Nanotech based filtration of advanced treatment of wastewater

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An-Najah National University
In this research a new innovative modification on the traditional tertiary filtration-treatment units using zinc oxide nano photocatalysis is suggested to improve the quality of the treated effluents. The value of this idea lies in using cheap nano materials in modifying the filtration medias which grantee longer operation time with less frequently need for backwash or regeneration of the filtration media what makes the filtration process more sustainable and economically convincing solution. In this research, the nano zinc oxide catalysis was successfully lab synthesized from high purity graded raw chemicals (99.5%) and also from commercial raw materials (purity ≥ 95%). No significant difference in the size of the produced catalysis based on the purity of the raw material. Where, the zinc oxide nano photocatalysis was produced in size of 69 nm from commercial zinc sulfate heptahydrate and size of 29 nm from graded zinc sulfate heptahydrate. In the same manner, nano ZnO catalysis which was produced from commercial micro-sized ZnO have a size of 28 nm which is greater than the nano ZnO catalysis originated from graded raw micro-sized ZnO by just 11 nm. Photocatalytic degradation ability of the produced nano catalysis was tested in batch experiments as powder or after pre-depositing it on the surface of activated carbon or recycled glass. The nano photocatalysis produced from commercial raw chemicals (ZnSO4.7H2O and micro-sized ZnO) shows high degradation ability for the pollutants in the secondary wastewater with efficiency reaches 85% of total chemical oxygen demand (COD) in the powder batch, and exceeds this value to 97% in the batch of pre-deposited nano catalysis on the surface of the recycled glass. Carbon and recycled glass were tested as nano photo catalysis carrier. The activated carbon didn’t show the sought after results where the nano catalysis easily escaped to the solution in the batch experiment moreover the black imperial structure of the AC obstructed sun light and ultraviolet light which activate the photo catalytic reaction causing deficiency in activation of the nethermost photocatalysis. Unlike AC filtration media, the filtration media made of crushed glass allows the UV to penetrate its structure and therefore activating the pre-doped nano photo catalysis even in the bottom layers of it. Finally, the results of this research are the milestone of other researches in order to develop a self-cleaning filtration media.