In this study, nanosized TiO2-containing organic wastewater was treated with a simultaneous electrocoagulation/electrofiltration (EC/EF) process using either a recirculation mode or a flow-through mode. In the EC/EF treatment module, iron and stainless steel (SS 304) were respectively selected as the anode and cathode, and polyvinylidene fluoride (PVDF) with a nominal pore size of 0.1 £gm was used in this work. Applied electric field strength (EFS), transmembrane pressure (TMP), and crossflow velocity (CFV) were selected as the operating parameters for studying their effects on permeate qualities and other performance criteria. In the recirculation mode, the residual chemical oxygen demand (COD) was found to decrease with increasing EFS up to the critical EFS (i.e., 166.7 V/cm) and leveled off. The optimal operating conditions were determined to be an EFS of 166.7 V/cm, a TMP of 1 kgf/cm2, and a CFV of 0.22 cm/s. Under the optimal operating conditions, the removal efficiencies for turbidity, conductivity, total dissolved solids (TSD), and titanium were determined to be 98.7%, 95.1%, 95.8%, and 99.9%, respectively. By using the same operating conditions except in the flow-through mode, the corresponding removal efficiencies were found to be 98.1%, 92.3%, 93.1%, and 99.9%, respectively. Experimental results also showed that the flow-through mode yielded a higher filtration rate than that of the recirculation mode (namely, 5.05 mL/min versus 4.75 mL/min). This is an indication of a lower extent of membrane fouling for the flow-through mode. This was also evidenced by the scanning electron microscope (SEM) micrographs of the post-treatment membranes. In the recirculation mode, a proper practice of backflushing (e.g., a period of 60 min and a duration of 0.5 min) was found to extend the service life of the membrane and to enhance the permeate flux. I so doing, a minimum treatment rate of 90L/hr with a treatment cost of NT$68.10 per cubic meters would be resulted. Permeate obtained was found to meet the criteria of make-up water for cooling towers. Overall speaking, the simultaneous EC/EF treatment module employed in this work is capable of treating nanosized TiO2-containing organic wastewater for the purpose of reclamation.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0730104-164013 |
| Date | 30 July 2004 |
| Creators | Chuang, Chih-Chuan |
| Contributors | D. T. Ray, H. H. Yeh, G. C. C. Yang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0730104-164013 |
| Rights | withheld, Copyright information available at source archive |
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