Organosilanol Compounds Removal in Water by Adsorbent Materials

Reference Presenter Authors
Amarillys Aviles Aviles, A.(University of Puerto Rico at Mayaguez); Tarafa, P.(University of Puerto Rico at Mayaguez); The National Aeronautics and Space Administration (NASA) has designed and established a water recovery system (WRS) intended to recycle and purify the wastewater mainly from crew urine and latent in order to address the high costs associated with payload transport of water for long-term space missions. However, the WRS is presenting limitations to obtain highly purified water due to the presence of organosilanols compounds (OSC) such as dimethylsilanediol (DMSD), trimethylsilanol (TMS), monomethylsilanetriol (MMST), and dimethylsulfone (DMSO2). The OSC’s are difficult to remove due to their low affinity with the adsorbent materials employed at the NASA WRS. The goal of this research is to evaluate alternatives adsorbent materials in the removal of OSC’s from water and, ultimately, understand their removal mechanisms. So far, zeolite, activated carbon, limestone, carbon nanotubes, and graphene oxide have been considered for preliminary analyses by conducting batch adsorption experiments. Preliminary tests having TMS as the adsorbate showed that more than 60% can be removed in terms of total organic carbon (TOC) for zeolite, activated carbon, limestone adsorbent materials. However, a total removal (i.e. adsorption) was not achieved. Activated carbon demonstrated the highest adsorption removal with an approximate 87% efficiency after 6 hours of contact, apparent desorption occurs after this time. The removal by the limestone is higher than the zeolite with an adsorption efficiency of 78% and 60%, respectively. Ongoing experiments are testing the efficiency of carbon nanotubes, and graphene oxide to remove the target compound. Future work will include evaluating the behavior of the adsorbent materials for dimethylsilanediol in batch and continuous process.
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