SEGH Articles

The nano way to cleaner water

04 April 2012
Nanomaterials provide potential for waste water remediation and metal removal and recycling. We envisage that this composite can cheaply and effectively be incorporated into a variety of configurations to improve water treatment.

Decontaminating polluted waste water costs millions but a new discovery by scientists at the University of Brighton could result in huge savings as well as delivering safer, cleaner water. The research, recently published in the journal Angewandte Chemie International Edition, represents a significant shift in our understanding of (nano)chemistry. Mercury is a serious contaminant so this breakthrough could save millions of pounds.

It is generally accepted that when silver is reduced to nano-sized particles, it can only extract a certain amount of mercury. However, Dr Kseniia Katok, working in the Nanoscience and Nanotechnology Group at Brighton, was able to reduce nanoparticles of silver to below 35 nano-metres in diameter (the equivalent of splitting a single human hair into 3,000 separate strands) and found that this allowed almost twice as much mercury to be removed from water.

The team's breakthrough opens the way for more effective, cheaper ways of cleaning mercury-contaminated water. Existing clean-up methods for mercury-contaminated water have either low mercury removal capabilities, leave a large chemical waste footprint or are not energy efficient.

Mercury is found naturally in the environment, but levels of inorganic mercury have increased significantly in recent decades as a result of industrial processes, and mining activities. If mercury contamination occurs, a hugely expensive decontamination process is required, as occurred in Squamish in Canada where the whole of the waterfront was subject to a huge clean-up starting in the 1990s. The seafront town had been subjected to years of industrial pollution because of its forestry industry which began in the early 20th century. Just the chemicals used to clean the water cost around $50,000,000. The Brighton scientists say their research shows that using silver nanoparticles would cost a few thousand rather than tens of millions of pounds for the materials, although a device containing the silver nanoparticles capable of processing large quantities of water would need to be developed.

Dr Raymond Whitby, head of the Nanoscience and Nanotechnology Group, said: "The amount of mercury taken into silver nanoparticles defies our current understanding and promises a number of exciting developments. For example, it should lead to improved water treatment, removing greater quantities of selected heavy metals more quickly and perhaps more cheaply than before."

One key element in Dr Katok's discovery is her use of chemically-modified quartz sand, which reduces silver particles to a nanoscale with a high degree of purity. Sergey Mikhalovsky, the university's Professor of Materials Chemistry and Dr Katok's co-supervisor, said: "This is the biggest difference between our silver and that prepared by other commonly-used methods such as citrate reduction, which typically leaves residual chemical groups on the surface of the silver nanoparticles. These can cause unwanted side reactions that may have limited its effectiveness." He anticipates that modified quartz could be used in other chemical groupings and might, in the future, aid the extraction and recycling of precious metals such as platinum, palladium and gold.

Andy Cundy, the university's Professor of Applied Geochemistry and Dr Katok's lead supervisor, said: "These findings enable a major shift towards the use of nanomaterials for waste water remediation and metal removal and recycling. We envisage that this composite can cheaply and effectively be incorporated into a variety of configurations to improve water treatment, initially targeting mercury, which remains one of the key environmental contaminants globally."

Professor Andy Cundy, University of Brighton.

Keep up to date

Submit Content

Members can keep in touch with their colleagues through short news and events articles of interest to the SEGH community.

Science in the News

Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

  • Spatial variability and geochemistry of rare earth elements in soils from the largest uranium–phosphate deposit of Brazil 2018-02-22


    The Itataia uranium–phosphate deposit is the largest uranium reserve in Brazil. Rare earth elements (REEs) are commonly associated with phosphate deposits; however, there are no studies on the concentrations of REEs in soils of the Itataia deposit region. Thus, the objective of the research was to evaluate the concentration and spatial variability of REEs in topsoils of Itataia phosphate deposit region. In addition, the influence of soil properties on the geochemistry of REEs was investigated. Results showed that relatively high mean concentrations (mg kg−1) of heavy REEs (Gd 6.01; Tb 1.25; Ho 1.15; Er 4.05; Tm 0.64; Yb 4.61; Lu 0.65) were found in surface soils samples. Soil properties showed weak influence on the geochemical behavior of REEs in soils, except for the clay content. On the other hand, parent material characteristics, such as P and U, had strong influence on REEs concentrations. Spatial distribution patterns of REEs in soils are clearly associated with P and U contents. Therefore, geochemical surveys aiming at the delineation of ore-bearing zones in the region can benefit from our data. The results of this work reinforce the perspective for co-mining of P, U and REEs in this important P–U reserve.

  • 2017 Outstanding Reviewers 2018-02-21
  • Seasonal occurrence, source evaluation and ecological risk assessment of polycyclic aromatic hydrocarbons in industrial and agricultural effluents discharged in Wadi El Bey (Tunisia) 2018-02-13


    Polycyclic aromatic hydrocarbons are of great concern due to their persistence, bioaccumulation and toxic properties. The occurrence, source and ecological risk assessment of 26 polycyclic aromatic hydrocarbons in industrial and agricultural effluents affecting the Wadi El Bey watershed were investigated by means of gas chromatographic/mass spectrometric analysis (GC/MS). Total PAHs (∑ 26 PAH) ranged from 1.21 to 91.7 µg/L. The 4- and 5-ring compounds were the principal PAHs detected in most of 5 sites examined. Diagnostic concentration ratios and molecular indices were performed to identify the PAH sources. Results show that PAHs could originate from petrogenic, pyrolytic and mixed sources. According to the ecotoxicological assessment, the potential risk associated with PAHs affecting agricultural and industrial effluents ranged from moderate to high for both aquatic ecosystem and human health. The toxic equivalency factor (TEF) approach indicated that benzo[a]pyrene and benz[a]anthracene were the principal responsible for carcinogenic power of samples.