Nano silica removal from IC wastewater by pre-coagulation and microfiltration.
Microfiltration (MF) coupled with pretreatment by coagulation was adopted in the treatment of chemical mechanical polishing (CMP) wastewater from IC manufacturing plants, containing high concentrations of silica. Poly-aluminium chloride (PACl) was the coagulant, while the cationic polyacrylamide (PAA) was the flocculant aid. Preliminary tests were performed with the raw CMP wastewater in order to determine the optimal coagulation condition for subsequent microfiltration. Analysis of the particle size distribution shows that nearly all silica particles were enlarged from nano scale to at least 4 microm in diameter after the pre-treatment. The pre-treated wastewater was then filtered through a polytetrafluoroethylene (PTFE) membrane with a pore size 0.5 microm at a constant vacuum pressure. Trace amounts of PAA in addition to the PACl coagulation can effectively increases the permeate flux.
Huang
C
C
Institute of Environmental Engineering, National Chiao Tung University, Hsinchu, Chinese Taiwan. cphuang@mail.nctu.edu.tw
Jiang
W
W
Chen
C
C
D000180:Acrylic Resins / Q000737:chemistry; D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000737:chemistry; D002412:Cations; D002712:Chlorides / Q000737:chemistry; D005427:Flocculation; D008567:Membranes, Artificial; D036103:Nanotechnology; D010316:Particle Size; D011108:Polymers / Q000737:chemistry; D011138:Polytetrafluoroethylene / Q000737:chemistry; D016062:Porosity; D012822:Silicon Dioxide / Q000302:isolation & purification*; D014462:Ultrafiltration / Q000379:methods*; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*; D000099166:Polyacrylamides
D000180:Acrylic Resins; D000077410:Aluminum Chloride; D017607:Aluminum Compounds; D002412:Cations; D002712:Chlorides; D008567:Membranes, Artificial; D011108:Polymers; D011138:Polytetrafluoroethylene; D012822:Silicon Dioxide; D000099166:Polyacrylamides