Abstract:
Ground water sources in some part of Ethiopia contain nitrate level beyond the permissible limit which can cause public health problems. Hence, the concentration of nitrate in drinking water should be removed to prevent health problems associated with high level of nitrate. Nanomaterial assisted removal of pollutants from drinking water and wastewater has got great attention. This study aimed to evaluate the removal of nitrate using zeolite and zeolite-ZnO nano composite. Zeolite-ZnO nano composite was prepared using co-precipitation method. The physico-chemical characteristics of the nano materials were determined using XRD, SEM and FTIR. The results revealed that; Zeolite-ZnO nanocomposites with 13.12 nm particle size have successfully been loaded into zeolite. In addition, its chemical composition was determined using AAS. The removal efficiency of nitrate from both spiked and real water was studied using batch experiment. The removal of nitrate was investigated as function of adsorbent dose, pH, initial concentration of nitrate, contact time, and agitation speed. Moreover, the adsorption isotherm and kinetics were also determined for both nitrate spiked and real water. The results showed that the removal of nitrate from spiked water was 95% at optimum dose of 0.5, pH 5, initial nitrate concentration of 50 mg/L, contact time of 1hour and agitation speed of 160 rpm. The removal efficiency of nitrate from spiked and real water was found to be 95% and 93% respectively. The removal nitrate from both sources have been fitted well by the Langmuir isotherm model with correlation coefficients of R2= 0.990 and 0.988, respectively. Thus, indicating to the applicability of monolayer coverage of the nitrate ion on the surface of the nano composite. The results found in adsorption kinetics study revealed that the adsorption of nitrate in both spiked and real water follows pseudo second order model with correlation coefficient of R2=0.988. The removal efficiency of nitrate in this study was compared to other chemical methods of water and wastewater analysis including available nano adsorbents. The work results might find application in reducing nitrate concentration in drinking water and meets the standards of water quality.