Precise Filtration Research Articles

無電解めっきによるガラス上へのニッケルマスクの形成

This paper addresses the formation of the nickel mask on glass using electroless nickel plating without a pinhole. The resultant fine-patterned mask formed on the glass using electroless Ni plating with precision filtration is almost pore-free. The optical density of the glass was greater than 4.0 because of the nickel deposits, with thickness greater than 0.15 μm. The adhesion strength between the deposited Ni and glass is slightly lower than that of the sputtered Cr. The adhesion strength is, however, increased and reaches an almost identical value after heat treatment at 350°C for 1 hr. Fine circuit patterns without a pinhole were formed by the etchant, a HNO3 and H3PO4 mixture. Furthermore, the conventional repair method for the chromium mask pattern is applicable for the repair of nickel patterns on glass.

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

The 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.

Precise filtration for the pharmaceutical industry

Ensuring the quality of its process water is one of the highest priorities of any pharmaceutical company. Membranes offer the level of contaminant removal required, with solvent cast membranes commonly used in this application. However, another technology exists - the track-etch membrane. L P Raman, Whatman Inc, USA, discusses why this technology is a viable alternative.

Microfiltration and stabilization of egg yolk phospholipid emulsions by a microporous glass membrane

AbstractA microporous glass membrane with a narrow‐range pore size was applied for the microfiltration of egg yolk phospholipid emulsions. The oil‐in‐water and water‐in‐oil emulsions were successfully filtered using the membrane without any coalescence of oil droplets or the breakdown of the emulsions. The filtrated oil‐in‐water emulsion was stable for at least 6 wk when stored at 5°C. The results obtained suggest that the technique would be valuable for the precise filtration of emulsions for food uses as well as intravenous fat and/or drug carrier emulsions, and offer the stabilization of the emulsions.

上水道における膜ろ過技術 中空糸型精密ろ過膜による浄水処理

上水道における膜ろ過技術 中空糸型精密ろ過膜による浄水処理

上水道における膜ろ過技術 空気逆洗型中空糸精密ろ膜を用いた上水処理

上水道における膜ろ過技術 空気逆洗型中空糸精密ろ膜を用いた上水処理

無電解銅めっきへの精密ろ過の応用

Electroless copper plating is an indispensable process in the manufacture of printed wiring boards, but extraneous deposition occurs during electroless plating especially if the copper plating bath is used for a long period. Baths used for five or more truns have been found to contain more that 2×106 inorganic particles (Si, Al, Na, etc.) of from 1∼5μm leading significantly to extraneous deposition. To solve this problem, precision filtration was applied, greatly reducing the numbers of particles by continuous filtration, eliminating extraneous deposition and improving the properties of the deposited film, Furthermore, electroless deposition of copper on the filter under high speed filtration was inhibited by the use of a tapered filter instead of a wound-depth type filter.

無電解銅めっきの精密ろ過効果

Investigation of the effects of continuous precision filtration on electroless copper plating has confirmed that the extraneous deposition phenomena occurring during long-term plating are caused by insoluble particles that accumulate in the plating bath. Simulation of 5 turnovers of an aging bath indicated the presence of more than two millions particles larger than 1μm diameter per liter of bath, and that they were mainly composed of Al, Si, Fe and Na.The properties of the copper film deposited were greatly influenced by this extraneous deposition, which decreased with batch type filtration, but tend to increase with the passage of plating time. Continuous precision filtration during plating, however, drastically suppressed extraneous deposition and increased the elongation of the deposited copper film about twofold.