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Browsing SCIENCE by Subject "(AZADIRACHTA INDICA),"

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    TREATMENT OF HOSPITAL WASTEWATER USING ACTIVATED CARBON FROM NEEM (AZADIRACHTA INDICA) HUSK AND SEED CAKE
    (2016-01) ALAU, KENNETH KUKHIYEP
    Management of hospital wastes remains a subject of public health interest due to their hazardous nature. Most of the hospital wastes are not easily degradable by natural phenomena of biochemical decomposition. However, they can be attenuated by adsorption on a suitable medium and recovered or isolated through various treatment techniques. Commercial adsorbents are expensive and not readily available locally although activated carbon has been developed from natural materials. The need to further research on these wastes to convert them into adsorbent in order to reduce waste and conserve cost is the key to the research work. The present research produced and used activated carbon from neem (Azadirachta indica) husk and seed cake to treat hospital wastewater. The wastewater sample used was obtained from the University of Abuja Teaching Hospital (UATH) wastewater treatment plant after certification and approval by the Hospital Ethical Committee (HEC). The raw neem husk and seed cake were carbonized at 400oC and activated with ZnCl2 and H3PO4 at 500oC and 550oC respectively. The moisture content of the Raw Neem Husk (RNH) and Raw Neem Cake (RNC) were found to be 4.45% and 8.95% respectively. The microstructural, structural and thermal properties of the adsorbents were studied using nitrogen gas adsorption analysis, SEM, FTIR and TGA. The surface areas and pore size of the neem activated carbons are in this order: NCH (352 m2g; 34.26 Å)> NCZ (252.18 m2g; 24.16 Å) > NHZ (238.56 m2g; 22.46 Å) >NHH (230.79 m2g; 22.22 Å). The FTIR results showed slight changes in the absorption band of the raw neem material compared to that of the activated neem carbon. This showed that the activation process was successful. The TGA results showed that the activated carbon were hydrophobic and thermally stable up to 450oC. The adsorbent has been found to be effective and efficient in reducing the viii investigated parameters in a multi component system. The adsorbents (Neem Cake activated with H3PO4 (NCH), Neem Cake activated with ZnCl2 (NCZ), Neem Husk activated with ZnCl2 (NHZ) and Neem Husk activated with H3PO4 (NHH)) reduced nitrates and chloride ions by 100%, phosphate ions by 95%, total bacterial load by 99%, total fungal load by 90%, chromium ion by 82%, lead ion by 70%, nickel ion by 61%, zinc ion by 59% and cadmium ion by 36%. The kinetic data were fed into the pseudo-second-order rate and the Weber and Morris intraparticle diffusion models. The results showed that the mechanism of removal of the pollutants was by chemisorption and that intraparticle diffusion was not the only rate determining step in the process. The Equilibria results were modelled using the Langmuir and Freundlich isotherm models. The adsorption pattern fitted into the two models but more favourably described by the Langmuir isotherm than the Freundlich isotherm, suggesting the adsorption was predominantly monolayer rather than multilayer. Column studies showed that the adsorption of nickel ion onto neem husk activated with H3PO4 (NHH) depends on flow rate, inlet concentration and bed height. This was analyzed using the Admas–Bohart model. Studies on regeneration and reuse of the adsorbent on the wastewater showed that the adsorbents can be reused up to the fifth cycle.