Water demineralisation by NF/MD integrated processes

Karakulski, Krzysztof; Gryta, Marek

doi:10.1016/j.desal.2004.11.018

Cited by 111 publications

(70 citation statements)

References 10 publications

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“…The clogging reduced the feed flow rate, thus increasing temperature and concentration polarization, which reduced the module flux. The fibrous structure of the deposits blocked the foulants from further entry into the membranes capillary, stabilizing the flux [59]. This indicates that silica scale may be of significantly more concern in hollow fiber capillary MD systems than in flat sheet membranes.…”

Section: Particulate and Colloidal Fouling In MDmentioning

confidence: 95%

“…Removal of the foulant with acidification combined with drying the membranes restored the initial flow rates only briefly [59]. This happened despite nanofiltration of the feed upstream of the MD membranes [59]. SEM-EDS analysis indicated that the deposit consisted of silicon, with small amounts of iron, calcium, zinc, and chlorine.…”

Section: Particulate and Colloidal Fouling In MDmentioning

confidence: 99%

“…The flux declined by 30% after 1100 hours of operation, mostly during the first 200-300 hours. Removal of the foulant with acidification combined with drying the membranes restored the initial flow rates only briefly [59]. This happened despite nanofiltration of the feed upstream of the MD membranes [59].…”

Section: Particulate and Colloidal Fouling In MDmentioning

confidence: 99%

“…[59] found precipitation of silica compounds on the membrane [59]. The silica clogged capillary membrane inlets, causing a gradual decline of the module efficiency.…”

Section: Particulate and Colloidal Fouling In MDmentioning

confidence: 99%

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Scaling and fouling in membrane distillation for desalination applications: A review

et al. 2015

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Section: Particulate and Colloidal Fouling In MDmentioning

confidence: 95%

Section: Particulate and Colloidal Fouling In MDmentioning

confidence: 99%

Section: Particulate and Colloidal Fouling In MDmentioning

confidence: 99%

“…[59] found precipitation of silica compounds on the membrane [59]. The silica clogged capillary membrane inlets, causing a gradual decline of the module efficiency.…”

Section: Particulate and Colloidal Fouling In MDmentioning

confidence: 99%

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Scaling and fouling in membrane distillation for desalination applications: A review

et al. 2015

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“…At present, pretreatment such as coagulation, sedimentation, sand filtration, microfiltration (MF) and ultrafiltration (UF) are increasingly being used for the removal of suspended solids and biological matter from RCW before RO systems. These pretreatment processes combined with RO process are integrated membrane systems (IMS) [4][5][6], which have become of great interest in recent years. However, the IMS have several drawbacks that have been difficult to overcome, such as the water recovery rates are usually lower than 70%, for a price often considered as uneconomic due to capital and energy costs, and have complicated pre-treatment and post-treatment, high operation and maintenance requirements.…”

Section: Introductionmentioning

confidence: 99%

Effect of coagulation pretreatment on membrane distillation process for desalination of recirculating cooling water

Wang

Tie³

et al. 2008

Separation and Purification Technology

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a b s t r a c tThe objective of this work was to study the performance of coagulation pretreatment and the effect of coagulation pretreatment on membrane distillation (MD) process for desalination of recirculating cooling water (RCW). In this study, RCW was desalinated by MD process after pretreated by coagulation, precision filtration, acidification and degassing. Pre-coagulation of RCW with poly-aluminum chloride (PACl) coagulant improves the elimination of total organic carbon (TOC), total phosphorus (TP) substances. The optimized pH value and PACl dosage were 7 and 15 mg/L, respectively. Compared with MD process without coagulation pretreatment, much slighter MD flux decrease was observed when coagulation pretreatment was employed for desalination of RCW using MD process. Compared with the membrane flux of MD process for the RCW without coagulation pretreatment, about 23% improvement of MD flux was obtained by employing coagulation pretreatment after 30 days operation. The variation of crystal morphology on membrane surface and hydrophobic character of PVDF hollow membranes were investigated. The results show that distorted rhombic magnesium-calcite scale formed on membrane surface when coagulation pretreatment was employed. However, the deposited magnesium-calcite on the membrane surface was loosely packed with particles of much smaller size when RCW without coagulation pretreatment was fed. It is because that the coagulation pretreatment removed most of the natural organic matter (NOM) and antiscalant additives in RCW, which act as an inhibitor to calcium carbonate crystal growth in water. After coagulation pretreatment, bigger crystal deposit formed on membrane surface with the increase in CF of RCW. It was rather difficult for bigger crystal to enter membrane pores and thus the formation of bigger crystal reduced partial wetting of membrane, which enhanced trans-membrane flux. The hydrophobic character of PVDF hollow membranes used in MD process can be easily recovered by chemical rinsing using acid-base solutions. The results indicate that the pretreatment with chemical coagulant, PACl, is effective for the desalination of RCW by MD process.Crown

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