Water Cleaning Research at The University of Liverpool

Nov 7, 2019
Applications: Water Treatment
Instruments: NanoBrook Series

Tightening regulations are presenting new challenges for the UK’s water treatment and distribution companies; but for colloids and surface science specialist, Mike Garvey, this offers new research opportunities.

After a period of twenty five years at ICI and Unilever Research as a senior scientist involved in several aspects of industrial colloid and surface science, Mike recently joined the University of Liverpool’s Surface Science Research Center. The SSRC is one of several multi-disciplinary research organizations set up in the early 1990’s to work at the cutting edge of science, where the traditional demarcations of chemistry, physics and biology no longer apply. It brings together chemists, physicists, materials scientists and engineers to tackle the problems of predicting and controlling behavior at surfaces. Mike’s particular interest is colloid and surface science – the study of submicron particles, macromolecules and the physical chemistry of interfaces.

In seeking partners for research collaboration, he found that the water companies offered some challenging opportunities. Colloid and surface science is becoming increasingly important to the water industry as the companies are working within an atmosphere of ever-tightening regulation. European Union directives on water quality are looming over the UK industry, and while the water companies are confident of meeting emerging regulations using current technology, they are exploring new ways to meet future controls without raising the cost of water to domestic industrial users.

One such regulation is the new European Directive on drinking water quality, which became part of UK law this year, and brings in new standards which the water companies will have to meet by 2003. These regulations include very stringent guideline values or maximum concentration limits for organic pollutants.

This is where Mike’s research has come in. “In order to help the water companies meet post 2003 targets, the EPSRC (the UK government’s Engineering and Physical Sciences Research Council) under the WITE scheme, wish to attract the input of academics who would not normally have any involvement with the water industry,” he said. The companies – and the government – hope that the fruits of this interaction will be novel, creative and cost-effective methods for improved water treatment. In collaboration with North West Water, Mike successfully attracted EPSRC funds for one year feasibility study to initiate colloid and surface science research in this area.

His work is based around the interaction of the charged particles added to clarify water and the components of natural organic matter. “These particles are generally positively charged, and most of the natural organic matter in untreated water- the material that gives the brown coloration – is negatively charged. The negatively charged material attaches itself to the positively charged particles, so that these particles become less positive or more negative. This tells us that something is happening at that surface and we use colloid science expertise to interpret what is involved.”

To achieve this, Mike, together with Paul Stevenson, the postdoctoral researcher appointed to the project, uses a technique called microelectrophoresis. This studies the movement of charged particles under the influence of a carefully controlled electrical field, and is used to measure the zeta-potential of the colloid in question. This property – related to the charge on the surface of a particle in a conduction solution and the concentration of the ions in that solutions – is important both in understanding the behavior of the whole system, and in determining the effectiveness of treatment methods. “This adsorption of organic matter by colloidal particles is often difficult to detect, because the quantities are small,” Mike explained. “But zeta potential measurement is extremely sensitive, so any charged material that adsorbs on the particle’s surface will give a change in its potential.”

Naturally, such research needs very advanced equipment and here, Mike’s industrial experience gave him a head-start. Whilst in industry, he head been instrumental in buying analytical equipment for university departments that the company supported. In particular, Mike had had a close relationship with Brookhaven Instruments, whose particle sizing and electrokinetic analysis equipment had been a mainstay of his research for several years. Respecting this company’s judgement as a fellow surface science specialist, he turned to Brookhaven’s Peter McFadyen to supply his microelectrophoresis setup, in the form of a ZetaPlus analyzer.

“One of the attractions of this equipment is that it offers a low capital cost for initial entry level equipment yet can be upgraded for broader applications and particle size measurement,” Mike explained. “We are now starting to foster links with other departments of Liverpool University who are expressing an interest in the ZetaPlus facility. For example, one group is researching nanotechnology – the manipulation of nanometer-sized particles to give high tech structures. Future collaboration in this field would make a great deal of use of this equipment,” he said.

But for now, Mike and Paul are focused on the project in hand – using the electrical data from his colloid studies to devise new ways of treating water. “The negatively charged molecules of the natural organic material in water is the material which is more readily removed, because the coagulant has a positive charge. You add the coagulant, it complexes with negatively charged species and it settles down to the bottom and takes this portion of the natural, organic matter – all the brown coloration – with it,” he said. “Our hypothesis is that the uncharged organic matter slips through, and while that hasn’t posed a problem up until now, tightening legislation means that new technology might be required to remove this too. The route that we are pursuing is to take the uncharged material and identify novel ways of removing it, using colloid and surface science.” This will include identification of additional coagulants/adsorbents.

Mike anticipates that his research could help the water companies to meet the anticipated more stringent regulations that will arrive in the near future. Water quality trends are tightening everywhere and already regulations in the US are tighter than in Europe.

Funding permitting, Mike’s feasibility project will attract additional funds for further three years, together with equipment funds to upgrade the ZetaPlus analyzer and rive the research further.