Experimental survey of temperature, time and cross-linking agent effects on polydimethylsiloxane composite membranes performances in sulfur removal

Electrospun nanofibrous poly(ether-block-amide) membrane for removing biogenic amines in acidic wastewater from the yellow rice wine factory

Compared with other techniques for wastewater treatment, adsorption offers an effective, economical and ecofriendly way to reduce the content of biogenic amines. Herein, the poly(ether-block-amide) (PEBA 2533) membranes were employed as the adsorbent to remove histamine, putrescine, cadaverine and tyramine in the synthetic and real wastewater from a local yellow rice wine factory. Electrospun PEBA membranes consisting of fine nanofibers were successfully obtained without the addition of surfactant for the first time. Characteristics of the prepared membranes were evaluated by their morphology, wetting behaviors and mechanical properties. Adsorption performance of the nanofibrous membrane was investigated in comparison to the dense membrane prepared by conventional casting. The fibrous membrane exhibited much higher adsorption rate over 10 times to the dense membrane along with 1.5 times more adsorption capacity towards the amines. In addition, the as-prepared membrane showed a promising reusability in the real wastewater treatment. The good balance of its chemical stability, adsorption capacity, selectivity, removal efficiency and reusability endows the electrospun membrane with an outstanding potential to be applied in the acidic wastewater treatment for the yellow rice wine industry.

Synthesis of Polyurethane Membranes Derived from Red Seaweed Biomass for Ammonia Filtration

The development of membrane technology is rapidly increasing due to its numerous advantages, including its ease of use, chemical resistant properties, reduced energy consumption, and limited need for chemical additives. Polyurethane membranes (PUM) are a particular type of membrane filter, synthesized using natural organic materials containing hydroxy (-OH) groups, which can be used for water filtration, e.g., ammonia removal. Red seaweed (Rhodophyta) has specific molecules which could be used for PUM. This study aimed to ascertain PUM synthesis from red seaweed biomass (PUM-RSB) by using toluene diisocyanate via the phase inversion method. Red seaweed biomass with a particle size of 777.3 nm was used as starting material containing abundant hydroxy groups visible in the FTIR spectrum. The PUM-RSB produced was elastic, dry, and sturdy. Thermal analysis of the membrane showed that the initial high degradation temperature was 290.71 °C, while the residue from the thermogravimetric analysis (TGA) analysis was 4.88%. The PUM-RSB section indicates the presence of cavities on the inside. The mechanical properties of the PUM-RSB have a stress value of 53.43 MPa and a nominal strain of 2.85%. In order to optimize the PUM-RSB synthesis, a Box–Behnken design of Response Surface Methodology was conducted and showed the value of RSB 0.176 g, TDI 3.000 g, and glycerin 0.200 g, resulting from the theoretical and experimental rejection factor, i.e., 31.3% and 23.9%, respectively.