Wen's Research Group​

Extraction of anhydrous volatile fatty acid with omniphobic membrane and hydrophobic deep eutectic solvents 

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Wen Zhang, Ph.D., P.E., BCEE

Principal Investigator

Phone: (973) 596-5520 
Fax: (973) 596-5790
Email: wen.zhang@njit.edu

Office Location: Colton Hall 211

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Volatile fatty acids (VFAs) derived from arrested anaerobic digestion (AD) can be recovered as a valuable commodity for value-added synthesis. However, separating VFAs from digestate with complex constituents and a high-water content is an energy-prohibitive process. Professor Zhiwu Wang at VT and Professor Wen Zhang at NJIT developed an innovative technology to overcome this barrier by integrating deep eutectic solvents (DESs) with an omniphobic membrane into a membrane contactor for efficient extraction of anhydrous VFAs with low energy consumption. There are mechanistic differences between this novel omniphobic membrane-enabled DES extraction and the previous hydrophobic membrane-enabled NaOH extraction. For example, omniphobic membranes repel both water and oil, which largely prevent membrane wetting by water or oily substances in digestate. Moreover, VFA extraction by the DES is a reversible adsorption process facilitating subsequent VFA separation via anhydrous distillation. High vapor pressure of shorter-chain VFAs and low Nester distribution coefficients of longer-chain VFAs contributed to DES-driven extraction, which could enable continuous and in-situ recovery and conversion of VFAs from AD streams.

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