Energy Recovery from Acid-Base Neutralization Through pH-Sensitive Polymers: Novel Application of Donnan Osmosis

[参考译文]利哈伊大学最近的研究表明，从涉及氢和羟基离子缔合的酸碱中和反应中产生有用能量的可能性。许多工业过程和自然生物地球化学过程（例如，酸性矿山排水）产生酸性（或碱性）废水流，在处理前需要中和。酸碱反应在热力学上是非常有利的，产生了大量的热能。由于经过处理的废酸溶液通常非常稀，中和反应中产生的大量热能导致体水相温度的微小升高。因此，任何能量回收几乎是不可能的，迄今为止还没有报道。在本项目中，建议在含有共价连接的弱酸或弱碱官能团的适当的ph敏感亲水性聚合物（或生物聚合物）内进行中和反应，可以回收大量有用的能量。科学地说，唐南渗透现象驱动了导致能量产生的过程，不需要外部膜。当与酸或碱接触时，pH值的变化导致官能团可逆地获得或失去其离子性质。这种变化产生了聚合物相内渗透压的开关模式，由于水进出聚合物相的运动，导致聚合物相可逆地膨胀（渗透）和收缩（解渗透）。因此，酸碱中和伴随着可用机械能的产生。值得注意的是，这个过程完全是碳中和的，不产生温室气体。所提出的工艺有潜力利用可重复使用的ph敏感聚合物从废酸和废碱流中产生全球能源。全球硫酸的年产量估计约为2亿吨。假设1%的这种酸出现在被提议的能源回收过程中和的废物流中，与使用化石燃料生产相同数量的能源的工厂相比，减少的二氧化碳排放量将超过6000万吨。

(Sengupta)1065651 Recent studies at Lehigh University have demonstrated the possibility of generating useful energy from acid-base neutralization reactions involving association of hydrogen and hydroxyl ions. Many industrial processes and natural biogeochemical process (e.g., acid mine drainage) produce acidic (or basic) wastewater streams and require neutralization prior to disposal. The acid-base reaction is thermodynamically very favorable with generation of significant amount of thermal energy. Since the waste acid solution undergoing treatment is often very dilute, the significant amount of thermalenergy generated in the neutralization reaction causes a miniscule increase in the temperature of the bulk aqueous phase. As a result, any energy recovery is nearly impossible and has not been reported to date. For this project, it is proposed that it is possible to recover significant amount of useful energy by carrying out the neutralization reaction inside an appropriate pH-sensitive hydrophilic polymer (or biopolymer) containing covalently attached weak-acid or weak-base functional groups. Scientifically, the phenomenon of Donnan osmosis drives the process leading to energy generation and no external membrane is necessary. When contacted with acid or base, the variation in pH causes the functional groups to reversibly acquire and lose its ionic character. This change gives rise to on-off pattern of generation of osmotic pressure inside the polymer phase causing it to reversibly swell (osmosis) andshrink (deosmosis) due to the movement of water in and out of the polymer phase. Thus, acid-base neutralization is accompanied by generation of usable mechanical energy. It is noteworthy that the process is completely carbon neutral and no greenhouse gas is produced. The proposed process has the potential to generate energy globally from waste acid and waste alkali streams using reusable pH-sensitive polymers. The global annual production of sulfuric acid is estimated to be approximately 200 million tons. Assuming 1% of this acid appears in the waste stream that is neutralized by the proposed energy recovery process, reduction in carbon dioxide emission in comparison with a plant producing the same amount of energy with fossil fuel will be over 60 million tons.