Beyond biorecovery: environmental win-win by biorefining of metallic wastes into new functional materials (B3)

30年来对从废物中生物回收金属的研究很少关注当代对以下的强烈需求：（i）保护日益减少的重要资源（例如铂族金属（PGM），最近是稀土元素（REE），贱金属（BM）和铀）和（ii）明确需要以无污染、低能耗的方式提取/精炼它们。21stC技术越来越依赖于纳米材料，这些材料具有散装材料中看不到的新特性。细菌可以制造纳米颗粒（NPs），自下而上，一个原子一个原子地制造，酶合成和生物支架提供了化学无法模仿的精细控制。生物纳米粒子在绿色化学、低碳能源、环境保护以及潜在的光子学应用中具有广泛的应用前景。细菌可以廉价地大规模生长，便于生产。我们已经证明，细菌可以从二次废物中制造纳米材料，在某些情况下，产生一种金属混合物，这种混合物可以比“纯”纳米颗粒表现出更好的活性。这种结构化双金属的制造可能难以化学实现。对于稀土和铀等一些金属（通常同时存在于废物中），从废料中进行生物回收，例如磁铁（稀土）和废物（铀/稀土混合物），分离后可以制成“浓缩”固体，用于进一步商业精炼，以制造新的磁铁（稀土）或核燃料（铀）。生物制造这些固体通常超出活细胞的能力，但它们可以形成支架，利用酶促过程制造生物矿物前体，通常是选择性的。B3将引发复杂性，成熟度和风险的分层水平。(i)贱金属采矿废物（如铜、镍）将被生物提炼成浓缩污泥，用于化学后处理，或用于制造贱金属生物纳米产品。(ii)贵金属废物将被转化为生物纳米材料，用于催化，环境和能源应用。(iii)稀土金属废料将被生物矿化，作为进一步精炼或新催化剂的浓缩原料。(iv)铀废料将被生物精炼成商业核燃料的矿物前体。总而言之，环境将免受一次污染源和从一次“原油”加工的高能源需求的双重影响。金属废料更坚硬，需要酸来溶解。这些方法将包括使用嗜酸细菌、使用碱化酶或使用细菌首先制造化学催化剂（良性），然后将浸漏液中的目标金属转化为新的纳米材料（已显示的生物/非生物混合系统）。环境友好的浸出和酸循环将通过现存的预测模型进行评估和优化浸出过程。生物学，化学，矿物学和物理学之间的界面，例如在其独特的“生化巢”中的纳米粒子，将受到特别关注，这是重大发现的地方;尖端技术将结构与功能联系起来，并验证上游废物掺杂或“混合”的贡献;生物提炼的二次废物将包括磁铁废料（稀土）、打印墨盒（贵金属）、道路灰尘（PMs、Fe、Ce）和冶金废物（混合稀土/贱金属/铀）。它们的复杂性，通常是耐火性质，比矿山废物具有更高的“风险”，但作为补偿，它们的体积较低，而制造/操纵工程纳米材料的“掺杂”或“操纵”范围相应较高。B3将对重点系统进行嵌入式重要（约15%）生命周期分析迭代评估，并进行最终用户试用（供应链;与工业平台结合进行验证）。B3欢迎通过合作伙伴网络备份带来的大量问题负责人中的新“加入者”。

30 years' research on metal biorecovery from wastes has paid scant attention to strong CONTEMPORARY demands for (i) conservation of dwindling vital resources (e.g platinum group metals (PGM), recently rare earth elements, (REE), base metals (BMs) and uranium) and (ii) the unequivocal need to extract/refine them in a non-polluting, low-energy way. 21stC technologies increasingly rely on nanomaterials which have novel properties not seen in bulk materials. Bacteria can fabricate nanoparticles (NPs), bottom up, atom by atom, with exquisite fine control offered by enzymatic synthesis and bio-scaffolding that chemistry cannot emulate. Bio-nanoparticles have proven applications in green chemistry, low carbon energy, environmental protection and potentially in photonic applications. Bacteria can be grown cheaply at scale for facile production. We have shown that bacteria can make nanomaterials from secondary wastes, yielding, in some cases, a metallic mixture which can show better activity than 'pure' nanoparticles. Such fabrication of structured bimetallics can be hard to achieve chemically. For some metals like rare earths and uranium (which often co-occur in wastes) their biorecovery from scraps e.g. magnets (rare earths) and wastes (mixed U/rare earths), when separated, can make 'enriched' solids for delivery into further commercial refining to make new magnets (rare earths) or nuclear fuel (U). Biofabricating these solids is often beyond the ability of living cells but they can form scaffolds, with enzymatic processes harnessed to make biomineral precursors, often selectively.B3 will invoke tiered levels of complexity, maturity and risk. (i) Base metal mining wastes (e.g. Cu, Ni) will be biorefined into concentrated sludges for chemical reprocessing or alternatively to make base metal-bionanoproducts. (ii) Precious metal wastes will be converted into bionanomaterials for catalysis, environmental and energy applications. (iii) Rare earth metal wastes will be biomineralised for enriched feed into further refining or into new catalysts. (iv) Uranium-waste will be biorefined into mineral precursors for commercial nuclear fuels. In all, the environment will be spared dual impacts of both primary source pollution AND the high energy demand of processing from primary 'crude'.Metallic scraps are tougher, requiring acids for dissolution. Approaches will include the use of acidophilic bacteria, use of alkalinizing enzymes or using bacteria to first make a chemical catalyst (benignly) which can then convert the target metal of interest from the leachate into new nanomaterials (a hybrid living/nonliving system, already shown). Environmentally-friendly leaching & acids recycle will be evaluated and leaching processes optimised via extant predictive models.The interface between biology, chemistry, mineralogy and physics, exemplified by nanoparticles held in their unique 'biochemical nest', will receive special focus, being where major discoveries will be made; cutting edge technologies will relate structure to function, and validate the contribution of upstream waste doping or 'blending'; these, as well as novel materials processing, will increase bio-nanoparticle efficacy.Secondary wastes to be biorefined will include magnet scraps (rare earths), print cartridges (precious metals), road dusts (PMs, Fe,Ce) & metallurgical wastes (mixed rare earths/base metals/uranium). Their complex, often refractory nature gives a higher 'risk' than mine wastes but in compensation, the volumes are lower, & the scope for 'doping' or 'steering' to fabricate/steer engineered nanomaterials is correspondingly higher. B3 will have an embedded significant (~15%) Life Cycle Analysis iterative assessment of highlighted systems, with end-user trialling (supply chains; validations in conjunction with an industrial platform). B3 welcomes new 'joiners' from a raft of problem holders brought via Partner network backup.