Membrane contactor for reactive extraction of succinic acid from aqueous solution by tertiary amine

Efficiently enhanced short-chain fatty acids (SCFAs) recovery from food waste condensate: Real-time wettability monitoring with supported liquid membrane contactor

Food waste condensate (FWC) is a valuable source for recovering short-chain fatty acids (SCFAs) through methods such as supported liquid membrane contactors. Containing organic compounds like acetate, propionate, and butyrate, FWC offers a rich substrate for efficient SCFA extraction. Recovering SCFAs from FWC provides notable environmental advantages, including reducing waste and generating high-value products for industries such as bioenergy and chemical production. This process not only contributes to carbon neutrality by recycling waste streams but also establishes a sustainable method for producing bio-based products from FWC. This study investigated the recovery efficiency and transport mechanisms of SCFAs from SCFA-rich wastewater (e.g., FWC) using both virgin hydrophobic PVDF membranes and membranes filled with organic extractants like tertiary amines (trihexhylamine and trioctylamine) and tertiary phosphines (trihexylphosphine and trioctylphosphine). Recovery efficiency for butyric acid was significantly improved when TOA (trioctylamine) was used, achieving 71.96 %, while acetic acid showed a lower recovery of 0.95 %, highlighting TOA's strong affinity for butyric acid due to ion-amine complex formation. The study also utilized real-time optical coherence tomography (OCT)-based monitoring to observe membrane wetting, finding that the virgin PVDF membrane was more prone to wetting and fouling, with a significant reduction in contact angle and surface energy. In contrast, the PVDF-TOA membrane demonstrated better resistance to wetting, showing minimal changes in contact angle and porosity, underscoring its potential for long-term applications in membrane contactors.

Advances in downstream processes and applications of biological carboxylic acids derived from organic wastes

Recovering carboxylic acids derived from organic wastes from fermentation broth is challenging. To provide a reference for future study and industrial application, this review summarized recent advances in recovery technologies of carboxylic acids including precipitation, extraction, adsorption, membrane-based processes, etc. Meanwhile, applications of recovered carboxylic acids are summarized as well to help choose suitable downstream processes according to purity requirement. Integrated processes are required to remove the impurities from the complicated fermentation broth, at the cost of loss and expense. Compared with chemical processes, biological synthesis is better options due to low requirements for the substrates. Generally, the use of toxic agents, consumption of acid/alkaline and membrane fouling hamper the sustainability and scale-up of the downstream processes. Future research on novel solvents and materials will facilitate the sustainable recovery and reduce the cost of the downstream processes.