Shegaw, Ahmed (PhD)Blen, Tadesse2019-01-042023-11-102019-01-042023-11-102018-11http://etd.aau.edu.et/handle/12345678/15550Tanning is the chemical process that converts animal hides and skin into leather and related products. The transformation of hides into leather is usually done by means of tanning agents and the process generates highly complex and characterized by high contents of organic, inorganic and nitrogenous compounds, chromium, sulfides, suspended solids and dissolved solids. This study deals with removal of chromium from tannery wastewater using modified Moringa oleifera seed pod (MMOSP) adsorbent. The collected MOSP crushed and sieved to a particle size between 125 and 250µm, Moringa oleifera seed pod was modified or treated with HNO 3 to remove metals and increase its surface area and after the acid treatment, the adsorbent was extracted with methanol to remove inorganic and organic matter from the sorbent surface. Finally washed with distilled water, dried at105 o c and characterized by FTIR and XRD. The adsorption efficiency MMOSP was evaluated as the function of adsorbent dosage, pH and contact time. Atomic absorption spectrometry (AAS) technique was used for the measurement of concentration of Cr (III) before and after adsorption. Batch adsorption experiments were conducted using model pollutant of tannery wastewater. The effects of independent variables on initial Cr (III) concentration of 150mg/L were evaluated. A Cr (III) removal efficiency of 99.78 % would be achieved at pH 5.5, 0.65g and 90min using modified Moringa oleifera seedpod. The experimental results have been fitted well by the Langmuir isotherm model with the higher correlation coefficients of R 2 = 0.999. Thus, indicating to the applicability of monolayer coverage of the Cr (III) on the surface of the MMOSP. Adsorption kinetics was determined using pseudo first order and pseudo second order models and it was found that the adsorption process follows pseudo second order model (R 2 =1). Generally, the results indicate that MMOSP may be used as a low cost adsorbent, alternative for treatment of effluents containing Cr (III).en-USCr (III) Removalmodified Moringa olifera seed podadsorption isotherm modelkinetics modelThesis