Cold Plasma Surface Treatment of UHMWPE Membranes to Improve Fouling Characteristics

Abstract

The influence of cold plasma internal surface treatment on the fouling characteristics of UHMWPE membranes was investigated. Two sets of sintered tubular UHMWPE membranes were manufactured. One set of membranes was prepared with as-received powdered UHMWPE and another set was prepared with the same powder sieved through #200 mesh. The tubular membranes were obtained by sintering the UHMWPE powders at 180°C for 130 min, and were characterized by SEM, contact angle and flow permeation. The flow permeation measurement was conducted in a locally built apparatus and the amount of permeated fluid was determined by gravimetry, as a function of time. Water collected from a local source was used in the tests. Modification of the membrane internal surface was achieved by methane cold plasma treatment, applied during 60 min. The data indicates for both membranes, fouling was reduced after plasma modification and that the effect was more pronounced for the membranes prepared with the sieved UHMWPE powder. This behavior was associated to the increased surface tension (after plasma modification) leading to solid particle repulsion by the membrane surfaces and to a better plasma surface modification on the smaller grain sizes displayed by the membranes prepared with the #200 mesh sieved UHMWPE powder.