Today's wastes, tomorrow's materials for environmental protection

Abstract

Abstract. Over the past 30 years the literature has burgeoned with bioremediation approaches to heavy metal removal from wastes. The price of base and precious metals has dramatically increased. With the resurgence of nuclear energy uranium has become a strategic resource. Other 'non-carbon energy' technologies are driven by the need to reduce CO 2 emissions. The 'New Biohydrometallurgy' we describe unites these drivers by the concept of conversion of wastes into new materials for environmental applications. The new materials, fashioned, bottom-up, into nanomaterials under biocontrol, can be termed 'Functional Bionanomaterials'. This new discipline, encompassing waste treatment along with nanocatalysis or other applications, can be summarized as 'Environmental Bionanotechnology'. Several case histories illustrate the scope and potential of this concept.

Microbial Reduction of Natural Fe(III) Minerals; Toward the Sustainable Production of Functional Magnetic Nanoparticles

“…Metal-reducing bacteria can respire a broad range of high oxidation state metals and mineral phases, influencing their biogeochemical fate in environmental systems. Harnessing these microbial processes "ex situ" can also offer biosynthetic routes for the formation of metallic nanoparticles with commercial potential (Macaskie et al, 2010;Ingale and Chaudhari, 2013). Such biosynthetic routes have a potential advantage over alternative chemical synthesis pathways, as they minimize the use of harsh chemicals and operate at ambient temperatures.…”

“…Although bionanomagnetite can be synthesized from a range of ferric iron mineral phases (Cutting et al, 2012), existing laboratory-scale methods usually employ precursors made by using analytical grade salts of iron and strong alkali, which if used at scale, would impact on overall production costs and increase environmental impact. Indeed, there is abundant literature on biogenic nanomaterials and their remediation potential (Lloyd, 2003;Macaskie et al, 2010;Lloyd et al, 2011) however, with insufficient data on manufacturing costs incurred during scale up operations, these bionanomaterials have not been able to compete commercially with their chemically synthesized counterparts. However, Fe(III) minerals are naturally abundant and can also be sourced from waste processes and may, therefore, offer suitable raw materials for the cost-effective synthesis of biogenic nanomaterials.…”

Novel bioremediation processes for treatment of seleniferous soils and sediment

“…In the order of abundance, Se ranks 69 th in the earth's crust. Se has many industrial applications like semiconductors and photoelectric cells, metallurgy and glass industries (Macaskie et al, 2010; and healthcare applications. Increasing the industrial demand of Se may be approached with its recovery from wastewater streams.…”

Catalytic applications of waste derived materials

“…In some instances the resulting metallated bacteria have been processed for use as carbon-based catalysts. Macaskie et al adapted this idea for a range of target metals and waste sources, 171 extracting precious metals such as Pd, Pt and Au from industrial wastewater 172,173 and metal leachates of electronic scrap, 174 for testing in the catalytic reduction of heavy metals pollutants (carcinogenic and mutagenic H 2 CrO 4 to noncarcinogenic Cr 2 O 3 ). The same group developed a series of catalysts using various bacterial strains and active metals for wide-ranging applications including semi-hydrogenation of alkynes, [175][176][177] carbon-carbon coupling, 178,179 dehalogenation, 180 oxidation of aromatic alcohols 181,182 and fuel cells.…”