| 1. |
- Jönsson, Ann-Sofi, et al.
(författare)
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Influence of pH and surfactants on ultrafiltration membranes during treatment of bleach plant effluent
- 1988
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631. ; 3:4, s. 159-165
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Tidskriftsartikel (refereegranskat)abstract
- The influence of pH and surfactants during treatment of E-stage effluent was studied. Three tubular ultrafiltration membranes were used in the experiment. The flux of the three membranes was at its highest level at the normal, high pH, of the effluent. In this experiment the densest membrane showed the greatest flux decrease, while the most ouen membrane was either unaffected bv variations in ph or experienced a more moderate decrease. The flux after treatment with a nonionic surfactant could be restored by cleaning with a commercial cleaning agent, but it was not possible to restore the initial flux when a cationic surfactant had been added to the effluent. The role of cleaning during membrane treatment is also discussed.
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| 2. |
- Jönsson, Ann-Sofi, et al.
(författare)
-
Membrane distillation - A theoretical study of evaporation through microporous membranes
- 1985
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Ingår i: Desalination. - : Elsevier BV. - 1873-4464 .- 0011-9164. ; 56, s. 237-249
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Tidskriftsartikel (refereegranskat)abstract
- Membrane distillation is a process in which, for example, water in a heated salt solution, evaporates through a porous membrane. The vapour condenses on a coolant surface on the other side of the membrane. The two liquid streams, the salt solution and the condensate, are separated by a highly porous hydrophobic membrane. Surface tension forces withhold liquids from the pores and prevent contact between the two liquids. The temperature difference, causing a corresponding vapour pressure difference across the membrane, provides the driving force of the membrane distillation process. Evaporation will occur at the solution surface if the vapour pressure on the solution side is greater than the vapour pressure at the condensate surface. Vapours then diffuse through the pores to the cooler surface, where they condense. The dependence of mass and heat transport upon different process and membrane parameters involved in membrane distillation has been investigated theoretically.
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| 3. |
- Jönsson, Ann-Sofi, et al.
(författare)
-
The application of membrane technology in the pulp and paper industry
- 1985
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Ingår i: Desalination. - : Elsevier BV. - 1873-4464 .- 0011-9164. ; 53:1-3, s. 181-196
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Tidskriftsartikel (refereegranskat)abstract
- A state of the art review on industrial applications of membrane technology in the pulp and paper industry is presented. Applications have been arranged under three headlines, effluent treatment, concentration and fractionation. Among new and promising applications are treatment of waste paper white water, effluent after deresination and concentration of spent liquor from chemi-mechanical pulping.
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| 4. |
- Jönsson, Ann-Sofi, et al.
(författare)
-
Treatment of C-stage and E-stage bleaching plant effluent by ultrafiltration
- 1989
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631. ; 4:3, s. 184-187
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Tidskriftsartikel (refereegranskat)abstract
- The influence of pH on membranes of different materials and different cut off has been studied. One ceramic microfiltration membrane and three synthetic ultrafiltration membranes were included in the study. The pH of an acidic (C-stage) and and alkaline (E-stage) bleaching effluent was varied. For the E-stage effluent the membrane performance seemed to be correlated to the cut off of the membrane. During treatment of the C-stage effluent the performance of the membranes was more disparate
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| 5. |
- Jönsson, Ann-Sofi, et al.
(författare)
-
Treatment of C-stage and E- stage effluents from a bleach plant using a ceramic membrane
- 1988
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631. ; 3:1, s. 4-7
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Tidskriftsartikel (refereegranskat)abstract
- C-stage effluent, E-stage effluent and a total effluent (C-stage and E-stage effluent mixed in proportion to the volumes of the effluents at the mill) have been treated with a ceramic microfilter membrane. The flux of the total effluent was considerably lower than of the separate effluents. The fluxes of the E-stage and C-stage effluents were 550 and 1,300 l/m2h, respectively, while the flux of the total effluent was only 150 l/m2h. The low filtration capacity is thought to be caused by adsorption of substances onto the membrane. The influence of pH on the filtration capacity of C- and E-stage effluent was clearly demonstrated.
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| 6. |
- Jönsson, Ann-Sofi
(författare)
-
Treatment of effluent from alkali extraction with ultrafiltration and reverse osmosis
- 1989
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631. ; 4:1, s. 33-37
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Tidskriftsartikel (refereegranskat)abstract
- Effluent from alkali extraction of chlorinated pulp was treated with ultrafiltration (UF). Three different ultrafiltration (UF) membranes were tested. The permeate from one of the UF membranes was further treated with reverse osmosis (RO). Titration curves for the permeates from the different UF and R0 membranes were determined. The concentration of charged compounds was calculated from the titration data and compared with the COD and AOX of the permeates. The retention of COD and AOX was between 50 and 90% for the UF membranes, whereas the retention of carboxylic acid groups was considerably lower, 15-45%. During the R0 treatment the retention of all compounds was found to be very high. For the densest R0 membrane the retention of AOX and compounds with carboxylic acid groups was higher than 99%. The retention of COD was 96%.
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| 7. |
- Jönsson, Ann-Sofi
(författare)
-
Ultrafiltration of bleach plant effluent
- 1987
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631. ; 2:1, s. 23-29
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Tidskriftsartikel (refereegranskat)abstract
- An up-to-date evaluation of capacity and retention of new membranes with regard to bleach plant effluents has been made. The results from a trial of seven reverse osmosis, ultrafiltration and microfiltration membranes are reported. The trial has even included membranes not yet commercially available. The trial has demonstrated that some of the tested membranes could probably combine a satisfactory flux and an acceptable retention. A rough estimate of the costs shows that treatment of the E-stage effluent with ultrafiltration could be performed within a total cost of approximately 25 SEK per tonne of pulp.
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