A synergistic use of microalgae and macroalgae for heavy metal bioremediation and bioenergy production through hydrothermal liquefaction
A synergistic use of microalgae and macroalgae for heavy metal bioremediation and bioenergy production through hydrothermal liquefaction
复制标题
DOI：
10.1039/c8se00408k
复制
发表时间：
2019-01-01
影响因子：
5.6
通讯作者：
Chuck, Christopher J.
中科院分区：
文献类型：
--
作者：
Piccini, Marco;Raikova, Sofia;Chuck, Christopher J.
在这项研究中，开发了一种新的协同方法，用于金属污染水的生物修复和生物能源生产。两种微藻，小球藻和钝顶节旋藻（螺旋藻），和两种大型藻类，石莼和海藻，被用来作为被动生物修复剂的金属镍（ii），锌（ii），镉（ii）和铜（ii）。金属被单独地和以10-150 mM之间的组合添加。然后通过水热液化处理金属污染的生物质以产生四个相：生物原油、水相、固体残余物和气体。两个C. vulgaris和A. Platensis的生物油收率分别为39和31wt%，而U. lactuca和S. muticum分别为14%和9%。最初的研究表明，向生物质原料中添加高达150 mM的目标金属硫酸盐不会显著影响生物原油的生产，并且对于微藻，超过99%的目标金属主要作为磷酸盐或氧化物分配到固相产物中。随后，废水和HTL的生物修复成功结合，超过80%的10 mM金属溶液被生物吸附，尽管功效在很大程度上取决于藻类物种。在HTL的修复生物质，生物原油的产量和组成没有显着变化。对于微藻，水相含有显著的氮、钾和磷酸盐水平，并且大部分目标金属沉积在固相中，当使用所有四种金属时，螺旋藻的金属回收率超过99.5%。大型藻类物种在该过程中不那么有效，在水相中具有有限的磷酸盐回收（尽管具有广泛的钾回收），并且对于所检查的石莼物种，小于50%的目标金属沉积在固体残留物中，这可能是由于金属对蛋白质物种而不是该物种中的多糖的亲和力。因此，将微藻生物修复与水热液化相结合是一种潜在的非常有效的修复污染废水沃茨的方法，而基于大型藻类的方法可以提供更便宜的替代方法，尽管功效大大降低。目标金属的回收和多种产物的形成提高了该过程的经济可行性，从而使生物修复过程增值并补贴环境清理。
In this investigation a novel synergistic approach for the bioremediation of metal-contaminated water and bioenergy production was developed. Two microalgae, Chlorella vulgaris and Arthrospira platensis (Spirulina), and two macroalgae, Ulva lactuca and Sargassum muticum, were used as passive bioremediation agents for the metals Ni(ii), Zn(ii), Cd(ii) and Cu(ii). The metals were added singularly and in combination between 10-150 mM. The metal contaminated biomass was then processed through hydrothermal liquefaction to yield four phases: a bio-crude oil, an aqueous phase, solid residue and gas. Both C. vulgaris and A. platensis gave high bio-crude yields of 39 and 31 wt% respectively, while U. lactuca and S. muticum gave 14% and 9% respectively. Initial studies demonstrated that the addition of up to 150 mM of the target metal sulfates to the biomass feedstock did not significantly affect bio-crude production, and, for microalgae, over 99% of the target metals were partitioned to the solid phase products predominantly as phosphates or oxides. Subsequently, bioremediation of waste water and HTL were successfully coupled, with over 80% of a 10 mM solution of the metals biosorbed, though efficacy depended heavily on the algal species. Upon HTL of the remediating biomass, the yield and composition of the bio-crude were not changed significantly. For the microalgae, the aqueous phase contained significant nitrogen, potassium and phosphate levels, and the majority of the target metals deposited in the solid phase, with over 99.5% metal recovery for Spirulina when all four metals were used. The macroalgal species were not as effective in this process, with limited phosphate recovery in the aqueous phase (albeit with extensive potassium recovery) and with less than 50% of the target metals depositing in the solid residue for the Ulva species examined, presumably due to the affinity of the metals to proteinous species rather than polysaccharide in this species. Combining microalgal bioremediation with hydrothermal liquefaction is therefore a potentially highly effective method of remediating contaminated waste waters, whilst a macroalgae based process may offer a cheaper alternative, albeit with substantially reduced efficacy. The recovery of the target metals and multiple product formation improves the economic viability of the process, thereby valorising the bioremediation process and subsidising environmental clean-up.