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

30年来关于从废物中生物回收金属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)和(2)以无污染、低能耗的方式提取/提炼这些资源的明确需要。21世纪的技术越来越依赖于纳米材料，这种材料具有块状材料所没有的新特性。细菌可以自下而上、一个原子一个原子地制造纳米粒子(NPs)，通过酶合成和生物支架提供的精细控制，这是化学无法模仿的。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应用等方面都有广泛的应用前景。细菌可以廉价地规模化培养，以便于生产。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，它可以显示出比“纯”纳米颗粒更好的活性。这种结构化双金属化合物的制造很难通过化学方法实现。对于一些金属，如稀土和铀(通常在废物中共存)，它们从废料中进行生物回收，例如磁铁(稀土)和废物(铀/稀土混合)，当分离时，可以制造“浓缩”的固体，然后运往进一步的商业提炼，以制造新的磁体(稀土)或核燃料(U)。这些固体的生物富集化通常超出了活细胞的能力，但它们可以形成支架，利用酶过程来制造生物矿物前体，通常是有选择的。B3将导致复杂性、成熟度和风险的分级。(1)贱金属采矿废物(如铜、镍)将被生物提炼成浓缩的淤泥，以便进行化学后处理，或者制成贱金属--生物阳极产品。(Ii)将贵金属废料转化为生物材料，用于催化、环境和能源应用。(3)稀土金属废料将被生物矿化，以供进一步提炼或制成新的催化剂。(4)铀废料将被生物提炼成用于商业核燃料的矿物前体。总而言之，环境将不会受到原生源污染和从原生“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性细菌，使用碱性酶或使用细菌首先制造化学催化剂(有益的)，然后可以将感兴趣的目标金属从渗滤液转化为新的纳米材料(一个混合的有生命/无生命系统，已经显示)。将通过现有的预测模型对环境友好型浸出和酸回收进行评估，并优化浸出过程。生物、化学、矿物学和物理之间的界面将受到特别关注，例如保存在其独特的“生化巢”中的纳米颗粒，这将是重大发现的地方；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；需要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)、道路粉尘(Pm、Fe、Ce)和冶金废物(混合稀土/贱金属/铀)。它们复杂的、通常是难熔的性质给出了比矿山废物更高的“风险”，但作为补偿，它们的体积更小，制造/引导工程纳米材料的“掺杂”或“引导”范围也相应更大。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；结合工业平台进行验证)。B3欢迎通过合作伙伴网络备份带来的一大批问题持有者的新“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.