Enhancement of polyvinyl alcohol adsorbent via crosslink with citric acid and L-lysine for biochemical recovery from food processing waste streams

Abstract

Industrial food wastewater typically contains rich organic matters and their discharge flows into water sources can cause severe environmental pollution. This study explored a novel generation of biodegradable adsorbent to extract carboxylates generated from fermented broth from the downstream wastewater in the food industry. A successful synthesis of Polyvinyl Alcohol (PVA) crosslinked Citric Acid (CA), foamed using Polyethylene Glycol (PEG), PVA–c–CA/PEG with CA 66% of total PVA – PEG (1:1 in weight) showed the maximum gel fraction and lowest swelling degree, the most effective crosslink materials. The incorporation with crosslinker L-lysine (Lys) into the polymer network of PVA – c-CA materials attained a considerable improvement in the material’s surface morphology and adsorption capacity. Lab-scale series of adsorption experiments with a model volatile fatty acid (VFA) as acetic acid in solution achieved a maximum adsorption capacity (Q_e) of 74 mg/g and 86 mg/g after 60 min and 120 min, respectively at approximately 1 g/L acetic acid solution. The carboxylates in the effluent were recovered by this innovative green adsorption film, can be used as a biochemical platform for number purposes such as productions of detergents, polymers and biofuels. The new direction of VFA extraction is an eco-friendly opportunity which is in line with national and international targets such as using resources wisely, making products last longer, and causing as little damage to the environment as possible.