Porous materials such as silica, carbons, metal organic framework materials, porous polymers and others, are used in a variety of environmental remediation applications such as removal of toxic pollutants from water. However, these materials are generally prepared under environmentally damaging conditions, leading to secondary pollution – this only shifts the pollution problem. Taking inspiration from biomineralisation, we have developed green nanomaterials (GN) synthesis. This green method (mild, one-pot and rapid synthesis in water, at room temperature and neutral pH) offers substantial reductions in resources, time and energy usage when compared to traditional routes, yet offers excellent control over the properties and function of the materials. With the examples of (A) anthraquinone dyes and (B) arsenic removal from water (detailed below), we demonstrate the applications of GN in water treatment. (A) The increased release of harmful dyes in water has placed under greater pressure to safely and effectively treat wastewater effluents. Anthraquinone dyes, used the textile industry, are resistant to breakdown and hence need specialised removal methods. In this presentation, we will show results from using GN to remove/destroy dyes via either adsorption or enzymatic action. It was found that dye adsorption on GN occurs spontaneously and the adsorption capacity (334 mg/g) is higher than other that reported in the literature. Separately, when GN were used to immobilise Peroxidase for enzymatic degradation of dye, the operational stability and reusability of the enzyme was improved but the immobilisation created mass transfer barriers. (B) For water treatment, bioinspired green synthesis was used to prepare, for the first time, a family of iron supported on GN. For arsenate ion removal, they exhibited high extraction efficiencies, high adsorption capacities and superior kinetics (threefold higher than the highest removal rates reported to date). Moreover, a method was developed to regenerate GN allowing for full recovery and reuse of the adsorbent in subsequent extractions; strongly highlighting the potential technological benefits of these new green materials. It is clear from the results presented herein that GN, which can be prepared with a substantial reduction in secondary pollution, form a viable alternative to traditional porous materials in separations.

Bioinspired nanomaterials for water remediation

2019 Fall National Meeting

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