Antifoams :
Unsung heroes of water treatment
Daniel Marr , group CCO of Airedale Chemical , explores the most effective way to combat unwanted foam and the science behind antifoams
Chemicals and water treatment are highly regulated industries and new guidelines can be added or amended on a regular basis . This means that the formulations used in water treatment need to be constantly updated and revised , as do the technologies in developing them , such as aeration , flocculation and active carbon adsorption , which have all changed the way our water is treated over the decades . There have been a host of developments in the marketplace over the last few years alone that have demanded improved foam control performance . Regulatory updates have wrought changes as an inexorable migration to a more water-based formulation landscape takes hold , in place of a traditional hydrocarbon- or solvent-based one . The consequence of enhanced use of surfactant-type emulsifiers has been processes and formulations becoming more prone to foaming . This is evident in industrial processing of water as well as in the use of solvent water in the paint and coatings sector . Productivity improvements have resulted from larger and more efficient processes being implemented , for instance in material recycling factories . Higher shear rates and faster water pumping regimes have contributed to increased air entrainment and unwanted foam generation .
Figure 1 - Points to consider in foaming liquid
Foam management
In other areas , such as consumerled choices in domestic laundry and dishwashing , the switch away from big-box powders to liquid-based cleaning concentrates has witnessed the necessity for new antifoam technologies offering greater stability to high pH and high surfactant environments . Wastewater companies are also embracing new technologies to optimise the water-cleansing outcome . For instance , novel polymeric membranes are now employed to neutralise , decolourise and deodorise water streams , facilitating the use of closed-loop systems and minimising freshwater draw . As a consequence there has been an increased demand for defoamers with efficient foam quenching in high suspended solids .
Besides the treatment of problematic foam on effluent and process waters , antifoams are key process aids in the production of many of the items consumers encounter throughout daily life . Many foodstuffs are processed in such a way that causes undesirable foaming , these include the boiling and pouring of hot sauces , soy milks for tofu and confectionery and filling activities for carbonated drinks and cordials . Alongside all this , there exists a substantial need to manage foams in products produced via fermentation . These include obvious consumer products , such as beers , wine and spirits , but also vitamins , yeasts and antibiotics . The good news is these antifoams are formulated and produced to the strictest regulatory
58 SPECIALITY CHEMICALS MAGAZINE ESTABLISHED 1981