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Silica fouling of utc-70 ultra low pressure reverse osmosis membrane in defluoridation of Chiang Mai basin groundwater |
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| รหัสดีโอไอ | |
| Title | Silica fouling of utc-70 ultra low pressure reverse osmosis membrane in defluoridation of Chiang Mai basin groundwater |
| Creator | Pharkphum Rakruam |
| Contributor | Suraphong Wattanachira |
| Publisher | Chulalongkorn University |
| Publication Year | 2551 |
| Keyword | Groundwater -- Purification, Water -- Purification -- Reverse osmosis process, Silica, Fluorides, น้ำใต้ดิน -- การทำให้บริสุทธิ์, น้ำ -- การทำให้บริสุทธิ์ -- กระบวนการออสโมซิสผันกลับ, ซิลิกา, ฟลูออไรด์ |
| Abstract | Ultra low pressure reverse osmosis membrane is a new technology, which apply to defluoridation from groundwater. This membrane can operated at verylow pressure. However, the major problem of reverse osmosis is membrane fouling. Membrane fouling can effect on fluoride rejection rate and cause ofmembrane degradation. In this study, the membrane fouling of UTC-70 ultra lowpressure reverse osmosis membrane in groundwater defluoridation was investigated. Chiang mai basin was selected as study area. In this area, groundwater contains high fluoride concentration. Two sites of groundwater in this area were selected as sampling point. Fisrt site is groundwater from Pra Too Khong, Lamphun, wheareas, the second site is San Kam Pang hot spring well, Chiang mai. Groundwater from two sites was filtrated with ULPRO membrane, which operated in cross-flow mode. The operating transmembrane pressure wasvaried at 0.3 and 0.5 MPa. Furthermore, the concentration polarization phenomenon was investigated. The NaF concentration varied at 0, 10, 25, and 50mM was used as feed solution. From the results, it was found that the mass transfercoefficient in solution was 2.73x10-5 and 1.75x10-5 m/s at 0.3 and 0.5 MPa,respectively. While, the average solute mass transfer coefficient through themembrane was 4.5x10-7 m/s under 0.3 and 0.5 MPa, respectively. For the groundwater defluoridation experiment, it was found that the high fluoride rejection rate more than 90% was obtained. In Pra Too Khong groundwater, thefluoride rejection rate was 95.7-96.7%, wheareas, in San Kam Pang hot spring wellwas 96.7-97.5%. From the results, it can be indicated that the higher fluoriderejection rate was obtained at higher transmembrane pressure (0.5 MPa). From theinvestigation of membrane fouling, it was found that the membrane was fouledwith dense-gel layer (polymerized fouled layer) in all case of experiment. Furthermore, the effect of silica fouling on groundwater defluoridation was investigated. The results showed that silica can effect on permeate flux and fluoride rejection rate in groundwater defluoridation. The presence of silica in feed water was cause of decreasing in fluoride rejection rate. While, the results of silicafouling showed that membrane was fouled with polymerized silica fouled layer. |
| URL Website | cuir.car.chula.ac.th |
