) and Congo red (CR). The synthesized materials were characterized using analytical techniques such as XRD, FT-IR, UV-Visible, and SEM. The FT-IR spectra of VA showed that the wavenumber absorption at 3470 cm-1 represented the hydroxyl (-OH) group, while at 2931 cm-1 characterized the C-H absorption. The peak observed at 1631 and 1402 cm−1 indicates C = C stretching and O-H bending of carboxylic acid, respectively. The band at 1173 cm−1 corresponds to the C-O stretching of an aromatic ester. The prominent absorption bands at 555 cm-1 and 648 cm-1, attributed to the stretching vibrations of the metal-oxygen bond corresponding to (Co3+ - O) and (Co2+- O) vibrations, respectively in NPs. A peak at 1628 cm-1 and 1401 cm-1 shows C=C, and C–N stretching vibration respectively. The characteristic band formed at 3368cm-1 corresponding to N–H stretching vibration of secondary amine and for pure PANI, The peak at 1622 cm−1 , 1404cm-1 is due to the C= C stretching vibration of the quinoid rings ((N=Q=N)) and benzenoid ring (N-B-N) respectively. Band at 1118 cm−1 is due to the C−N stretching of a secondary aromatic amine. XRD patterns revealed the crystalline sizes of the materials, with average particle sizes 19.25nm, 8.24nm, 11.03 for Co3O4 NPs, PANI powder, and NCs respectively. Morphological investigations indicated unique structures for each material. UV Visible spectra provided band gap energy values for the synthesized materials (1.69 and 3.93 for Co3O4 NPs; 1.57, 3.1 and 4.12 for PANI: 3.26, 3.80 and 5.3 for NCs). The photocatalytic degradation study demonstrated that Co3O4 NPs and Co3O4/PANI NCs efficiently degraded MB and CR under natural sunlight irradiation. The degradation efficiency was influenced by catalyst dose, initial concentration, pH, and exposure time. Maximum degradation percentages were achieved under optimized conditions for both dyes (93.69% in Co3O4/PANI NCS and 90.79% in Co3O4 NPs for CR and 91.66% in Co3O4/PANI NCs and 89.60% in Co3O4 NPs for MB). Co3O4/PANI NCs exhibited higher degradation efficiency than Co3O4 NPs due to interactions between inorganic semiconductors and conducting polymers. Kinetic studies revealed that MB followed pseudo zero-order kinetics, while CR degradation followed pseudo first-order kinetics with the R2 = 0.993 and 0.992 respectively.
GREEN SYNTHESIS OF CO3O4/POLYANILINE NANOCOMPOSITES USING VERNONIA AMYGDALINA LEAF EXTRACT FOR PHOTOCATALYTIC DEGRADATION OF METHYLENE BLUE AND CONGO RED UNDER SOLAR IRRADIATION
(HAWASSA UNIVERSITY, 2024-11) BEZABIH KASAHUN KAYIMO
PANI, Co3O4 NPs, and Co3O4/PANI nanocomposites were successfully synthesized using a green synthesis method and applied for the photocatalytic degradation of Methylene blue (MB) and Congo red (CR). The synthesized materials were characterized using analytical techniques such as XRD, FT-IR, UV-Visible, and SEM. The FT-IR spectra of VA showed that the wavenumber absorption at 3470 cm-1 represented the hydroxyl (-OH) group, while at 2931 cm-1 characterized the C-H absorption. The peak observed at 1631 and 1402 cm−1 indicates C = C stretching and O-H bending of carboxylic acid, respectively. The band at 1173 cm−1 corresponds to the C-O stretching of an aromatic ester. The prominent absorption bands at 555 cm-1 and 648 cm-1 , attributed to the stretching vibrations of the metal-oxygen bond corresponding to (Co3+ - O) and (Co2+ - O) vibrations, respectively in NPs. A peak at 1628 cm-1 and 1401 cm-1 shows C=C, and C–N stretching vibration respectively. The characteristic band formed at 3368cm -1 corresponding to N–H stretching vibration of secondary amine and for pure PANI, The peak at 1622 cm−1 , 1404cm-1 is due to the C= C stretching vibration of the quinoid rings ((N=Q=N)) and benzenoid ring (N-B-N) respectively. Band at 1118 cm−1 is due to the C−N stretching of a secondary aromatic amine. XRD patterns revealed the crystalline sizes of the materials, with average particle sizes 19.25nm, 8.24nm, 11.03 for Co3O4 NPs, PANI powder, and NCs respectively. Morphological investigations indicated unique structures for each material. UVVisible spectra provided band gap energy values for the synthesized materials (1.69 and 3.93 for Co3O4 NPs; 1.57, 3.1 and 4.12 for PANI: 3.26, 3.80 and 5.3 for NCs). The photocatalytic degradation study demonstrated that Co3O4 NPs and Co3O4/PANI NCs efficiently degraded MB and CR under natural sunlight irradiation. The degradation efficiency was influenced by catalyst dose, initial concentration, pH, and exposure time. Maximum degradation percentages were achieved under optimized conditions for both dyes (93.69% in Co3O4/PANI NCS and 90.79% in Co3O4 NPs for CR and 91.66% in Co3O4/PANI NCs and 89.60% in Co3O4 NPs for MB). Co3O4/PANI NCs exhibited higher degradation efficiency than Co3O4 NPs due to interactions between inorganic semiconductors and conducting polymers. Kinetic studies revealed that MB followed pseudo zero-order kinetics, while CR degradation followed pseudo first-order kinetics with the R2 = 0.993 and 0.992 respectively
GREEN SYNTHESIS OF COPPER OXIDE NANOPARTICLE US SOLANECIO GIGAS LEAF EXTRACT ( YESHKOKO-GOMEN) AND APPLICATION IN CATALYTIC DEGRADATION OF CRYSTAL VIOLATE
(HAWASSA UNIVERSITY, 2025-03) ZEHERIYA JATORO AREBO
Metal nanoparticles have enhanced much consideration in the field of organic catalysis and catalytic reactions due to the toxicological problems caused by organic dyes to the environment and human health. In the current study, CuO nanoparticle was synthesized through green method using Solanecio gigas leaf extract and, then evaluated for its catalytic degradation activity. The synthesized CuO nanoparticle was confirmed through visual inspection of colour changes and characterized by using UV-Vis, FT-IR, XRD and SEM techniques. From XRD data, the particle sizes of the synthesized CuO nanoparticle were calculated and found to be 38.91nm and appears to be more crystalline in nature. UV-vis analysis of CuO nanoparticles showed continuous absorption in the visible range. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed the presence of several functional groups, particularly hydroxyl, present in the extracts, which may be responsible for capping of nanoparticles. SEM micrographs showed a combination of different shaped and grain size CuO nanoparticle. From the catalytic degradation study, it is possible to conclude that this green route synthesized CuO nanoparticles have high efficiency to degrade Crystal violet. In the degradation of Crystal violet by CuO nanoparticle, maximum degradation efficiency was 90.57% under optimum condition (catalyst dose 0.08 gram, initial concentration 9 ppm, sodium borohydride 0.10 M, reaction time 20 min and pH of 6) The pseudo kinetic study indicates catalytic degradation of Crystal violate in the surface of CuO nanoparticle follows pseudo- zero-order kinetics. The results from this study illustrate that green synthesized CuO nanoparticles offer a cost-effective, environmentally friendly and efficient means for catalytic degradation of dyes.
LEVELS OF SELECTED ESSENTIAL AND NON-ESSENTIAL METALS IN THE SOIL AND GINGER (ZINGIBER OFFICINALE) CULTIVATED IN KAMBATA ZONE, HADERO TUNTO WOREDA CENTERAL ETHIOPIA
(2024-10) BEYENE BADEBO BATAMO
Ginger is a common spice and condiment for many foods and beverage. Its extracts are widely utilized in the culinary, beverage, and confectionary industries for making product like liquors, biscuits , pickles, chutney, marmalade and ginger beer. The levels of essential (Ca, Zn, Cu, Co, Cr, Mn, and Ni) and non-essential (Pb) metals in ginger cultivated in four different sites of kembata zone Ethiopia and the soil where it was grown were determined by flame atomic absorption spectrometry. 0.5 g of oven dried ginger and soil samples were digested using 3 mL of HNO3 and 2 mL of HClO4 at 230°C for 2:30 h and a mixture of 6 mL aqua-regia and 2 mL H2O2 at 250°C for 3 h, respectively. The mean metal concentration (mg/Kg dry weight basis) ranged in the ginger and soil samples, respectively, were: Ca (874–1253, 801–1550), Zn (4.16– 7.1, 48–110), Cu (3.3–5.4, 8.4–13.3), and Mn (231–321, 527– 673), the other metals like Pb, Cr, Ni and Co were not detected in both the ginger and soil samples. There was good correlation between some metals in ginger and soil samples. This study revealed that gingers samples taken from sample site are good source of essential metals and free from toxic metal Pb, Cr, Co and Ni.
MICROBIAL FUEL CELL WITH GREEN SYNTHESIZED CuO BASED POLYANILINE COMPOSITE AS EFFICIENT BIOANODE MODIFIER CATALYST
(HAWASSA UNIVERSITY, 2024-05) BETELEHEM GUTA
Microbial fuel cell is a new technology device that converts chemical energy stored in organic waste into electrical energy by using microorganisms as a catalyst with simultaneous waste water treatment. In this study, low-cost phyto-synthesized CuO nanoparticles integrate with conducting polyaniline (PANI) matrix to form CuO/PANI hybrid nanocomposite was synthesized by in situ polymerization methods and PANI was synthesized by oxidative polymerization method. The synthesized sample were characterized through UV-Vis spectroscopy, FTIR, SEM, and XRD, instruments to examine their optical properties, intermolecular bonding and the existence of functional groups, morphology and crystalline structural respectively. Four single chambered microbial fuel cells (MFCs) was constructed with bare pencil graphite anode, pencil graphite anode modified with CuO, PANI, CuO/PANI nanocomposites and PGEs cathode for all four devices. The average crystalline size for CuO NPs, PANI and CuO/PANI NCs was 28.05 nm, 3.2 nm and 20.6 nm respectively. It was found that the maximum open circuit voltage (OCV) obtained by bare PGE, CuO/ PGE,PANI/PGE and CuO/PANI/PGE was 229 ± 11.3 mV, 315 ± 35.3 mV, 485± 15.5 mV, and 630 ± 10.6 mV respectively. The maximum power density and corresponding current density obtained by CuO/PGE, and PANI/PGE have a value 265.75 mWm−2 & 2134.34 mA m−2 and 387.91 mWm−2 & 2418.06 mAm−2 respectively. A maximum of 416.01 mWm-2 , and 2429.56 mAm-2 power density at corresponding current densities was produced by CuO/PANI/PGE respectively. This was 6.3and 4-fold higher in power and current densities than unmodified PGE have values of 65.67 mWm-2 and 580.21 mAm-2 . From above results modifying anode of MFC with CuO nanoparticles based PANI composite gives a better output as compared with bare PGE in the MFC energy conversion system
OBSTACLES IN CHEMISTRY LABORATORY IMPLEMENTATION: A STUDY OF TWO SCHOOLS IN KAMBATA ZONE, ETHIOPIA
(Hawassa University, 2025-03) TADESE SHOMORO
The effective implementation of chemistry practical work faces numerous challenges globally, particularly in developing nations. Common obstacles include insufficient laboratory facilities, insufficient funding for practical science instruction, equipment, and supplies, as well as a shortage of qualified teachers. This study investigated the factors obstacle laboratory implementation in chemistry instruction at Angacha and Funamura Secondary Schools in Kabata Zone, Central Regional State, Ethiopia. A total of 213 individuals participated in the study, comprising 192 students, 14 teachers, 2 laboratory technicians, and 5 school principals from public secondary schools within the zone. Employing a descriptive survey research design and a quantitative approach, data collected from the target population were analyzed using SPSS version 26. The findings revealed that the availability of laboratory technicians, along with the attitudes of students, laboratory technicians, and teachers, significantly influenced the use of chemistry experiments in teaching and learning. Furthermore, while laboratories existed in the schools, they were underutilized due to a lack of adequate apparatus.
PHOTOCATALYTIC DEGRADATION OF CRYSTAL VIOLET UNDER SOLAR IRRADIATION USING A BIOSYNTHESIZED ZnOBASED POLYANILINE
(HAWASSA UNIVERSITY, 2024-05) BELAYNESH SIRIYE TALILA
A morphologically modified PANI/ZnO Nanocomposite was synthesized using leaf extract from Solanecio gigas (S. gigas) a reducing and capping agent for the photocatalytic degradation of Crystal Violet (CV) under natural sunlight irradiation. Additionally, PANI and pure ZnO NPs were synthesized via a green route, and the nanomaterials were characterized using spectroscopic techniques such as UV-Vis, FT-IR, SEM, and XRD. The blue-shift in the absorption peak of PANI/ZnO NCs suggests a change in electronic structure, potentially due to a type-II heterojunction between PANI and ZnO. FTIR analysis revealed red-shifted peaks, indicating hydrogen bonding between ZnO and PANI. Morphologically, the composite material combines the roughness of ZnO NPs with the smoothness of PANI. XRD patterns showed overlapping peaks from the composite with a crystalline size of 5.577 nm, which is smaller than the crystalline size of ZnO NPs (9.455 nm). This reduction in size is likely due to the formation of a polymer-Zn complex on the nanoparticle surface. The photocatalytic activity of the polyaniline/ZnO nanocomposite in degrading CV in aqueous solution under natural sunlight irradiation was evaluated and compared with that of ZnO nanoparticles. The effects of experimental conditions such as pH, photocatalyst dosage, and CV concentration were investigated with 91.20% and 99.06% at pH 11, 99.47% and 99.97% at 0.12 g, and 94.93% and 96.20% at 20 ppm for both ZnO NPs and PANI/ZnO NCs. The ZnO/polyaniline nanocomposite exhibited higher photocatalytic activity at 98.25% compared to ZnO nanoparticles at 92.76% under optimal conditions after 60 minutes of sunlight exposure. Kinetics studies indicated that the degradation rate fit well with the pseudo-first-order kinetics model, showing an R2 value of 0.968 for PANI/ZnO NCs. The composite demonstrated good catalytic activity with four cycles of reusability time compared to non-coated ZnO NPs. These findings highlight the potential of S. gigas plant-assisted PANI/ZnO NCs as effective and sustainable nanocatalysts with promising applications in catalytic decomposition of organic contaminants for environmental remediation