Departments of Chemistry
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Item REMOVAL OF SELECTED TRACE METALS FROM WASTE WATER USING SOURSOP (ANNONA MURICATA L.) SEED(Hawassa University, 2025-03) WONDIMAGEGN BIRHANUThe effective removal of heavy metals from industrial wastewater is among the most important issues for many industrialized countries. Removal of lead (II), nickel (Ni) and copper (II) from aqueous solutions were studied using adsorbent prepared from soursop (annonamuricata l. Seed. The surface groups present on the adsorbrnt surface were determined by the Fourier Transform Infrared Spectroscopy (FTIR) analysis. Batch adsorption experiments were performed as a function of pH, contact time, initial concentration, temperature and adsorbent dose. The optimum pH required for maximum adsorption was found to be 6,6 and 5 for lead (II), nickel (Ni) and copper (II) respectively. The maximum contact time for the equilibrium condition is 90 min at the sorbent dose rate of 0.16 g. The maximum efficiencies of lead, Nickel and copper removal by adsorbent were 92%, 93 % and 94 %, respectively. Thermodynamic investigation stated endothermic and spontaneous nature of the system with the participation of a chemical adsorption process. Equilibrium data were represented better by the Freundlich model than the Langmuir model by which describes multilayer adsorptions. The linear regression analysis of kinetic data confirmed that pseudo-second order rate expression.Item THE EFFECT OF IRRIGATION AROUND ZIWAY ON HEAVY METAL CONTENT OF MAIZE GRAIN AND SOIL(Hawassa University, 2024-11) SILESHI TEFERRAThe aim of the current study was to determine the metallic concentration of maize of irrigated versus rain fed and soil of irrigated versus rain fed and the water used for irrigation. This is to investigate the influence of irrigation on the concentration of heavy metals in the maize grains and soil. This was done by comparing with rain fed farms. The concentrations of copper (Cu), zinc (Zn), chromium (Cr), nickel (Ni), and lead (Pb) in acid digested sample were determined using flame atomic absorption spectrometry. A composite purposive sampling method was used to collect samples from sample site of ziway city, Ethiopia. Microsoft Excel was used for Descriptive statistical analysis of the results and one way ANOVA was employed to compare the mean difference of heavy metals concentration between irrigated and rain fed. In maize samples (rain fed and irrigated maize) the mean concentrations of Pb, Cr, Ni, Cu and Zn were (0.42 – 1.25) for rain fed and irrigate maize, (not detected (nd) – 0.42) for rain fed and irrigated maize, (0.62 –0.93) for rain fed and irrigated maize, (10.8 – 12.3) for rain fed and irrigated maize and (20.23 – 24.3) for rain fed and irrigated maize. In soil samples mean concentration of Pb, Cr, Ni, Cu and Zn were in the range of (9.46 – 12.36) for rain fed and irrigated, (4.4 – 5.36) for rain fed and irrigated, (4.3 – 6.4) for rain fed and irrigated, (56.4 – 66.3) for rain fed and irrigated and (74.26 – 86. 35) for rain fed and irrigated. The mean concentrations of metals in water used for irrigation were (mg/L) of Pb (0.24), Cr (0.065), Ni (0.051), Cu (1.23) and Zn (0.92) in the irrigated water samples were above the limit set by US EPA (2004). The study show that irrigated (maize and soil) contained higher concentration of heavy metals and were above the limit set by US EPA which show that it was contaminated and would be unsave for human consumption.Item 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 ASHENAFISoil 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.