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

30年来对废物中金属生物回收的研究很少注意到当代对以下方面的强烈需求：(1)保护日益减少的重要资源（例如铂族金属（PGM），最近的稀土元素（REE），贱金属（BMs）和铀）以及(2)以无污染，低能源的方式提取/精炼这些资源的明确需要。21stC技术越来越依赖于纳米材料，这些材料具有在块状材料中看不到的新特性。细菌可以制造纳米粒子（NPs），自下而上，一个原子一个原子，通过酶合成和生物支架提供的精细控制，化学无法模仿。生物纳米颗粒在绿色化学、低碳能源、环境保护以及潜在的光子应用方面有着广泛的应用。细菌可以廉价地大规模培养，便于生产。我们已经证明，细菌可以从次级废物中制造纳米材料，在某些情况下，产生的金属混合物比“纯”纳米颗粒表现出更好的活性。这种结构双金属的制造很难用化学方法实现。对于一些金属，如稀土和铀（通常同时出现在废物中），它们从废料(例如磁铁（稀土）和废物（混合U/稀土）中进行生物回收，当分离时，可以制造“浓缩”固体，用于进一步的商业精炼，以制造新的磁铁（稀土）或核燃料(U)。生物制造这些固体通常超出了活细胞的能力，但它们可以形成支架，利用酶的过程制造生物矿物前体，通常是选择性的。B3将调用分层的复杂性、成熟度和风险级别。贱金属采矿废物（例如铜、镍）将被生物精炼成浓缩污泥，用于化学再加工或制成贱金属-生物纳米产品。贵金属废物将转化为生物纳米材料，用于催化、环境和能源应用。稀土金属废料将被生物矿化，作为浓缩饲料进一步精炼或制成新的催化剂。铀废料将被生物提炼成商业核燃料的矿物前体。总而言之，环境将免受主要来源污染和主要“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。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），然后可以将目标金属从渗滤液转化为新的纳米材料（一种生物/非生物混合系统，已经展示）。环境友好的浸出和酸回收将通过现有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将受到特别的关注，以纳米粒子在其独特的“生化巢穴”中的表现为例，因为在那里将会有重大发现；尖端技术将把结构与功能联系起来，并验证上游废物掺杂或“混合”的贡献；这些，以及新的材料加工，将提高生物纳米颗粒的功效。生物精炼的二次废物包括磁铁废料（稀土）、打印墨盒（贵金属）、道路粉尘（pm、Fe、Ce）和冶金废物（混合稀土/贱金属/铀）。它们的复杂性，通常是难熔性，比矿山废物具有更高的“风险”，但作为补偿，它们的体积更小，“掺杂”或“操纵”制造/操纵工程纳米材料的范围相应更高。B3将对突出显示的系统进行嵌入式重要（~15%）生命周期分析迭代评估，并进行最终用户试验（供应链；与工业平台结合的验证）。B3欢迎通过Partner网络备份带来的大量问题持有者中的新“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.